DRAFT INTERNATIONAL STANDARD
ISO/DIS 19223
ISO/TC 121/SC 4
Voting begins on:
2016-03-18
Secretariat: ANSI
Voting terminates on:
2016-06-18
Lung ventilators and related equipment — Vocabulary and
semantics
Ventilateurs pulmonaires et équipement associé — Vocabulaire et sémantique
ICS: 01.040.11; 11.040.10
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Reference number
ISO/DIS 19223:2016(E)
© ISO 2016
ISO/DIS 19223:2016(E)
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© ISO 2016 – All rights reserved
ISO/DIS 19223:2016(E)
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Contents
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* Scope ........................................................................................................................................................14
2
Conformance ...........................................................................................................................................14
2.1
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General....................................................................................................................................................... 14
3
Normative references .........................................................................................................................16
4
Terms, definitions, symbols, units and abbreviated terms ...............................................16
4.1
4.1.1
4.1.2
4.1.3
4.1.4
4.1.5
4.1.6
4.1.7
4.1.8
4.1.9
4.1.10
4.1.11
4.1.12
4.1.13
4.1.14
4.1.15
4.1.16
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.2.6
4.2.7
4.2.8
4.2.9
4.2.10
4.2.11
4.2.12
4.2.13
4.2.14
4.2.15
4.2.16
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6
4.3.7
4.3.8
4.3.9
Breath terminology .............................................................................................................................. 18
breath ......................................................................................................................................................... 18
breathe....................................................................................................................................................... 19
spontaneous breath ............................................................................................................................. 19
natural breathing .................................................................................................................................. 19
unrestricted breath.............................................................................................................................. 19
respiratory activity .............................................................................................................................. 19
inspiratory effort................................................................................................................................... 20
additional breath .................................................................................................................................. 20
concurrent breath................................................................................................................................. 20
inspiration................................................................................................................................................ 20
expiration exhalation .......................................................................................................................... 20
unassisted breath.................................................................................................................................. 21
supported breath .................................................................................................................................. 21
assisted breath ....................................................................................................................................... 21
synchronised breath............................................................................................................................ 21
controlled breath .................................................................................................................................. 21
Positive-pressure inflation terms and definitions................................................................. 22
inflation positive-pressure inflation ventilator inspiration .............................................. 22
inflation-type .......................................................................................................................................... 22
volume-control VC ................................................................................................................................ 23
pressure-control PC ............................................................................................................................. 23
dual-control ............................................................................................................................................. 23
pressure-support PS ............................................................................................................................ 23
proportional effort support pES ..................................................................................................... 24
spontaneous/timed pressure-control S/T ............................................................................... 25
flow-regulation....................................................................................................................................... 25
pressure-regulation ............................................................................................................................. 25
rise time..................................................................................................................................................... 25
primary-inflation .................................................................................................................................. 25
additional primary-inflation............................................................................................................ 26
assured delivery .................................................................................................................................... 26
support-inflation ................................................................................................................................... 26
volume targeted vt................................................................................................................................ 26
Time, phase and cycle terminology .............................................................................................. 27
expiratory time tE .................................................................................................................................. 27
expiratory phase ................................................................................................................................... 27
BAP phase ................................................................................................................................................. 28
BAP time tB ............................................................................................................................................... 28
expiratory-flow time............................................................................................................................ 29
expiratory pause ................................................................................................................................... 29
expiratory-pause time ........................................................................................................................ 29
expiratory hold ...................................................................................................................................... 29
expiratory-hold time ........................................................................................................................... 29
© ISO 2016 – All rights reserved
ISO/DIS 19223:2016(E)
4.3.10
4.3.11
4.3.12
4.3.13
4.3.14
4.3.15
4.3.16
4.3.17
4.3.18
4.3.19
4.3.20
4.3.21
4.3.22
4.4
4.4.1
inspiratory time tI ................................................................................................................................. 30
inspiratory phase .................................................................................................................................. 30
inspiratory-flow time .......................................................................................................................... 30
inspiratory pause .................................................................................................................................. 30
inspiratory-pause time....................................................................................................................... 30
inspiratory hold ..................................................................................................................................... 31
inspiratory-hold time.......................................................................................................................... 31
inflation phase........................................................................................................................................ 31
respiratory cycle cycle ........................................................................................................................ 31
respiratory cycle time cycle time................................................................................................... 32
primary-inflation cycle....................................................................................................................... 32
phase time ratio I:E ratio .................................................................................................................. 32
inspiratory time fraction tI:tTOT ratio .......................................................................................... 32
Rate terminology................................................................................................................................... 32
Principle rate concepts - for general use in preference to those listed under
4.4.2, secondary rate concepts ........................................................................................................ 32
4.4.1.1 rate Rate .................................................................................................................................................... 32
4.4.1.2 total respiratory rate total rate RR ............................................................................................... 33
4.4.1.3 spontaneous respiratory rate spontaneous rate RRspont ISO spontaneousbreath rate................................................................................................................................................ 33
4.4.1.4 ventilator-initiated inflation rate ventilator-initiated rate RRvent ................................. 34
4.4.2 Secondary rate concepts – rate terms for use if required for specific purposes...... 34
4.4.2.1 primary-inflation rate......................................................................................................................... 34
4.4.2.2 support-inflation rate ......................................................................................................................... 34
4.4.2.3 assisted breath rate ............................................................................................................................. 34
4.4.2.4 synchronised breath rate .................................................................................................................. 35
4.4.2.5 controlled breath rate......................................................................................................................... 35
4.4.2.6 unassisted breath rate ........................................................................................................................ 35
4.4.2.7 additional breath rate......................................................................................................................... 35
4.4.2.8 patient-triggered primary-inflation rate ................................................................................... 35
4.4.2.9 concurrent supported-breath rate................................................................................................ 36
4.4.2.10 concurrent unassisted-breath rate ....................................................................................... 36
4.4.2.11 non-concurrent unassisted-breath rate.............................................................................. 36
4.4.2.12 patient-triggered inflation rate .............................................................................................. 36
4.4.2.13 total inflation rate ......................................................................................................................... 36
4.4.2.14 additional primary-inflation rate .......................................................................................... 36
4.5
Pressure Terminology ........................................................................................................................ 37
4.5.1 airway pressure PAW .............................................................................................................................. 37
4.5.2 inspiratory pressure............................................................................................................................ 37
4.5.3 peak inspiratory pressure ................................................................................................................ 38
4.5.4 plateau inspiratory pressure plateau pressure ...................................................................... 38
4.5.5 inspiratory-pressure relief ............................................................................................................... 38
4.5.6 Δ delta......................................................................................................................................................... 38
4.5.7 Δ inspiratory pressure Δ pressure Δp ......................................................................................... 39
4.5.8 end-inspiratory pressure .................................................................................................................. 39
4.5.9 expiratory pressure ............................................................................................................................. 39
4.5.10 expiratory pressure-relief ................................................................................................................ 40
4.6
Flow terminology .................................................................................................................................. 40
4.6.1 inspiratory flow Flow .......................................................................................................................... 40
4.6.2 peak inspiratory flow .......................................................................................................................... 41
4.6.3 inspiratory-termination flow .......................................................................................................... 41
4.6.4 end-inspiratory flow............................................................................................................................ 41
4.6.5 expiratory flow....................................................................................................................................... 41
4.6.6 expiratory-termination flow............................................................................................................ 42
4.6.7 end-expiratory flow ............................................................................................................................. 42
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4.6.8 bias flow .................................................................................................................................................... 42
4.6.9 continuous flow...................................................................................................................................... 42
4.6.10 descending ramp flow pattern ........................................................................................................ 43
4.6.11 concave decreasing-flow pattern................................................................................................... 43
4.6.12 demand flow ............................................................................................................................................ 43
4.6.13 airway leak............................................................................................................................................... 44
4.6.14 ventilator breathing system leak VBS leak ............................................................................... 44
4.7
Volume terminology ............................................................................................................................ 44
4.7.1 tidal volume V T ....................................................................................................................................... 44
4.7.2 delivered volume V DEL......................................................................................................................... 45
4.7.3 inspiratory volume V I .......................................................................................................................... 45
4.7.4 expired tidal volume V TE .................................................................................................................... 46
4.7.5 leakage tidal volume V TLeak ............................................................................................................... 46
4.7.6 minute volume V M ................................................................................................................................. 46
4.7.7 delivered minute volume V MDEL ...................................................................................................... 47
4.7.8 inspiratory minute ventilation V MI ................................................................................................ 47
4.7.9 expired minute volume V ME .............................................................................................................. 47
4.7.10 leakage minute volume V MLeak ......................................................................................................... 47
4.7.11 assured minute volume V Massd......................................................................................................... 48
4.7.12 additional minute volume V Maddn ................................................................................................... 48
4.8
Mode Terminology ............................................................................................................................... 48
4.8.1 ventilator mode ..................................................................................................................................... 48
4.8.2 ventilation mode ................................................................................................................................... 48
4.8.3 ventilation-pattern ............................................................................................................................... 49
4.8.4 *ventilation-mode groups ................................................................................................................. 50
4.8.4.1 ventilation-mode Group 1 ................................................................................................................. 50
4.8.4.1.1 Group 1a ............................................................................................................................................ 50
4.8.4.1.2 Group 1b ............................................................................................................................................ 50
4.8.4.2 ventilation-mode Group 2 ................................................................................................................. 51
4.8.4.2.1 Group 2a ............................................................................................................................................ 51
4.8.4.2.2 Group 2b ............................................................................................................................................ 51
4.8.4.3 ventilation-mode Group 3 ................................................................................................................. 51
4.8.4.3.1 Group 3a ............................................................................................................................................ 51
4.8.4.3.2 Group 3b ............................................................................................................................................ 51
4.8.5 *assured ventilation mandatory ventilation............................................................................. 52
4.8.6 CMV continuous mandatory ventilation .................................................................................... 52
4.8.7 Assist/Control Ventilation A/CV .................................................................................................... 53
4.8.8 IMV intermittent mandatory ventilation ................................................................................... 53
4.8.9 SIMV synchronised intermittent mandatory ventilation.................................................... 54
4.8.10 CSV continuous spontaneous ventilation SPONT ................................................................... 54
4.8.11 MMV minimum minute volume ...................................................................................................... 55
4.8.12 * APRV airway pressure release ventilation APRV .............................................................. 55
4.8.13 CPAP continuous positive airway pressure ............................................................................. 56
4.8.14 apnoea ventilation apnea ventilation.......................................................................................... 57
4.8.15 back-up ventilation .............................................................................................................................. 57
4.8.16 systematic ventilation-mode name............................................................................................... 57
4.8.17 alternative mode name alternative ventilation-mode name ............................................ 57
4.8.18 superordinate mode ............................................................................................................................ 58
4.8.19 breathing therapy mode .................................................................................................................... 58
4.9
Mode Adjunct and Bi-level Terminology .................................................................................... 58
4.9.1 adjunct ventilation-mode adjunct ................................................................................................. 58
4.9.2 ACAP assured constant airway pressure.................................................................................... 58
4.9.3 ACAPL ACAP-low assured constant airway pressure, low.................................................. 59
4.9.4 ACAPH ACAP-high assured constant airway pressure, high .............................................. 60
4.9.5 bi-level ventilation bi-level............................................................................................................... 61
© ISO 2016 – All rights reserved
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4.9.6 bi-level positive airway pressure bi-level PAP BPAP ........................................................... 61
4.9.7 BAP pressure-low pL ........................................................................................................................... 61
4.9.8 pressure-low phase pL phase............................................................................................................ 62
4.9.9 time-low tL ................................................................................................................................................ 62
4.9.10 BAP-high pressure-high pH ............................................................................................................... 62
4.9.11 BAP-high phase pressure-high phase pH phase ....................................................................... 63
4.9.12 time-high t H ............................................................................................................................................. 63
4.10 Initiation and termination terminology ..................................................................................... 63
4.10.1 initiate ........................................................................................................................................................ 63
4.10.2 trigger......................................................................................................................................................... 64
4.10.3 flow trigger............................................................................................................................................... 64
4.10.4 pressure trigger ..................................................................................................................................... 64
4.10.5 trigger level.............................................................................................................................................. 64
4.10.6 patient-trigger event trigger-event .............................................................................................. 65
4.10.7 breath synchronization ...................................................................................................................... 65
4.10.8 synchronisation window ................................................................................................................... 65
4.10.9 mandatory ................................................................................................................................................ 65
4.10.10
auto trigger....................................................................................................................................... 66
4.10.11
breath stacking ............................................................................................................................... 66
4.10.12
ventilator-initiation ..................................................................................................................... 66
4.10.13
remote inflation-initiation ........................................................................................................ 66
4.10.14
termination ...................................................................................................................................... 66
4.10.15
flow-termination ........................................................................................................................... 66
4.10.16
pressure-termination .................................................................................................................. 67
4.10.17
time-termination ........................................................................................................................... 67
4.11 Baseline and PEEP terminology ..................................................................................................... 67
4.11.1 BAP baseline airway-pressure baseline pressure PEEP ..................................................... 67
4.11.2 PEEP positive end-expiratory pressure ...................................................................................... 68
4.11.3 expiratory-control algorithm .......................................................................................................... 69
4.11.4 total PEEP tPEEP.................................................................................................................................... 70
4.11.5 dynamic PEEP dPEEP........................................................................................................................... 71
4.11.6 delta PEEP ΔPEEP.................................................................................................................................. 71
4.12 Safety limits and alarm terminology ............................................................................................ 71
4.12.1 Safety limits ............................................................................................................................................. 71
4.12.1.1 pressure limit airway-pressure limit ................................................................................... 71
4.12.1.2 pressure-limited pLim .................................................................................................................. 72
4.12.1.3 maximum limited pressure maximum limited airway-pressure ............................ 72
4.12.1.4 maximum deliverable airway-pressure ............................................................................. 72
4.12.1.5 high-airway-pressure limit ....................................................................................................... 72
4.12.1.6 high-pressure relief limit high-airway-pressure relief limit..................................... 73
4.12.1.7 high-pressure termination limit high-airway-pressure termination limit ........ 73
4.12.1.8 maximum settable inspiratory pressure............................................................................ 74
4.12.1.9 adjustable pressure limit adjustable airway pressure limit APL ............................ 74
4.12.2 Alarm conditions ................................................................................................................................... 74
4.12.2.1 alarm condition .............................................................................................................................. 74
4.12.2.2 high-pressure alarm condition high-airway-pressure alarm condition .............. 74
4.12.2.3 continuing pressure alarm condition continuing airway-pressure alarm
condition ................................................................................................................................................... 75
4.12.2.4 low inspiratory-pressure alarm condition ........................................................................ 75
4.12.2.5 low PEEP alarm condition ......................................................................................................... 75
4.12.3 Alarm limits ............................................................................................................................................. 75
4.12.3.1 alarm limit ........................................................................................................................................ 75
4.12.3.2 high-airway-pressure alarm limit ......................................................................................... 75
4.12.3.3 low inspiratory-pressure alarm limit .................................................................................. 76
4.13 General artificial ventilation terminology................................................................................. 76
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4.13.1 ventilator lung ventilator ................................................................................................................. 76
4.13.2 airway......................................................................................................................................................... 76
4.13.3 airway device .......................................................................................................................................... 76
4.13.4 airway resistance .................................................................................................................................. 76
4.13.5 lung compliance..................................................................................................................................... 77
4.13.6 ventilation ................................................................................................................................................ 77
4.13.7 artificial ventilation ............................................................................................................................. 77
4.13.8 automatic ventilation .......................................................................................................................... 77
4.13.9 mechanical ventilation ....................................................................................................................... 77
4.13.10
positive-pressure ventilation .................................................................................................. 77
4.13.11
negative-pressure ventilation NPV ....................................................................................... 78
4.13.12
non-invasive ventilation NIV.................................................................................................... 78
4.13.13
tube compensation TC................................................................................................................ 78
4.13.14
lung ...................................................................................................................................................... 79
4.13.15
lungs .................................................................................................................................................... 79
4.13.16
respiratory system........................................................................................................................ 79
4.13.17
respiratory system coefficients .............................................................................................. 79
4.13.18
ventilator breathing system VBS anaesthesia breathing system ............................ 79
4.13.19
set ......................................................................................................................................................... 80
4.13.20
measured........................................................................................................................................... 80
4.13.21
preset value...................................................................................................................................... 81
4.13.22
actual value ...................................................................................................................................... 81
4.13.23
limit...................................................................................................................................................... 81
4.13.24
normal use ........................................................................................................................................ 81
4.13.25
intended use intended purpose .............................................................................................. 82
4.13.26
normal condition ........................................................................................................................... 82
4.13.27
single fault condition ................................................................................................................... 82
4.13.28
accompanying document ........................................................................................................... 82
4.14 Gas Port Terminology ......................................................................................................................... 82
4.14.1 port .............................................................................................................................................................. 82
4.14.2 gas intake port........................................................................................................................................ 82
4.14.3 emergency air intake port ................................................................................................................ 83
4.14.4 exhaust port............................................................................................................................................. 83
4.14.5 gas output port ....................................................................................................................................... 83
4.14.6 gas return port ....................................................................................................................................... 83
4.14.7 gas input port .......................................................................................................................................... 83
4.14.8 patient-connection port patient connection............................................................................. 83
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Annex A (Informative) Rationale and Guidance ..................................................................................................85
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A.1
A.2
General guidance................................................................................................................................... 85
Rationale for particular clauses and sub-clauses................................................................... 85
Annex B (Informative) not used ...................................................................................................................................90
Annex C Illustrations of Ventilation Terms (Informative) ...............................................................................91
Figure C.1 —Format used in this International Standard for representations of
ventilation patterns and inflation-types ...................................................................................... 92
Figure C.2 (1 of 5) — Illustrations of the application of defined ventilation terms in
designating key features of typical inflation waveforms .................................................... 93
Figure C.2 (2 of 5) —Illustrations of the application of ventilation terms in
designating key features of typical inflation waveforms .................................................... 94
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Figure C.2 (3 of 5) — Illustrations of the application of ventilation terms in
designating key features of typical inflation waveforms .................................................... 95
Figure C.2 (4 of 5) —Illustrations of the application of ventilation terms in
designating key features of typical inflation waveforms .................................................... 96
Figure C.2 (5 of 5) — Illustrations of the application of ventilation terms in
designating key features of typical inflation waveforms .................................................... 97
Figure C.3 — Typical airway pressure and flow waveforms for a CMV-PC mode..................... 98
Figure C.4 — Typical airway pressure and flow waveforms for a CMV-VC <ACAPL>
mode............................................................................................................................................................ 99
Figure C.5 — Typical airway pressure and flow waveforms for a CMV- PC <ACAP>
mode set with extended phase times ......................................................................................... 100
Figure C.6 — Typical airway pressure and flow waveforms for a CMV- PC <ACAP>
mode set with an extreme inverse I:E ratio ............................................................................ 101
Figure C.7 — Typical airway pressure and flow waveforms for an A/CV - PC mode............ 102
Figure C.8 — Typical airway pressure and flow waveforms for an A/CV – VC mode........... 103
Figure C.9 — Typical airway pressure and flow waveforms for an A/CV – PC <ACAP>
mode......................................................................................................................................................... 104
Figure C.10 — Typical airway pressure and flow waveforms for an SIMV- PC\PS mode... 105
Figure C.11 (1 of 4) — Typical airway pressure and flow waveforms for variations on
an SIMV- PC\PS\PS <ACAP> mode................................................................................................ 106
Figure C.12 — Typical airway pressure and flow waveforms for a CSV - PS mode ............... 110
Figure C.13 — Characteristics of a concurrent breath ...................................................................... 112
Figure C.14 (1 of 6) — Ventilation patterns (a) Key to symbols used in b) to f)..................... 113
Figure C.14 (2 of 6) — Ventilation patterns (b) CMV ventilation-pattern ................................. 114
Figure C.14 (3 of 6) — Ventilation patterns c) Assist/Control ventilation-pattern .............. 115
Figure C.14 (4 of 6) — Ventilation patterns (d) IMV ventilation-pattern .................................. 116
Figure C.14 (5 of 6) — Ventilation patterns (e) SIMV ventilation-pattern ................................ 117
Figure C.14 (6 of 6) — Ventilation patterns (f) CSV ventilation-pattern.................................... 118
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Annex D Classification of Inflation-types and Modes (Normative) ........................................................... 119
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D.1
Classification of Inflation-types ................................................................................................... 119
Table D.1a —Inflation-type ........................................................................................................................... 123
Table D.1b —Coding Scheme for variants of Volume Control inflation-types......................... 124
Table D.1c — Systematic coding scheme for Inflation-types ......................................................... 125
D.2
Classification of Ventilation-modes ............................................................................................ 127
Table D.2 — Systematic classification of typical ventilation-modes, with an ACAP
adjunct as a third designation ...................................................................................................... 128
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Annex E Conceptual Relationships between Ventilator Actions and Inspiratory Breaths
(Informative) 129
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Figure E.1 — Diagram showing the concepts of the relationship between breath and
inflation related terms in the vocabulary of the International Standard................. 131
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Annex F Concepts Relating to Baseline Airway Pressures and PEEP as Used in this Standard
(informative) 132
Figure F.1 (1 of 2) — Illustrations of the application of BAP and PEEP terminology......... 134
Figure F.1 (2 of 2) — Illustrations of the application of BAP and PEEP terminology......... 135
Figure F.2 — The BAP/Expiratory phase ............................................................................................... 136
Figure F.3 (2 of 2) — Illustrations of the function of the expiratory-control algorithm
on ventilators with an ACAPL adjunct (or an equivalent function) during BAP
phases ...................................................................................................................................................... 138
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Annex G Conventions followed in this International Standard (Informative) .................................... 139
G.1
G.2
G.3
G.4
G.5
G.6
G.7
G.8
G.9
Avoidance of repetition ................................................................................................................... 139
Post-coordinated terms .................................................................................................................. 139
Use of hyphens..................................................................................................................................... 139
Flows and pressures ......................................................................................................................... 139
Measurements ..................................................................................................................................... 140
Multiplicity of terms ......................................................................................................................... 140
Use of the terms expiration and exhalation ........................................................................... 140
The use of symbols to represent defined terms................................................................... 141
Bi-level terminology ......................................................................................................................... 141
Annex H Terminology — Alphabetized index of defined terms (Normative) ...................................... 143
Annex I Index of figures (Informative)................................................................................................................... 154
I.1
Annex E Figures................................................................................................................................... 155
I.2
Annex F Figures................................................................................................................................... 155
Bibliography
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ISO/DIS 19223:2016(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national
standards bodies (ISO member bodies). The work of preparing International Standards is
normally carried out through ISO technical committees. Each member body interested in a
subject for which a technical committee has been established has the right to be represented on
that committee. International organizations, governmental and non-governmental, in liaison with
ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance
are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed
for the different types of ISO documents should be noted. This document was drafted in
accordance with the editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. ISO shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in
the Introduction and/or on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does
not constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO's adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
This first edition of ISO 19223 was prepared with the cooperation of ISO TC 121/SC3 Lung
ventilators and related equipment, , IHE Patient Care Devices, Rosetta Terminology Mapping
Ventilators, International Healthcare Terminology Standards Development Organization:
Anaesthesia Special Interest Group, HL7 Anesthesia Special Interest Group.
This is the first edition of ISO 19223.
In this standard, the following print types are used:
 Definitions: roman type.
 Material appearing outside of tables, such as notes, examples and references: in smaller type.
 Terms defined in clause 4 of this standard or as noted: italic type
In this standard, the conjunctive “or” is used as an “inclusive or” so a statement is true if any
combination of the conditions is true.
The verbal forms used in this standard conform to usage described in Annex H of the ISO/IEC
Directives, Part 2. For the purposes of this standard, the auxiliary verb:
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 “shall” means that compliance with a requirement or a test is mandatory for compliance with
this standard;
 “should” means that compliance with a requirement or a test is recommended but is not
mandatory for compliance with this standard;
 “may” is used to describe a permissible way to achieve compliance with a requirement or
test.
An asterisk (*) as the first character of a title or at the beginning of a paragraph or table title
indicates that there is guidance or rationale related to that item in Annex A.
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Introduction
The ventilation modes of current automatic lung ventilators are not well understood by many
healthcare providers. The currently used terminology used for their description is based on that
introduced in the early days of mechanical ventilation but with the advances in ventilators, and
the modes of ventilation, that have evolved over recent years, the language used had to be
continuously adapted. In the absence of any international coordinating action this had inevitably
led to increasing inconsistencies in the way in which well-established terms and their derivatives
are used.
To further compound the difficulties in understanding this complex area, ventilator
manufacturers have created new proprietary terms to describe some of these new ways to
ventilate patients, and some have used existing terms that have different definitions in different
situations. This has led to patient safety hazards as, for example, clinical ventilator orders for one
model of ventilator may be quite different to that required get the same result from a different
ventilator.
Recognizing these difficulties, ISO Technical Committee (TC) 121 Subcommittee (SC) 4 was
requested to completely review the terminology and semantics for patient ventilation with a view
to creating an International Standard to suit current and, as far as possible, future practice. The
intention was, first, to use as much existing terminology as possible while clarifying its meaning
as well as putting a limit on its misuse by defining it more precisely. Secondly, to introduce new
terms only where there was no alternative; either in order to name new concepts or where the
misuse of existing vocabulary has become so widespread that the term has become meaningless
or ambiguous. Emphasis was to be placed on creating a terminology that would communicate a
clear mental model of the selected ventilator/patient interaction to the operator/user and
designers of health information technology systems.
In order to harmonize the terms over several applications for patient care, research and incident
reporting, this International Standard has been developed with the cooperation and assistance of
other standards development organizations, as detailed in the Foreword, and of major
international ventilator manufacturers. The applications include lung ventilation equipment,
medical data systems facilitating clinical care and research, interoperability incident reporting
and equipment maintenance.
In their review before producing this standardised vocabulary, the subcommittee found that it
was necessary to revert to first principles; an approach that included consideration of automatic
ventilation from a systems perspective. In the early use of automatic ventilation the patient was
ventilated with little regard for the patient’s own respiratory activity and much of the current
terminology has its origins in that practice. Modern ventilators interact with the patient as a
‘ventilator-patient system’ resulting in interactions are non-deterministic. This means that one
cannot, with any certainty, predict ahead of time how a patient will interact with a ventilator. It
is often no longer possible for an operator to set a ventilator and foresee the exact form of the
resultant pressure and flow waveforms unless the patient is anesthetized and given a
neuromuscular blocking drug.
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The terminology in this vocabulary must, therefore, be defined and used in a way that makes it
capable of facilitating, unambiguously, both the setting of a ventilator and then describe and
record the result of the ventilator-patient interaction, after the event has occurred, at defined
points within the course of ventilation. This includes the result of the complex interactions within
simultaneous respiratory cycles as may occur, for example, during APRV (airway pressure release
ventilation).
This International Standard seeks to provide both a consensus view and to lead to a coherent
language for describing ventilator function. Now that ventilation practice has matured it has been
possible to review the boundaries between the various established ventilation modes and
methods of artificially inflating a patient’s lungs and to formulate descriptions that clarify the
common elements and the distinctions. Terms that were relevant to earlier technology and
practice but are not adaptable to current practice have been deprecated or discarded and the
application of many other terms has been constrained to more specific definitions. The objective
is to encourage a more disciplined use of ventilator terminology so that operators trained in the
standardised language will be able to move easily from one ventilator to another and operate each
one, with confidence, after a minimum of training. Although change will not be immediate it is
expected that this discipline will feed through into articles, textbooks and training so that over
time a standard basic language of artificial ventilation will become internationally established.
Examples of application of this vocabulary are illustrated in the Figures of Annexes C and F but
these are not intended to indicate a requirement nor to impose any restriction on the design of
ventilation devices.
The semantics of defined terms, along with their classification schemes, are explained, both in
notes to individual entries into this vocabulary and in associated Annexes.
Many of the terms in this vocabulary are intended for the technical explanation on how the
various inflation-types, breaths, and ventilation-modes function and may be found to be needed
only within technical descriptions.
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Lung Ventilators and related equipment—Vocabulary and
Semantics
1 * Scope
This International Standard establishes a vocabulary of terms and semantics for all fields of
respiratory care such as intensive-care ventilation, anaesthesia ventilation, home-care ventilation
including sleep apnoea breathing therapy equipment and emergency and transport ventilation. It
may be used:
 in lung ventilator and breathing therapy device standards
 in health informatics standards
 for labelling on medical electrical equipment and medical electrical systems
 in medical electrical equipment and medical electrical systems instructions for use
and accompanying documents
 for medical electrical equipment and medical electrical systems interoperability
 in electronic health records
This International Standard may also be used for those accessories intended by their manufacturer to be connected
to a ventilator breathing system, or to a ventilator, where the characteristics of those accessories can affect the basic
safety or essential performance of the ventilator and ventilator breathing systems.
NOTE
The vocabulary may also be used for other applications involving lung ventilation including research,
description of critical events, forensic analysis and adverse event (vigilance) reporting systems.
This International Standard does not specify terms specific to high-frequency ventilation or
negative-pressure ventilation, or to respiratory support using liquid ventilation, extra-corporeal
gas exchange, or use of gas mixtures not primarily composed of nitrogen and oxygen.
Many terms entered into this clause of this International Standard originated in ISO 4135. On
publication of this International Standard, this vocabulary will supersede the equivalent
vocabulary in ISO 4135. It is intended that ISO 4135 will then be appropriately revised, restricting
its scope to only deal with terms outside the scope of this International Standard.
2
Conformance
2.1 General
In order to claim conformance with the vocabulary of this International Standard, in this first
edition the minimum requirement is that, wherever relevant, any terms used for the labelling of
a ventilator and in its accompanying documents that do not conform to its vocabulary are listed
alongside the equivalent standardised term in a dedicated section of the product information that
is readily accessible to the operator. In particular, all ventilation modes that may be selected on
the conforming ventilator are required to be listed using the coded form of the systematic name
as specified in this International Standard alongside the labelled name used on the ventilation
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device or equipment. These listings should be accompanied by brief descriptions of the basic
modes available on the ventilator, using the vocabulary of this International Standard.
Although there are no further requirements in order to conform to this first edition of this
International Standard, it is the intention that the present requirements will be extended as
further editions are published. In preparation for such changes it is expected that this vocabulary
will be adopted by authors, and in teaching and training, so that users will become familiar with
its usage before it is widely implemented in the marking and Instructions for Use of ventilators.
The following informative guidelines are provided to indicate how the vocabulary of this
International Standard is intended to be used.
This International Standard is intended to contribute to the effectiveness and safety of the
practice of artificial ventilation by providing a coherent vocabulary covering. It has been
structured so that it is sufficiently adaptable to facilitate the description of novel deviations but
is recognized that some future innovations may require the use of terms and concepts not covered
by this edition of this vocabulary.
The terms, names and acronyms listed in this Standard have been described in a manner that
formalizes their interpretation to the extent that it minimizes ambiguity and provides a rigid
usage discipline for formal data handling and informatics, whilst retaining phraseology that is
suitable for user instructions and clinical dialog.
In the application of the vocabulary of this International Standard, the full term should always be
used wherever any ambiguity must be avoided and where there is no trade-off with conciseness,
for example, in the formulation of data bases. However, in many applications the context of use
may make some of the parts of a compound preferred term redundant, in which case
abbreviations, symbols and permitted terms may be used, as appropriate.
In the particular case of terms representing set, actual or measured values, qualifications such as
‘set’ or ‘measured’ may be omitted where the meaning is obvious from the context of use.
Where space is particularly limited such as on a typical user interface, or conciseness is
necessary, it is permissible to use abbreviations or symbols to represent a preferred term,
providing the context makes it self-evident as to whether it relates to a set, actual or measured
value and that the instructions for use relate the abbreviation or symbol to the preferred term.
As examples, in a section on a user interface designated for ‘settings’ the input key for
inspiratory flow may be marked simply as ‘Flow’ and that for inspiratory time an appropriate
symbol such as ‘tI ’. However, where abbreviations and symbols are used in this way their
meaning and the associated full term are to be provided in the instructions for use.
Symbols are not within the scope of this International Standard and have only been included as
alternative preferred or admitted terms where there appears to be an existing general
consensus relating to their use in representing the main terms used when setting a ventilator.
Their inclusion is only for guidance and their format and use is not a normative requirement.
For further information and recommendations refer to Annex G.8.
Even with these considerations, the exclusive use of the terms listed in this International Standard
may still be too formal for some applications and the intention is that in conformance with future
editions of this International Standard manufacturers will still be able to still retain their
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proprietary names and acronyms and substitute their own phraseology in preparing instructions
for use, subject to the following:
a) The standardised term should be used in preference to any other where it is applicable.
b) The standardised terms may be used in a variety of post co-ordinations and with any
alternative grammatical forms provided that the meaning conveyed is in accordance with
the definitions of the terms and concepts in this International Standard.
c) Where proprietary and trade names and acronyms for modes and control algorithms are
used they shall be explained in terms of the concepts defined in this International
Standard in an appropriate section of, or supplement to, the instructions for use and, as
a minimum requirement after major upgrades or on new models, on a help screen on the
ventilator.
d) The meaning conveyed by any proprietary term, where applicable, should be the same
as that described in this International Standard for the same concept or combination of
concepts.
e) Text prepared by the manufacturer and others to explain and describe artificial
ventilation may use their own phraseology in expressing the concepts involved but the
underlying concepts defined in this International Standard is to be adhered to.
f) Descriptions of artificial ventilation practice not directly covered by the vocabulary of
this International Standard may use appropriate new terms where necessary but it is
required that these terms are described in respect of the concepts described in this
International Standard wherever possible.
3
g) Terms conforming with this International Standard under the permitted exceptions b)
to f) are required to be chosen and used in a manner that avoids any conflicts that could
cause confusion to those trained in the vocabulary in this International Standard.
Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
Not used
NOTE 1 Informative references are listed in the bibliography on page 156.
4
Terms, definitions, symbols, units and abbreviated terms
NOTE
For convenience, an index and list of sources of all defined terms used in this document are given
in Annex H.
4.0 General
Many terms in the vocabulary of this International Standard originated in ISO 4135. On
publication of this International Standard its vocabulary will supersede the equivalent vocabulary
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in ISO 4135. It is intended that ISO 4135 will then be appropriately revised, restricting its scope
to only deal with terms outside the scope of this International Standard.
4.0.1 Guidance followed in the writing of this International Standard
Vocabulary and terminology standards are required by ISO to be prepared taking into
account the guidance of ISO 704, Terminology work - Principles and methods, ISO 102411, Terminological entries in standards - Part 1: General requirements and examples of
presentation, and the ISO/IEC Directives, Part 2, 2011 -- Rules for the structure and
drafting of International Standards.
The following concepts extracted from ISO 704 were considered to be of particular
relevance to the formatting of the vocabulary in this International Standard:
Standardized terminologies should reflect a coherent terminological system that
corresponds to the concept system of the subject field in question. The terminology
defined in an International Standard should be precise and lead to increased clarity in
communication.
A primary function of a standardised terminology is to indicate preferred, admitted, and
deprecated terms. A term recommended by a technical committee shall be considered a
preferred term whereas an admitted term shall represent an acceptable synonym for a
preferred term. Deprecated terms are terms that have been rejected. Terms are rejected
or deprecated for a number of reasons. A term may be a synonym for the preferred term
but is deprecated in the interests of monosemy (having a single meaning). Alternatively
a term may be flawed, inaccurate or may be used with a different definition.
[SOURCE: ISO 704]
4.0.2 Explanation of the principles adopted in the preparation of the vocabulary entries
in this clause
As stated in the preceding extracts, a primary function of a standardised terminology is to
indicate preferred, admitted, and deprecated terms. In subject fields where there is no
standardised terminology, such as is the case with respect to artificial ventilation, it is inevitable
that there is often more than one term in common use for the designation of a given concept.
However, in choosing a preferred term in this vocabulary it was recognised that in the
vocabulary of ventilation a compromise often has to be made between the conflicting
requirements for the avoidance of ambiguity and the need for conciseness. In this vocabulary
the preferred term has been chosen as the one that is most generally used; with admitted terms
(synonyms), abbreviations and symbols sometimes also listed for use where appropriate,
depending on the context of use. Where a term is listed as ‘deprecated’, this means that it is
deprecated as a synonym for the preferred term, although some such terms are used as
preferred terms for the designation of other concepts.
In accordance with the ISO 10241-1:2011 Clause 6.4.4, the definitions of terms entered into this
clause are intensional definitions. Such definitions are required to consist of a single phrase
specifying the concept being designated, and if possible, to reflect the position of the concept in
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the concept system; containing only information that makes the concept unique. A definition
given without an indication of its applicability is to be taken as representing the general
meaning of the term. Any additional descriptive information deemed necessary is included in
notes to entry or in examples. Notes to entry follow different rules from notes integrated into
other text; they provide additional information that supplements the terminological data.
Because a ventilator is a device that, typically, interacts with a patient in accordance with inputs
from an operator, certain of the concepts of artificial ventilation are of quantities with a value
that may be either the actual value or the intended value as set, directly or indirectly, by an
operator. In these instances, the definition is used to represent the general meaning of the term.
If it is, or may be, used to represent either, or both, a set value or an actual value, this is stated in
a note to entry. An actual value exists as a concept whether it can be measured or not and is,
therefore, unaffected by the accuracy of measurement or the method by which it may be
displayed or recorded. For this reason, the vocabulary of this International Standard only
addresses actual values, set values and measured values as concepts. It is for particular
standards to specify any requirements regarding measurement accuracy and units of
measurement.
The terminological entries hereunder are formatted in accordance with the current ISO rules for
the presentation of terminology standards. The vocabulary of this International Standard is
primarily arranged in a systematic order, with a secondary alphabetical order. An alphabetical
list of terms is provided at the end of this document.
For further information concerning set, actual and measured values, and on how this vocabulary
is intended to be applied, particularly with respect to context and qualification, see also Clause
2, Conformance. For further information concerning some of the conventions followed in this
clause see informative Annex G.
4.1 Breath terminology
4.1.1
breath
increase in the volume of gas in the lung resulting from an inward gas flow through the airway,
paired with a corresponding decrease in volume resulting from its expiration
Note 1 to entry: The inward flow may be caused by a positive-pressure inflation, a patient inspiratory effort, or a
combination of the two. The outward flow results from a patient’s exhalation.
Note 2 to entry: A breath is composed of two phases: an inspiratory phase (4.3.11), or an inflation phase (4.3.17), and
an expiratory phase (4.3.2).
Note 3 to entry: The volume of gas that enters and leaves the lung during a breath may differ due to physical and/or
compositional changes between inspired and exhaled gas, and leakages at the connection to the patient’s airway..
Temporarily, it may also differ, breath-to-breath, in the event of, for example, dynamic hyper-inflation or specific
patient actions.
Note 4 to entry: This definition accommodates the concept of additional breaths occurring within the period of a
primary-inflation cycle.
Note 5 to entry: See also lung (4.13.11), inspiratory volume (4.7.3), expired tidal volume (4.7.4), tidal volume (4.7.1)
and additional breath (4.1.8).
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4.1.2
breathe
take gas into the lungs and then expire it
Note 1 to entry: Breathing is a spontaneous human activity that may be detected by a ventilator but in this
vocabulary is never considered to be a ventilator function.
Note 2 to entry: This term is typically used to designate this action as a continuously repeated physiological process
but may be used to designate the taking of a single breath or even an inspiration or expiration.
4.1.3
spontaneous breath
breath initiated by the patient
Note 1 to entry: This definition is patient-centric and independent of a ventilator or sleep apnoea breathing-therapy
device.
Note 2 to entry: The detection of a spontaneous breath by a medical device depends on the set detection threshold of
a relevant physiological parameter(s), which may include a parameter(s) that relate to the patient’s intention to
breathe and not the actual movement of gas.
Note 3 to entry: The qualifier ‘spontaneous’ makes it clear that such breaths occur as a result of the patient's,
generally subconscious, physiological processes, and consequently have elements of unpredictability in initiation,
size and duration.
Note 4 to entry: From an artificial ventilation perspective a spontaneous breath is also one to which the patient has
contributed at least a proportion of the work of inspiration. More specific terms, which provide an indication of
relative magnitude, are subsets of the general term and range from ‘breathing effort’ and ‘breathing activity’ to
‘natural breath’. These are all parts or types of spontaneous breaths, as are spontaneous inspiration and spontaneous
expiration.
Note 5 to entry: See also breath (4.1.1).
4.1.4
natural breathing
breathing with a workload within the range that a patient might expect to experience when not
requiring artificial ventilation and not connected to a ventilator
Note 1 to entry: See also breathe (4.1.2), unassisted breath (4.1.12) and unrestricted breathing (4.1.5).
4.1.5
unrestricted breath
unassisted breath with a workload within the range that a patient might expect to experience
during natural breathing
Note 1 to entry: See also unassisted breath (4.1.12) and natural breathing (4.1.4).
4.1.6
respiratory activity
activity of the patient's respiratory system related to the desire to breathe
Note 1 to entry: This term typically serves as a reference to the minimum detectable form of the physiological
indications of the patient’s respiratory intentions, which may be used to improve the interaction between the
ventilator and the patient. The term also serves as the reference to the level of effort to be supported during
proportional effort support inflations.
Note 2 to entry: This term may be expressed as the activity during either of the phases of a breath, i.e., a patient
inspiratory activity or a patient expiratory activity.
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Note 3 to entry: Respiratory activity may be detected as a patient generated change in flow or pressure of gas in the
airway, respiratory muscle activity, respiratory control-centre activity or other neural signals.
4.1.7
inspiratory effort
effort by the patient's respiratory muscles that contributes to the work of inspiration or that
generates detectable changes sufficient to cause a patient-trigger event
Note 1 to entry: This definition is patient-centric and independent of the ventilator or sleep apnoea therapy
equipment.
Note 2 to entry: See also breathe (4.1.2).
4.1.8
additional breath
one of any breaths per minute that are additional to the ventilator set rate in modes where a rate
is set
Note 1 to entry: The additional breath rate is the total respiratory rate minus the set rate.
Note 2 to entry: With assist/control ventilation (A/CV) modes it is sometimes not possible to identify any one breath
as an additional breath; it is only possible to deduce the number of additional breaths per minute by comparing the
total respiratory rate with the set rate as explained in note 1 to entry.
Note 3 to entry: All separate inspirations that occur concurrently with or between primary-inflations are counted as
additional breaths, whether unassisted or supported. Patient-trigger events that initiate a primary-inflation are only
counted as additional breaths if they initiate additional primary-inflations. See also additional primary-inflation
(4.2.13).
Note 4 to entry: The concept of additional breaths facilitates the identification of additional-breath rate (4.4.2.7) and
additional minute volume (see 4.7.12).
4.1.9
concurrent breath
additional breath, or phase of a breath, initiated during an inflation phase
Note 1 to entry: Inspiratory phases of the breath may be unassisted, or supported.
Note 2 to entry: This is a separate breath, or phase of a breath, following a change of airway flow direction or zero
airway flow, while the lung is still inflated. Complete concurrent breaths are only possible with the provision of ACAP
or ACAPH .
Note 3 to entry: It is only the detection of the inspiratory phase of a concurrent breath that contributes to the total
respiratory rate but the volume change of either concurrent phase is included in the respective minute volume. (See
spontaneous-breath rate (4.4.1.3)).
EXAMPLE: See Figures C.5, C.6, C.11a - d, and C.13 (Annex C).
4.1.10
inspiration
DEPRECATED AS SYNONYM: inhalation
DEPRECATED AS SYNONYM: inhale
process of gas entering the lungs through the patient’s airway
4.1.11
expiration
exhalation
process of gas leaving the lungs through the patient’s airway
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Note 1 to entry: The admitted term, in its various grammatical forms, may be used instead of expiration in reference
to a patient action, wherever the use of certain grammatical forms of expiration may seem inappropriate in the
presence of patients. This admitted use is considered to be generally not necessary for impersonal purposes such as
in medical databases and computer records.
Note 2 to entry: This definition recognises that expiration, during both natural breathing and artificial ventilation, is a
process that typically extends beyond the time during which gas is actually flowing out from the lungs and only
terminates when inspiratory flow next starts.
4.1.12
unassisted breath
spontaneous breath by a patient connected to a ventilator, with no assistance from an inflation
Note 1 to entry: An increase of airway pressure applied during the inspiratory phase of a spontaneous breath, with the
declared intended use of compensating for any work of breathing imposed by an airway device or the functioning of
the ventilator, is not classed as an inflation in this vocabulary. (See also tube compensation (4.13.13)).
Note 2 to entry: The patient’s work of breathing when taking a spontaneous breath may be reduced by the provision
of ACAP or CPAP, but because no assistance is provided, such a breath is unassisted. (See also ACAP (4.9.2)).
Note 3 to entry: Unless demand flow is provided by the ventilation mode selected, or by an ACAP adjunct, an
unassisted inspiration may require an unsustainable inspiratory effort.
4.1.13
supported breath
spontaneous breath with assistance from a pressure support or proportional effort support
inflation-type
Note 1 to entry: See also pressure support (4.2.6) and proportional effort support (4.2.7).
4.1.14
assisted breath
spontaneous breath with assistance from a patient-triggered primary-inflation at a rate in excess
of that set
Note 1 to entry: An assisted breath is assisted by a primary-inflation of the selected type but only occurs if initiated
before the next assured delivery is due to occur, at an interval determined by the set rate. Each assisted breath,
therefore, occurs at a rate higher than that set; a rate which is solely determined by the patient.
Note 2 to entry: A spontaneous breath that is supported by a pressure support or proportional effort support
inflation-type, or by a primary-inflation within a synchronisation window, although also assisted, is separately
identified by the specific characteristic that distinguishes it from an assisted breath, namely, supported breath or
synchronised breath, respectively.
Note 3 to entry: See also supported breath (4.1.13) and synchronised breath (4.1.15).
4.1.15
synchronised breath
spontaneous breath with assistance from a primary-inflation, initiated by a patient-trigger event
within a synchronisation window
Note 1 to entry: Synchronised breaths are assured to occur at the set rate.
Note 2 to entry: See also synchronisation window (4.10.8) and assisted breath (4.1.14).
4.1.16
controlled breath
breath associated with a ventilator-initiated primary-inflation
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Note 1 to entry: A controlled breath is always initiated by the ventilator and subsequently, in the absence of any
ensuing spontaneous breathing activity by the patient, generated entirely by the inflation waveform set or selected by
the operator. Controlled breaths, therefore, are assured to occur at the set rate.
Note 2 to entry: See also set rate (4.4.1.1)
4.2 Positive-pressure inflation terms and definitions
4.2.1
inflation
positive-pressure inflation
ventilator inspiration
ventilator action intended to increase the volume of gas in the lung by the application of an
elevated-pressure waveform to the patient-connection port until a specified termination
criterion is met
Note 1 to entry: An elevation of the airway pressure, above the end-expiratory pressure of the previous phase,
generates, in the absence of total airway obstruction, an inspiratory flow that will either assist or totally control the
inflation of the patient's lungs.
Note 2 to entry: If the inflation is pressure-regulated and the inspiratory phase is set to extend beyond the
inspiratory-flow time then the lungs are held distended until the inflation is terminated. During this inspiratory pause,
concurrent breathing may be possible, to the extent determined by the specific ventilation mode selected and whether
an ACAP adjunct is provided.
Note 3 to entry: Although, typically, there will be more than one inflation-termination criterion, for patient safety
reasons, these will always include time-termination, intended as either a primary or secondary means.
Note 4 to entry: If an inflation is terminable by means additional to time, this vocabulary requires that this is
indicated, at least in the instructions for use, in accordance with the inflation-type systematic naming and coding
tables, D.1a, D.1b and D.1c (Annex D).
Note 5 to entry: The elevated pressure waveform is implemented by either a flow-regulation function or a pressureregulation function.
Note 6 to entry: This is a context-sensitive term designating an intermittent elevated-pressure ventilator parameter,
as distinct from a negative-pressure ventilator inflation or a lung inflation resulting solely from a patient’s inspiratory
effort. When used in its defined context the preferred term is used by itself but in cases of possible ambiguity the
qualified form, ‘positive-pressure inflation’, should be used.
Note 7 to entry: The admitted term ventilator inspiration is included to facilitate translation into languages that do
not have a translation for the word inflation as it is used in this context.
4.2.2
inflation-type
property-class named, type of inflation characterised by its temporal delivery pattern following
initiation, and its termination criteria
Note 1 to entry: Inflation-types are designated in this vocabulary by their property-class common names, wherever
possible. They are more precisely designated by a systematic coding scheme, which uses the abbreviations of the
common names, where available, but which also often includes designators of additional properties and designates
inflation-types with no common name as yet attributed to them.
Note 2 to entry: A group of Inflation-types that might be selected for a specific purpose are sometimes given a
purpose-class name but such a name is not an alternative name for that inflation-type. As an example, one of a
selection of inflation-types may be selected to serve as the primary-inflation within a mode but the inflation-type
selected becomes the primary ‘inflation-type’, not an inflation of a ‘primary type’.
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Note 3 to entry: For further normative information on inflation-type designations see Types of Inflations and Modes
(Annex D).
4.2.3
volume-control
VC
property-class named inflation-type that generates inspiratory flow to a selected flow-waveform,
for a set time, or until the set volume has been delivered
Note 1 to entry: The selected inspiratory-flow waveform is typically that of a constant flow at a set value or of a
declining-ramp flow pattern, sometimes after a set rise time. This is maintained for the duration of the inflation phase
by means of a flow-regulation function.
Note 2 to entry: The flow-regulation function may either maintain a constant set flow rate or make inflation-toinflation adjustments to ensure that the set volume is delivered in the set time, particularly when compensating for
ventilator breathing system characteristics or airway leakage.
Note 3 to entry: See also Figure C.2 (Annex C) and Classification of Types of Inflations and Modes (Annex D)).
4.2.4
pressure-control
PC
property-class named inflation-type that acts to generate a constant inspiratory pressure at a set
level, following a set pressure rise time
Note 1 to entry: During and after the set rise time the set inspiratory pressure is maintained by means of a pressureregulation function.
Note 2 to entry: If the patient makes a spontaneous inspiratory effort during a pressure-control inflation this will
result in a corresponding increase in inspiratory flow, although not necessarily an increased delivered volume.
Note 3 to entry: If the patient makes a spontaneous expiratory effort during a pressure-control inflation the
inspiratory pressure will rise above that set, which may cause immediate termination of the inflation. See also high
pressure relief limit (4.12.1.6) and high-pressure termination limit (4.12.1.7).
Note 4 to entry: See also Figure C.2 (Annex C), Classification of Types of Inflations and Modes (Annex D).
4.2.5
dual-control
type of inflation in which the regulated variable changes from pressure to flow, or vice versa,
during an inflation phase in accordance with the inflation algorithm
Note 1 to entry: A dual-control designation is incomplete without reference to the names of the inflation-types that
most closely represent the initial and secondary functions within the dual-control inflation. For examples see Tables
D.1a and D.1c (Annex D).
Note 2 to entry: Pressure limitations, as may be achieved by a relief system or flow limitations and, as a consequence,
where the set delivered volume may not be achieved, are not considered to be components of a dual-control inflationtype.
Note 3 to entry: See also Tables D.1a and D.1c, and D.1, Ref #17 (Annex D).
4.2.6
pressure-support
PS
property-class named inflation-type that acts to generate a constant airway pressure, following a
set pressure rise time, and is intended to be terminated in response to a patient respiratory
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activity. It is only made available for selection with ventilation modes where it cannot be
initiated other than in response to a patient-trigger event
Note 1 to entry: During and after the set rise time the set inspiratory pressure is maintained by means of a pressureregulation function.
Note 2 to entry: Pressure-support inflation-types are so named because they are specified and configured to be used
only to provide assistance to spontaneous breathing.
Note 3 to entry: Pressure support inflations are typically flow-terminated but may be terminated by other means.
Note 4 to entry: It is possible for flow-termination to be actioned by the passive characteristics of the patient's
respiratory system alone, without any patient respiratory activity, in which case it is misleading to refer to the inflation
as having been patient-terminated. Because current ventilators cannot make this distinction, in this vocabulary flowterminated inflation-types are not referred to as being patient-terminated.
Note 5 to entry: As noted under, inflation, pressure-support (PS) inflations are time-terminated if not terminated
within the set inspiratory time; a setting that may be pre-set or operator adjustable.
Note 6 to entry: By convention, set inspiratory pressures for pressure-support (PS) inflations are usually set relative
to their related baseline airway-pressure but all relative pressures are required in accordance with this International
Standard to be identified as such by the use of the differential symbol, Δ (see 4.5.6).
Note 7 to entry: For Group 2 modes with an ACAP or ACAPH adjunct, a single pressure-support inflation setting may be
arranged to support breaths throughout the full primary-inflation cycle if its set inspiratory-pressure level is higher
than the set inspiratory pressure for the primary-inflation. Alternatively, there may be a second level of pressuresupport, relative to the set inspiratory pressure for the primary-inflation, for the assistance of concurrent breaths.
Note 8 to entry: A pressure-control (PC) inflation that is flow-terminated is not classified as pressure support (PS) if
used in modes where it may be initiated mandatorily; it is then classified as either a spontaneous/timed pressurecontrol (S/T) inflation or a pressure-control, flow-terminated (PC(q)) inflation.
Note 9 to entry: See also assured ventilation (4.8.5), flow-termination (4.10.15), ACAP (4.9.2) and Figure C.2
(Annex C).
4.2.7
proportional effort support
pES
property-class name of an inflation-type that generates an airway-pressure waveform that is intended to be
proportional to a patient’s effort as indicated by the measured respiratory activity parameters
Note 1 to entry: The intention of this inflation-type is to off-load increased work of breathing due to worsened
respiratory system coefficients and thereby to get closer to natural breathing.
Note 2 to entry: The respiratory activity is typically detected as the airway resistance or lung stiffness components of
the patient’s inspiratory effort or as neural signals.
Note 3 to entry: The required airway-pressure waveform is typically calculated moment-by-moment by a ventilator
algorithm, using the instantaneous measurement of inspiratory flow or electromyography signals; it is put into effect
by means of a pressure-regulation function.
Note 4 to entry: If the proportional effort support (pES) inflation is based on measurement of inspiratory flow, the
support is most commonly determined by the sum of the independently set proportions of the resistive and/or
stiffness components of the patient's inspiratory effort, and the inflation is typically terminated when the inflation
flow has declined to a set inspiratory-termination flow threshold.
Note 5 to entry: As noted under pressure-control (PC) inflation, proportional effort support (pES) inflations are timeterminated if not terminated by other means within the set inspiratory time; a setting that may be pre-set or operator
adjustable.
Note 6 to entry: See also Table D.1a, Table D.1c and D.1, Refs # 12 - 14 (Annex D).
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4.2.8
spontaneous/timed pressure-control
S/T
property-class named inflation-type that acts to generate a characteristic airway-pressure
waveform for a set time if ventilator initiated and terminated by a means responsive to a patient
respiratory activity if initiated by a patient-trigger event
4.2.9
flow-regulation
function of the ventilator that varies the airway pressure as necessary with time to generate an
intended inspiratory-flow waveform irrespective of changes to the respiratory system
coefficients or of respiratory activity
Note 1 to entry: See also pressure-regulation (4.2.10).
4.2.10
pressure-regulation
function of the ventilator that regulates the airway pressure as necessary with time to generate
an intended airway-pressure waveform irrespective of changes to the respiratory system
coefficients or of concurrent unassisted inspirations
Note 1 to entry: See also concurrent breath (4.1.9), unassisted breath (4.1.12) and flow-regulation (4.2.9).
4.2.11
rise time
indication of the time for the regulated parameter to rise to a set value following the initiation of
an inflation
Note 1 to entry: The rise time is often expressed as the slope of a ramp or as the time-constant of the rise although
neither of these terms depicts the actual typical trajectory of this pressure rise precisely.
Note 2 to entry: For pressure-regulation this is the time to reach a set inspiratory pressure, for flow-regulation it is
the time to reach a set inspiratory flow.
Note 3 to entry: see also Figure C.2 (Annex C).
4.2.12
primary-inflation
purpose-class named inflation-type that has been selected for assured delivery at the set rate
Note 1 to entry: In this vocabulary, inflations are classified either by their purpose or by their properties in terms of
their characteristic waveform. This term is a purpose-classification, as distinct from the name of an inflation-type,
which is a property-classification. See inflation-type (4.2.2).
Note 2 to entry: Primary-inflations may be initiated either by the ventilator or by a patient-trigger event.
Note 3 to entry: All assured deliveries are of primary-inflations but not all primary-inflation deliveries are assured.
Note 4 to entry: With some modes the primary-inflations may be delivered at a greater rate than that set, in response
to patient-trigger events. See also additional primary-inflation (4.2.13).
Note 5 to entry: Primary-inflations are typically terminated by the ventilator.
Note 6 to entry: The breath associated with a primary-inflation is ‘assisted’, ‘synchronised’ or ‘controlled’.
Note 7 to entry: This qualified term is used in this vocabulary in reference to ventilation with additional breaths,
particularly when these are assisted by another inflation-type(s).
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Note 8 to entry: An inflation-type that has been selected for assured delivery may also be initiated by a patient-trigger
event, for example, in Assist/control ventilation (A/CV) modes and in SIMV modes.
Note 9 to entry: See also respiratory cycle (4.3.18) for derivation of the post-coordinated term primary-inflation cycle.
Note 10 to entry: See also support-inflation (4.2.15) and C.10, C.11a, C.11b and C.11d (Annex C).
4.2.13
additional primary-inflation
primary-inflation initiated by an additional breath
Note 1 to entry: In Group 1b) modes any patient-trigger event will cause the primary-inflation rate to exceed that set.
Any primary-inflations per minute in excess of those assured to occur by the set rate (4.4.1.1) become additional
primary-inflations. These may be recorded and displayed as the additional-breath rate (4.4.2.7) and give rise to
additional minute volume (4.7.12).
Note 2 to entry: See also ventilation-mode Group 1b (4.8.4.1.2), patient-trigger event (4.10.6) and assist/control
ventilation (4.8.7).
4.2.14
assured delivery
delivery of a selected inflation-type at the set rate
Note 1 to entry: The inflation-type selected for assured delivery is designated as a primary-inflation.
Note 2 to entry: The operator has the assurance that the selected inflation type will be delivered at either on average
the set rate, or at least the set rate, depending upon the selected ventilation-pattern.
Note 3 to entry: Assured is used in this vocabulary as the preferred synonym to the legacy term, mandatory. It
conveys the concept which mandatory is used to elicit in this vocabulary but avoids the ambiguities which that term
engenders. For the reasons explained in the rationale to 4.8, mandatory is only used in this vocabulary when
explaining the meaning of legacy ventilation-patterns that incorporate this term.
Note 4 to entry: See also Figures C.7, C.8 and E.1, set rate (4.4.1.1), ventilation-pattern (4.8.3) and mandatory (4.10.9)
4.2.15
support-inflation
purpose-class named inflation-type that is intended to be terminated in response to the patient’s
respiratory activity and is used in modes where it can only be initiated in response to a patienttrigger event
Note 1 to entry: Support-inflations are so named because they are specified and configured to be used only to provide
assistance to spontaneous breathing.
Note 2 to entry: It is not generally possible to designate support-inflations as ‘patient-terminated’ because, typically,
they may be also terminated by the patient’s passive lung in the absence of respiratory activity.
Note 3 to entry: The breath associated with a support-inflation is ‘supported’. See supported breath (4.1.13).
4.2.16
volume targeted
vt
automatic inflation-to-inflation adjustment of the set inspiratory pressure, for inflations in which
the delivery is pressure-regulated, with the target of achieving a set delivered volume for each
breath
Note 1 to entry: The term ‘target’ is used because the inevitable inflation-to-inflation delay, possible respiratory
activity and other limitations in the adjustment result in less precise control or each delivered volume than is achieved
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by direct feedback (for example, as is used for the pressure-regulation function) although the average delivered
volume will typically converge towards the set value.
Note 2 to entry: This term is applicable to all inflations in which the delivery is pressure-regulated to a set value,
including those classified as pressure support (PS) but not to those that respond to patient parameters according to an
alternative algorithm, for example, pES. The systematic code becomes, for example, vtPC, vtPS. Such a code becomes
the generic classification for established proprietary terms such as ‘Autoflow’, ‘PRVC’, ‘Volume Support’, ‘Volume
Guarantee’ and ‘VC+’.
Note 3 to entry: See also Table D.1a, Table D.1b and D.1, Refs # 2 and 3 (Annex D).
4.3 Time, phase and cycle terminology
4.3.1
expiratory time
tE
duration of an expiratory phase
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20) .
Note 2 to entry: The symbol, tE, in various fonts, is typically used to designate the expiratory time setting, particularly
where space is limited such as on operator interfaces.
Note 3 to entry: As a set quantity the expiratory time is either the intended actual duration, the intended average
duration or the assured maximum duration of the expiratory phase of the primary-inflation, depending on the mode
selected.
Note 4 to entry: As a measured quantity the expiratory time is that of the longest respiratory cycle unless otherwise
specified.
Note 5 to entry: On many ventilators the expiratory time is typically set indirectly, for example, by means of a set rate
and inspiratory time.
Note 6 to entry: With expiratory phases alternatively labelled as BAP phases, expiratory time becomes BAP time. In
modes labelled as bi-level ventilation, the expiratory time may be identified by the term BAP time or time-low. Further
details are given in 4.9.
Note 7 to entry: For information on the use of symbols in the labelling of ventilation equipment see Clause 2 –
Conformance and Annex G.5.
Note 8 to entry: See also primary-inflation (4.2.12), respiratory cycle (4.3.18), Figures C.3, C.4, C.7 and C.8 (Annex C)
and Figure F.2 (Annex F).
[SOURCE: ISO 4135: 2001, 3.4.6]
4.3.2
expiratory phase
interval from the start of expiratory flow to the start of inspiratory flow within a respiratory cycle
Note 1 to entry: If additional spontaneous breaths are possible their expiratory phase may occur within the expiratory
phase of a primary-inflation cycle.
Note 2 to entry: In accordance with the conceptual framework of this vocabulary, the phase between inflations in
any respiratory cycle is the expiratory phase of that cycle. For ventilators where there may be concurrent respiratory
cycles it may not be clear as to which of the cycles is being referenced unless it is specifically associated with the
primary-inflation cycle each time it is used. In order to avoid that possible ambiguity with concision, the alternative
name, BAP phase, has been introduced for use on ventilators that facilitate additional breaths in the phase between
primary inflations.
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Note 3 to entry: See also BAP phase 4.3.3, additional breath (4.1.8), respiratory cycle (4.3.18), primary-inflation cycle
(4.3.19), primary-inflation (4.2.12) and Annex C.
[SOURCE: ISO 4135: 2001, 3.4.5, modified]
4.3.3
BAP phase
alternative name for the phase between primary-inflations, in particular on ventilators where
unassisted or supported spontaneous inspirations are facilitated during that phase in at least
one of the selectable modes on that ventilator
Note 1 to entry: Although this is also the expiratory phase of the primary-inflation cycle, unless that association is
made clear each time it is used, if there are additional respiratory cycles there is ambiguity as to which expiratory
phase is being referred to. The use of the term BAP phase is therefore much more concise. This is particularly
relevant with SIMV and bi-level ventilation modes that may use extended BAP phases of up to 30 seconds or more.
Note 2 to entry: This phase is designated as the BAP phase because, although the conceptual baseline at this set level
is continuous, it is only required as a continuous reference following termination and up till the point of initiation of a
primary-inflation phase. If additional breaths concurrent with a primary-inflation are possible, these will be
superimposed on a higher baseline, at the inspiratory-pressure level, which may be alternatively labelled as BAP-high.
Note 3 to entry: The reason for labelling all expiratory phases as BAP phases on ventilators with at least one mode
where that is applicable, is to ensure consistent labelling on any one device. The term may also be applied to the
expiratory phases of other classes of inflation if the resulting consistency is assessed as improving usability.
Note 4 to entry: See also unassisted breath (4.1.12), supported breath (4.1.13), spontaneous breath (4.1.3), additional
breath (4.1.8), primary-inflation cycle (4.3.20), respiratory cycle (4.3.18) and BAP-high (4.9.10) bi-level ventilation
(4.9.5) and Annex C.
4.3.4
BAP time
tB
duration of a BAP phase
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: The symbol, tB, in various fonts, is typically used to designate the BAP time setting, particularly
where space is limited such as on operator interfaces.
Note 3 to entry: As a set quantity the BAP time is either the intended actual duration, the intended average duration
or the assured maximum duration of the BAP phase of the primary-inflation, depending on the mode selected.
Note 4 to entry: As a measured quantity the BAP time is that of the longest respiratory cycle.
Note 5 to entry: On many ventilators the BAP time is typically set indirectly, for example, by means of a set rate and
inspiratory time.
Note 6 to entry: In modes labelled as bi-level ventilation, the BAP time may be alternatively identified by the term
time-low. Further details are given in 4.9.
Note 7 to entry: For information on the use of symbols in the labelling of ventilation equipment see Clause 2 –
Conformance and Annex G.5.
Note 8 to entry: See also primary-inflation (4.2.12), respiratory cycle (4.3.18), Annex C and Figure F.2 (Annex F).
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4.3.5
expiratory-flow time
duration of the interval from the start of expiratory flow to its cessation
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20
Note 2 to entry: In practice, it may be difficult to measure the actual flow time precisely because of its slow decline
but this term is unlikely to be used in the description of situations where precision is critical.
Note 3 to entry: The expiratory flow time and the expiratory time can be equal.
Note 4 to entry: See also Figures C.2 and C.10 (Annex C).
4.3.6
expiratory pause
portion of the expiratory phase from the end of expiratory flow to the start of inspiratory flow
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: See also expiratory hold (4.3.8).
[SOURCE: ISO 4135: 2001, 3.4.3, modified]
4.3.7
expiratory-pause time
duration of an expiratory pause
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
[SOURCE: ISO 4135: 2001, 3.4.4]
4.3.8
expiratory hold
execution of a ventilator function intended to temporarily maintain a constant lung volume
during a set extension of the expiratory phase
Note 1 to entry: The maintenance of a constant lung volume is typically used to either facilitate the measurement of
dynamic PEEP or to temporarily immobilise the torso (e.g., for diagnostic imaging).
Note 2 to entry: This function can be achieved by temporarily occluding the airway, by maintaining pressure at the
patient-connection port or by other means. For the measurement of dynamic PEEP it is necessary to use an expiratory
hold achieved with an occluded airway.
Note 3 to entry: Both the initiation and the duration of the function are settings.
Note 4 to entry: See also expiratory-hold time (4.3.9) and expiratory pause (4.3.6).
4.3.9
expiratory-hold time
duration of an expiratory hold
Note 1 to entry: The hold time may be set by selecting a time or determined by the duration of a manual input.
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4.3.10
inspiratory time
tI
duration of an inflation or inspiratory phase
Note 1 to entry: In addition to its direct reference, this term or its symbol, tI , may be used, in context or by
qualification, to designate this concept as a set quantity (4.13.19) or a measured quantity (4.13.20)
Note 2 to entry: The symbol, tI , in various fonts, is typically used to designate the inspiratory time setting, particularly
where space is limited such as on operator interfaces.
Note 3 to entry: For information on the use of symbols in the labelling of ventilation equipment see Clause 2 –
Conformance and G.5.
[SOURCE: ISO 4135: 2001, 3.4.13, modified]
4.3.11
inspiratory phase
interval from the start of inspiratory flow to the start of expiratory flow during an unassisted
breath
Note 1 to entry: If additional spontaneous breaths are possible their inspiratory phase may occur within the inflation
phase of a primary-inflation cycle.
Note 1 to entry: See also Figure C.12 (Annex C)
[SOURCE: ISO 4135:2001, 3.4.12, modified]
4.3.12
inspiratory-flow time
duration of the interval from the start of inspiratory flow to its cessation
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: This term becomes relevant as a separate concept with inflations where there is an inspiratory pause.
Where there is no inspiratory pause it has the same value as the inspiratory time.
Note 3 to entry: See also Figure C.12 (Annex C)
4.3.13
inspiratory pause
interval from the end of inspiratory flow to the start of expiratory flow
Note 1 to entry: There is no inspiratory pause when the inspiratory flow ends with the transition to expiratory flow.
Note 2 to entry: See also Figure C.2c (Annex C)
[SOURCE: ISO 4135: 2001, 3.4.10]
4.3.14
inspiratory-pause time
duration of an inspiratory pause
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
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Note 2 to entry: See also Figure C.2c (Annex C)
[SOURCE: ISO 4135: 2001, 3.4.11]
4.3.15
inspiratory hold
ventilator function intended to temporarily maintain a constant lung volume, or to maintain a
constant airway pressure, during a set extension of the end of an inspiratory or inflation phase
Note 1 to entry: This function can be achieved by temporarily occluding the airway, by maintaining pressure at the
patient-connection port or by other means.
Note 2 to entry: The maintenance of a constant lung volume is typically used to facilitate a separate clinical
procedure, e.g., the measurement of lung parameters or a diagnostic imaging examination.
Note 3 to entry: Both the initiation and the duration of the function are determined by the operator.
Note 4 to entry: See also inspiratory pause (4.3.13)).
4.3.16
inspiratory-hold time
duration for an inspiratory hold
Note 1 to entry: The hold time may be determined by an elapsed time setting or by the duration of a manual input.
4.3.17
inflation phase
interval from the start of the inspiratory flow at the initiation of an inflation to the start of the
expiratory flow resulting from its termination
Note 1 to entry: See also concurrent breath (4.1.9) and Figures C.2 – C.12 (Annex C).
4.3.18
respiratory cycle
cycle
complete sequence of respiratory events that leads to an increase, followed by a corresponding
decrease, of gas volume in the lung regardless of how it is generated
Note 1 to entry: The term respiratory cycle has become a generic term for a complete breath cycle, whether it is
assisted or unassisted, spontaneous or assured. Its use addresses a problem that arises because in common usage the
word ‘breath’ is often used to refer to either a single phase alone or a complete breath cycle. It is also helpful in the
consideration of the occurrence of additional breaths within a primary-inflation cycle. The term ‘respiratory cycle’ is
more concise than having to qualify ‘breath’ in a way that removes all ambiguity.
Note 2 to entry: This generic term is not intended for use as a universal substitute for any more specifically
applicable terms defined in this vocabulary. Its use should be restricted to the improvement of concision and
readability in instances such as those cited in note 1 to entry.
Note 3 to entry: For a primary-inflation, the respiratory cycle starts with its initiation and ends with the initiation of
the next primary-inflation. See also primary-inflation cycle (4.3.20).
Note 4 to entry: Additional, separate respiratory cycles can be initiated within a primary-inflation cycle; see also
additional breath (4.1.8).
Note 5 to entry: See also breath (4.1.1).
EXAMPLE 1:
An unassisted, spontaneous inspiratory phase followed by an expiratory phase.
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EXAMPLE 2:
The sequence of respiratory events following the initiation of a primary-inflation, through to the
subsequent initiation of the following primary-inflation.
EXAMPLE 3:
A pressure-support (PS) inflation phase followed by its expiratory phase.
4.3.19
respiratory cycle time
cycle time
duration of a respiratory cycle
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: The set respiratory cycle time of a primary-inflation (in minutes) is typically determined indirectly by
taking the reciprocal of the set rate.
4.3.20
primary-inflation cycle
respiratory cycle of a primary-inflation
Note 1 to entry: In modes such as SIMV, supported or unassisted additional breaths may be taken during the
expiratory phase of the primary-inflation cycle; also during the inspiratory phase if an ACAP adjunct is provided.
Note 2 to entry: See also Annex C
4.3.21 phase time ratio
I:E ratio
ratio of the inspiratory time to the expiratory time in a respiratory cycle
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: By mathematical convention, a colon or a slash is used to designate a ratio between two values so the
addition of the word ‘ratio’ is not strictly necessary. However, its addition is widely practiced and is considered to
add to the readability of descriptive texts and lists.
4.3.22 inspiratory time fraction
tI:tTOT ratio
ratio of the inspiratory time to the respiratory cycle time
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: This ratio may also be expressed as a fraction or a percentage.
4.4 Rate terminology
4.4.1 Principle rate concepts - for general use in preference to those listed under 4.4.2,
secondary rate concepts
4.4.1.1
rate
Rate
DEPRECATED: f
number of primary-inflations that are assured to occur in a specified period of time, expressed
as inflations per minute
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Note 1 to entry: Following established custom and practice, when used in context and without further qualification,
this abbreviation of ‘inflation rate’, and its symbol, Rate, has been adopted in this vocabulary for the designation of
this concept as a set quantity (4.13.19).
Note 2 to entry: The operator may select the rate directly or indirectly by means of an algorithm (See example 4).
Note 3 to entry: This setting assures the operator that, in the absence of patient-trigger events, primary-inflations will
be delivered at intervals not exceeding, on average, 60/(set rate) seconds. The actual interval between any two
successive inflations may differ from the set interval by up to the duration of the synchronisation window with modepatterns that maintain delivery of primary-inflations at the set rate (e.g., Synchronised intermittent mandatory
ventilation (SIMV)).
EXAMPLE 1:
With an Assist/control ventilation (A/CV) mode the set rate is the assured minimum ventilatorinitiated inflation rate; with any patient-initiated (Assist) inflations the total rate becomes higher. See Figure C.14b
(Annex C).
EXAMPLE 2:
With an Intermittent Mandatory Ventilation (IMV) mode the set rate is the rate at which the
primary-inflations are initiated. See Figure C.14c (Annex C).
EXAMPLE 3:
With a Synchronized Intermittent Mandatory Ventilation (SIMV) mode the set rate is the average
rate at which the primary inflations are initiated. See Figure C.14d (Annex C).
EXAMPLE 4:
With one means of achieving a Minimum minute volume (MMV) mode the mode-control algorithm
reduces the effective ventilator set rate as necessary with the objective of maintaining the patient’s minute volume at
the set level.
4.4.1.2 total respiratory rate
total rate
RR
number of respiratory cycles initiated in a specified period of time, expressed as respiratory
cycles per minute
Note 1 to entry: In addition to its direct reference, this term, and its symbol, RR is only used, in context or by
qualification, to designate this concept as a measured quantity (4.13.20).
Note 2 to entry: The total respiratory rate is the spontaneous respiratory rate plus the ventilator-initiated inflation
rate.
Note 3 to entry: Separate respiratory cycles initiated within primary inflation cycles are counted as part of the total
Note 4 to entry: See also additional breath (4.1.8), respiratory cycle (4.3.18) and primary-inflation cycle (4.3.20).
4.4.1.3
spontaneous respiratory rate
spontaneous rate
RRspont
ISO spontaneous-breath rate
total number of spontaneous breaths initiated in a specified period of time, expressed as breaths
per minute
Note 1 to entry: In addition to its direct reference, this term, and its symbol, RRspont , is only used, in context or by
qualification, to designate this concept as a measured quantity (4.13.20).
Note 2 to entry: The spontaneous respiratory rate is the difference between the total respiratory rate and the
ventilator-initiated inflation rate.
Note 3 to entry: The detection of the beginning and end of a breath is dependent on the sensitivity of the ventilator
sensors and the thresholds of the detection algorithms. For further information concerning the reliability of using the
patient-triggered rate as a measure of the spontaneous-breath rate see patient-trigger event (4.10.6).
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Note 4 to entry: Because there is no dependent action required, as is the case with assisted breaths, the counting of an
unassisted spontaneous breath may be delayed until its inspiratory phase has terminated, thereby allowing a higher
level of discrimination between actual breaths and spurious events.
Note 5 to entry: Many legacy ventilators display and log the spontaneous breath rate as the unassisted breath rate
plus the support breath rate. While true for CSV modes this practice does not include the spontaneous breaths that
may initiate primary inflations, for example, in A/CV and SIMV modes, making the spontaneous rate measurement
mode dependent. This practice is considered to be misleading and is not supported in this vocabulary. The admitted
term ISO spontaneous-breath rate has been included for use where it is necessary to highlight this distinction.
4.4.1.4
ventilator-initiated inflation rate
ventilator-initiated rate
RRv ent
number of inflations initiated by a timed signal within the ventilator in a specified period of time,
expressed as inflations per minute
Note 1 to entry: In addition to its direct reference, this term, and its symbol, RRv ent , is only used, in context or by
qualification, to designate this concept as a measured quantity (4.13.20) .
Note 2 to entry: Ventilator-initiated inflations generate controlled breaths. See also controlled breaths (4.1.16).
Note 3 to entry: In this vocabulary an inflation initiated by a patient-trigger event is classed as a patient-triggered
inflation; not as a ventilator-initiated inflation. See also primary-inflation (4.2.12).
4.4.2 Secondary rate concepts – rate terms for use if required for specific purposes
4.4.2.1
primary-inflation rate
number of primary-inflations initiated in a specified period of time, expressed as inflations per
minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: In Group 1a) and Group 2 modes the primary inflation rate is assured to be equal to the set inflation
rate; in Group 1a) modes the primary inflation rate is assured to be at least equal to the set inflation rate but will be
higher if there are additional breaths.
4.4.2.2
support-inflation rate
total number of support-inflations initiated in a specified period of time, expressed as inflations
per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20) .
Note 2 to entry: See also support-inflation (4.2.15) and supported breath (4.1.13).
4.4.2.3
assisted breath rate
number of assisted breaths initiated in a specified period of time, expressed as breaths per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to
designate this concept as a measured quantity (4.13.20).
Note 2 to entry: See also assisted breath (4.1.14).
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4.4.2.4
synchronised breath rate
number of synchronised breaths initiated in a specified period of time, expressed as units of
breaths per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20) .
Note 2 to entry: See also synchronised breath (4.1.15).
4.4.2.5
controlled breath rate
number of ventilator-initiated inflations initiated in a specified period of time, expressed as
breaths per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: See also controlled breath (4.1.16).
4.4.2.6
unassisted breath rate
number of spontaneous breaths with no assistance from an inflation, initiated in a specified
period of time, expressed in units of breaths per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20) .
Note 2 to entry: See also unassisted breath (4.1.12).
4.4.2.7
additional breath rate
number of additional breaths in a specified period of time, expressed as breaths per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: The additional-breath rate is the difference between the total respiratory rate and the set
rate.
Note 3 to entry: See also additional breath (4.1.8).
4.4.2.8
patient-triggered primary-inflation rate
number of primary inflations initiated by a patient-trigger event in a specified period of time,
expressed as inflations per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity ((4.13.20)).
Note 2 to entry: Patient-triggered primary-inflations generate assisted and synchronised breaths. See also assisted
breath (4.1.14) and synchronised breath (4.1.15).
Note3 to entry: See also primary-inflation (4.2.12).
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4.4.2.9
concurrent supported-breath rate
number of support-inflations initiated during primary-inflation phases in a specified period of
time, expressed as inflations per minute
Note 1 to entry:
In addition to its direct reference, this term is only used, in context or by qualification, to
designate this concept as a measured quantity (4.13.20).
Note 2 to entry: See also supported breath (4.1.13) and concurrent breath (4.1.9).
4.4.2.10
concurrent unassisted-breath rate
number of unassisted spontaneous breaths initiated during primary-inflation phases in a
specified period of time, expressed as breaths per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to
designate this concept as a measured quantity (4.13.20).
Note 2 to entry: See also unassisted breath (4.1.12) and concurrent breath (4.1.8).
4.4.2.11
non-concurrent unassisted-breath rate
number of unassisted-breaths initiated between primary-inflation phases in a specified period of
time, expressed as breaths per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20) .
Note 2 to entry: See also unassisted breath (4.1.12) and concurrent breath (4.1.8).
4.4.2.12
patient-triggered inflation rate
number of inflations initiated by a patient-trigger event in a specified period of time, expressed
as inflations per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
4.4.2.13
total inflation rate
total number of inflations initiated in a specified period of time, however initiated, expressed as
inflations per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: The total inflation rate is equal to the primary-inflation rate (4.4.2.1) plus the support-inflation rate
(4.4.2.2).
4.4.2.14
additional primary-inflation rate
number of additional primary-inflations initiated in a specified period of time, expressed as
inflations per minute
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
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Note 2 to entry: The additional primary-inflation rate is the primary-inflation rate minus the set inflation rate.
Note 3 to entry: See also additional breath (4.1.8) and additional primary-inflation (4.2.13). Pressure terminology
4.5 Pressure Terminology
4.5.1
airway pressure
PAW
DEPRECATED AS SYNONYMS: See note 6 to entry
DEPRECATED AS SYNONYMS: See note to deprecated terms
pressure at the patient-connection port, relative to ambient pressure unless otherwise specified
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20)
Note 2 to entry: The site(s) of actual measurement(s) may be anywhere in the ventilator breathing system providing
the indicated value is referenced to that at the patient-connection port.
Note 3 to entry: This is the generic term for this fundamental concept. Post-coordinated terms (e.g., peak inspiratory
pressure and baseline airway pressure) are used in particular contexts.
Note 4 to entry: Although providing no explicit indication as to where along the patient’s airway this pressure is
measured, this term, along with its symbol, has become almost universally adopted as referencing the pressure at the
point at which an artificial-ventilation equipment is connected to the patient's airway or to an airway device. This is
the final site where a common and replicable pressure can be continuously monitored before breathing gas enters the
patient.
Note 5 to deprecated terms: The following terms are deprecated for use as synonyms for airway pressure: patient
pressure; proximal pressure; mouth pressure; pressure at the Y-piece; respiratory pressure; working pressure;
inflation pressure; delivered pressure; applied pressure; ventilator pressure. Some of these terms may be valid
synonyms but, as reiterated in 4.0, one of the objectives of a terminology standard is to nominate just one preferred
term to represent a given concept.
4.5.2
inspiratory pressure
DEPRECATED: See note 5 to entry
airway pressure during an inspiratory or inflation phase
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity ((4.13.20)).
Note 2 to entry: As a setting, the value of this quantity is the intended constant pressure level to be attained following
a set rise time. Inflation-types that are pressure-regulated to a constant level include pressure-control and pressuresupport.
Note 2 to entry: As a measurement, this is the general term for the pressure at any point in time during an inspiratory
or inflation phase. It will typically be qualified to indicate the point in the phase to which the observation applies,
examples being, peak inspiratory pressure, plateau pressure and end-inspiratory pressure. It may also be displayed as
a waveform. See alsoG.5 (Annex G).
Note 3 to entry: The inspiratory pressure is always relative to ambient, that is, independent of the baseline airwaypressure unless indicated otherwise by the differential symbol, Δ, as a prefix.
Note 4 to entry: This term is applicable to both primary-inflations and support-inflations.
Note 5 to entry: The following terms are deprecated as synonyms for the term inspiratory pressure: delivered
pressure; support pressure; plateau pressure; pressure limit; respiratory pressure; working pressure; target pressure;
end-inspiratory pressure; insufflation pressure.
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Note 5 to entry: See also Δ inspiratory pressure (4.5.7)
4.5.3
peak inspiratory pressure
maximum inspiratory pressure
Note 1 to entry: Peak inspiratory pressure is always referenced to the ambient pressure.
Note 2 to entry: Unless otherwise indicated, peak pressure is always indicated for the previous primary-inflation
cycle.
Note 3 to entry: This International Standard deprecates the use of this term in reference to a setting.
Note 4 to entry: See also Figure C.2 (Annex C).
4.5.4
plateau inspiratory pressure
plateau pressure
airway pressure after stabilisation to a constant level during an inspiratory-hold with a volumecontrol inflation-type or during the intended constant-pressure portion of a pressure-regulated
inflation
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20). The corresponding set value is that of the inspiratory pressure.
Note 2 to entry: Although the plateau inspiratory pressure during a pressure-regulated inflation is intended to be
constant, there will be inevitable minor variations whenever the inspiratory flow is varying, particularly when it
changes direction during concurrent breathing. These possible variations should be taken into consideration when
measurements of the plateau pressure are required to be made.
Note 3 to entry: Unless the airway pressure reaches its intended constant level during an inflation there will be no
plateau pressure and, therefore, no valid measurement can be made.
Note 4 to entry: When given sufficient time at its stabilised level, the plateau pressure will typically be an indication
of the end-inspiratory average alveolar pressure.
Note 5 to entry: Although it will often have the same value this term is not a synonym for end-inspiratory pressure.
Note 6 to entry: See also inspiratory pressure (4.5.2), inspiratory hold (4.3.15), inspiratory pause (4.3.13), endinspiratory pressure (4.5.8) and Figure C.2d (Annex C).
4.5.5
inspiratory-pressure relief
means of limiting the maximum inspiratory pressure to the set level by discharging excess
inspiratory flow to the atmosphere
Note 1 to entry: The intended maximum inspiratory pressure is determined by the set pressure limit (4.12.1.1).
Note 2 to entry: This form of pressure limitation will often result in the delivered volume falling below that set as the
set relief-pressure is approached. Awareness of this characteristic is important for operators of the simple gaspowered ventilators that typically use such pressure-limitation means and in which there is no independent
measurement of the actual tidal volume.
4.5.6
Δ
delta
difference between two quantities
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Note 1 to entry: This symbol is used in this vocabulary as a prefix to denote that the qualified parameter is
referenced to another parameter. In particular, it is used in this vocabulary to qualify an inspiratory or expiratory
pressure to denote when it is referenced to a baseline airway pressure level instead of to the default, ambient pressure
level.
Note 2 to entry: In verbal communication, Δ, as used in this vocabulary, is expressed as either ‘delta’ or ‘differential’.
Note 3 to entry: See also Δ inspiratory pressure (4.5.7), and (Annex C).
4.5.7
Δ inspiratory pressure
Δ pressure
Δp
differential airway pressure relative to baseline airway pressure during an inflation phase
Note 1 to entry: In addition to its direct reference, this term or its symbol, Δp, may be used, in context or by
qualification, to designate this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: There is no agreed convention as to whether an inspiratory pressure must always be expressed as an
absolute quantity relative to ambient pressure or an absolute quantity for one group of inflation-types and relative for
another. This has unacceptable patient-safety implications that must be addressed in a vocabulary of lung ventilation.
The letter Δ is sometimes used as a symbol to make this distinction and that convention has been adopted as a
requirement in this vocabulary. This means that respiratory pressures are always to be considered to be relative to
ambient pressure unless prefixed by Δ. In this vocabulary, Δ, when associated with a respiratory pressure, indicates
that that pressure is relative to the set BAP level. In modes where there is a second, higher, baseline airway-pressure,
then the indicating symbol for a pressure relative to that higher pressure level becomes Δh.
Note 3 to entry: The sum of the set baseline airway pressure level and the Δ inspiratory pressure equals the inspiratory
pressure. This applies to both settings and measurements of this parameter.
Note 4 to entry: See also Δ (4.5.6) and Figures C.2a and b (Annex C).
4.5.8
end-inspiratory pressure
airway pressure at the end of an inflation phase
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20) .
Note 2 to entry: This pressure is displayed or recorded as the last measured value of the inspiratory pressure before
the initiation of inflation termination.
Note 3 to entry: This pressure may be coincident with the peak inspiratory pressure or the end of an inspiratory
pressure plateau and hence have the same value.
Note 4 to entry: The end-inspiratory pressure is always recorded and displayed as an airway pressure, that is, as
relative to ambient pressure, unless indicated otherwise by the differential symbol, Δ, as a prefix.
Note 5 to entry: See also Δ inspiratory pressure (4.5.7) and Figures Figures C.2a and b (Annex2).
4.5.9
expiratory pressure
respiratory pressure during an expiratory phase
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
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Note 2 to entry: In this vocabulary, an expiratory pressure is taken to be an airway pressure unless used in a
compound (post-coordinated) term, in which case the new name or its definition may indicate an alternative
measurement reference site or reference pressure level.
Note 3 to entry: As a measurement, this is the general term for the pressure at any point in time during an expiratory
phase. It will typically be qualified to indicate the point in the phase or the site to which the observation applies. It
may also be displayed as a waveform. See also G.5 (Annex G).
Note 4 to entry: The expiratory pressure is always relative to ambient pressure, that is, independent of the baseline
airway-pressure unless indicated otherwise by the differential symbol, Δ, as a prefix.
Note 5 to entry: See also Figures C.2a (Annex 2) and Figures F.1a to c (Annex F).
4.5.10
expiratory pressure-relief
function that relieves expiratory pressure by allowing expiratory flow to pass through to the
exhaust port with minimal resistance when above the BAP level, but which prevents expiratory
flow below that level
Note 1 to entry: Separate valves providing this function (often referred to as PEEP valves) are, typically, standard
accessories with bag-valve-mask ventilators.
Note 2 to entry: With this function acting alone during a BAP phase, an unassisted inspiration may incur additional
work of breathing, and if there is a leak in the ventilator breathing system or at the connection to the patient, the
airway pressure may fall towards the ambient pressure, which will result in a loss of the intended PEEP. Such
consequences may be mitigated by the provision of a bias flow or prevented by the provision of demand flow or an
ACAP adjunct, active at the BAP level.
4.6 Flow terminology
4.6.1
inspiratory flow
Flow
DEPRECATED: peak flow
flow of gas delivered through the patient-connection port to the patient during an inspiratory or
inflation phase
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: The symbol, Flow, in various fonts, is typically used to designate the inspiratory flow setting,
particularly where space is limited such as on operator interfaces.
Note 3 to entry: Where an inflation serves to augment a patient’s spontaneous breath then, conceptually, inspiratory
flow can be seen as being comprised of a component of demand flow resulting from the patient’s inspiratory efforts
and a component of flow due solely to the raised pressure of the inflation. However, currently, most ventilators
cannot separate these two components and so the unattributed inclusive term, inspiratory flow, has been adopted in
this vocabulary for general use. The term demand flow is included in this vocabulary for use when there is a necessity
to make reference to the flow resulting solely from the patient’s inspiratory efforts as a separate concept.
Note 4 to entry: The set inspiratory flow will be a good representation of the actual flow that generates the tidal
volume when it all enters the patient’s respiratory tract. This is frequently not the case due to, for example, leakage at
the patient/airway device interface (particularly in neonatal and non-invasive ventilation) and from the operatordetachable part of the ventilator breathing system. With these conditions, a more reliable indication of the actual flow
that will enter the respiratory tract will be provided if the inspiratory flow is leak-compensated relative to that set.
Note 5 to entry: For further information on the semantics of measured quantities and the term ‘Flow’ in this
vocabulary see sub-clause 4.0, and G.4 and G.5 (Annex G).
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Note 6 to entry: See also Figure C.2, inspiratory effort (4.1.7), demand flow (4.6.12), tidal volume (4.7.1), delivered
volume (4.7.2) inspiratory volume (4.7.3) and Annex C.
4.6.2
peak inspiratory flow
highest flow of gas delivered to the patient through the patient-connection port during an
inspiratory or inflation phase
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a measured value but in this vocabulary is not used to designate this concept as a set value (4.13.19).
Note 2 to entry: See also Figures C.2a and b (Annex C).
4.6.3
inspiratory-termination flow
inspiratory flow threshold at which the termination of a flow-terminated inflation-type is
initiated
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 2 to entry: This threshold flow is typically expressed as either a set inspiratory-termination flow rate or a set
percentage of the peak inspiratory flow rate.
Note 3 to entry: See also inspiratory flow (4.6.1), flow-termination (4.10.15), termination (4.10.14) peak inspiratory
flow (4.6.2) and Figure C.2b (Annex C).
4.6.4
end-inspiratory flow
flow at the point when inflation termination is initiated
EXAMPLE 1: See Figure C2.
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: This flow is that measured before the inspiratory-flow waveform trajectory transitions towards zero
in response to a termination signal; the inflation phase itself does not terminate until the airway flow passes through
zero.
Note 3 to entry: This flow is that measured before the inspiratory-flow waveform trajectory transitions towards zero
in response to a termination signal; the inflation phase itself does not terminate until the airway flow rate passes
through zero.
Note 4 to entry: See also termination (4.10.14), inspiratory flow (4.6.1) and inflation phase (4.3.17).
4.6.5
expiratory flow
flow from the patient through the patient connection port during an expiratory phase
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20) .
Note 2 to entry: See also Figures C.2a to e (Annex C).
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4.6.6
expiratory-termination flow
expiratory flow threshold at which the termination of a flow-terminated expiratory phase is
initiated
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 2 to entry: A flow-termination means of this type is sometimes used, for example, to minimise the time that the
expiratory pressure is at the BAP level in an APRV (airway pressure release ventilation) mode.
Note 3 to entry: This threshold flow is typically expressed as either a set expiratory-termination flow rate or a set
percentage of the peak expiratory-flow rate.
4.6.7
end-expiratory flow
expiratory flow at the point when an inflation is initiated
EXAMPLE 1: See Figure C2.
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: This flow is that measured before the expiratory-flow waveform trajectory transitions towards zero
in response to an inflation initiation signal; the expiratory phase itself does not terminate until the airway flow rate
passes through zero.
Note 3 to entry: As a measured value, end-expiratory flow is an indication of dynamic PEEP that has not fully
dissipated and, therefore, that the pressure in the lungs may be higher than the intended minimum.
4.6.8
bias flow
flow that passes through the ventilator breathing system to the exhaust port but is not intended
to contribute to the work of lung ventilation
Note 1 to entry: In addition to its direct reference, this term may be used to designate this concept, in context or by
qualification, as a set value (4.13.20).
Note 2 to entry: The term bias flow is used to refer to an intended low-level flow that passes right through the
ventilator breathing system with the purpose of improving the responsiveness and accuracy of the ventilator’s control
and detection systems, and of minimising the rebreathing of expired gas.
4.6.9
continuous flow
gas flowing continuously through the ventilator breathing system, with a proportion
intermittently passing to the patient’s lung whenever the airway pressure is raised by the
ventilator or an operator action, or flow is demanded by a patient’s inspiratory effort
Note 1 to entry: In addition to its direct reference, this term may be used to designate this concept, in context or by
qualification, as a set value (4.13.20).
Note 2 to entry: A constant, continuous flow in the inspiratory limb of the ventilator breathing system is commonly
used in the artificial ventilation of neonatal and paediatric patients.
Note 3 to entry: The airway pressure may be intermittently raised to a set inspiratory pressure, for example, by timed,
pressure-limited occlusions of the expiratory valve.
Note 4 to entry: See also ventilator breathing system (4.13.18) and airway pressure (4.5.1).
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4.6.10
descending ramp flow pattern
DEPRECATED: decelerating-flow pattern
linearly decreasing flow waveform
Note 1 to entry: This term is applicable to the description of a selectable inspiratory flow-waveform pattern.
Note 2 to entry: In most applications the precise linearity of such a waveform is not critical and so this term is
appropriate to describe a range of waveforms that includes those that may have minor nonlinearities, providing these
are essentially inconsequential.
4.6.11
concave decreasing-flow pattern
DEPRECATED: decelerating-flow pattern
declining flow waveform, the gradient of which decreases with time
Inspiratory
flow
EXAMPLE
Concave
declining-flow
pattern
Time
Note 1 to entry: This term is applicable to the flow-waveform pattern resulting from a pressure-regulated inflation
or of a typical expiratory-flow pattern. Although not a common feature, this term is alternatively applicable to the
description of a selectable inspiratory flow waveform pattern of this form; a selectable pattern appropriate to
simulate a pressure-control (PC) inflation waveform.
Note 2 to entry: A pattern of this form is typical of the airway flow waveform observed in situations where the
applied pressure difference across the airway resistance is changing due to the charging or discharging of the
compliant lung. Such a pattern is sometimes referred to as an exponential waveform but there is generally too much
nonlinearity in the system for that to be even approximately the case.
Note 1 to deprecated term: Although a commonly used term, it is incorrect in that the rate of flow of a gas, which is
essentially a measure of its velocity, cannot be ‘decelerated’; it is only a volume of the gas that can be accelerated and
decelerated - not the velocity of that gas.
4.6.12
demand flow
flow generated by a ventilator solely to meet the flow demand of the patient while acting to
maintain the airway pressure at its intended value
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: This term denotes the specific subset of inspiratory flow that is solely due to the patient’s
spontaneous inspiratory efforts when connected to a ventilator. In certain contexts, a term for this distinction is
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helpful but where this is unimportant the concept may be assumed to be included within the scope of the generalised
term, inspiratory flow.
Note 3 to entry: During unassisted breathing, the intention is that the demand flow will meet the patient’s flow
demands in a manner that provisions for unrestricted breathing at the applicable BAP level. This may involve the use
of a function that temporarily elevates the airway pressure slightly, with the intention of compensating for the
possible pressure drop across an airway device or for the inevitable pressure drop that is necessary for the pressureregulation function to provide flow in proportion to the demand. Alternatively, it may be provided by the provision of
ACAP, an adjunct that facilitates unrestricted breathing by the generation of demand flow in proportion to the patient’s
demand, with no dependency on a patient-trigger event.
Note 4 to entry: Where spontaneous breaths are given assistance by an inflation, the flow through the patientconnection port during the inflation phase will be the sum of that due to the raised pressure of the inflation and that
due to the flow demand resulting from the patient’s inspiratory effort. Because there is currently no reliable way to
separate these two components, in this vocabulary the total of the flow generated is denoted by the inclusive, general
term, inspiratory flow.
Note 5 to entry: See also inspiratory flow (4.6.1).
4.6.13
airway leak
loss of respiratory gas from its pathway between the patient connection port connector interface
and the lungs
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20).
Note 2 to entry: Loss of gas at the patient connection port connector interface is part of an airway leak.
Note 3 to entry: An airway leak may be expressed as a flow rate or a volume and during an inspiratory or expiratory
phase, or during a period of time.
4.6.14
ventilator breathing system leak
VBS leak
loss of gas from the ventilator breathing system
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a measured value (4.13.20).
Note 2 to entry: With this definition, this leak does not include any loss of gas at or beyond the interface in the
patient connection port connector.
Note 3 to entry: The term may be applied to the total ventilator breathing system leakage or, more specifically, to any
leakage that influences the displayed values of delivered volume or expired minute volume. Any such implications
should be disclosed by the manufacturer.
Note 4 to entry: International Standards generally require that ventilator breathing system leakage is expressed as a
rate of flow at BTPS (body temperature and pressure, saturated).
Note 5 to entry: See also ventilator breathing system (4.13.18), patient connection port (4.14.8), delivered volume
(4.7.2) and expired minute volume (4.7.9).
4.7 Volume terminology
4.7.1
tidal volume
VT
volume of gas that enters and leaves the lung during a breath
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Note 1 to entry: In addition to its direct reference, this term or its symbol, VT , may be used, in context or by
qualification, to designate this concept as a set quantity (4.13.19). As a measured quantity it is only used to designate
this concept when expressed as a compensated value.
Note 2 to entry: In practice, the volumes that enter and leave the lung are typically measured as a delivered volume
and an expired tidal volume because, even without leakage, these two quantities will only be nominally equal due to
physical and/or compositional changes of the gas and normal physiological variation in end-expiratory lung volume.
Leakages between the point at which the flow towards the patient is measured and the lung, such as occur at the
connection to the patient’s airway, will increase these discrepancies.
Note 3 to entry: Without leakage compensation the measured expired tidal volume will be a better representation of
the actual tidal volume because leakage is less during expiration than during delivery due to the lower mean airway
pressure. Where leakage compensation is in operation the actual delivered and inspiratory volumes are typically
greater than the set tidal volume but the compensated tidal volume provides a better representation of the actual tidal
volume.
Note 4 to entry: With ventilation equipment where no inspiratory or expired volume measurements are available the
actual tidal volume may deviate from the set value as a result of the factors referred to in note 2 to this entry.
4.7.2
delivered volume
V DEL
net volume of gas delivered to the operator-detachable part of the ventilator breathing system
during an inflation or inspiratory phase
Note 1 to entry: In addition to its direct reference, this term or its symbol, VDEL, may only be used, in context or by
qualification, to designate this concept as a measured quantity (4.13.20).
Note 2 to entry: The delivered volume is a good representation of the actual tidal volume when all of the delivered
volume enters the patient’s respiratory tract. This is frequently not the case due to, for example, leakage at the
patient/ventilator interface (particularly in neonatal and non-invasive ventilation). However, where the actual
delivered volume is leak compensated relative to that set the setting is considered to be a sufficiently reliable
indication of the tidal volume for it to be so labelled.
Note 3 to entry: The delivered volume is defined as a net volume because it is the actual volume delivered minus any
volume that passes through the expiratory valve as a consequence of a bias flow.
4.7.3
inspiratory volume
VI
volume of gas delivered through the patient connection port during an inflation or inspiratory
phase
Note 1 to entry: In addition to its direct reference, this term or its symbol, VI, may only be used, in context or by
qualification, to designate this concept as a measured quantity (4.13.20).
Note 2 to entry: This is the concept designated by entry 3.4.2, delivered volume, in ISO 4135:2001; a term that has
not been widely adopted to date. It is a concept relevant to measurements of volume made close to the patient
connection port, such as is typically the case with self-contained, multi-parameter patient monitors, as distinct from
the redefined delivered volume (4.7.2), which is applicable to ventilators where the inspiratory flow is determined or
measured within the body of the ventilator. The closer site of measurement means that this quantity only differs from
the actual volume entering the lung by the amount of any volume leakage occurring at the connection to the patient’s
airway.
Note3 to entry: See also delivered volume (4.7.2) and tidal volume (4.7.1).
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4.7.4
expired tidal volume
V TE
volume of gas leaving the lung through the patient connection port during an expiratory phase
Note 1 to entry: In addition to its direct reference, this term is used, in context or by qualification, to designate this
concept as a measured quantity (4.13.20).
Note 2 to entry: Where there is concurrent breathing, although the ventilator can determine the inspiratory volume of
the additional breaths their expiration may be combined with the primary expiration, which is typically displayed
with no separate attributions.
Note 3 to entry: This term would be appropriate to designate this concept, in context or by qualification, as a set
(4.13.20) target value for this quantity but this is typically not currently practiced because of other factors that would
have to be taken into account.
4.7.5
leakage tidal volume
V TLeak
volume of gas lost from the measured volume passing to the patient, before it enters the lung, in
a single respiratory cycle
Note 1 to entry: In addition to its direct reference, this term is used, in context or by qualification, to designate this
concept as a measured quantity (4.13.20).
Note 2 to entry: This leakage is typically estimated based on a comparison of the measured volume passing to the
patient with the measured expired tidal volume, and the mean inspiratory and expiratory pressures.
4.7.6
minute volume
VM
DEPRECATED: V�
volume of gas either passing to or leaving the lung during inspiratory or inflation phases, or
expiratory phases, respectively, expressed as a volume per minute
Note 1 to entry: In addition to its direct reference, this term or its symbol, VM , may be used, in context or by
qualification, to designate this concept as a set quantity (4.13.19). As a measured quantity it is only used to designate
this concept when expressed as a compensated value.
Note 2 to entry: Unless otherwise qualified, this term designates the volume either passing to or leaving the lung
during all of the respective inspiratory or inflation phases, or expiratory phases that have occurred during the period
of measurement. This term is appropriately qualified when used to denote the minute volumes resulting from
specific types of inflations or breaths (for an example see assured minute volume (4.7.11)).
Note 3 to entry: While a minute volume is expressed as a volume per minute, the actual measurement period will
typically be that of a specified number of complete respiratory cycles or of a time other than one minute, in order to
provide a more consistent average value. The term by itself suggests that its value is that of a volume but experience
has indicated that users prefer the assurance of it being expressed as an average flow rate, that is, as a Volume/min.
Note 4 to entry: In practice the volumes that enter and leave the lung per minute are typically measured as a
delivered minute volume and an expired minute volume because, even without leakage, these two quantities will only
be nominally equal due to physical and/or compositional changes of the gas and normal physiological variations in
end-expiratory lung volume. Leakages between the point at which the flow towards the patient is measured and the
lung, such as occur at the connection to the patient’s airway, will increase these discrepancies.
Note 5 to entry: Without leakage compensation the measured expired minute volume is expected to be a better
representation of the actual minute volume because leakage is less during expiration than during delivery due to the
lower mean airway pressure. Where leakage compensation is in operation the actual delivered and inspiratory
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minute volumes are typically greater than the set minute volume but the compensated minute volume provides a
better representation of the actual minute volume.
Note 6 to entry: With ventilation equipment where no inspiratory or expired volume measurements are available the
actual minute volume may deviate from the set value as a result of the factors referred to in note 2 to this entry.
Note 1 to deprecated term: The symbol V�� is sometimes used as a designation for minute volume. This is incorrect
because V� is a symbol for the differential of volume with time, that is, dV/dt, which is an instantaneous flow rate.
Minute volume is the integral of a varying flow rate and so is an average rate of flow. For correct representation this
would require the addition of ‘ ¯ ‘ above the V� , which presents typological difficulties.
4.7.7
delivered minute volume
V MDEL
net volume of gas delivered to the operator-detachable part of the ventilator breathing system
during all inflation and inspiratory phases, expressed as a volume per minute
Note 1 to entry: Delivered minute volume is also referred to as minute volume when all of the delivered volume
enters the patient’s respiratory tract. This is frequently not the case due to, for example, leakage at the
patient/ventilator interface (particularly in neonatal and non-invasive ventilation). However, where the displayed
minute volume of gas delivered is leak compensated the observation is considered to be a sufficiently reliable
indication of the minute volume for it to be so labelled.
4.7.8
inspiratory minute ventilation
V MI
volume of gas delivered through the patient connection port during all inflation and inspiratory
phases, expressed as a volume per minute
Note 1 to entry: In addition to its direct reference, this term or its symbol, VMI , may only be used, in context or by
qualification, to designate this concept as a measured quantity (4.13.20).
Note 2 to entry: This is the concept designated by entry 3.4.1, delivered ventilation, in ISO 4135; a term that has not
been widely adopted to date. It is a concept relevant to measurements of volume made close to the patient
connection port, such as is typically the case with self-contained, multi-parameter patient monitors, as distinct from
the redefined delivered minute volume (4.7.7), which is applicable to ventilators where the inspiratory flow is
determined or measured within the body of the ventilator. The closer site of measurement means that this quantity
only differs from the actual volume entering the lung per minute by the amount of any leakage minute-volume
occurring at the connection to the patient’s airway.
4.7.9
expired minute volume
V ME
DEPRECATED: expired ventilation
volume of gas leaving the lung through the patient connection port during all expiratory phases,
expressed as a volume per minute
Note 1 to entry: In addition to its direct reference, this term is used, in context or by qualification, to designate this
concept as a measured quantity (4.13.20).
4.7.10
leakage minute volume
V MLeak
gas lost from the measured volumes passing to the patient, before they enter the lung, during a
specified time or number of respiratory cycles, expressed as a volume per minute
Note 1 to entry: In addition to its direct reference, this term is used, in context or by qualification, to designate this
concept as a measured quantity (4.13.20).
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Note 2 to entry: This leakage is typically estimated based on a comparison of the known delivered flows/volume
with the measured expiratory flows/volume, and the mean inspiratory and expiratory pressures.
4.7.11
assured minute volume
V Massd
minute volume due to the ventilation set rate
EXAMPLE 1: The minute volume resulting from all the primary inflations in an SIMV mode.
EXAMPLE 2: The minute volume resulting from the set number of primary inflations in an A/CV mode.
Note 1 to entry: In addition to its direct reference, this term is used, in context or by qualification, to designate this
concept as a measured quantity (4.13.20).
Note 2 to entry: The assured minute volume is the minute volume resulting only from inflations delivered at intervals
determined by the set rate.
Note 3 to entry: In A/CV modes, where the measured primary-inflation rate is in excess of the set rate then the assured
minute volume is the set-rate/primary-rate proportion of the expired minute volume resulting from primary-inflations.
Note 4 to entry: Where leakage compensated measurements of this quantity are available these may be used in the
place of expired minute volume measurements.
4.7.12
additional minute volume
V Maddn
minute volume that is additional to the minute volume which is due to the ventilation set rate
EXAMPLE 1: The volume resulting from all unassisted and supported breaths.
EXAMPLE 2: The volume resulting from the number of inflations in excess of the set number per minute in A/CV.
Note 1 to entry: In addition to its direct reference, this term is used, in context or by qualification, to designate this
concept as a measured quantity (4.13.20).
Note 2 to entry: This is the minute volume resulting from any unassisted breaths and from inflations delivered in
addition to the set rate.
Note 3 to entry: In A/CV modes, the additional minute volume is determined as the additional breath-rate/total
primary-inflation rate proportion of the expiratory minute volume resulting from primary-inflations.
Note 4 to entry: Where leakage compensated measurements of this quantity are available these may be used in the
place of expired minute volume measurements.
4.8 Mode Terminology
4.8.1
ventilator mode
way in which a ventilator is set to operate
EXAMPLES: standby; calibration; non-invasive ventilation (NIV); breathing system check
4.8.2
ventilation mode
specified manner in which a ventilator performs its ventilatory function when connected to a
patient
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Note 1 to entry: Although a large number of ventilation modes have been described since mechanical ventilation was
introduced, all can be seen to be comprised of two key features. These are, the method employed to make the
necessary contribution to the inflation of the patient’s lungs and the patterns with which these contributions occur,
based on elapsed time or relative to any respiratory activity of the patient. Increasingly, these two features have been
separately identified, classified and taught, and this practice has been formalised in this vocabulary; the development
of which led to the adoption of the terms inflation-type and ventilation-pattern for their separate designation.
More recently, microprocessor controls have led to the construction of adult ventilators with an inbuilt facility for
patient to be able to make unrestricted expirations, as well as inspirations, at any time, including during an inflation at
a constant pressure level; a feature previously restricted to infant ventilators. This feature is separately identified in
this vocabulary as a ventilation adjunct.
Note 2 to entry: In this vocabulary, specific classification schemes have been introduced for ventilation modes,
inflation-types, ventilation-patterns and ventilation-mode adjuncts. These serve, not only to facilitate their
identification and relationships, but as a basis for systematic naming and coding. For further information see D.2 and
Table D.2 (Annex D).
Note 3 to entry: If a ventilation mode is automatically switched between that and an alternative ventilation mode,
when specified conditions are fulfilled, whether or not it generates an alarm condition, in this vocabulary this
arrangement may be given a superordinate mode name. However, its systematic coding will require both ventilationmodes to be identified by its systematic code and to be linked by arrow symbols, as used to indicate dual-control
inflation-types, for example, CSV-PS  CMV-VC. (See Ref # 17, Annex D for dual-control inflation-types).
Note 4 to entry: Some ventilation modes, or specific setting protocols for such a mode, have a particular feature(s)
that has been seen to justify an alternative name; a name that places emphasis on that feature. Such names, which
may be generic or proprietary, are classified as alternative mode names (4.8.17). Examples of such generic mode
names are bi-level ventilation and airway pressure release ventilation (APRV).
Note 5 to entry: Other implementations of ventilation modes have an additional supervisory function that is
considered to distinguish it from the underlying pattern-based mode to the extent that it too justifies a separate
identity. Such a mode is separately classified as a superordinate mode. Most of such modes have proprietary names
but an example of a generic mode of this type is MMV.
Note 6 to entry: Although alternative and superordinate mode names, whether generic or proprietary, are adopted or
permitted by this International Standard as indicators of the additional or supervisory feature, they will not provide a
complete description of the ventilation mode without reference to the systematic code of the ventilation-mode on
which it is based, along with an explanation of the alternative or additional feature.
Note 7 to entry: See also ventilation-pattern (4.8.3), inflation-type (4.2), ventilation-pattern group (Error! Reference
source not found.), alternative mode name (4.8.17), superordinate mode (4.8.18) and Table D.2.
4.8.3
ventilation-pattern
specified temporal pattern of sequenced interactions between a ventilator and the patient,
including which, when and by what selected inflation-types are initiated
Note1 to entry: The ventilation-pattern also determines which inflation-types are appropriate for use with that
pattern.
Note 2 to entry: Ventilation patterns are invariably too complex to fully classify using a few simple words. It has
therefore become customary to identify them by means of short descriptive names or by easily-remembered
associated abbreviations or acronyms although, because of a lack of standardisation, the meanings attached to these
identifiers have become very variable. However, in most cases the name has not been restricted to use with a specific
inflation-type and is therefore equally suitable to name just the ventilation-pattern. In this vocabulary, well
established, non-proprietary mode acronyms, or their names, have been adopted wherever possible as the generic
names for the principle ventilation-patterns associated with them.
Note 3 to entry: When a named ventilation-pattern is selected the features specified for that pattern in this vocabulary
will be made available for setting and described in the instruction for use. However, it is necessary to recognise that,
with some modern ventilators, particularly those with an ACAP adjunct, it is inevitable that some ventilation modes
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can be set so as to generate specific pressure or flow waveforms that could also be obtained with specific settings of a
ventilation mode with a different ventilation-pattern selected.
Note 4 to entry: The names or codes used to identify ventilation-patterns in this vocabulary are only used as
systematic names or codes for modes that conform to the definition provided in this vocabulary. A ventilation-pattern
that does not conform in this way should be described in terms of the most similar ventilation-pattern, with an
explanation of the differences. .
Note 5 to entry: A specified ventilation-pattern, together with a specified inflation-type(s) and the type of any mode
adjunct, constitutes the core, systematic name of any mode used for positive-pressure ventilation.
Note 6 to entry: A ventilation-pattern is independent of the inflation-type(s) selected and of the set values for
parameters such as the set rate, inspiratory pressure and phase-time ratio.
Note 7 to entry: See also Table D.2 (Annex D).
4.8.4
*ventilation-mode groups
groups of ventilation-modes that share fundamental features with respect to the characteristics
of their ventilation-patterns
Note 1 to entry: The characterisation of ventilation modes into groups in the labelling of ventilators is not a
requirement in conformity with this International Standard but where such a grouping is used conformance is
required.
Note 2 to entry: See also Table D.2 (Annex D).
4.8.4.1
ventilation-mode Group 1
group of ventilation modes sharing ventilation-patterns in which only one inflation-type can be
selected at a time, this being assured to be initiated at least at the set rate
4.8.4.1.1
Group 1a
subset of Group 1 ventilation modes with no provision for the selected inflation-type to be
initiated by a patient-trigger event
EXAMPLE: CMV (continuous mandatory ventilation) mode.
4.8.4.1.2
Group 1b
subset of Group 1 ventilation modes in which the selected inflation-type is assured to be
delivered at successive intervals determined by the set rate when not initiated within such an
interval by a patient-trigger event.
EXAMPLE: assist/control ventilation (A/CV) mode.
Note 1 to entry: The inflation-type selected is also referred to in this vocabulary by its generic, purpose-classification,
that is, primary-inflation (see primary-inflation (4.2.12)).
Note 2 to entry: In the absence of patient-trigger events, primary-inflations will be delivered at intervals of 1/ Rate
minutes.
Note 3 to entry: Patient-trigger events cause an increase in the total respiratory rate above the set rate.
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4.8.4.2
ventilation-mode Group 2
group of ventilation modes sharing ventilation-patterns in which an inflation-type is selected to
be initiated at the set rate. Between, these assured deliveries spontaneous breathing is possible,
which may be either unassisted or supported by a second selected inflation-type
4.8.4.2.1
Group 2a
subset of Group 2 ventilation modes with no provision for the assured-deliveries to be initiated
by a patient-trigger event
4.8.4.2.2
Group 2b
subset of Group 2 ventilation modes with the initiation of each assured delivery being
synchronised with any spontaneous breathing while maintaining the set rate
Note to Group 2b): See also rate (4.4.1.1).
Note 1 to entry: The inflation-type selected for delivery at the set rate is also referred to in this vocabulary by its
generic, purpose-classification, that is, primary-inflation (see also primary-inflation (4.2.13)).
Note 2 to entry: The second inflation-type selected is also referred to in this vocabulary by its generic, purposeclassification, that is, support-inflation (see also support-inflation (4.2.16)). This grouping does not preclude the
possibility for the second inflation-type to be set to provide zero support in order to facilitate unrestricted breathing
between primary-inflations.
Note 3 to entry: On ventilators with an ACAP adjunct any inspirations occurring concurrently with a pressure-control
primary inflation-type, may be assisted by either the selected support-inflation or by an additional, third selected
inflation-type (which is also referred to as the second support-inflation).
Group 4 to entry: Group 2 ventilation-modes include those based on the well-established ventilation-patterns used in
IMV (Intermittent Mandatory Ventilation) and SIMV (Synchronised intermittent mandatory ventilation)modes. The
scope of any mode in this group is independent of whether spontaneous breaths are set to be supported or not
between the primary-inflations or whether these inflations are assured to be initiated at an unusual set rate, for
example, at only once per minute, in order to recruit the patient's lungs.
Note 5 to entry: See also primary-inflation (4.2.12), primary-inflation cycle (4.3.20), ACAP (4.9.2), adjunct
(4.9.14.2.12) and support-inflation (4.2.15).
4.8.4.3
ventilation-mode Group 3
group of ventilation modes sharing ventilation-patterns that enable continuous unrestricted
breathing or continuous supported breathing, always with a constant baseline airway pressure at
the set BAP level
4.8.4.3.1
Group 3a
subset of Group 3 ventilation modes with provision to support each inspiratory activity that
exceeds a threshold value
4.8.4.3.2
Group 3b
subset of Group 3 ventilation modes with no provision to support any inspiratory activity
Note1 to entry: In this group of modes no inflation is assured to be initiated. If apnoea ventilation is provided for
instances of apnoea then this is classified in this vocabulary as an automatic change of ventilation-mode. (See Note 3
to 4.8.2).
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Note 2 to entry: Group 3 ventilation-modes include those based on the well-established ventilation-patterns used in
CSV (Continuous spontaneous ventilation) and CPAP (Continuous Positive Airway pressure) modes.
Note 3 to entry: The support provided in Group 3a ventilation modes may be by means of pressure support (PS) or
proportional effort support (pES) inflation-types. With pressure support the threshold value will be a set value, with
proportional effort support the threshold will be the minimum value resolvable by the ventilator.
Note 4 to entry: See also unrestricted breathing (4.1.5), supported breath (4.1.13), baseline airway-pressure (4.11.1),
pressure support ( 4.2.6 ), proportional effort support 4.2.7), CSV (Continuous Spontaneous Ventilation) (4.8.10) and
CPAP (Continuous Positive Airway pressure) (4.8.13).
4.8.5
*assured ventilation
mandatory ventilation
patient ventilation by primary-inflations delivered at intervals determined by the set rate
Note 1 to entry: The duration of an assured ventilation episode may be that of a single breath or of a sequence of
breaths, ending when a non-synchronising patient-trigger event occurs.
Note 2 to entry: The term assured ventilation is used in this vocabulary to better represent the core concept of the
classical ventilation modes, CMV (Continuous mandatory ventilation), IMV (Intermittent Mandatory Ventilation) and
SIMV (Synchronised intermittent mandatory ventilation). Mandatory ventilation is retained as an admitted term for
this concept in order to provide a link between the use of the word mandatory in the mode name and the more
relevant interpretation of its meaning in this vocabulary, that is, the assurance provided by its being required to
occur. (See also mandatory (4.2.14)).
Note 3 to entry: It is only primary-inflations delivered at the set rate that contribute to assured ventilation. Primaryinflations that are patient-initiated, and that increase the rate above that set, do not contribute to assured ventilation.
(See also primary-inflation (4.2.13)).
Note 4 to entry: Although assured ventilation comprises solely primary-inflations, which could therefore be described
as assured inflations, not all primary-inflations can be so described.
Note 5 to entry: With some Group (ii) ventilation-modes, e.g., SIMV, the assured inflations are assured to be delivered
at the set rate but are also required to be synchronised with any spontaneous breaths. This is achieved by the use of a
synchronisation window that is opened at equal intervals. The actual initiation or that inflation is then either patienttriggered within that window or ventilator-initiated as the window is terminated. This ensures that the assured
inflations will be delivered at the set rate although there may be small variations in the inflation-to-inflation time as a
consequence of the synchronisation.
Note 6 to entry: It is the intent of the committee to deprecate the admitted term mandatory ventilation in future
editions of this Standard.
4.8.6
CMV
continuous mandatory ventilation
DEPRECATED AS SYNONYM: continuous mechanical ventilation
DEPRECATED AS SYNONYM: controlled mechanical ventilation
DEPRECATED AS SYNONYM: IPPV
DEPRECATED AS SYNONYM: CPPV
property-class name of a ventilation-pattern in which a selected inflation-type is assured to be
delivered at intervals determined by the set rate, with no facility for any inflation to be initiated
by a patient-trigger event
Note 1 to entry: The selected inflation-type is classed as the primary-inflation.
Note 2 to entry: The interval determined by the set rate is 1/Rate minutes.
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Note 3 to entry: This is the characteristic ventilation-pattern of Group 1a ventilation-modes.
Note 4 to entry: The initialism, CMV, related to this concept is retained because it is well established, although a
number of different names have been associated with it. In this vocabulary it is used only for a ventilation-pattern
that does not respond to patient-trigger events of any magnitude (that is, its function is the same as Assist/control
ventilation (A/CV) with its trigger function off).
Note 5 to entry: On ventilators with an ACAP adjunct it is possible to set this ventilation mode to replicate IMV
(Intermittent Mandatory Ventilation). In such a case the manufacturer’s description of the ventilation mode
determines its appropriate designation.
Note 6 to entry: See Figure C.14a (Annex C) for a schematic illustration of this pattern.
4.8.7
Assist/Control Ventilation
A/CV
DEPRECATED: assist control ventilation
DEPRECATED: AC
property-class name of a ventilation-pattern in which a selected inflation-type is assured to be
initiated at intervals determined by the set rate, unless initiated by an earlier patient-trigger
event
Note 1 to entry: The selected inflation-type is classed as the primary-inflation.
Note 2 to entry: With this ventilation-pattern any patient-trigger event will cause the primary-inflation rate to exceed
that set. Any primary-inflations per minute in excess of those assured to be delivered by the set rate (4.4.1.1) become
additional primary-inflations (which give rise to additional minute volume (4.7.12).
Note 3 to entry: With this ventilation-pattern, if one or more inflations are initiated by a patient-trigger event,
although all the inflations are still primary-inflations, there are no specific inflations that can be identified as ‘assured’
or ‘additional’. However, the operator is assured that that the set number of primary-inflations will be delivered per
minute and that any inflations per minute above that set will be additional primary-inflations.
Note 4 to entry: The interval determined by the ventilator set rate is 1/Rate minutes.
Note 5 to entry: This ventilation-pattern name is descriptive of its function in that every patient-trigger event initiates
the generation of an assisted breath whereas a controlled breath is generated if no patient-trigger event occurs within
the interval determined by the set rate. See also assured delivery (4.2.14).
Note 6 to entry: This is the characteristic ventilation-pattern of Group 1b ventilation-modes.
Note 7 to entry: See Figure C.14b (Annex C) for a schematic illustration of this pattern.
Note 8 to entry: See also Figures C.7 – C.9 (Annex C).
Note 1 to deprecated terms: The legacy abbreviation A/C became the established written form for this term. Forms
of the term without the forward slash have been used more recently but this practice is deprecated because it fails to
convey the OR function implied by the written forms of the preferred term.
4.8.8
IMV
intermittent mandatory ventilation
property-class name of a ventilation-pattern in which a selected inflation-type is always initiated
at a constant interval, as determined by the ventilator set rate. Between these assured
deliveries, unrestricted breathing is possible or spontaneous inspirations may be supported by
a second selected inflation- type
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Note 1 to entry: The inflation-type selected for delivery at the set rate is classed as the primary-inflation and the
second inflation-type selected is classed as a support-inflation.
Note 2 to entry: On ventilators with an ACAP adjunct any inspirations occurring concurrently with a pressure-control
primary inflation-type, may be assisted by either the selected support-inflation or by an additional, third selected
inflation-type (which is also referred to as the second support-inflation).
Note 3 to entry: This is the characteristic ventilation pattern of Group 2a ventilation-modes.
Note 4 to entry: The interval determined by the ventilator set rate is 1/Rate minutes.
Note 5 to entry: It is possible to set ventilation-modes conforming to this pattern to replicate modes with a CMV
(Continuous mandatory ventilation) ventilation-pattern on ventilators with an ACAP adjunct. In such cases the
manufacturer’s description of the ventilation mode determines its appropriate designation.
Note 6 to entry: See Figure C.14c (Annex C) for a schematic illustration of this pattern.
Note 7 to entry: See also ventilation pattern (4.8.3), ventilation-mode groups (4.8.4) and Table D.2, (Annex D).
4.8.9
SIMV
synchronised intermittent mandatory ventilation
property-class name of a ventilation-pattern in which a selected inflation-type is initiated at the
set rate, with each inflation being synchronised with any spontaneous breathing. Between these
assured deliveries unrestricted breathing is possible or spontaneous inspirations may be
supported by a second selected inflation-type
Note 1 to entry: Synchronisation is achieved by the use of a synchronisation window, which provides time for the
assured delivery to be in phase with any preceding spontaneous breath in order to minimise the possibility of breath
stacking.
Note 2 to entry: The synchronisation window is configured so that the initiation of each inflation is synchronised with
any spontaneous breathing while maintaining the assured average rate of delivery as determined by the set rate.
Note 3 to entry: The inflation-type selected for delivery at the set rate is classed as the primary-inflation and the
second inflation-type selected is classed as a support-inflation.
Note 4 to entry: On ventilators with an ACAP adjunct any inspirations occurring concurrently with a pressure-control
primary inflation-type, may be assisted by either the selected support-inflation or by an additional, third selected
inflation-type (which is also referred to as the second support-inflation).
Note 5 to entry: This is the characteristic ventilation-pattern of Group 2b ventilation-modes.
Note 6 to entry: See Figure C.14d (Annex C) for a schematic illustration of this pattern.
Note 7 to entry: See also ventilation-pattern (4.8.3), unrestricted breathing (4.1.5), assured delivery (4.2.14), rate
(4.4.1.1 ), primary-inflation (4.2.12), support-inflation 4.2.15), synchronisation window (4.10.8), ACAP (4.9.2), breath
stacking (4.10.11), IMV (Error! Reference source not found.), Figures C.10 and C.11a to d (Annex C) and Table D.2
(Annex D).
4.8.10
CSV
continuous spontaneous ventilation
SPONT
property-class name of a ventilation-pattern that enables continuous, supported breathing with
a constant baseline airway pressure
Note 1 to entry: No support-inflation is assured to be delivered.
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Note 2 to entry: With pressure support set to ‘zero’ or ‘none’ modes using this ventilation-pattern function in the same
manner as the CPAP (Continuous Positive Airway pressure) ventilation-pattern but because pressure-support is
available it cannot be designated as CPAP; in this vocabulary a ventilation mode classification is independent of the
setting used.
Note 2 to entry: This is the characteristic ventilation-pattern of Group 3a ventilation-modes.
Note 4 to entry: See Figure C.14e (Annex C) for a schematic illustration of this pattern.
Note 5 to entry: See also ventilation-pattern (4.8.5), supported breath (4.1.13), assured delivery (4.2.14), Figure C.12,
(Annex C) and Table D.2 (Annex D).
Note to admitted term: Modes using this ventilation-pattern are commonly labelled on operator interfaces with
abbreviations of ‘spontaneous’, such as ‘SPONT’, ‘SPN’ and ‘SPON’, used as symbols.
4.8.11
MMV
minimum minute volume
generic name of an autonomous ventilation mode that provides assurance to the operator that
the patient will receive at least the set minimum minute volume in accordance with the selected
mode algorithm
EXAMPLE 1: Mode using an SIMV ventilation pattern where the set rate is adjusted by the MMV algorithm to maintain
the set minute volume until the lower limit of the setting is reached.
EXAMPLE 2: Mode using an A/C ventilation-pattern with vtS/T type inflations where the set rate and the set target
volume are both continually adjusted in relation to each other in accordance with an established equation, in order to
maintain the minute volume at its set level wherever possible.
Note 1 to entry: It is possible for the patient to demand minute volumes in excess of the set value.
Note 2 to entry: This is not to be confused with ‘mandatory minute ventilation’, which was the first implementation of
a mode that was described by this initialism. That implementation was an adaptation of a ventilator intended for use
during anaesthesia in the operating room and did not provide for spontaneous ventilation in excess of the set minute
volume. It was not, therefore, suitable in that form for longer term ventilation. Subsequent developments of the
concept have eliminated that restriction and led to its replacement by various forms of ‘minimum minute volume’
ventilation.
Note 3 to entry: This is an autonomous ventilation mode because its name does not describe a mode pattern; it is
simply a named ventilatory objective. This objective can be implemented with more than one pattern-based mode but
in each case necessarily involving the operator transferring the responsibility for the adjustment of certain parameter
settings to the mode algorithm. Intrinsic to such algorithms, is the automatic adjustment of certain initial settings
over time, according to the spontaneous activity of the patient.
4.8.12
* APRV
airway pressure release ventilation
APRV
alternative name for a specific setting protocol of a bi-level ventilation mode in which the patient
is intended to take natural breaths during an extended primary-inflation phase at BAPH and in
which the BAP phase is set to terminate as soon as the alveolar pressure has had time to descend
to the set BAP level
Note 1 to entry: APRV is an alternative name for a specific setting protocol for modes such as IMV-PC <ACAP> or IMVPC[S] <ACAP>; setting that give extreme inverse phase-time ratios (tH :tL) such that the patient takes unrestricted
breaths at a relatively high BAP and but is artificially ventilated by short intermittent pressure releases.
Note 2 to entry: Ventilators supporting this mode may offer the extreme phase-time ratios required either as a
suitable time setting or as the result of an algorithm, for example, based on the time for the expiratory flow to reduce
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by a set amount or to a set level. With these extreme phase-time ratios available, it is possible to achieve the intended
function of airway pressure release ventilation (APRV) by making specific settings on any of a range of bi-level modes,
of which IMV-PC <ACAP> is an example.
Note 3 to entry: The terminology used in this definition is that which is appropriate for the labelling of a bi-level mode
to be set to an APRV protocol.
Note 4 to entry: See also Figures C.6 and C.11b and c (Annex C).
4.8.13
CPAP
continuous positive airway pressure
ventilation mode in which the patient breathes continuously at a set baseline airway pressure
level (BAP), above ambient
Note 1 to entry: CPAP is intended to maintain the airway pressure at its set value with the exception of the inevitable
minor deviations that are necessary for it to perform its function. Although there are currently no tests for acceptable
levels for such deviations, they are expected to neither add to nor subtract from the patient’s perceived work of
breathing to a greater extent than may be experienced during natural breathing.
Note 2 to entry: This definition excludes the use of the term to describe ventilation modes where spontaneous
inspirations are supported by intermittently elevated pressures other than with the intention to compensate for any
actual or perceived imposed work of breathing.
Note 3 to entry: Because, as used for this ventilation mode, the concept of a CPAP level coincides with that of a
baseline airway pressure the setting could be designated as for either concept but as the intention of the operator
selecting this ventilation mode will be to achieve a specific CPAP level this becomes the preferred term to designate
the set quantity.
Note 4 to entry: Although at the periphery of what constitutes a ventilation-mode, CPAP is included in this vocabulary
because it may be used as part of a continuum of a patient’s treatment without the necessity to change to another
device.
Note 5 to entry: It is possible for a CPAP ventilation mode to be realised on a ventilator by the use of CSV (Continuous
spontaneous ventilation) with the pressure-support (PS) set to ‘zero’ or ‘none’ but, for the reasons stated in note 1 to
entry, CPAP is not equivalent to CSV.
Note 6 to entry: On ventilators with ACAP, this adjunct will enable unrestricted breathing whenever CPAP is selected.
CPAP may also be implemented on a ventilator by employing the ventilator’s CSV algorithms but with the pressuresupport preset to its ‘zero’ or ‘none’ settings.
Note 7 to entry: CPAP is a Group 3b ventilation-mode. Because no inflation-type is selected this ventilation-mode is
identical to its ventilation-pattern and there is no necessity to distinguish between them. The systematic mode code
is, therefore, simply, CPAP. On ventilators where CPAP is enabled by means of an ACAP adjunct the systematic code
becomes CPAP <ACAP>.
Note 8 to entry: When used for sleep-apnoea breathing therapy CPAP is not classed as a ventilation mode; it becomes
a sleep-apnoea breathing therapy mode. Although the principle clinical intention of such a therapy mode is to
maintain a positive pressure in the patient’s airway during sleep in order prevent airway obstruction by the soft
tissues in the throat it has become a common practice to reduce this pressure during expiration to improve patient
comfort. Modes with this feature are typically identified with names that allude to this use of two levels of positive
airway pressure. The generic name adopted for the designation of such a breathing therapy mode in this vocabulary is
Bi-level PAP.
Note 9 to entry: See also unrestricted breath (4.1.5), baseline airway-pressure (4.11.1), pressure support (4.2.6),
breathing therapy mode (4.8.19), CSV (Continuous spontaneous ventilation) (4.8.10), ACAP (4.9.2), CSV (4.8.10) and bilevel PAP (Error! Reference source not found.).
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4.8.14
apnoea ventilation
apnea ventilation
safety provision by which the ventilator automatically switches to a predetermined ventilation
mode that generates controlled breaths whenever a hypoventilation alarm condition occurs
Note 1 to entry: A second preferred term for this concept is included in this vocabulary because each form of the key
base word, apnoea, is universally used in specific spheres of influence; both within and outside of the scope of this
vocabulary.
Note 2 to entry: See also controlled breaths (4.1.16), alarm condition (4.12.2.1) and backup ventilation (4.8.15)
4.8.15
back-up ventilation
DEPRECATED AS SYNONYM: apnea ventilation
DEPRECATED AS SYNONYM: apnoea ventilation
provision by which the ventilator automatically switches to a predetermined alternative
ventilation mode intended to maintain patient safety in the event of a component, sensor or
function becoming inoperable; or artificial ventilation by means of a second device in case of
malfunction of the first
Note 1 to entry: The second device could be an operator-powered resuscitator.
Note 2 to entry: See also apnoea ventilation (4.8.14).
4.8.16
systematic ventilation-mode name
systematised name for a ventilation mode, comprising elements that designate its ventilationpattern, the selected inflation-type(s) and the type of provision for unassisted breathing, if
provided
Note 1 to entry: The systematic name may be expressed as the full name but it is most useful in the more concise,
coded form, using the abbreviated forms of the ventilation-pattern, the inflation-type(s) and the ACAP adjunct type,
whenever this is a function of the ventilator. For examples of this coding scheme, see Table D.2 (Annex D).
Note 2 to entry: See also ventilation-pattern (4.8.3), inflation-type (4.2.2), Tables D.1a, D.1b, D.1c and D.2 (Annex D)
and ACAP (assured constant airway pressure) (4.9.2).
4.8.17
alternative mode name
alternative ventilation-mode name
name used to identify a ventilation mode, or a specific setting protocol for a ventilation mode,
which is alternative to the systematic ventilation-mode name, with the intention of placing
emphasis on a particular characteristic feature of that ventilation mode or the manner in which
it may be used
Note 1 to entry: The alternative name may identify a single ventilation mode, or several ventilation modes with the
same characteristic feature or features.
Note 2 to entry: The alternative name may be either a standardised generic name or a proprietary name.
Note 3 to entry: The specification of an alternatively named ventilation mode is incomplete without reference to its
systematic ventilation-mode name.
Note 4 to entry: The selection of a ventilation-pattern and inflation-types is fundamental to all modes but some
ventilation modes have overriding, clinically significant, combinations of features that have been considered to justify
their own generic or proprietary name. Such ventilation modes may use higher-order or interventional control
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algorithms in order to achieve additional objectives, for example, a ventilation strategy or procedure, and which have
therefore been identified solely by a name relating only to that objective. In other instances, specific combinations of
ventilation-pattern, inflation-type(s) and range of settings have been characterised by a name that puts emphasis on a
particular ventilation concept. Although this practice may be useful as a shorthand reference such mode names do
not provide a complete description: a ventilation mode set on a ventilator using vocabulary conforming to that of this
International Standard will enable identification of the standardised selected ventilation-pattern and selected
inflation-type(s).
Note 5 to entry: Example of generic alternative names used in this vocabulary are bi-level ventilation and APRV
(Airway Pressure Relief Ventilation).
4.8.18
superordinate mode
one of a group of ventilation modes that has a significant additional feature to those of the
underlying ventilation pattern-based mode, and by which it is separately identified
Note 1 to entry: The additional feature is typically a supervisory function that automatically makes adjustments to
the controls of the ventilator with the intention of achieving a progressive care plan with the patient.
Note 2 to entry: Examples of proprietary superordinate-mode names are SmartCare™, Automode and ASV.
Note 3 to entry: See also alternative mode name (4.8.17)
4.8.19
breathing therapy mode
ventilation mode that delivers a respirable gas at therapeutic breathing pressures to the
patient’s airway with a primary intention other than to provide a proportion of the patient’s
work of breathing
4.9 Mode Adjunct and Bi-level Terminology
4.9.1
adjunct
ventilation-mode adjunct
functional state of the ventilator that provides actions that are superimposed on those of
suitable ventilation modes whenever they are selected
Note 1 to entry: Suitable ventilation modes are those that have the specific characteristics that the adjunct can modify
to the potential benefit of the patient’s treatment.
Note 2 to entry: An installed ventilation-mode adjunct is typically permanently available and becomes active
whenever a suitable ventilation mode is selected, but it may be selectable. Additional properties that are selectable by
the operator in order to modify a specific ventilation-pattern or inflation-type are considered to be optional
variations, not a mode adjunct.
4.9.2
ACAP
assured constant airway pressure
adjunct that enables unrestricted breathing by acting to maintain the airway pressure at its set
value, irrespective of inspiratory or expiratory flows, or specified permitted leakage, whenever it
is intended to be at a constant level
Note 1 to entry: This adjunct is intended to maintain the airway pressure at its set value with the exception of the
inevitable minor deviations that are necessary for it to perform its function. Although there are currently no tests for
acceptable levels for such deviations, they are expected to neither add to nor subtract from the patient’s perceived
work of breathing to a greater extent than may be experienced during natural breathing.
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Note 2 to entry: If the ventilator is connected to the patient with an airway device with sufficient resistance to hinder
unrestricted breathing it is expected that its effect may be offset by the operator-selection of a tube compensation (TC)
function.
Note 3 to entry: An ACAP adjunct is typically made possible in a microprocessor-controlled ventilator with a
construction incorporating additional gas-control elements that are used to generate required airway-pressure
waveforms irrespective of both inspiratory and expiratory flow and during both the inspiratory and expiratory phases
of a primary-inflation. With this adjunct the patient is able to inspire and expire at any time at any BAP level;
inspirations may be unassisted or supported and intended expiratory-pressure waveforms are maintained under the
control of an expiratory-control algorithm. Unassisted inspirations are enabled by the provision of demand flow that is
proportional to the patient’s demands, with no dependency on a patient-trigger event.
A typical implementation of ACAP on a gas-powered ventilator may involve the use of a proportional expiratory valve
under the continuous control of the expiratory-control algorithm. When this is controlled in unison with the control
of a proportional inspiratory valve it becomes possible to generate the required pressure waveform, irrespective of
the possibly rapidly changing inspiratory and expiratory flows of natural breathing. This adjunct may also be
achieved on a ventilator that uses alternative proportional gas control or generation elements.
Note 4 to entry: ACAP is typically preselected to be active wherever appropriate - depending on the ventilation mode
that has been selected.
Note 5 to entry: Examples of instances of where ACAP is active, when provided, are
•
•
•
•
during the intended constant-pressure portion of the waveform of a pressure-control (PC) primary-inflation,
after the expiratory pressure has stabilised at its BAP level during the expiratory phases of primary-inflation
cycles and between any support inflations,
between any support inflations during CSV and continuously when pressure-support (PS) is set to ‘zero’ or
‘off, and
during CPAP ventilation modes.
Note 6 to entry: The constant pressure levels at which ACAP is active become the baseline airway-pressures for that
activity.
Note 7 to entry: For unassisted breaths, an ACAP adjunct facilitates unrestricted breathing by the generation of
demand flow in proportion to the patient’s demands, without any trigger threshold, during inspiration and by
4.2.12the provision of minimal resistance during expiration.
Note 8 to entry: Although this adjunct may not be required to maintain the baseline airway-pressure if pressure
support is provided during an expiratory phase, it will serve to prevent the pressure dropping below the set baseline
airway-pressure towards the end of expiration due, for example, to any ventilator breathing system or airway leakage.
It also allows unrestricted breathing below the set trigger level, or when any pressure support is switched off.
Note 9 to entry: Some of the functions of ACAP may also be achievable by using specific settings with certain
ventilator modes but, although such settings may be described as providing an equivalent function to ACAP, because
its function is dependent on set values such an arrangement does not constitute an ACAP adjunct. If equivalence is
claimed, the means used to facilitate unrestricted breathing should be described in the Instructions for Use.
Note 10 to entry: Group 2 ventilation-modes with an ACAP adjunct may be denoted by the alternative ventilation
mode name bi-level ventilation.
Note 11 to entry: See also adjunct (4.9.1), unrestricted-breathing (4.1.5), natural-breathing (4.1.4), primary-inflation
(4.2.12), baseline airway-pressure (4.11.1), bi-level ventilation (4.9.5) and demand flow (4.6.12).
4.9.3
ACAPL
ACAP-low
assured constant airway pressure, low
adjunct that enables unrestricted breathing by acting to maintain the expiratory pressure at its
set BAP baseline level, irrespective of inspiratory or expiratory flows, or specified permitted
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leakage, after the expiratory pressure has decreased to its baseline level during the expiratory
phases of primary-inflation cycles and between any support inflations
Note 1 to entry: As an adjunct that is only active during the expiratory phases of a primary-inflation cycles, it may be
the most appropriate for use, for example, with a ventilation mode using a flow-regulated inflation-type as the
primary-inflation.
Note 2 to entry: This adjunct is intended to maintain the airway pressure at its set value with the exception of the
inevitable minor deviations that are necessary for ACAPL to perform its function. Although there are currently no
tests for acceptable levels, with ACAPL, such deviations are expected to neither add to nor subtract from the patient’s
perceived work of breathing to a greater extent than may be experienced during natural breathing.
Note 3 to entry: Where provided, ACAPL is typically preselected to be active wherever appropriate - depending on the
ventilation mode that has been selected.
Note 4 to entry: For unassisted breaths, an ACAPL adjunct typically facilitates unrestricted breathing by the generation
of demand flow in proportion to the patient’s demands, without any trigger threshold, during inspiration and by the
provision of minimal resistance during expiration.
Note 5 to entry: Although this adjunct may not be required to maintain the baseline airway pressure if pressure
support is provided during an expiratory phase, it will serve to prevent the pressure dropping below the set baseline
airway pressure towards the end of expiration due, for example, to any ventilator breathing system or airway leakage.
It also allows natural breathing below the set trigger level, or when any pressure support is switched off.
Note 6 to entry: Some of the functions of ACAPL may also be achievable with the use of specific settings with certain
ventilation modes but, although such settings may be described as providing an equivalent function to ACAPL, because
its function is dependent on set values such an arrangement does not constitute an ACAPL adjunct. If equivalence is
claimed, the means used to facilitate unrestricted breathing should be described in the Instructions for Use.
Note 7 to entry: See also the Notes to entry 4.9.2, adjunct (4.9.1), baseline airway-pressure (4.11.1), demand flow
(4.6.12) and primary-inflation (4.2.12).
4.9.4
ACAPH
ACAP-high
assured constant airway pressure, high
mode adjunct that maintains the airway pressure at its set primary-inflation inspiratory-pressure
value, irrespective of inspiratory or expiratory flows, whenever it is intended to be constant at
that level
Note to 1 entry: This adjunct is provided for use only during the inflation phases of pressure-regulated primaryinflation cycles. ACAPH is not applicable during inflations with flow-regulated inflation-types, for example, volumecontrol, because the inspiratory pressure is not intended to be at a constant level during such inflations. If additional
inspiratory flow is provided on demand with a volume-control inflation-type, this is classed as a dual-control inflation
not volume-control with ACAP.
Note 2 to entry: This adjunct is intended to maintain the airway pressure at its set value with the exception of the
inevitable minor deviations that are necessary for ACAPH to perform its function. Although there are currently no
tests for acceptable levels, with ACAPH, such deviations are expected to neither add to nor subtract from the patient’s
perceived work of breathing to a greater extent than may be experienced during natural breathing.
Note 3 to entry: Where provided, ACAPH is typically preselected to be active wherever appropriate - depending on
the ventilation mode that has been selected.
Note 4 to entry: For unassisted breaths, an ACAPH adjunct facilitates unrestricted breathing by the generation of
demand flow in proportion to the patient’s demands, without any trigger threshold, during inspiration and by the
provision of minimal resistance during expiration.
Note 5 to entry: Some of the functions of ACAPH may also be achievable by using specific settings with certain
ventilator modes but, although such settings may be described as providing an equivalent function to ACAPH, because
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its function is dependent on set values such an arrangement does not constitute an ACAPH adjunct. If equivalence is
claimed, the means used to facilitate unrestricted breathing should be described in the Instructions for Use.
Note 6 to entry: See also the Notes to entry 4.9.2, adjunct (4.9.1), baseline airway-pressure (4.11.1), dual-control
(4.2.5) and primary-inflation (4.2.12).
4.9.5
bi-level ventilation
bi-level
alternative name for Group 2 modes with a pressure-control primary inflation-type and ACAP as
an adjunct, where the intention is to place emphasis on the facility for unrestricted breathing at
both baseline airway pressure levels of the primary-inflation cycle
Note 1 to entry: With the provision of ACAP, unrestricted breathing is possible at two
alternating pressure levels, thereby adding to the ventilation provided by the primary, pressurecontrol inflations.
Note 2 to entry: It is common practice to also adopt an alternative naming scheme for the set and measured
quantities that are affected by this intended change of emphasis. Figures in Annex E that illustrate modes that may be
alternatively designated as bi-level ventilation also show how the alternative terms, standardised for that purpose, are
used. Preferred and admitted terms for these quantities are listed in following entries in this sub-clause, 4.9.
Note 3 to entry: This is the generic name for a class of modes based on one originally introduced with the proprietary
name BIPAP™ - which is not to be confused with the proprietary name BiPAP™
Note 4 to entry: See also Group 2 ventilation-modes (4.8.4.2), ACAP (4.9.2), bi-level PAP (Error! Reference source
not found.), APRV (4.8.12) and Figure C.11a to d (Annex C).
4.9.6
bi-level positive airway pressure
bi-level PAP
BPAP
sleep-apnoea breathing-therapy mode in which the positive airway pressure level that is
therapeutically required during the inspiratory phase is reduced during each expiratory phase,
with the sole intention of improving patient comfort
Note 1 to entry: The two levels of positive-airway-pressure (PAP) invoked by the various names that have been given
to this breathing-therapy mode are typically identified by the terms IPAP and EPAP, with IPAP representing the
required airway pressure level during the inspiratory phase and EPAP the lower airway pressure during the expiratory
phase.
Note 2 to entry: This is the generic name for a breathing-therapy mode often identified by the proprietary name
BiPAP™, which is not to be confused with the proprietary name BIPAP™.
Note 3 to entry: See also bi-level ventilation (Error! Reference source not found.).
4.9.7
BAP
pressure-low
pL
alternatively named lower baseline airway-pressure level in ventilation modes labelled as bilevel ventilation
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
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Note 2 to entry: The admitted term and its symbol are included in this edition of this International Standard based on
their common current usage and the possible need for a longer transition time for the change-over to the use of the
term BAP, should this prove necessary.
Note 3 to entry: The use of this alternative term, or its admitted synonym, in modes labelled as bi-level ventilation is
optional.
Note 3 to entry: See also BAP-high (Error! Reference source not found.), bi-level ventilation (Error! Reference
source not found.), Figures C (Annex C) and Figure F.2 (Annex F).
4.9.8
pressure-low phase
pL phase
admitted synonym for BAP phase
Note 1 to entry: This admitted term and its abbreviation are included in this edition of this International Standard
based on their common current usage as an alternative name for this concept and the possible need for a longer
transition time for the change-over to the use of the term BAP phase, should this prove necessary.
Note 3 to entry: The use of this alternative admitted name, or its admitted abbreviation, in modes labelled as bi-level
ventilation is optional.
Note 4 to entry: See also BAP phase (Error! Reference source not found.), bi-level ventilation (Error! Reference
source not found.), BAP (Error! Reference source not found.), and BAP-high (Error! Reference source not
found.).
4.9.9
time-low
tL
alternatively named duration of a BAP, or pressure-low, phase
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: This term is only relevant to modes labelled as bi-level ventilation and is only used in combination
with the term BAP-high (or pressure-high) for the designation of the higher baseline airway pressure.
Note 3 to entry: See also baseline airway pressure (4.11.1), BAP-high (Error! Reference source not found.), bi-level
ventilation (Error! Reference source not found.) time-high (Error! Reference source not found.) and Figures
C.11c and d (Annex C).
4.9.10
BAP-high
pressure-high
pH
alternatively named higher baseline airway-pressure level in modes labelled as bi-level
ventilation
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 2 to entry: The admitted term and its symbol are included in this edition of this International Standard based on
their common current usage and the possible need for a longer transition time for the change-over to the use of the
term BAP-high, should this prove necessary.
Note 3 to entry: The use of this alternative term, or its admitted synonym, in modes labelled as bi-level ventilation is
optional.
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Note 4 to entry: See also BAP (4.16.3), bi-level ventilation (Error! Reference source not found.) and Figures C.11c
and d (Annex C).
4.9.11
BAP-high phase
pressure-high phase
pH phase
alternatively named primary inflation-phase in ventilation modes labelled as bi-level ventilation
Note 1 to entry: The admitted term and its symbol are included in this edition of this International Standard based on
their common current usage and the possible need for a longer transition time for the change-over to the use of the
term BAP-high phase, should this prove necessary.
Note 2 to entry: The use of this alternative term, or its admitted synonym, in ventilation modes labelled as bi-level
ventilation is optional.
Note 3 to entry: See also bi-level ventilation (Error! Reference source not found.), BAP (4.11.1) and Figures C.11c
and d (Annex C).
4.9.12
time-high
tH
alternatively named duration of a BAP-high (or pressure-high) phase
Note 1 to entry: In addition to its direct reference, this term may be used, in context or by qualification, to designate
this concept as a set quantity (4.13.19) or a measured quantity (4.13.20).
Note 2 to entry: This term is only relevant to ventilation modes labelled as bi-level ventilation and is only used in
combination with the term BAP-high (or pressure-high) for the designation of the higher baseline airway pressure.
Note 3 to entry: With inflations that provide synchronised termination the measured duration, averaged over several
respiratory cycles, will be determined by the set time-high, even though the duration of any individual pressure-high
phase may vary from the set rate as allowed by the synchronisation algorithm.
Note 4 to entry: See also bi-level ventilation (Error! Reference source not found.), baseline airway pressure (4.11.1),
BAP-high (Error! Reference source not found.), BAP-high phase (Error! Reference source not found.), time-low
(Error! Reference source not found.) and Figures C.11c and d (Annex C).
4.10 Initiation and termination terminology
4.10.1
initiate
cause a process or action to begin
Note 1 to entry: This word has been adopted in this vocabulary as the general term to designate the concept of
causing a process or action to begin. This is to counter a tendency to use the word ‘trigger’ for this purpose; a trend
that removes the ability of that term to differentiate its own special meaning from that of a simple timed switching
action. In this vocabulary an inflation can be initiated by, for example:
•
•
•
•
patient-trigger events
timed signals
manual inputs
signals from a remote device
Note 2 to entry: In this vocabulary, an inflation that is initiated by a timed signal may is referred to as being
ventilator-initiated.
Note 3 to entry: See also trigger (4.10.2), ventilator-initiation (4.10.12) and patient-trigger event (4.10.6).
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4.10.2
trigger
DEPRECATED: time trigger
DEPRECATED: manual trigger
DEPRECATED: remote trigger
function that detects that the measured value(s) of a parameter(s) that can be attributed to the
patient has reached a threshold value
Note 1 to entry: This is the definition of the basic concept of a trigger function, as the term is used in this vocabulary.
In practice, some such functions may monitor the value of more than one parameter and make use of dedicated
detection algorithms in order that sensitive settings can be used with a minimum risk of auto-triggering.
Note 2 to entry: This term is used to differentiate that class of inflation initiation signals that depend upon the
attainment of a threshold by the measured value of a patient parameter, and hence involve a sensitivity setting, from
those generated directly by the operation of simple timed, manual or remote, binary-switch functions.
Note 3 to entry: See also initiate (4.10.1) and patient-trigger event (4.10.6).
4.10.3
flow trigger
function that detects when changes of flow in the ventilator breathing system due to inspiratory
effort reach a set threshold level
Note 1 to entry: This is a classification for the means of detecting a patient’s inspiratory effort in generating a patienttrigger event. As explained in note 1 to4.10.2 , in practice, some such functions may monitor the value of more than
one parameter and make use of dedicated detection algorithms in order that sensitive settings can be used with a
minimum risk of auto-triggering. In a flow-trigger algorithm, flow will be the dominant parameter in determining
attainment of the threshold level.
Note 2 to entry: The change of flow detected may be a change in the bias flow or a change in the flow through the
patient-connection port.
Note 3 to entry: See also patient-trigger event (4.10.6), pressure trigger (4.10.4) and bias flow (4.6.8).
4.10.4
pressure trigger
function that detects when pressure changes in the ventilator breathing system reach a set
threshold level
Note 1 to entry: This is a classification for the means of detecting a patient’s inspiratory effort in generating a patienttrigger event. As explained in note 1 to 4.10.2 in practice, some such functions may monitor the value of more than
one parameter and make use of dedicated detection algorithms in order that sensitive settings can be used with a
minimum risk of auto-triggering. In a pressure-trigger algorithm, pressure will be the dominant parameter in
determining attainment of the threshold level.
Note 2 to entry: The change of pressure detected may be a change in a measured pressure or a change in a rate of a
pressure change.
Note 3 to entry: See also patient-trigger event (4.10.6), flow trigger (4.10.3) and bias flow (4.6.8).
4.10.5
trigger level
threshold value for a trigger function
Note 1 to entry: This term is used, in context or by qualification, only to designate this concept as a set value
(4.13.20).
Note 2 to entry: The level may be labelled in units of pressure or flow, or with a simple sensitivity scale.
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4.10.6
patient-trigger event
trigger-event
signal resulting from a measured value(s) of a parameter(s), which can be attributed to the
patient, reaching a threshold value
Note 1 to entry: Typical patient respiratory parameters that are monitored for this purpose are airway pressure, flow
or volume, and electromyography signals (EMG). Far less commonly used parameters are chest-wall motion and
transthoracic impedance. The detection algorithm may involve more than one of these parameters.
Note 2 to entry: An inflation initiated by a patient-trigger event may be referred to as being patient-triggered or by
the method of detection, for example, pressure-triggered, flow-triggered, etc.
Note 3 to entry: The initiation of an inflation by means of a manual input is not a manual trigger event; it is a manual
initiation.
Note 4 to entry: It is important that users are made aware that a patient-trigger event may result from the detection
of a spurious perturbation on a measurement, especially if the threshold value is set at too sensitive a level.
Note 5 to entry: See also trigger (4.10.2) and auto trigger (4.10.10).
4.10.7
breath synchronization
timing adjustment of each initiation and/or termination of an assured delivery so as to match the
pattern of any spontaneous inspiratory and/or expiratory efforts, while still maintaining the set
rate
Note 1 to entry: Any such timing adjustment will alter the respiratory cycle time of the assured delivery, breath to
breath, but the average delivery rate will be maintained at set value.
4.10.8
synchronisation window
time interval following the scheduled initiation or termination, of an assured delivery during
which actual initiation or termination of an inflation may be synchronised with a respiratory
activity of the patient
Note 1 to entry: See Figures C.10, C.11c, C.11d and C.14d (Annex C) for illustrations of the function of a
synchronisation window.
4.10.9
mandatory
required to occur
Note 1 to entry: This term is defined as used in this vocabulary, with a specific meaning of the word mandatory,
which in natural language has a spectrum of meanings. It has become firmly established in the vocabulary of artificial
ventilation but because of its ambiguity it can denote either ‘total control’ or, as in this definition, ‘required to occur’.
In early artificial ventilation practice it was usual for all aspects of the patient's ventilation to be taken over by the
ventilator and so every breath could be described as mandatory in its broadest sense. Since then, with the
introduction of patient triggering and the concept of support for spontaneous breathing, only a small percentage of
patients currently have their ventilation totally controlled. However, there remains a mandatory component to all
forms of artificial ventilation but a key aspect for an operator when setting a modern ventilator is being assured that,
when a selected inflation occurs within the selected ventilation-pattern, it will provide a minimum level of assistance
and, in the case of apnoea, that the ventilation will be totally controlled.
These developments have led manufacturers to increasingly restrict the use of the term ‘mandatory’ to the context of
ventilation that is assured to occur by the programmed delivery of a selected inflation-type, in predetermined
patterns, independent of the patient's respiratory activity. This is the only sense in which the term mandatory is used
in this vocabulary; which is mainly in the explanation of the classical mode names such as continuous mandatory
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ventilation, intermittent mandatory ventilation and synchronised intermittent mandatory ventilation. For other
purposes, wherever possible, the term assured is used in its place.
Note 3 to entry: See also assured delivery (4.2.14) and assured minute volume (4.7.11).
4.10.10
auto trigger
DEPRECATED AS SYNONYM: autocycle
initiation of an inflation as a result of a false patient-trigger event
Note 1 to entry: A false patient-trigger event may be caused, for example, by external perturbations such as a
movement of the breathing tube or a cardiac impulse creating pneumatic disturbances.
4.10.11
breath stacking
situation in which the ventilator delivers another inflation, or the patient makes an inspiratory
effort, before the previous breath has been adequately expired
Note 1 to entry: This situation may be caused by auto triggering or by the expiratory time being set to be too short.
4.10.12
ventilator-initiation
initiation of an inflation by means of a timed signal generated after a set interval
4.10.13
remote inflation-initiation
initiation of an inflation by means of a recognised signal caused by an event external to the
ventilator
EXAMPLES: a signal from another medical device; a synchronization signal from x-ray equipment
4.10.14
termination
DEPRECATED: cycle
bringing to an end
Note 1 to entry: In this vocabulary this term is used in reference to the ending of either of the two principal breath
phases. The means of termination constitutes the secondary classification of inflation-types.
Note 2 to entry: See also inspiratory-termination flow (4.6.3) and expiratory-termination flow (4.6.6).
Note 1 to deprecated term: The term ’cycle’ is currently commonly used in some countries with the meaning of
‘termination’ but it is, in fact, an abbreviation of ‘cycle-off’’. These terms originated when ventilators simply cycled
between ‘on’ and ‘off’. Typically, ventilators are now equipped with a variety of means to terminate an inflation and
the term ‘cycle’ is considered to be misleading in this context; it also causes confusion with the true dictionary
meaning of the term ‘cycle’ as used in this vocabulary.
4.10.15
flow-termination
DEPRECATED: flow cycled
termination of a pressure-regulated inflation, or of an expiratory phase, as a result of a reduction
of the phase flow to the set termination-flow threshold
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.20).
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Note 2 to entry: This method of termination provides the means for the patient's respiratory activity to be used to
influence the duration of an inflation or expiratory phase in order to improve the match of the duration with the
patient's own breathing pattern. See pressure-support for an example of an inflation-type that is typically pressureregulated and flow-terminated.
Note 3 to entry: Patient-safety considerations dictate that a time-termination is provided as a backup where flowtermination is the intended to be the primary means of termination. This time-termination may be preset, operator
adjustable or set by an algorithm.
Note 4 to entry: Flow-terminated pressure-support inflation-types have often been referred to as patient-terminated.
The use of that term is deprecated in this vocabulary unless the ventilator is able to specifically indicate that the
termination is due to the patient's respiratory activity and neither due to the inevitable decline in inspiratory flow as
the passive lungs are inflated in the absence of any such activity, nor due to time-termination.
Note 5 to entry: See also pressure-support 4.2.6), end-inspiratory flow (4.6.4) and end-expiratory flow (4.6.7).
4.10.16
pressure-termination
DEPRECATED: pressure cycled
termination of an inflation phase when the inspiratory pressure attains a set level
Note 1 to entry: The set level may be either the primary termination criterion for the inflation-type or a set safety
limit for the protection of the patient during normal condition or under a single fault condition.
Note 2 to entry: See also normal condition (4.13.26), single fault condition (4.13.27), pressure limit (4.12.1.1) and
pressure control (4.2.4).
4.10.17
time-termination
DEPRECATED: time cycled
termination of an inflation or expiratory phase after an elapsed time, either as set or as derived
by an algorithm
Note 1 to entry: Patient-safety considerations dictate that all inflation-types have a directly or indirectly set timetermination. It may be the operator-set primary means of termination or it may be a preset back-up to an alternative
primary means of termination
4.11 Baseline and PEEP terminology
4.11.1
BAP
baseline airway-pressure
baseline pressure
PEEP
reference airway-pressure level that may be positively offset from the ambient pressure by a set
amount and at which a patient breathes when unassisted and upon which inflations are
superimposed
Note 1 to entry: The acronym BAP is employed in this vocabulary for the designation this concept as a set quantity
(4.13.19) and in reference to baseline levels at a set level. The full term is used in reference to the concept and its
function. For examples of this usage see the notes to sub-clauses relating to baseline airway pressure and the relevant
sub-clauses in 4.9 and 4.11.
Note 2 to entry: Because of its established use, the acronym PEEP is retained as an admitted term to designate the
setting for the baseline airway-pressure level, in this edition of this International Standard. This is in order to
provision for a longer transition time in the change-over to the use of the term BAP, should this prove necessary. It
may also remain to be a more appropriate term for a setting on basic ventilators and resuscitators, where the concept
of a baseline airway pressure is not relevant.
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Note 3 to entry: The baseline airway-pressure level for humans breathing without a ventilator is that of the ambient
environment. Most ventilators have the capability for the patient to be ventilated and be able to breathe, with a
baseline pressure level(s) that is artificially raised relative to the ambient pressure. In addition to the baseline at
ambient pressure, this vocabulary utilises baselines at the set BAP level (see note 4 to entry); at the set primaryinflation inspiratory-pressure level (see note 6 to entry); and at the set level in CPAP ventilation modes (see note 8 to
entry). In modes designated as bi-level ventilation the baseline at the inspiratory pressure level may be designated as
BAP-high.
Note 4 to entry: Baselines at the set BAP level become the reference level for,
•
•
•
•
•
the intended minimum alveolar pressure level throughout expiratory phases of inflations initiated from that
baseline,
any inflation-cycles initiated from that baseline,
an ACAP adjunct if active at that level,
the expiratory-control algorithm for any inflation-cycles initiated from that baseline, and
the intended PEEP (positive end-expiratory pressure) at the patient connection port.
Note 5 to entry: The adoption of the concept of a baseline at a set BAP level, to replace that of a PEEP setting, which
only determines a positive pressure at the end of each expiratory phase, is necessary because of the increasing
number of ventilators that incorporate ventilation-mode adjuncts. These are able to generate required airway
pressure waveforms irrespective of both inspiratory and expiratory flow and during both inspiratory and expiratory
phases of a primary-inflation. With such an adjunct activated the patient is able to inspire and expire at any time at any
BAP level. Such inspirations may be unassisted or supported and intended expiratory-pressure waveforms are
maintained under the control of an expiratory-control algorithm. Unassisted inspirations are enabled by the provision
of demand flow that is proportional to the patient’s demands, with no dependency on a patient-trigger event. The
possibilities that such functions open up require a vocabulary that includes the concept of one or more continuous
baseline airway pressures in addition to one that only specifies a pressure requirement at the end of an expiratory
phase.
Note 6 to entry: If an ACAP adjunct is provided during a pressure-control (PC) primary-inflation the set inspiratory
pressure level becomes the baseline for,
•
•
•
any concurrent support inflations initiated from that baseline,
the ACAP adjunct at that level, and
the expiratory-control algorithm for any inflation cycles initiated from that baseline.
Note 7 to entry: Ventilation modes in which ACAP is always active, at both the BAP and inspiratory pressure levels,
may alternatively be labelled as bi-level ventilation modes.
Note 8 to entry: In a CPAP ventilation mode, the baseline at the set CPAP pressure level becomes the reference level
for the ACAP adjunct that enables continuous unrestricted breathing at that constant level.
Note 9 to entry: See also PEEP (4.11.2), ACAP (4.9.2), bi-level ventilation (4.9.5), CPAP (4.8.13), BAP phase (4.3.3)
BAP-high (4.9.10) and Figures C11 (Annex C).
4.11.2
PEEP
positive end-expiratory pressure
respiratory pressure at the end of an expiratory phase
Note 1 to entry: In addition to its direct reference, this term or its acronym, is used in this vocabulary to designate
this concept as a measured quantity. Without qualification the quantity is always that at the patient connection port
and relative to ambient pressure. When used as part of a post-coordinated term it may be attributed to other
measurement sites or reference pressure levels. The term, in its acronym form only, may also be used as an admitted
term for the designation of the set value of the baseline airway pressure level (which encompasses the setting for the
end-expiratory pressure), thereby acting as a synonym for BAP. For further information on PEEP as an admitted term
see 4.11.1.
Note 2 to entry: As a measured quantity, the qualification ‘positive’ is not strictly necessary but its use is retained
because it places emphasis on one of the main purposes for which PEEP is used: that of wanting to retain at least a
minimum ‘positive’ pressure in the alveoli in order to guard against their collapse.
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Note 3 to entry: Since its early use, this term has been used to designate this concept as both a setting and measured
value with very little clarity as to which. As the term for a measurement it has been post-coordinated to form terms
such as auto-PEEP, intrinsic PEEP, alveolar PEEP, total PEEP, dynamic intrinsic PEEP, dynamic extrinsic PEEP,
dynamic total PEEP and applied PEEP. The term extrinsic PEEP has also been used to designate the PEEP at the
patient connection port but it is usually not clear whether that is for the set or the actual value. Although, ideally both
will have the same value the actual value is not dependent on the set value alone and may have a higher or lower
value, depending on other factors such as the expiratory time, any ventilator breathing system or airway device
leakage, or patient effort. An inspection of current ventilator labelling demonstrates that there is very little
consistency in the way these various forms of the term are used and what they designate.
In practice, on modern electronically controlled ventilators, there is still only the need for one term for the
designation of the intended PEEP but a need for an increasing number of terms to designate the various measured
outcomes that can be displayed. With the increased significance of the concept of a baseline airway-pressure on such
ventilators (for further information see 4.11.1), and because the intended PEEP is simply a specific point on that
baseline, there is now a strong case for using the set BAP as the designator for both. This then leaves the acronym
PEEP, along with its various post-coordinations, free to designate only measured quantities on those ventilators
where there are one or more measured values to be displayed or recorded. However, on basic ventilators and
resuscitators, where the concept of baselines is not relevant, and where no independent measured PEEP values are
displayed or recorded, then it is logical to retain PEEP as the designator for the set value. These considerations are
the basis for the notation adopted in this vocabulary.
Note 4 to entry: The measured value of this quantity informs the operator as to how closely the actual airway
pressure at the end of expiration corresponded with the set BAP value. Ideally, it will have the same value as the set
BAP, but is not dependent on this setting alone and may, therefore, have a higher or lower value, depending on other
factors such as the expiratory time, any ventilator breathing system or airway device leakage, or patient effort.
Note 5 to entry: See BAP (4.11.1) for further information on the context in which PEEP is used in this vocabulary.
Note 6 to entry: See also total PEEP (4.11.4), dynamic PEEP 4.11.5) and F.1 (Annex F).
4.11.3
expiratory-control algorithm
algorithm that determines the expiratory-pressure waveform of an expiratory phase
Note 1 to entry: The algorithm used for a specific mode is specified by the manufacturer.
Note 2 to entry: The expiratory-control algorithm takes the relevant baseline airway-pressure as its reference
throughout the corresponding phases. See note 1 to the baseline airway pressure entry (4.11.1).
Note 3 to entry: The main purpose of the algorithm is that of managing the expiratory-pressure waveforms following
inflations and unassisted inspirations in order to achieve a required objective(s) throughout each expiratory phase.
Note 4 to entry: A basic expiratory-control algorithm may be no more than that of switching the expiratory valve to
its open state, leaving the expiratory flow waveform and the minimum expiratory pressure to be determined by an
expiratory pressure-relief function (commonly known as a PEEP valve), which is set to the required BAP level. This
relieves expiratory pressure by allowing expiratory flow to pass through to the exhaust port with minimal resistance
when above the BAP level, but which prevents expiratory flow below that level. However, with this arrangement,
once the expiratory flow has ceased, any leakage from the ventilator breathing system or from an airway device may
cause the pressure to continue to fall so that by the end of expiration the measured airway-pressure, PEEP, could be
below that set. For further information on expiratory pressure-relief see 4.5.10.
Note 5 to entry: An increasing number of ventilators now incorporate ventilation control functions that are able to
generate required expiratory-pressure waveforms irrespective of both inspiratory and expiratory flow during both the
inspiratory and expiratory phases of a primary inflation. With these functions activated the patient is able to inspire
and expire at any time at either the BAP or the primary-inflation inspiratory pressure (or BAP-high) level. These
inspirations may be unassisted or supported.
During expirations an expiratory-control algorithm may be used to continuously control the expiratory-pressure
waveform in order to achieve an optimum rate of pressure decay. This may include, for example, achieving a faster
lung deflation rate by temporarily reducing the airway pressure below the baseline level in early expiration but
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bringing it back up to baseline pressure early enough to ensure that the pressure in the lungs never decreases below
the baseline level during that phase
With this function acting alone during a BAP phase, an unassisted inspiration may incur additional work of breathing,
and if there is a leak in the ventilator breathing system or at the connection to the patient, the airway pressure may fall
towards the ambient pressure, which will result in a loss of the intended PEEP. Such consequences may be mitigated
by the provision of a bias flow or prevented by the provision of demand flow or an ACAP adjunct, active at the BAP
level.
Note 6 to entry: See also the notes to the baseline airway-pressure entry (4.10.1), Figure F.1 and Figures F.3a to d
(Annex F).
4.11.4
total PEEP
tPEEP
DEPRECATED: intrinsic PEEP
DEPRECATED: auto PEEP
airway pressure at the end of an expiratory-hold procedure that temporarily occludes the upper
airway, in the absence of any respiratory effort
Note 1 to entry: In addition to its direct reference, this term is only used in this vocabulary, in context or by
qualification, to designate this concept as a measured quantity (4.13.20).
Note 2 to entry: As the pressure at the patient-connection port falls during expiration, there is an unavoidable
dynamic lag in the corresponding rate of fall of the alveolar pressure, mainly due to airway-resistance and flow
limitation factors. Normally, the effects of this lag will have fully dissipated by the end of the expiratory phase, but
with shorter expiratory times or with diseased lungs, the average alveolar pressure may still be above the measured
expiratory pressure at the end of the expiratory phase. The amount by which this average alveolar pressure exceeds
the measured positive end-expiratory pressure, PEEP, cannot be measured directly but its presence and order of
magnitude is commonly ascertained by the use of an expiratory-hold procedure. The airway pressure measurement at
the end of this procedure is the average of that of the pressurised gas in the alveoli that has been able to distribute
uniformly throughout the lung during the expiratory-hold time, but it may not fully include the contribution of any
trapped gas to the true average pressure.
Note 3 to entry: This term is typically only used in relation to the ventilation of patients with diseased lungs, where
the presence of dynamic PEEP may be indicated or suspected. In the absence of any dynamic PEEP, a measured total
PEEP has the same value as the measured PEEP for the same expiration and, therefore, has no relevance, other than to
show that there is no dynamic PEEP.
Note 4 to entry: Because of the diverse nature of diseased lungs there is currently no precise definition of a single
concept of total PEEP in an artificially ventilated patient, other than the value measured at the end of an inspiratoryhold procedure during which there is no respiratory effort. This has, therefore, been adopted as the reference
method for the determination of the value of this quantity in this vocabulary although a substantially equivalent value
may be determined by other methods.
Note 5 to entry: See also dynamic PEEP (4.11.5), PEEP (4.11.2), baseline airway-pressure (4.11.1), and Figures F.1a –
F.1d (Annex F).
Note 1 to deprecated terms: These terms are deprecated as synonyms for total PEEP in this vocabulary because,
although they are both widely used, there is a clear lack of consensus in the scientific literature and in manufacturer’s
labelling as to whether either or both refer to total PEEP or dynamic PEEP.
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4.11.5
dynamic PEEP
dPEEP
DEPRECATED: intrinsic PEEP
DEPRECATED: auto PEEP
portion of total PEEP that is above PEEP
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured quantity (4.13.20)
Note 2 to entry: As the pressure at the patient-connection port falls during expiration, in the absence of respiratory
efforts there is an unavoidable dynamic lag in the corresponding rate of fall of the alveolar pressure, mainly due to
airway-resistance and flow limitation factors. Dynamic PEEP represents the portion of total PEEP resulting from this
dynamic lag that would not have been present if the expiratory (or BAP) time had been extended by the duration of
the expiratory hold.
Note 3 to entry: If there is insufficient expiratory time for the expiratory pressure to reach its baseline airway-pressure
level before the end of expiration then PEEP will be greater than that intended by the BAP setting.
Note 4 to entry: See also total PEEP (4.11.4), PEEP (4.11.2), baseline airway-pressure (4.11.1), and Figures F.1a – F.1d
(Annex F).
Note 1 to deprecated terms: These terms are deprecated as synonyms for dynamic PEEP in this vocabulary because,
although they are both equally widely used, there is a clear lack of consensus in the scientific literature and in
manufacturer’s labelling as to whether either or both refer to dynamic PEEP or total PEEP.
4.11.6
delta PEEP
ΔPEEP
quantity by which PEEP exceeds BAP
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a measured or calculated quantity (4.13.20).
Note 2 to entry: Typically there will be no difference between PEEP and the set BAP, but where a difference arises the
operator should be aware of the possible implications. A positive difference may indicate too short an expiration time
or a restriction in the ventilator’s expiratory pathway (for example, a contaminated filter). A negative difference may
indicate that the alveolar pressure is being allowed to drop below the intended minimum level due to uncompensated
leakage from the ventilator breathing circuit or at the airway device.
Note 3 to entry: See also Figure F.1a – F.1d (Annex F), BAP (4.11.1) and PEEP (4.11.2).
4.12 Safety limits and alarm terminology
4.12.1 Safety limits
4.12.1.1
pressure limit
airway-pressure limit
airway-pressure threshold value for the initiation of an action to protect the patient during
normal use
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 2 to entry: This is a general, pre-coordinated term that is the basic definition for high and low limitation
functions and for associated functions such as defining alarm conditions and other means of protection.
Note 3 to entry: The limit is to be taken to be for a rising pressure unless specified otherwise. This not only accords
with common usage but also avoids a possible confusion resulting from the use of the word ‘high’, which is used in
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the limit and alarm terms in this vocabulary with a meaning of ‘higher than intended’, as distinct from ‘the opposite of
low’.
Note 4 to entry: See also limit (4.13.23).
4.12.1.2
pressure-limited
pLim
inspiratory pressure limited to the set pressure limit during normal use, by means of an
inspiratory pressure relief function
Note 1 to entry: This limitation is typically used in conjunction with volume control inflation-types where the
intention is to limit the maximum pressure that can be generated at the patient connection port during normal use
Note 2 to entry: A pressure relief function spills excess regulated flow to atmosphere, if necessary to avoid the
inspiratory pressure exceeding the set level. This results in a possibly un-quantified loss of the delivered volume. See
also inspiratory pressure relief (4.5.5).
Note 3 to entry: This function may be associated with an alarm condition.
Note 4 to entry: See Figure C.2 (Annex C) for an example of a pressure limited inflation.
4.12.1.3 maximum limited pressure
maximum limited airway-pressure
DEPRECATED: maximum circuit pressure limit
highest airway pressure during normal use or under single fault condition
Note 1 to entry: In addition to its direct reference as a requirement, this term is only used, in context or by
qualification, to designate this concept as a set quantity (4.13.19).
Note 2 to entry: As with all unqualified airway pressures, this limited pressure is that at the patient connection port
and relative to ambient pressure.
Note 3 to entry: As this is the highest level precaution against excessive pressures being applied to the patient’s
airway this is a manufacturer’s set value.
[SOURCE: ISO/IEC 80601-2-12: 2011, modified by the addition of semantic notes.]
4.12.1.4
maximum deliverable airway-pressure
DEPRECATED: maximum working pressure
maximum airway pressure that can be generated by the ventilator during intended use and
normal condition
Note 1 to entry: This information is usually documented in the instructions for use as it is valuable to determine
whether a ventilator is suitable for use with a particular patient with poor lung compliance.
4.12.1.5
high-airway-pressure limit
<setting> threshold value at which a protection device prevents any further rise in the airway
pressure
Note 1 to entry: The protection device may maintain the pressure at a level close to the threshold value, reduce the
pressure to the set baseline airway pressure (BAP) or terminate the inflation phase. One or more of these alternatives
will be required by the particular standard that covers the class of ventilator to which the term may be applied.
Note 2 to entry: The set limit may be:
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•
•
•
•
independently adjustable
connected to an adjustable pressure limit
connected to the high airway pressure-alarm limit
related to the set inflation pressure.
Note 3 to entry: See also inspiratory pressure relief (4.5.5)
4.12.1.6
high-pressure relief limit
high-airway-pressure relief limit
airway pressure threshold value used by a ventilator to determine when a protection device
prevents any further rise in airway pressure during normal use
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 2 to entry: As with all unqualified airway pressures, this limited pressure is that at the patient connection port
and relative to ambient pressure.
Note 3 to entry: During an inflation, the high pressure relief protection device is intended to maintain the airway
pressure at the threshold value, without terminating the inflation.
Note 4 to entry: Activation of this form of airway pressure limitation will often cause a drop in the inspiratory volume.
Operator awareness of this characteristic may be important for patient safety.
Note 5 to entry: The set limit may be independently adjustable, linked with an adjustable pressure limitation, related
to the set inspiratory pressure or determined by an algorithm but it must always be at a higher value than the
maximum inspiratory-pressure that will result from the operator’s settings during normal use.
Note 6 to entry: The set limit may be associated with an alarm limit.
Note 7 to entry: See also high pressure termination limit (4.12.1.7)
4.12.1.7
high-pressure termination limit
high-airway-pressure termination limit
airway pressure threshold value used by a ventilator to determine when a protection device
terminates the current inflation phase during normal use
Note 1 to entry: This form of airway pressure limitation will often result in the delivered volume falling below the
intended tidal volume. Operator awareness of this characteristic is important for patient safety.
Note 2 to entry: As with all unqualified airway pressures, this limited pressure is that at the patient connection port
and relative to ambient pressure.
Note 3 to entry: The set limit may be independently adjustable, connected to an adjustable pressure limitation, may
be related to the set inflation pressure or may be determined by an algorithm but it must always be at a higher value
than the maximum inspiratory-pressure that will result from the operator’s settings during normal use.
Note 4 to entry: This function may be associated with an alarm condition. Particular Standards may have specific
requirements
Note 5 to entry: This may have the same as or different threshold from the high-airway-pressure alarm condition.
Particular Standards may have specific requirements
Note 6 to entry: See also high pressure relief limit (4.12.1.6) and Figure C.2c (Annex C).
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4.12.1.8
maximum settable inspiratory pressure
maximum inspiratory-pressure that can be set by the operator
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19), which will typically be pre-set by the manufacturer or the responsible
organization
Note 2 to entry: As with all unqualified airway pressures, this inspiratory pressure is that at the patient connection
port and relative to ambient pressure unless prefixed with ‘delta’ or the symbol Δ. See inspiratory pressure (4.5.2).
4.12.1.9
adjustable pressure limit
adjustable airway pressure limit
APL
<setting> operator-set limitation on the airway pressure under normal condition
EXAMPLE: APL valve on anaesthesia breathing system
4.12.2 Alarm conditions
4.12.2.1
alarm condition
state of the alarm system when it has determined that operator awareness or response is
required for a potential or actual hazardous situation
Note 1 to entry: An alarm condition can be invalid, that is, a false positive alarm condition.
Note 2 to entry: An alarm condition can be missed, that is, a false negative alarm condition
Note 3 to entry: The alarm condition may be patient related, technical, healthcare provider related or environmental
Note 4 to entry: This definition has been submitted to the ISO/IEC joint working group on Medical Device Alarm
Systems for inclusion in the next edition of IEC 60601-1-8
Note 5 to entry: It is intended that the term alarm condition be used by standards writers within post-coordinated
terms, for example, high spontaneous breathing rate alarm condition
[SOURCE: IEC 60601-1-8 2006+A1:2012 Clause 3.1, modified]
4.12.2.2
high-pressure alarm condition
high-airway-pressure alarm condition
alarm condition resulting from a high airway pressure
Note 1 to entry: The high-airway-pressure alarm condition may be subject to an alarm condition delay or there may
be an alarm signal generation delay after the onset of an alarm condition.
Note 2 to entry: This may have the same or a different threshold than the high-pressure relief or termination limit.
Particular standards may specify specific requirements for such alternative possibilities.
Note 3 to entry: As with all unqualified airway pressures, this alarm limit pressure is that at the patient connection
port and relative to ambient pressure.
Note 4 to entry: See also high-airway-pressure relief limit (4.12.1.6) and high-airway-pressure termination limit
(4.12.1.7).
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4.12.2.3
continuing pressure alarm condition
continuing airway-pressure alarm condition
alarm condition resulting from an airway pressure that has remained at or exceeded a threshold
level for a threshold length of time
Note 1 to entry: The threshold level and length of time will be as disclosed in the instructions for use.
Example: An alarm condition determined when the airway-pressure is held at the set inspiratory-pressure for 3
seconds longer that the set inspiratory time.
Example: In an anaesthesia ventilator breathing system (anaesthesia VBS) in CSV mode with the airway pressure limit
valve closed or partially closed with medical gas flowing into the VBS.
4.12.2.4
low inspiratory-pressure alarm condition
state of the alarm system when it has determined that operator awareness or response is
required for a potential or actual hazardous situation caused by low inspiratory airway pressure
4.12.2.5
low PEEP alarm condition
alarm condition determined when the end-expiratory pressure is less than the set BAP
4.12.3 Alarm limits
4.12.3.1
alarm limit
threshold used by an alarm system which likely differentiates between safe use (tolerable risk)
and potential or actual harm
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 2 to entry: The set alarm limit parameter may be independently adjustable, linked with an adjustable parameter
limitation, related to a set parameter or determined by an algorithm.
Note 3 to entry: This definition has been submitted to the ISO/IEC joint working group on Medical Device Alarm
Systems for inclusion in the next edition of IEC 60601-1-8
[SOURCE: IEC 60601-1-8 2006+A1:2012 Clause 3.3, modified]
4.12.3.2
high-airway-pressure alarm limit
upper airway pressure threshold used by an alarm system which likely differentiates between
safe use (tolerable risk) and potential or actual harm
Note 1 to entry: the threshold is always greater than the maximum inspiratory pressure intended by the operator’s
settings
Note 2 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 3 to entry: The set high-airway-pressure alarm limit may be independently adjustable, connected to an
adjustable pressure limitation or may be related to the set inspiratory pressure.
Note 4 to entry: The high-airway-pressure alarm limit setting may be different from that of the high-pressure limit.
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4.12.3.3
low inspiratory-pressure alarm limit
lower airway pressure threshold used by an alarm system which likely differentiates between
safe use (tolerable risk) and potential or actual harm
Note 1 to entry: In addition to its direct reference, this term is only used, in context or by qualification, to designate
this concept as a set quantity (4.13.19).
Note 2 to entry: The set low-inspiratory-pressure alarm limit may be independently adjustable or may be related to
the set inspiratory pressure.
4.13 General artificial ventilation terminology
4.13.1
ventilator
lung ventilator
medical device or medical electrical equipment intended to automatically contribute to, or
totally control, the ventilation of the lungs of the patient
Note 1 to entry: See also ventilation (4.13.6).
[SOURCE: ISO 80601-2-12:2011, definition 201.3.222 modified]
4.13.2
airway
connected, gas-containing cavities and passages within the respiratory system, that conduct gas
between the alveoli and the oral and nasal orifices on the surface of the face, or the patientconnection port if an airway device is used
Note 1 to entry: This is a well-established term that is commonly used in isolation in references to the airway of a
patient. Depending on the context, it is sometimes more helpful to use the qualified term, patient’s airway.
Note 2 to entry: See also airway device (4.13.3).
4.13.3
airway device
device intended for use as an interface between the patient-connection port of a ventilator and
the patient's airway, and which has no auxiliary features on which the ventilator is dependent
for its normal operation
EXAMPLES: endotracheal tube; tracheotomy tube; face mask; supralaryngeal airway.
Note 1 to entry: The connection to the patient’s airway may be at the face or internal to the patient.
Note 2 to entry: A face mask that intentionally vents respiratory gas to atmosphere by means of a bleed orifice is a
functional part of the ventilator breathing system and therefore not an airway device. With that arrangement the face
seal of the mask becomes the patient-connection port and there is no patient-connection port connector, nor an airway
device.
4.13.4
airway resistance
drop in pressure between the patient connection port and the alveoli per unit rate of airway
flow
Note 1 to entry: The airway resistance is normally expressed as a single coefficient, with the implicit assumptions
that it is independent of the flow rate and of the direction of flow. In practice, these assumptions are typically only
approximately valid.
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Note 2 to entry: See also airway (4.13.2).
4.13.5
lung compliance
measure of the ability of the lung to expand, expressed as the unit change of lung volume
required to achieve unit change of transpulmonary pressure
Note 1 to entry: The lung compliance is normally expressed as a single coefficient, with the implicit assumptions that
it is independent of the volume of gas in the lung and of any hysteresis between increasing and decreasing volumes.
In practice, these assumptions are typically only approximately valid.
4.13.6
ventilation
movement of gas into and out of the lungs
Note 1 to entry: This may be by external or spontaneous means, or by a combination of both.
Note 2 to entry: See also spontaneous breath (4.1.3), artificial ventilation (4.13.7), automatic ventilation (4.13.8),
mechanical ventilation (4.13.8), negative-pressure ventilation (4.13.11), positive-pressure ventilation (4.13.10) and
inflation (4.2.1).
4.13.7
artificial ventilation
ventilation in which a non-zero proportion or all of the work of breathing is provided by
external means
Note 1 to entry: Examples of the means used to provide artificial ventilation are: manual resuscitation; mouth-tomouth resuscitation; automatic ventilator; mechanical ventilator; manually-triggered resuscitator.
Note 1 to entry: Common classifications of areas of application of artificial ventilation are: emergency; transport;
home-care; anaesthesia; critical care; rehabilitation.
Note 2 to entry: Classifications used to denote means used for artificial ventilation include: positive-pressure;
negative-pressure; gas-powered; operator-powered; electrically-powered.
4.13.8
automatic ventilation
continuous artificial ventilation by means of an automatic device
Note 1 to entry: With automatic ventilators within the scope of this International Standard, artificial ventilation is
achieved by the use of positive-pressure ventilation.
4.13.9
mechanical ventilation
continuous artificial ventilation by means of a mechanical device
Note 1 to entry: This term has become the commonly used term for any form of artificial ventilation that involves a
specifically designed equipment having several mechanical or electrical/electronic parts.
Note 2 to entry: A mechanical ventilator may provide artificial ventilation automatically or by manual operation and
may provide positive-pressure ventilation or negative-pressure ventilation.
4.13.10
positive-pressure ventilation
DEPRECATED AS SYNONYM: IPPV
artificial ventilation achieved by the intermittent elevation of the airway pressure above the set
baseline airway pressure
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Note 1 to entry: This is a general term for artificial ventilation achieved by the intermittent application of a raised
pressure to some part of the patient’s airway in order to assist or control an increase in the volume of gas in the lung.
Each such intermittent elevation of the airway pressure constitutes an inflation.
Note 2 to entry: The original term for this means of applying artificial ventilation was intermittent positive-pressure
ventilation (IPPV) but since the almost universal adoption of the practice of retaining some level of positive airway
pressure at the end of expiration the ‘positive pressure’ is no longer intermittent because the airway pressure is
continuously positive. Although it is only possible to achieve positive-pressure artificial ventilation by intermittently
changing the airway pressure, whether it is intermittent elevation or intermittent release of the pressure depends on
the objective and settings. With its now wide acceptance in the practice of artificial ventilation, the qualifying term
‘positive-pressure’ is, therefore, all that is required to distinguish it from alternative means of artificial ventilation.
Note 3 to entry: See also inflation (4.2.1), airway pressure (4.5.1) and baseline airway pressure (4.11.1).
4.13.11
negative-pressure ventilation
NPV
artificial ventilation achieved by intermittently changing a negative pressure applied to the
exterior of the patient's thorax
Note 1 to entry: Although many of the terms will be common, the scope of this edition of this International Standard
does not include vocabulary specific to negative-pressure ventilation.
Note 2 to entry: See Scope (1)
4.13.12
non-invasive ventilation
NIV
positive-pressure ventilation without the use of an invasive airway device
Note 1 to entry: The connection to the patient is typically by means of a specially designed face or nasal mask.
Note 2 to entry: This vocabulary is equally applicable to non-invasive ventilation (NIV) systems but the modes and
settings made available for intended non-invasive ventilation use may be specifically adapted to accommodate the
particular characteristics and uncertainties of that procedure.
Note 3 to entry: In this vocabulary, this term is not applicable to the designation of breathing therapy equipment as a
class separate from ventilation equipment.
4.13.13
tube compensation
TC
assistive offset of pressure provided by the ventilator during the inspiratory phase of an
unassisted or assisted spontaneous breath, or during an expiratory phase, solely in order to
compensate, at least in part, for the added airway resistance imposed by an airway device
Note 1 to entry: Tube compensation is not classified as an inflation-type because its intention is to provide
compensation for an artificially imposed resistive load and not to contribute to the patient’s work-of-breathing.
Note 2 to entry: The assistive offset is typically calculated by the ventilator, based on information entered by the
operator, for example, the inside diameter of an endotracheal tube.
Note 3 to entry: The assistive offset is not intended to support the patient's elastic load.
Note 4 to entry: To achieve compensation during the expiratory phase of a breath the airway pressure may be reduced
below the baseline airway pressure for part of the expiratory phase but this vocabulary does not sanction the
intentional application of sub-ambient pressures to the patient connection port.
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4.13.14
lung
shorthand name for the connected, respiratory-gas containing cavities within the respiratory
system, extending from the surface profile of the face, or from the patient connection port if an
airway device is used, through to the alveoli
Note 1 to entry: In the absence of a more suitable term it has become common practice to use this name to identify
the respiratory-gas containing parts of the respiratory system identified by this definition. It is inclusive of what is
generally referred to as the airway as well as the lobes containing the alveoli. In this simplified model, one, or two,
compliant chamber(s) are connected to a patient-connection port connector by means of a pneumatic resistance. This
concept has proven to be useful in discussing lung mechanics and as the basis for the pneumatic simulation of the
respiratory system by what has become known as a test lung.
Note 2 to entry: This name is not a synonym for the lungs, the clinical name for the pair of organs within the ribcage,
which contain the alveoli.
Note 3 to entry: See also lungs (4.13.15).
4.13.15
lungs
pair of organs within the ribcage (thorax), connected to the atmosphere by an airway through
which, during natural breathing, air is cyclically drawn and then expelled, and which provide
gas/blood interfaces that enable oxygen from the air to pass into the blood and carbon dioxide
to be removed
4.13.16
respiratory system
anatomical system related to breathing including the upper airway, lower airways, lungs, chest
wall, pleural space, brainstem respiratory control centre, phrenic nerves, neuromuscular
junctions, diaphragm and accessory muscles of ventilation
4.13.17
respiratory system coefficients
value of those parameters that affect the work of breathing (for example lung and airway
compliance and resistance), but which are not directly affected by a patient's respiratory activity
NOTE1: Although generally treated in respiratory mechanics as having a constant value,
respiratory system coefficients vary with volume and flow, as appropriate. They may also vary
with time, sometimes rapidly, during a ventilation procedure.
4.13.18
ventilator breathing system
VBS
anaesthesia breathing system
pathways through which gas flows to or from the patient at respiratory pressures, bounded by
the port through which respirable gas enters, the patient-connection port and the gas exhaust
port
Note 1 to entry: These pathways typically extend within and outside the body of the ventilator, with those outside
being operator-detachable.
Note 2 to entry: The port of entry of a respirable gas into the ventilator breathing system may be inside the body of
the ventilator and should not be confused with an external connection port into which respirable gas enters before
being reduced to respirable pressures.
Note to admitted term: This admitted term is included in this vocabulary for use in reference to the specific class of
ventilators that are configured to ventilate patients with an anaesthetic gas mixture. With this application the
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definition may be made more specific with ‘respirable gas’ becoming ‘anaesthetic gases and the ‘port through which
respirable gas enters’ becoming the ‘fresh-gas inlet’.
[SOURCES: ISO 4135:2001, definitions 3.1.6 and 4.1.1, modified and 80601-2-12:2011, definition
201.3.221, modified]
4.13.19
set
prescribed in advance
EXAMPLE 1:
EXAMPLE 2:
A set pressure limit.
The set inspiratory pressure.
Note 1 to entry: This term is used in this vocabulary as a prefix to distinguish an intended value of a quantity from an
actual or measured value of the same quantity. In common usage it is sometimes used as a prefix to such terms as
‘mode’, ‘inflation-type’ or ‘function’ but the word ‘selected’ is considered more appropriate for that purpose.
Note 2 to entry: As a prefix, this term qualifies a term denoting a quantity if this attribution is not clear from the
context of use, although such a qualification is unnecessary when the base term is used in the context of ‘settings’, for
example, on a labelled key in the ‘settings’ sector of a users’ interface.
Note 3 to entry: A set value may be determined directly or indirectly.
Note 4 to entry: A value is directly set if the operator sets or selects a value that is intended to become the actual
value of that quantity, for example, the intended duration of an inspiratory time.
Note 5 to entry: A value is indirectly set if the operator sets or selects a value that:
→
→
→
only partially contributes to the actual set value,
sets or selects values of more than one setting, which, together, result in a calculated set value, or
selects an algorithm that determines the setting based on other settings or measurements.
Note 6 to entry: A value may also be set by other means, for example, remotely, as a default setting by the responsible
organization, or by accessing a pre-set value.
Note 7 to entry: Examples of set values are the indicated value on a calibrated setting device and the displayed value
on a calibrated device that is independent of the setting device.
Note 8 to entry: See also the reference to settings in 4.13.19 and inAnnex G.
4.13.20
measured
determined by a measuring device or system
Note 1 to entry: This term is used in this vocabulary as a prefix to distinguish the value of a quantity as determined
by a measuring device or system, from an actual value or set value of the same quantity.
Note 2 to entry: Measured values may be displayed or recorded as discrete values or as a continuous waveform.
Note 3 to entry: As a prefix, this term is used to appropriately qualify a term denoting a quantity if this attribution is
not clear from the context of use but such a qualification is unnecessary when the base term is used in the context of
‘measured values’, for example, on a labelled display in the ‘measurements’ sector of a user interface or on a
continuous trace of measured ventilation parameters.
Note 4 to entry: The value of the quantity being measured may be the direct result of its setting, the composite result
of a setting and other influences not being directly regulated, or completely independent of any ventilator settings.
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The displayed measured value of a quantity resulting from a setting is sometimes referred to as the ‘set’ value but
wherever this is done the distinction is to be maintained.
Note 5 to entry: A displayed or recorded measured value may be a value calculated from the results of more than one
measurements of other quantities.
Note 6 to entry: See also Annex G.2.
4.13.21
preset value
one of a set of stored configuration parameter(s), including selection of algorithms and initial
values for use by algorithms, which affect or modify the performance of the ventilator
Note 1 to entry: Presets are commonly configured by the manufacturer or a responsible organization.
Note 2 to entry: Access to a pre-set value(s) is typically controlled by:
-
-
a tool,
a responsible organization password and a technical description, separate from the
instructions for use,
an individual operator password,
voice recognition, or
biometric means.
4.13.22
actual value
value of a quantity as it exists in fact
Note 1 to entry: This is the true value of a quantity, which may, or may not, be determinable by a measuring device.
Note 2 to entry: The definitions of terms denoting quantities, in this vocabulary, denote the actual value of that
quantity. Set values are the means by which an operator informs the ventilator of the intended actual value and
measured values are displays or records of the actual value, to the accuracy and resolution of the measuring system.
4.13.23
limit
point or level beyond which the value of a patient parameter may not pass without an action by
the ventilator
Note 1 to entry: The action may be a notification or the implementation of means to prevent or mitigate a hazardous
situation.
Note 2 to entry: In this Vocabulary this term is restricted to the designation of safety constraints that provide patient
protection that is completely independent of the controlled ventilation parameters.
Note 3 to entry: An alarm system uses an alarm limit in determining an alarm condition.
Note 4 to entry: See also safety limits and alarm terminology (4.12).
4.13.24
normal use
operation, including routine inspection and adjustments by any operator, and stand-by, according
to the instructions for use
Note 1 to entry: Normal use should not be confused with intended use. While both include the concept of use as
intended by the manufacturer, intended use focuses on the medical purpose while normal use incorporates not only
the medical purpose, but maintenance, service, transport, etc. as well.
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[SOURCE: IEC 60601-1:2005, definition 3.71]
4.13.25
intended use
intended purpose
use of a product, process or service in accordance with the specifications, instructions and
information provided by the manufacturer
Note 1 to entry: Intended use should not be confused with normal use. While both include the concept of use as
intended by the manufacturer, intended use focuses on the medical purpose while normal use incorporates not only
the medical purpose, but maintenance, service, transport, etc. as well.
[ISO 14971:2000, definition 2.5]
4.13.26
normal condition
condition in which all means provided for protection against hazards are intact
[SOURCE: IEC 60601-1:2005, definition 3.70]
4.13.27
single fault condition
condition in which a single means for reducing a risk is defective or a single abnormal condition
is present
[SOURCE: IEC 60601-1:2005, definition 3.116]
4.13.28
accompanying document
document accompanying medical electrical equipment, a medical electrical system, equipment
or an accessory which contains information for the responsible organization or operator,
particularly regarding basic safety and essential performance
[SOURCE: IEC 60601-1:2005, definition 3.4, modified]
4.14 Gas Port Terminology
4.14.1
port
opening for the passage of a fluid through a specified interface
Note 1 to entry: Typical interfaces where ports occur are
•
•
•
where gas enters a medical device,
where operator detachable tubing is connected to a medical device and
where a ventilator breathing system is connected to the patient or to an airway device.
Note 2 to entry: A port will be typically, but not necessarily, in the form of a specific connector.
4.14.2
gas intake port
port through which a respiratory gas is drawn for use by the patient
Note 1 to entry: For anaesthetic ventilators the respiratory gas is typically the fresh gas from an anaesthetic machine
and for blower-based ventilators it will be typically ambient air.
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[SOURCE: ISO 80601-2-12, definition 201.3.208 modified]
4.14.3
emergency air intake port
dedicated intake port through which ambient air may be drawn when the supply of respiratory
gas is insufficient or absent
[SOURCE: ISO 4135:2001, definition 3.2.3 modified]
4.14.4
exhaust port
port of the medical electrical equipment or device from which gas is discharged to the
atmosphere during normal use, either directly or via an anaesthetic gas scavenging system.
[SOURCE: ISO 80601-2-12, definition 201.3.205 modified]
4.14.5
gas output port
port of the medical electrical equipment or device through which gas is delivered at respiratory
pressures to an operator-detachable part of the ventilator breathing system
[SOURCE: ISO 4135:2001, definition 3.2.8 modified]
4.14.6
gas return port
port of the medical electrical equipment or device through which gas is returned at respiratory
pressures through an operator-detachable part of the ventilator breathing system, from the
patient-connection port
[SOURCE: ISO 80601-2-12, definition 201.3.210 modified]
4.14.7
gas input port
port to which gas is supplied under pressure
Note 1 to entry: Gas input ports may be labelled as for inflating gas, driving gas, high-pressure gas or low-pressure
gas.
[SOURCE: ISO 4135:2001, definition 3.2.10 modified]
4.14.8
patient-connection port
patient connection
port of a me equipment or device intended for connection to the patient or to an airway device
Note 1 to entry: The patient-connection port is generally part of the ventilator breathing system and is at the end
proximal to the patient.
Note 2 to entry: Although patient-connection port is the correct formal term as used in ISO ventilator standards it is
unnecessarily long for general use and the abbreviated term patient connection is adequate for use in that context.
Note 3 to entry: Particular standards invariably specify that the patient-connection port is required to be in the form
of a specific standardised connector(s), for example, one or more connectors conforming to ISO 5356.
Note 4 to entry: In ventilators designed to provide non-invasive ventilation (NIV) and where the ventilation function is
dependent upon a design feature of a component that connects the ventilator to the patient’s airway, then the patient-
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connection port becomes the contact line of the seal to the patient’s face and there is no patient-connection-port
connector.
Note 5 to entry: See also non-invasive ventilation (4.13.12).
[SOURCE: ISO 80601-2-12:2011, definition 201.3.218 modified]
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Annex A
(Informative)
Rationale and Guidance
A.1 General guidance
This Annex provides rationale for the important clauses of this document and is intended for
those who are familiar with the subject of this document but who have not participated in its
development. An understanding of the reasons for the main requirements is considered to be
essential for its proper application. Furthermore, as clinical practice and technology change, it is
believed that rationale for the present requirements will facilitate any revision of this document
necessitated by those developments.
The clauses and sub-clauses in this annex have been so numbered to correspond to the clauses
and subclauses in this International Standard to which they refer. The numbering is, therefore,
not consecutive.
A.2 Rationale for particular clauses and sub-clauses
Rationales for particular sub-clauses of Clause 4
The numbering of the following rationales corresponds to the numbering of the clauses in this
document. The numbering is, therefore, not consecutive.
Sub-clause 4.4 Rate terminology
The ventilation rate terms in this sub-clause have been grouped into two further sub-clauses. The
first of these groups comprises the terms that are commonly used on ventilator user interfaces.
The second group comprises those that may be required for specific purposes such as in technical
descriptions, clinical papers or data logging. The purpose of listing and defining them is to ensure
that, when used, they are always denoted by the same term.
As with other terms in this vocabulary, the purpose of these rate terms is solely to provide
standardised terms to reference to each of a range of related particular concepts. There is no
implied requirement that manufacturers should make use of every one of these terms in the
instructions for use and descriptions of their ventilation equipment.
Sub-clause 4.8
Mode terminology
The Introduction summarises the factors that led to a comprehensive review of the vocabulary of
artificial ventilation and the preparation of this International Standard. A key term in the review
was that of ventilation mode because the concepts behind it are fundamental to the structure of
the terminology presented in this vocabulary. An explanation of how the definitions associated
with it were derived is, therefore, an essential background to understanding that structure.
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Early devices for delivering automatic ventilation by means of intermittent positive pressure,
operated to a fixed cyclical pattern with a range of settings for just the basic parameters. As new
devices were developed additional ventilation patterns became available and these were
proposed and offered as selectable modes of operation. In order that specific modes could be easily
identified for selection in order to provide particular treatments these modes were given names
or acronyms.
However, with the increasing flexibility offered by electronic control systems, more and more
permutations and combinations of the basic elements of gas delivery were devised – to the point
where it was no longer practical to provide every set pattern with a unique name. Today, nearly
100 different names and approaching 30 mutually exclusive modes make it impossible to teach,
comprehensively, which mode to use in which clinical situation. Consequently, most users have
only been taught just a limited range of these modes and it has become very difficult for them to
relate different manufacturers’ modes to each other – a problem compounded by a lack of
consistency in the terminology used to describe them.
A simple analysis of the structure of these modes reveals that they all require the selection of both
the regulated parameter used to inflate the lungs and a pattern that determines when inflations
occur; functions that can be conveniently referred to as the inflation-type and the ventilation
pattern. It also becomes clear that, conceptually and from a clinical perspective, in most cases the
choice of inflation-type is largely independent of the choice of ventilation pattern.
In the vocabulary of this International Standard, this concept has been formalised with the
ventilation mode becoming a composite of two independent, operator-selectable elements,
classified as a mode pattern and an inflation-type, with the inflation-type determining how the
airway pressure and flow will be regulated during an inflation, once initiated, and the ventilation
pattern determining how the ventilator will respond to patient-trigger events and what and when
it will cause to be delivered irrespective of any patient actions.
This is a logical step because most of the clinically distinctive characteristics of the classical modes
that still form the foundation of modern ventilation modes are those that relate to the time-pattern
of interactive events between the ventilator and the patient, and which are largely independent
of the delivery-regulation means.
In practice, many manufacturers have already, at least partially, informally introduced such a
separation in the manner in which they have labelled their ventilator control panels and
structured their instructions for use.
From this perspective, it is pertinent to note that part of the confusion with respect to ventilation
modes resulted from manufacturers labelling their modes with names that feature just one of
these attributes; some modes may be labelled SIMV - a ventilation pattern, and others VCV – an
inflation-type. In accordance with this vocabulary both of these mode labels would be incomplete;
the correct mode designation requires both an indication of the ventilation pattern and the set
inflation-types; the examples would be, SIMV-PC or SIMV-VC and CMV-VC.
The above approach reduces the number of pre-coordinated names required significantly as any
of a number of inflation-types can be independently selected for use with each ventilation pattern
- instead of N*M different mode names to learn there become just M ventilation patterns plus N
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inflation-types. Ventilator operation can therefore be described as if made up from elements of a
construction set. As an example, it enabled a list of 58 mode names, taken from manufacturers’
literature, to be reduced to just 8 ventilation patterns and 8 inflation-types – each of which can be
placed into one of an even smaller number of easily remembered groups.
This format focuses on the pattern to which inflations are initiated and of the type of inflation that
is delivered, irrespective of which ventilation-pattern and inflation-type combination can be used
with which setting, and for which clinical intention. Not only is the number reduced but the
structured format of these names improves ventilator usability that is much easier to teach,
recognise, learn and remember.
With this perception of what constitutes a ventilation mode in current practice, in order to
understand how modes relate to each other, it is necessary to create a classification system that
groups them in terms of what they have in common and in what way they differ. It is considered
that present trends are likely to increase this disconnection between a functional classification of
ventilation patterns and clinical intention and that the only viable option is to base mode
classifications on function alone. When this is done, only three groupings are required. Teaching
can then be in terms of the common characteristics of, and mutual differences between, the
ventilation patterns in each group, and the appropriate settings for each of these ventilation
patterns for different clinical intentions. Additionally, with only 3 or 4 basic families of inflationtypes the instructions can be centred on the clinical considerations of the alternative methods of
inflation and of its termination. Most of this will be independent of the ventilation pattern with
which it will be used but some instruction will be necessary where the selected inflation-type may
affect the clinical intention of the resultant ventilation modes. Although, conceptually, around 20
standardised types of inflation could be made available for operator selection with each
ventilation pattern, in practice manufacturers will only offer the much more limited range of
combinations likely to be most used in clinical practice.
When viewed in this way it can be seen that, in the past, many ‘new’ modes that have been
introduced, with their own proprietary names, have in fact been nothing more than an easily
described sub-set of a standard inflation-type.
However, users will always be looking to use shorthand names in the day-to-day operation of
ventilators and this need is addressed in this vocabulary, as far as possible, by retaining commonly
used names as standardising generic ventilation-pattern and inflation-type names; although using
each one with its own standard definition. This will enable users to be able to operate current
ventilators the same as at present. The difference is that the named ventilation patterns and
inflation-types are classified into the main groups so those users interested in the differences
between modes will find that these are always explained from the same reference points. These
classifications also form the basis of the framework for the unique identification by name and
code for any mode within the scope of this vocabulary.
A further question may be as to where the trigger function for patient initiation fits into these
classifications. In some previous classification proposals, in which initiation is considered to be a
property of the inflation-type, the triggering-function was also included in these properties. In the
classification system of this vocabulary the initiation of an inflation is a property of the ventilation
pattern. However, a ventilation pattern is just a set of rules defining how the ventilator responds
© ISO 2016 – All rights reserved
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to various inputs. Logically, therefore, the ventilation pattern is simply responding to a signal from
a ventilator detection function indicating that the measurement of a patient parameter(s) has
passed a set threshold value. With this concept, the trigger function becomes just another
ventilation monitoring function that provides a signal to the ventilator control system. In practice,
most major manufacturers treat patient-triggering in this way - as an independently-selectable,
settable monitoring function to provide a signal when the monitored parameter reaches a set
level, as may be required by the selected ventilation pattern algorithm.
Sub-clause 4.8.4 - ventilation-mode groups
Mode groups have been introduced solely to provide a means of classifying modes to assist with
the understanding and teaching of how the large numbers of modes currently in use are related
to each other. There is no requirement for manufacturers to include reference to these groups in
product labelling but where used it is required to be in accordance with this International
Standard.
In this International Standard four mode groups have been specified; three based on ventilation
patterns and one comprised of named modes that relate, in particular, to supervisory and ancillary
functions. The defining characteristics of each of these groups are given in entry 4.8.4 ventilationmode groups.
Sub-clause 4.8.5 - assured ventilation
The admitted term, mandatory ventilation, is included in this International Standard because it
has become firmly established over several decades by its use in the mode names of CMV, IMV and
SIMV. In the early implementations of these modes both the initiation and the delivery was
imposed on the patient but with the modern approach to ventilation, which allows the patient to
contribute to their own ventilation as much as they are able, the term only makes sense when
used to convey the concept of the assured initiation of a selected inflation. This is the only sense
in which it is used in this International Standard. However, because the word mandatory is
ambiguous when used as a term in this context, in that it can allow the term to be taken to mean
either of these, and because this has allowed it to be used to give the appearance of unifying a
range of different concepts, the word is only used in the vocabulary in this International Standard
in reference to the traditional mode patterns that have it incorporated into their name. For other
purposes, natural language phrases such as ‘assured to be’ are used to convey the defined concept
wherever possible, in preference to the term mandatory or its inflected forms.
In the related semantics, the delivery of a mandatory-inflation causes mandatory ventilation of
the patient’s lungs but only in the sense that the selected type of inflation is assured to be initiated;
not that the inflation-type, in itself, will necessarily deliver an assured volume. It follows that the
term mandatory minute volume is the sum of the tidal volumes per minute that are due to
mandatorily initiated primary inflations. This may be less than the set minute volume although
the total minute volume will never be less than that set.
Sub-clause 4.8.13 - APRV (airway pressure release ventilation)
The rational for the introduction of this mode and its name was to allow patients with acute
oxygenation failure to breathe with better coordination, improved gas exchange and less
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barotrauma. The periodic release and near immediate subsequent build-up of airway pressure
was intended to assist the patient's own breathing efforts while not allowing the lungs to collapse.
Although that rational describes the essential concept of APRV it is recognised that, with this mode
selected, many manufacturers now permit the operator to set the BAP phase time (tL) to values
far in excess of any expected exhalation flow times. The justification for this is that the ongoing
treatment of a patient requiring APRV during the initial acute period may well involve the
progressive adjustment of the two BAP levels and also the two phase times, both as individual
values and their differentials, in order to provide a step-less continuity of treatment - working
towards a single, reducing, level of CPAP, without the discontinuity involved in changing over to
a different mode.
© ISO 2016 – All rights reserved
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Annex B
(Informative)
not used
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Annex C
Illustrations of Ventilation Terms
(Informative)
An important aspect identified in the development of the vocabulary of this International
Standard is that part of the present confusion in the use of ventilation terminology is the lack of
distinction between the setting perspective and the outcome perspective.
Most representations of ventilation patterns and inflations are based on typical waveforms as
seen on user interface displays, which is inevitably an outcome perspective. This is a helpful
approach when describing the interpretation of the function of a specific ventilator but
inevitably such a display introduces indeterminate artefacts and these can detract from the
clarity of a formal diagrammatical representation of the changes of state that are actually set to
occur.
In particular, although set flow changes can be made to occur almost instantaneously this is not
possible with pressure changes because of the impedance characteristics of a patient’s
respiratory system. With such changes at the initiation and termination of an inflation where,
conceptually, the set value makes a step change, in practice, the responses of pressure-regulator
functions have to be suitably restrained to set rise times in order to avoid excessive overshoots
and subsequent oscillations.
With this perspective, and as appropriate, diagrammatic representations of settings are shown
without artefacts whereas those of typical outcomes include them. The examples shown in
Figure C.1 illustrate typical differences, highlighted by the use of the colour coding employed in
other diagrams in this International Standard, with blue representing set parameters and green
representing outcomes.
Additionally, some of the figures in this Annex illustrate the waveforms that result when unusual
settings are used with named ventilation patterns; although these settings are within the range
available for such modes on currently manufactured ventilators.
These unusual waveforms are not shown with any intention of advocating the use of such settings
for a particular treatment, but to demonstrate how actual waveforms can be very different from
those normally provided to illustrate a mode function. Such illustrations highlight that the
ventilation waveforms that can be generated with a specific classical pattern-based mode, but
with unusual settings, are not necessarily all unique and some may overlap those that can be
generated with another of the classical patterns.
© ISO 2016 – All rights reserved
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1 Airway
pressure,
pAW
3
Inspiratory
pressure,
2
4
Ambient
pressure
6
Flow-regulated
Inflations
7
5 PEEP
BAP
Inspiratory time, tI
Inspiratory
flow
9
Inspiratory
flow
0
10
8
Expiratory
flow
Expiratoryflow time
11
Expiratory flow
waveform
1 Airway
pressure,
pAW
12
Rise time
13
Inspiratory pressure
2
4 BAP
Ambient
pressure
6
5
PEEP
Inspiratory time, tI (PC), (PS)
Pressure-regulated
Inflations
14
7
Inspiratory
flow
Peak
inspiratory
flow
0
8
Expiratory
flow
Figure C.1 —Format used in this International Standard for representations of ventilation
patterns and inflation-types
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2 Rise time
1 Airway
pressure
pAW
Inspiratory-pressure:
3 Waveform 4 Instantaneous
Expiratory-pressure:
9 Waveform 10 Instantaneous
5 Inspiratory
pressure
6 Peak
inspiratory
pressure
7
Δ Inspiratory
pressure
8 End
inspiratory
pressure
21
Ambient
pressure
11 BAP
12 PEEP
22 Baseline airway pressure
13 Inspiratory time
Key to colour scheme:
Set value
Measured value
14
Inspiratory
flow
16 Peak
inspiratory
flow
20 Expiratory flow time
0
17 Inspiratory flow time
15
Expiratory
flow
19 Peak
expiratory
flow
18 Expiratory-flow
waveform
© NSJ
(a) Typical airway pressure and flow waveforms for a pressure-control inflation
Figure C.2 (1 of 5) — Illustrations of the application of defined ventilation terms in
designating key features of typical inflation waveforms
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3 Rise time
2 Inspiratory
pressure
1
Airway
pressure,
pAW
Inspiratory-pressure:
4 Waveform 5 Instantaneous
Expiratory-pressure:
9 Waveform 10 Instantaneous
6 Peak
inspiratory
pressure
7
Δ Inspiratory
pressure
12 PEEP
11 BAP
22 Baseline airway
pressure
8 End
inspiratory
pressure
23 Ambient
pressure
Key to colour scheme:
Set value
Measured value
13
Inspiratory
flow
15 Peak
inspiratory
flow
16 Termination
flow
0
17 Inspiratory time
14
Expiratory
flow
20 Expiratory flow
time
19 Peak
expiratory
flow
18 Expiratory-flow
waveform
© NSJ
(b) Typical airway pressure and flow waveforms for a pressure-support inflation
Figure C.2 (2 of 5) —Illustrations of the application of ventilation terms in designating key
features of typical inflation waveforms
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2 Rise time
1 Airway
pressure,
pAW
3
Inspiratory
pressure
5 High
pressure
termination
limit
4
Δ Inspiratory
pressure
13
6 PEEP
7 BAP
14 Ambient
pressure
8
Inspiratory
flow
Key to colour scheme:
Set value
Measured value
10 Peak
inspiratory
flow
0
11 Inspiratory time
12 Peak
expiratory
flow
9
Expiratory
flow
© NSJ
(c) Typical airway pressure and flow waveforms for a pressure-terminated pressure-control inflation
Figure C.2 (3 of 5) — Illustrations of the application of ventilation terms in designating key
features of typical inflation waveforms
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2 Inspiratory-pressure
waveform
1 Airway
pressure,
pAW
8 Peak
inspiratory
pressure
7
Inspiratory
pressure
3
Expiratory-pressure:
Plateau
Waveform
4
5 Instantaneous
pressure
6 PEEP
9 BAP
20 Baseline
airway pressure
21 Ambient
pressure
10 Inspiratory time
12 Rise time
(if applicable)
11
Inspiratory
flow
14 Inspiratory
pause time
13
Inspiratory
flow
Key to colour scheme:
Set value
Measured value
19 Expiratory
flow time
0
16 Inspiratory flow time
15
Expiratory
flow
17 Peak
expiratory
flow
18
Expiratory-flow
(waveform)
© NSJ
(d) Typical airway pressure and flow waveforms for volume-control inflation with an inspiratory pause
Figure C.2 (4 of 5) —Illustrations of the application of ventilation terms in designating key
features of typical inflation waveforms
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2 Inspiratory-pressure
(waveform)
4
Pressure
limit
1 Airway
pressure,
pAW
3 Peak
inspiratory
pressure
5 PEEP
6 BAP
14 Baseline airway pressure
15 Ambient
pressure
10 Inspiratory time
11 Inspiratory
flow waveform
7 Rise time
(if applicable)
8
Inspiratory
flow
Key to colour scheme:
Set value
Actual value
10
Inspiratory
flow
0
9
Expiratory
flow
12 Peak
expiratory
flow
13
Expiratory-flow
(waveform)
© NSJ
(e) Typical airway pressure and flow waveforms for a pressure-limited volume-control inflation
Figure C.2 (5 of 5) — Illustrations of the application of ventilation terms in designating key
features of typical inflation waveforms
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1 Airway
pressure,
pAW
3
Inspiratory pressure
4 PEEP
2 Ambient
pressure
6 Inspiratory
time, tI
5 BAP
7 Expiratory time, tE
8 Cycle time (1/Rate)
9
Inspiratory
flow
0
10
Expiratory
flow
©NSJ
Figure C.3 — Typical airway pressure and flow waveforms for a CMV-PC mode
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1 Airway
pressure,
pAW
3
Inspiratory pressure
2
Ambient
pressure
4 PEEP
5 BAP
6 Inspiratory time, 7 Expiratory time, tE
tI
8 Cycle time (1/Rate)
11 Primaryinflation 12 Primary expiratory phase
phase
13 Primary-inflation cycle
9
Inspiratory
flow
14 Inspiratory
phase
0
10
Expiratory
flow
16 Expiratory
phase
15 Unrestricted
breath
©NSJ
Figure C.4 — Typical airway pressure and flow waveforms for a CMV-VC <ACAPL> mode
© ISO 2016 – All rights reserved
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1 Airway
pressure,
pAW
3 Inspiratory pressure
or BAP-high
2
Ambient
pressure
4 PEEP
6 Inspiratory time, tI
or BAP-high time, tH
5 BAP
7 Expiratory time, tE
or BAP time, tL
8 Cycle time (1/Rate)
9 Primary-inflation phase
or BAP-highphase
10 Primary expiratory phase
or BAP phase
11 Primary-inflation cycle
or Bi-level cycle
12
Inspiratory
flow
14 Concurrent
breath
15 Inspiratory
phase
16 Inspiratory
phase
0
13
Expiratory
flow
17 Concurrent
expiration
18 Concurrent
inspiration
19 Expiratory
phase
20 Expiratory
phase
©NSJ
Figure C.5 — Typical airway pressure and flow waveforms for a CMV- PC <ACAP> mode set
with extended phase times
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1 Airway
pressure,
pAW
3
Inspiratory pressure
or BAP-high
2
Ambient
pressure
5 BAP
4 PEEP
6 Inspiratory time, tI
or BAPH time, tH
7 Expiratory time, tE
or BAP time, tL
8 Cycle time (1/Rate)
9 Primary-inflation phase
or BAP-high phase
10 Primary expiratory phase
or BAP phase
11 Primary-inflation cycle or Bi-level cycle
12
Inspiratory
flow
14 Inspiratory phases
or BAPH phases
15 Concurrent
breath
0
13
Expiratory
flow
16 Expiratory phases
or BAP phases
©NSJ
Figure C.6 — Typical airway pressure and flow waveforms for a CMV- PC <ACAP> mode set with an extreme inverse I:E ratio
Note to figures C.5 and C.6: The figures on these pages illustrate unusual settings of this mode which are possible with the range of settings available on currently
manufactured ventilators. As explained in the introduction to this Annex (C.1), such illustrations are not shown with the intention of advocating such settings, but to
demonstrate how actual waveforms can be very different from those normally provided to illustrate a mode function. Such illustrations highlight that the ventilation
waveforms that can be generated with a specific classical ventilator pattern-based mode, but with unusual settings, are not necessarily all unique and some may overlap
those that can be generated with another of these modes.
© ISO 2016 – All rights reserved
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3 Assured
delivery
1 Airway
pressure,
pAW
4
Inspiratory
pressure
2
Ambient
pressure
5 PEEP
7 Inspiratory 8 Expiratory time
time, tI
10 Primaryinflation
phase
13
Inspiratory
flow
9 Cycle time (1/Rate)
10 Primary11 Primary
inflation
expiratory phase
phase
12 Primary-inflation cycle
6 BAP
11 Primary expiratory
phase
12 Primary-inflation cycle
0
14
Expiratory
flow
15 Assisted
breath
16 Controlled
breath
©NSJ
Figure C.7 — Typical airway pressure and flow waveforms for an A/CV - PC mode
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1 Airway
pressure,
pAW
17
End-inspiratory
pressure
2
Ambient
pressure
5 PEEP
8 Expiratory
time
6 BAP
18 Set period (1/Rate)
10 Primaryinflation
phase
11 Primary expiratory
phase
12 Primary-inflation cycle
13
Inspiratory
flow
3 Assured
delivery
19
Inspiratory
flow
0
14
Expiratory
flow
7 Inspiratory
time, tI
15 Assisted
breath
16 Controlled
breath
©NSJ
Figure C.8 — Typical airway pressure and flow waveforms for an A/CV – VC mode
© ISO 2016 – All rights reserved
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1 Airway
pressure,
pAW
2
Ambient
pressure
3
Inspiratory
pressure
5 PEEP
4 BAP
6 Inspiratory
time, tI
9 Primaryinflation
phase
8 Set period (1/Rate)
7 Expiratory time
10 Primary expiratory
phase
11 Primary-inflation cycle
9 Primaryinflation
phase
10 Primary expiratory
phase
11 Primary-inflation cycle
12
Inspiratory
flow
16 Flowtrigger level
0
13
Expiratory
flow
14 Unrestricted breath (cycle) below
the trigger level.
Inspiration followed by expiration
15 Concurrent unrestricted
expiration followed by
inspiration
©NSJ
Figure C.9 — Typical airway pressure and flow waveforms for an A/CV – PC <ACAP> mode
(No pressure-support inflation-type is permitted with this mode but it could be optionally labelled: Bi-level ventilation (A/CV – PC <ACAP>).)
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1 Airway
pressure,
pAW
4 Primary-inflations
3 Support-inflations
2
Δ Inspiratory
pressure
5
Δ Inspiratory
pressure
7 BAP
6 PEEP
9 Inspiratory 10 Expiratory
time
time
8 Synchronisation
window
14 Expiratory
phase
13 Inflation
phase
15 Support-inflation cycle
11 Inspiratory
time, tI
12 Set period (1/Rate)
16 Primaryinflation
phase
17 BAP phase
or Primary expiratory phase
18 Primary-inflation cycle
19
Inspiratory
flow
27 Flow-trigger
level
23 Unassisted-breath
0
20
Expiratory
flow
21 Primary
expiratory-flow
time
22 Primary expiratory-flow pause time
25 Expiratory
phase
24 Inspiratory
phase
26 Supported-breath cycle
©NSJ
Figure C.10 — Typical airway pressure and flow waveforms for an SIMV- PC\PS mode
© ISO 2016 – All rights reserved
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5 Primary-inflations
1 Airway
pressure,
pAW
3 Δ Inspiratory
pressure
4 ΔhInspiratory
pressure
6 Support-inflations
2
Inspiratory
pressure
8 BAP
7 PEEP
10 Inflation
phase
9 Expiratory
phase
11 Support-inflation
cycle
13 BAP time, tL
12 Inspiratory time, tI
14 Set period (1/Rate)
15 Primary-inflation phase
16 BAP phase
17 Primary-inflation cycle
18
Inspiratory
flow
21 Unassisted-breath
22 Flow-trigger
level
0
19
Expiratory
flow
20 Concurrent
supported
breath
24 Expiratory phase
23 Inspiratory
phase
©NSJ
a) with typical settings for the simulation of Bi-level ventilation
Figure C.11 (1 of 4) — Typical airway pressure and flow waveforms for variations on an SIMV- PC\PS\PS <ACAP> mode
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1 Airway
pressure,
pAW
2 Primary-inflations
3
Inspiratory pressure, pI
4 PEEP
4 PEEP
6 Inspiratory time, tI
5 BAP
7 Expiratory
time, tE
8 Set period (1/Rate)
9 Primary-inflation phase
10 BAP phase
11 Primary-inflation cycle
12
Inspiratory
flow
14 Inflation
phase
15 Expiratory
phase
0
13
Expiratory
flow
16 Concurrent
unassisted breath
©NSJ
b) with typical settings for the simulation of APRV
Figure C.11 (2 of 4) — Typical airway pressure and flow waveforms for variations on an SIMV- PC\PS\PS <ACAP> mode
© ISO 2016 – All rights reserved
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1 Airway
pressure,
pAW
4 Δ Inspiratory
pressure
3 ΔhInspiratory
pressure
BAP-high
2
5 BAP
6 PEEP
7 Synchronisation
window (typical)
8 Set period (1/Rate)
9 Time-high, tH
8 Set period (1/Rate)
10 Time-low
14 Expiratory
phase
13 Inflation
phase
17
Inspiratory
flow
15 Support-inflation cycle
10 Time-low
9 Time-high, tH
11 BAP-high phase
12 BAP phase
16 Primary-inflation cycle
Flow-trigger
level
0
18
Expiratory
flow
©NSJ
c) with a PC{S} primary inflation-type and optionally labelled as a Bi-level ventilation mode
Figure C.11 (3 of 4) — Typical airway pressure and flow waveforms for variations on an SIMV- PC\PS\PS <ACAP> mode
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1 Airway
pressure,
pAW
2 Primary-inflations
3
BAP-high (or pH)
4 PEEP
4 PEEP
6 Time-high, tH
8 BAP-high phase
5 BAP (or pL)
7 Time-low, tL
6 Synchronisation
window (typical)
9 BAP phase
10 Primary-inflation cycle
11
Inspiratory
flow
13 Inspiratory
phase
14 Expiratory
phase
0
12
Expiratory
flow
15 Concurrent
unrestricted breath
©NSJ
d) with a PC[S] primary inflation-type, no pressure-support at BAP level and optionally labelled as intended for
APRV (airway pressure release ventilation)
Figure C.11 (4 of 4) — Typical airway pressure and flow waveforms for variations on an SIMV- PC\PS\PS <ACAP> mode
© ISO 2016 – All rights reserved
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1 Airway
pressure,
pAW
3 Δ Inspiratory
pressure
2
Ambient
pressure
4 PEEP
6 Inflation
phase
5 BAP
7 Expiratory phase
8 Support-inflation cycle
9
Inspiratory
flow
11 Expiratory time
0
10
Expiratory
flow
12 Inspiratory time
©NSJ
Figure C.12 — Typical airway pressure and flow waveforms for a CSV - PS mode
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1 Airway
Pressure
Previous figures have shown waveforms for pressure-control inflationtype deliveries on a ventilator with an ACAP adjunct, and with illustrative
concurrent spontaneous breaths. In practice there could be several
concurrent breaths and they could take many forms. On the right are
shown other possible flow waveforms and these raise the question of
what a breath is in this situation.
The flow waveform A shows the delivered volume, as a result of the
elevated pressure of the inflation a, as the area b. It can be seen that the
set inspiratory time greatly exceeds the inspiratory flow time and so there
is an inspiratory flow pause before the delivered volume is expired. The
expired volume is represented by the area c. It is therefore clear that b
and c represent the breath resulting from the inflation a, and that d and e
represent a concurrent spontaneous breath.
Waveform B shows a spontaneous expiration f before an inspiration g.
To do this the patient would have to have made an active expiratory effort
but this is a possible occurrence and in this case the forced expiration
coupled with the inspiration still constitutes the requirement for a breath.
The complete waveform therefore shows the result of the inflation and two
concurrent spontaneous breaths.
Waveform C shows the patient’s inspiratory efforts augmenting the
delivered volume resulting from the inflation, and subsequently expiring it,
but there is no spontaneous breath because the inspiratory component h
is not independent of the ventilator-imposed component.
Waveform D shows a reflexive expiration during the flow pause following
the imposed delivered volume. As in the previous example because k is
not associated with a specific inspiration it does not constitute part of a
separate, spontaneous breath.
From these examples it can be seen that, a concurrent breath is one in
which an inspiratory flow is detected either following a period with no
airway flow or following an expiratory flow.
© ISO 2016 – All rights reserved
a
2 Airway
Flow
b
A
3Baseline airway pressure
tI
d
e
B
c
g
f
C
h
D
k
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Figure C.13 — Characteristics of a concurrent breath
112
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Coloured rectangle representing the inflation-type that has been selected
for assured deliveries. The same inflation-type may also be initiated by a
patient-trigger event in accordance with the ventilation-pattern.
Red arrow in this symbol represents an assured occurrence and the
clock signifies that this is set to occur at a timed interval from the
previous assured occurrence. This timed interval (1/Rate) is determined
by the ventilator set rate.
Symbol representing the delay period that has
been named as the ‘synchronisation window’.
Symbol representing the ventilator initiation of the
assured inflation in the absence of any patient-trigger
event during the preceding synchronisation window.
Composite symbol representing the function of the
synchronisation window. After an assured instigation at
the timed interval, determined by the ventilator set rate,
it provides time for the expiration of any previously
inspiration but responds immediately to a patient-trigger
event by initiating the already assured inflation.
Coloured rectangle representing the inflation-type that has
been selected for initiation solely in response to a
spontaneous occurrence.
Arrow used to represent an envisaged pattern of patienttrigger events. They are shown with a broken outline in the
following figures because they represent the setting
perspective of what ‘could’ happen.
Figure C.14 (1 of 6) — Ventilation patterns (a) Key to symbols used in b) to f)
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1 Airway
pressure
2
Representative pressure-control inflation-types
3
1/Rate
1/Rate
1/Rate
Setting Perspective
4
5
Time
1/Rate
6 Function of the ventilation-pattern in initiating inflations
7
Inspiratory
Flow
9
Typical consequent Flow Waveform
8
Expiratory
Flow
©NSJ
Figure C.14 (2 of 6) — Ventilation patterns (b) CMV ventilation-pattern
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1 Airway
pressure
2
Representative pressure-control inflation-types
3
Setting Perspective
4
5
1/Rate
1/Rate
1/Rate
1/Rate
1/Rate
1/Rate
1/Rate
6 Function of the ventilation-pattern in initiating inflations
7
Inspiratory
Flow
9
Typical consequent Flow Waveform
8
©NSJ
Expiratory
Flow
Figure C.14 (3 of 6) — Ventilation patterns c) Assist/Control ventilation-pattern
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Time
ISO/DIS 19223:2016(E)
2
Airway
pressure
1
Representative pressure-control inflation-types
3
Setting Perspective
5
1/Rate
1/Rate
1/Rate
6 Function of the ventilation-pattern in initiating inflations
7
Inspiratory
Flow
9
Typical consequent flow waveform
4
8
Expiratory
Flow
©NSJ
Figure C.14 (4 of 6) — Ventilation patterns (d) IMV ventilation-pattern
116
Time
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ISO/DIS 19223:2016(E)
2
Airway
pressure
1
Representative pressure-control inflation-types
3
Setting Perspective
5
1/Rate
1/Rate
1/Rate
6 Function of the ventilation-pattern in initiating inflations
7
Inspiratory
Flow
9
Typical consequent flow waveform
4
Time
8
Expiratory
Flow
©NSJ
Figure C.14 (5 of 6) — Ventilation patterns (e) SIMV ventilation-pattern
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1 Airway
pressure
2
Setting Perspective
3
Time
4 Function of the ventilation-pattern in initiating inflations
5
Inspiratory
Flow
7
Typical consequent flow waveform
6
©NSJ
Expiratory
Flow
Figure C.14 (6 of 6) — Ventilation patterns (f) CSV ventilation-pattern
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Annex D
Classification of Inflation-types and Modes
(Normative)
D.1 Classification of Inflation-types
The principle individual terms relating to currently available inflation-types are defined in subclause 4.2. However, there is a large number of possible variations of the waveforms that could
be adopted for this purpose and Tables D.1a and D.1b have been included in order to demonstrate
how both defined inflation-types and known variations are systematically identified and allocated
their systematic names. Table D.1c has been included in order to demonstrate the structure of
the schematic coding scheme used in this vocabulary; it provides a template for the naming of
current and future inflation-types that are not already specifically designated. It also includes
examples of systematic codes but for a more complete list see Tables D.1a and D.1b.
The primary classification of possible inflation-types have been based, in accordance with
convention, on the two basic ventilation parameters that can be conveniently regulated - pressure
and flow – along with a hierarchy of letters used to codify how an inflation will be managed - after
initiation.
The core element of the coding is a pair of capital letters that have been universally adopted in
current ventilation terminology and which are defined in sub-clause 4.2, namely, VC, PC, and PS.
In this vocabulary, these pairs, each in isolation, represent an inflation-type that, once initiated in
accordance with the selected ventilation-pattern, regulate the delivered flow or pressure to the
set value until terminated by time, flow, pressure or volume criteria.
Variations from these specific conditions are designated by the attachment, to the base pair, of
leading lower case letters and contained trailing letters - the containment being by means of
round brackets for termination parameters, curly brackets for conditional termination means and
square brackets for additional regulation parameters.
Leading lower case letters are used to indicate features that provide additional functionality to
the basic control. These can be either specific to the particular control to which it is attached, in
which case it is in italics, or of more general application. An examples of the latter are the letters
vt (volume-targeted), which are applicable to PC and PS inflation-types and indicate that the set
inspiratory pressure is automatically adjusted, typically inflation-to-inflation, in order to get closer
to achieving the set tidal volume with the next inflation.
In these classifications, where the primary means of inflation termination is shown to be other
than by time, safety considerations dictate that there will always be some sort of ultimate time
limit on every automatically delivered inflation. This may be a factory-set default or an operatorsettable value with a limit on the maximum setting but such secondary time limits are not included
in the coding so as to keep them as brief as possible.
Allowance has also been made to accommodate the possibility of switching between regulated
parameters during an inflation phase.
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In this vocabulary, inflation-type systematic codes are used as symbols, as PC, VC and PS are used
at present, with the spoken form being either the spoken abbreviation or the full name that has
been abbreviated as written in bold type in the following headings. The term descriptions are
related to the lines in Tables D.1a and D.1b, as well as those in Table D.1c, by means of the
allocated reference number (Ref #). The descriptive notes against the following headings give
further information on the specific inflation-types identified by their Ref #:
Refs # 1a – 1f: volume-control; inflation-types that are all flow-regulated to a constant value (or a
specified declining-flow pattern) and time-terminated, which, by convention, have been identified
under their more generally applicable name of volume-control, with the abbreviation, VC. There
are various ways of achieving a required tidal volume within these restraints and most of these
are separately referenced by one of the trailing letters, a – f. In practical use, the differences are
typically incidental to most operators, and will be evident from the method by which the volume
is set. For this reason, as is current practice, for general use all of these alternative possibilities
retain the label, VC. However, the specific characteristics that identify the differences in this
vocabulary should be always described in the operator’s Instructions for Use (IFU).
Inflation-types that are flow-regulated to a constantly declining value and time terminated, which,
by convention, have also been identified under their more generally applicable name of volumecontrol, with the abbreviation, VC, are identified with the prefix df or cdf.
All volume control inflations delivering leak compensated volumes are identified with the suffix
LC.
The attachment of suffixes or prefixes is not generally necessary if the selection of the represented
function is otherwise indicated in associated text or by an indicator on the user interface.
Refs # 2 & 3: volume-targeted; inflation-types, which unlike VC, do not control the delivered
volume directly but which target a set volume by adjusting the inspiratory settings of a pressureregulated inflation, typically inflation-to-inflation, depending on measurements of previous
deliveries.
Ref # 4: pressure-limited volume-control; a variant of VC in which, when the inspiratory pressure
attains a set level during normal operation, excess regulated flow is spilt to atmosphere if
necessary to avoid the inspiratory pressure exceeding the set level, resulting in a possibly unquantified loss of the delivered volume. This variant is indicated by the addition of the trailing code
{pLIM}. As this loss is part of the normal operation of this inflation-type an alarm condition is not
generated, but if there is any loss of delivered tidal volume patient safety considerations dictate
that it should be indicated. If the pressure is limited by pressure-regulation then the code becomes
VC→PC (see 4.2.5).
Ref # 5: pressure-control; an inflation-type that, after an initial rise time, is pressure-regulated to
a constant value and time-terminated. By convention, it has been identified with the name
pressure-control, with the abbreviation, PC.
Ref # 6: pressure support or flow-terminated pressure-control; a pressure control (PC) inflationtype that is intended to be terminated by patient respiratory activity reducing the flow to a set
flow level before the set time termination, and which is only used with ventilation-patterns in
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which it can only be initiated by a patient-trigger event, has become identified with the name
pressure-support, with the abbreviation, PS. If used in a mode pattern in which it may be timeinitiated its code reverts to that of a variant of PC, that is, PC{q}.
Ref # 7: spontaneous/timed; a PC inflation-type that is terminated by time if time-initiated, but
which is terminated by flow if initiated by a patient-trigger event occurring before the set time, is
identified as a conditional variant of PC, i.e., PC{q/t}. This inflation type has become associated
with a ventilation mode which is commonly referred to as an S/T mode. As an S/T mode is
dependent on this inflation-type, and as the systematic name is too complicated when spoken, S/T
has been adopted as the common name for this inflation-type in this vocabulary on the basis that
the termination is conditional on whether the initiation is due to a spontaneous breath or a set
time. It is typically used in an assist/control ventilation pattern, in which case the systematic
mode designation becomes A/CV-S/T (see Table D.2a).
Ref # 8: volume-assisted pressure-support; a PS inflation-type that is extended by the maintenance
of the termination flow if the delivered volume has not by then attained the set minimum value.
It’s abbreviated systematic designation is PC→VC, with the common name, VAPS.
Ref # 9: pressure-control with ACAP or ACAPH; conceptually, this is a PC primary-inflation with a
separately provided ACAP ventilation-pattern adjunct that is active at the inspiratory pressure
baseline level (BAPH), which enables concurrent expirations in addition to unrestricted
inspirations.
Ref #10: - - synchronised-termination; an inflation-type, intended for use with ACAP or ACAPH
adjuncts, where the patient may expire spontaneously during the set inflation phase without
terminating the delivery. It then uses a synchronisation window to modulate the actual
termination point of each inflation to coincide with the patient’s expiratory activity (see 4.10.7
and 4.10.8). The presence of this feature is indicated by the conditional-termination variation
trailing code {S}, spoken as ‘pressure-control with synchronised-termination’.
Ref # 11: flow-regulated, pressure-limited; an inflation type with no specific name but which is
typically used in basic paediatric ventilators, where the system is referred to as a T-piece occluder.
A set regulated flow is fed to one port of a T-piece and another is periodically occluded either
manually by a thumb, or by a timed mechanical occluder. The required pressure is maintained
by a variable relief valve.
Refs # 12 - 14: proportional effort support; a variant of a PS inflation-type that is pressureregulated to a non-constant waveform that is dependent upon the instantaneous value of a
patient variable(s) that indicates the patient effort at that point in time, with the intention of
providing support to the breathing that is always proportion to the patient’s effort. The variables
used are typically either those relating to the loads imposed by airway resistance and the lung
stiffness or the neural signals that determine respiratory effort. The concept is identified with
the name proportional effort support, with the abbreviation, pES. The full systematic name for a
proportional effort support inflation-type will include a reference to which of these indicators of
specific patient efforts are supported, i.e., increase in lung volume [v], flow [q], increase in lung
volume and flow [q.v], or the electromyographic activity of the diaphragm and intercostal muscles
[EMG].
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There is currently no agreed name to designate these following, additional regulation parameters,
other than the use of a verbal description.
The following references relate to entries in Table D.1c only:
Ref # 15: flow-regulated, pressure-terminated; a flow-regulated inflation that is pressure
terminated and with which, as a consequence, there is no direct correlation between the setting
and the volume delivered. It is not, therefore, a variant of VC and is classified as a flow-regulated,
pressure-terminated inflation-type. This inflation-type is not currently used in mainstream
ventilators but is still sometimes used in low-cost, gas-powered resuscitators. These devices are
commonly known as pressure-cycled resuscitators on the basis that each phase change is
initiated when a measured pressure reaches a set level.
Ref # 16: volume-terminated, pressure-control; this code represents a variant of a PC inflationtype in which the inflation is terminated after a set volume has been delivered. As a variant it is
coded as PC(v).
Ref # 17: dual-control; these codes represent hybrid inflations that start with the first inflationtype but under specified conditions may be changed to an alternative type during the course of
the delivery. These changes may be bi-directional or unidirectional as indicated by the coupling
arrows.
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Operator’s primary Regulated
intent
parameter Secondary intent(s)
Deliver a specified
volume through the
patient connection
port
Deliver a specified
flowrate through the
patient connection
port
Flow
Pressure
Flow
Deliver a specified
Flow
volume to the trachea
Consequent requirements
Coded form of full
systematic name
Primary
Secondary
Ref # classification classification
Time termination
See Table D.1b for options for consequent requirements
FR(t ) which becomes VC
1a - 1d VC
Constant flow at set value
Time becomes dependent variable
FR(v ) which becomes VC
Time termination
If inspiratory pressure is adjusted inflation-to-inflation the
outcome is volume targetted not VC
If inspiratory pressure is adjusted inflation-to-inflation the
outcome is volume targetted not VC
vtPC
1e
2
VC
vtPS
3
vtPS
Pressure limit
VC[p Lim]
4
FC
Time termination
FR(t ) which becomes VC
1f
VC
Flow termination of a pressuresupport inflation
Time termination
See Table D.1b for options for consequent requirements
At least two of: delivered volume,
inspiratory flow and inspiratory time
vtPC
VC Ref VC
#/LC
VCLC
Set parameters
Tidal volume and inspiratory time
Tidal volume and end-flow
[p Lim]
Inspiratory flow & time and pressure
limit
Delivered flow and inspiratory time
LC
Tidal volume and inspiratory time
PC
PC(q ) or PS
5
6
PC
PS
PC(q/t ) which becomes
S/T
PCVC which becomes
VAPS
PC
PC[S]
7
S/T
8
PCVC
9
10
PC
PC
[S]
Inspiratory pressure and time
Pressure limited, time terminated Provision of pressure-limit function
FR[p Lim]
11
FR
[p Lim]
Inspiratory flow and time, and
pressure limit
Support patient effort Pressure
Not otherwise specified
Support as proportion of a
specified patient effort
Parameters determined by settings
Measurement of EMG signals
Measurement and intergation of inspiratory flow
pES
pES[EMG]
pES[q.v ], pES[q ] or pES[v ]
12
13
14
ES
ES
ES
[EMG]
[q.v ], [q or [v ]
Key to abbreviations: VC
PC
VS
FC
vt
LC
pES
EMG
S
Volume control
Pressure control
Volume support
Flow control
Volume targetted
Leak compensated
Proportional effort support
Electromyography
Synchronised
t
p
q/t
q
v
p LIM
ACAP
dr
cdf
Time termination
Flow termination
Flow or time terminated
Deliver a specified
inflation pressure
Pressure
Flow
Assured minimum volume
Inflation is flow terminated if patient-triggered and time
terminated if time initiated
Inspiratory time is extended
Facilitate concurrent expiration
Provision of either ACAP or, at least, ACAPH as mode adjunct
Facilitate concurrent expiration
and flow termination
Provision of either ACAP or, at least, ACAPH as mode adjunct
Time
Airway pressure
Conditional, flow or time termination
Inspiratory flow
Cumulated delivered flow
Pressure-limited
Assured constant airway pressure
Declining-ramp flow pattern
Concave descending-flow pattern
Proportion of effort parameter-value
to be supported
Note: The primary and secondary classifications, and the set
parameters, are what will typically be presented as separate selections
on the user interface.
 2016 NSJ
Table D.1a —Inflation-type
© ISO 2016 – All rights reserved
Inspiratory pressure and time
PS (2nd setting, Inspiratory pressure and end-flow
where appliacble)
Inspiratory pressure and time, and
end-flow
Inspiratory pressur and flow, and
delivered volume
Inspiratory pressure and time
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Operator’s
primary intent
Deliver a set
volume to a
specified part of
the ventilator
breathing system
Deliver a set
volume to the
trachea
Regulated
parameter Secondary intent(s)
Flow
Abreviated form of
full systematic name
Consequent requirements
Time termination; Constant flow Set constant-flow is automatically offset to compensate for
repeatable deviations due to, e.g., flow rise time & back
Time termination; Set constant Flow may be set to less than necessary to achieve volume in
flow
set time, thereby providing an inspiratory pause.
Time termination; Substantially Continuous intra-inflation correction of set flow so as to
constant flow
achieve delivered volume in set time
Constant flow at set value
Time becomes dependent variable
Time terminated; Descendingramp flow pattern
Time terminated; Concave
decreasing-flow pattern
Flow
VC
VC
VC
Ref #
1a
1b
1c
Secondary
classification(s
Primary
classification )
Set parameters
VC
VC
VC
VC
drVC
1d VC
VC Ref VC
#/dr
cdfVC
VC Ref VC
#/cdf
cdf
dr
Time termination
Delivered flow is substantially constant and compensated for
measured leak and other deviations
VCLC
VC Ref VC
#/lc
LC
Time terminated; Descendingramp flow pattern
Time terminated; Concave
decreasing-flow pattern
Delivered flow is to a descending-ramp flow pattern and
compensated for measured leak and other deviations
Delivered flow is to a concave decreasing-flow pattern and
compensated for measured leak and other deviations
VC Ref VC
#/lc
VC ref VC
#/lc
dr; LC
drVCLC
cdfVCLC
At least two of:
delivered or
inspiratory volume,
delivered or
inspiratory flow, or
inspiratory time
Tidal volume and
inspiratory time
cdf; LC
 2016 NSJ
Table D.1b —Coding Scheme for variants of Volume Control inflation-types
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Means of
Time
Termination Flow
Pressure
Volume
Conditional
Variation on Synchronised
Termination
Flow-regulation See
Group
Ref Pressure-regulation Group
FR(t ) becomes VC #1 PR(t ) becomes PC
PR(q ) becomes PS or PC(q )
Not applicable
See
Ref
#5
#6
FR(p )
#15 N.A
FR(v ) becomes VC #1 PR(v) becomes PC(v )
PR{q /t } becomes S/T
Not applicable
#16
#7
Not applicable
{S};
e.g., PC{S}
#10
Not applicable
pPS becomes pES
#12
Variation on
Regulation
Proportional
Dual-control
VCPS, VCPC #17 PCVC
Additional factors VC{p Lim }
Variation on
Algorithm
Volume-targeted Not applicable
#4
[q &v ], [q ], [v ], [EMG];
e.g., pES[EMG]
vt;
e.g., vtPC
* *
Inflation-type code: variation designators
Inflation-type that conditionally interchanges
with characteristics of second inflation type
Trailing codes
(*)
Parameter used for termination
{*}
Conditional variation on termination means
[*]
Additional regulation parameters
Key for trailing codes:
t
Time
p
Pressure
v
Volume that has been added to lung
q
Flow
q/t
Flow or pressure, depending on means of
EMG
initiation
Electromyographic activity of the diaphragm
and intercostal muscles
p Lim
Pressure limit
#17
#12
- 14
Prefix codes
Lower-case
Variation on general inflation algorithms,
e.g., vt, pES
#2
&3
Key for prefix codes:
General Notes:
All Inflations are required by device standards to be pressure-limited, or pressureterminated, at an independent, operator-set, safe-pressure limit for the patient.
Inflations that are not time-terminated are taken to be also time-limited, whether operatorsettable or not.
vt
Volume targeted
 2016 NSJ
Table D.1c — Systematic coding scheme for Inflation-types
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D.2 Classification of Ventilation-modes
The principle individual terms relating to currently available ventilation-modes and how these are
combined to arrive at a systematic name and code are defined and explained in sub-clause 4.8. The
rationale to sub-clause 4.8 gives further explanation. Table D.2 has been included in this
International Standard in order to provide an illustration of how these individual concepts are
combined to provide a scheme that enables the large number of possible ventilation-modes to be
individually named and systematically identified.
The primary classification is the mode grouping as defined in 4.8.4, with 3 basic groups, each of which
is then broken down into 2 further sub-groups. These groupings are determined solely by the
ventilation-pattern as defined in sub-clause 4.8.3. As made clear in the entries to 4.8, the use of these
groups is not a necessary condition for conformance with this International Standard but such use
does provide a helpful primary classification.
Each row in Table D.2 represents a specific ventilation mode. The two left hand columns serve to
segregate these examples into the ventilation mode Groups.
In order to create a mode it is necessary to combine a ventilation-patterns with one or more
appropriate inflation-types, the major systematic classifications of which are described in sub-clause
4.2 - with more comprehensive details being tabulated in Annex D.1.
If the ventilator is of a construction that provides an ACAP adjunct, this adds a further level of
classification.
The third column lists the systematic code for typical examples of possible specific modes within each
group. Examples involving all the characteristic ventilation-patterns of each group are included along
with typically associated inflation-types but, as is indicated by the number of entries in Tables D.1,
the possible combinations of these two features is far greater than shown. However, the intention is
to demonstrate the pattern of use, not to include every possibility. The presence of an ACAP adjunct
on the ventilator providing the mode is indicated by the use of its acronym within angled brackets as
the final entry to the code. Typically, where present, this adjunct will be applicable to all modes
available on any specific ventilator, although it may be appropriate to restrict its activity to only one
phase of the primary inflations of certain modes, as illustrated in some of the examples.
The fifth column lists the full systematic name of each ventilation mode (although an exception has
been made with the acronym ACAP due to presentational restraints). The comparison of these names
with the associated systematic code demonstrates the practicality and conciseness achieved with the
adoption of the code as the primary means of ventilator-mode identification.
The shaded rows in the systematic code column indicate examples of modes that may be alternatively
labelled as ‘bi-level ventilation modes’. The notes in the fourth column indicate examples of modes
that may be settable to achieve APRV (airway pressure release ventilation), depending on the range of
settings made available.
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Group
Group 1 a
System atic code
Notes
Full system atic nam e
CMV-VC
Continuous mandatory ventilation w ith volume-control
CMV-VC <ACAPL>
Continuous mandatory ventilation w ith volume-control and an assured constant airw ay pressure adjunct during the expiratory phase
CMV-PC
Continuous mandatory ventilation w ith pressure-control
CMV-vtPC
Continuous mandatory ventilation w ith volume-targeted pressure-control
CMV-PC <ACAP>
Continuous mandatory ventilation w ith pressure-control and an ACAP adjunct
CMV-vtPC <APAP>
Continuous mandatory ventilation w ith volume-targeted pressure-control and an ACAP adjunct
A/CV-VC
Assist/Control ventilation w ith volume-control
A/CV-PC
Assist/Control ventilation w ith pressure-control
A/CV-vtPC
Assist/Control ventilation w ith volume-targeted pressure-control
A/CV-S/T
Assist/Control ventilation w ith support/timed inflation-type
A/CV-PC <ACAP>
Assist/Control ventilation w ith pressure-control and an ACAP adjunct
A/CV-vtPC <ACAP>
Assist/Control ventilation w ith volume-targeted pressure-control and an ACAP adjunct
IMV-VC
Intermittent mandatory ventilation w ith volume-control
Group 1
Group 1 b
IMV-VC <ACAPL>
Intermittent mandatory ventilation w ith volume-control and an ACAPL adjunct during the primary expiratory phases
IMV-PC\PS
Intermittent mandatory ventilation w ith pressure-control and pressure-support
IMV-vtPC\PS
Intermittent mandatory ventilation w ith volume-targeted pressure-control and pressure-support
IMV-PC\PS\PS <ACAP>
Group 2 a
IMV-PC <ACAPH>
Intermittent mandatory ventilation w ith pressure-control, tw o levels of pressure-support and an ACAP adjunct
#2
IMV-vtPC\PS <ACAP>
IMV-PC[S]\PS\PS <ACAP>
Group 2
Group 2 b
Group 3a
Group 3
Group 3b
Intermittent mandatory ventilation w ith pressure-control and an ACAPH adjunct during the inflation phases
Intermittent mandatory ventilation w ith volume-targeted pressure-control, pressure-support and an ACAP adjunct
Intermittent mandatory ventilation w ith synchronised-termination pressure-control, tw o levels of pressure-support and an ACAP adjunct
IMV-PC[S] <ACAP>
#1
Intermittent mandatory ventilation w ith synchronised-termination pressure-control and an ACAP adjunct
IMV-PC[S] <ACAPH>
#1
Intermittent mandatory ventilation w ith synchronised-termination pressure-control and an ACAPH adjunct during the inflation phases
IMV-PC\-\PS <ACAPH>
#2
Intermittent mandatory ventilation w ith pressure-control, and an ACAPH adjunct and pressure-support at the higher pressure level only
SIMV-VC\PS
Synchronised intermittent mandatory ventilation w ith volume-control and pressure-support
SIMV-VC <ACAPL>
Synchronised intermittent mandatory ventilation w ith volume-control and an ACAPL adjunct during the expiratory phases
SIMV-PC\PS
Synchronised intermittent mandatory ventilation w ith pressure-control and pressure-support
SIMV-vtPC\PS
Synchronised intermittent mandatory ventilation w ith volume-targeted pressure-control and pressure-support
SIMV-PC\PS\PS <ACAP>
Synchronised intermittent mandatory ventilation w ith pressure-control, tw o levels of pressure-support and an ACAP adjunct
SIMV-PC\-\PS <ACAP>
Synchronised intermittent mandatory ventilation w ith pressure-control, an ACAP adjunct and pressure-support at the higher pressure level only
SIMV-vtPC\PS <ACAP>
Synchronised intermittent mandatory ventilation w ith volume-targeted pressure-control, pressure-support and an ACAP adjunct
SIMV-PC[S]\PS <ACAP>
Synchronised intermittent mandatory ventilation w ith synchronised termination pressure-control, pressure-support and an ACAP adjunct
CSV-PS
Continuous spontaneous ventilation w ith pressure-support
CSV-p ES <ACAP>
Continuous spontaneous ventilation w ith proportional effort-support and an ACAP adjunct
CSV-vtPS <ACAP>
Continuous spontaneous ventilation w ith volume-targeted pressure-support and an ACAP adjunct
CPAP
Continuous positive airw ay pressure
CPAP <ACAP>
Continuous positive airw ay pressure w ith an ACAP adjunct
Note #1 Common implementations of APRV
 2016 NSJ
Note #2 The code for possible implementations of APRV
Table D.2 — Systematic classification of typical ventilation-modes, with an ACAP adjunct as a third designation
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Annex E
Conceptual Relationships between Ventilator Actions and Inspiratory Breaths
(Informative)
Explanation of the relationships shown in Figure E.1
Figure E.1 is a diagrammatical representation of the patient-ventilator interaction and the relationship
between breaths and inflations. The figure demonstrates the relationship between the action of a ventilator
and the resulting breath that is provided, taking into account the contribution of the patient’s respiratory
activity.
In this vocabulary, breaths are defined from the patient perspective. Five types of breath are designated by
the type of inspiratory assistance that might be provided by various means of artificial ventilation. These
types of breath are - :
1. Spontaneously taken while connected to a ventilator but with no form of inspiratory assistance
selected
2. Initiated by spontaneous respiratory activity but assisted by a support-inflation
3. Initiated by spontaneous respiratory activity but assisted by an ‘assist’ primary-inflation
4. Initiated by spontaneous respiratory activity within a synchronisation window occurring at assured
intervals but assisted by a ‘synchronised’ primary-inflation
5. Completely controlled by a ventilator, as determined by its settings
The interaction between the patient and the ventilator during inspiratory or inflation phases for each of these
types of breath is as illustrated in Figure E.1 and explained as follows:
1. Breaths taken by the patient when connected to a ventilator but without assistance from any type of
artificial inflation are all classified as unassisted breaths. However, the work of breathing imposed
by the ventilator in response to spontaneous breathing activity could vary from that of a near
complete blockage to the perception of unrestricted breathing.
Figure E.1 illustrates how an unassisted breath generates a ‘patient demand’, which is seen as a drop
in airway pressure in an attempt to obtain more flow. If the ventilator is designed to accommodate
unassisted breaths it will generate sufficient ‘demand flow’ to satisfy the patient’s demands, which
will reduce the pressure drop and, thereby, the work of inspiration. If there is no specific provision
for the ventilator to provide a demand flow, the patient may be able to draw in ambient air through
an emergency intake valve but the breathing is likely to feel restricted. Without such a valve
unassisted breathing may be severely impeded.
Where demand flow is available, it may be provided by meeting the patient’s flow demands by
means of a patient-triggered pressure-regulated inflation-type with the inspiratory pressure set to its
minimum value of 1 or 2 cmH2O above the baseline pressure level. Alternatively, it may be
provided by the provision of ACAP, an adjunct that facilitates unrestricted breathing by the
generation of demand flow in proportion to the patient’s demand without a set trigger threshold.
See unrestricted breathing (4.1.5), pressure-support (4.2.6) and ACAP (4.9.2).
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2. Depending upon the ventilation mode selected, some of the patient’s respiratory activity that is
sufficient to causes a patient-trigger event may initiate a support-inflation that assists that activity to
an extent determined by the support inflation-type selected and its settings. This support inflationtype is only used in modes where it can only be initiated by a patient-trigger event and which can be
terminated by the patient’s respiratory activity. The resulting breaths are designated as supported
breaths and are addition to the set rate.
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3. With an assist/control ventilation (4.8.7) mode selected, any patient’s respiratory activity that is
sufficient to causes a patient-trigger event initiates a primary-inflation that assists that activity to an
extent determined by the inflation-type selected and its settings. The resulting breaths are
designated as assisted breaths. (If the patient fails to initiate a subsequent primary-inflation during
the maximum expiratory time assured by the set rate it will be initiated by the ventilator and
generate a controlled breath.)
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4. Spontaneous breaths taken during a timed synchronisation window when an IMV or SIMV mode are
selected, are designated as synchronised breaths. The synchronisation windows are initiated at a set
rate. The primary-inflation is initiated either when a patient-trigger event occurs while the window
is open; or if no trigger event is detected, when the synchronisation window closes. The primaryinflations therefore contribute to the patient’s work of breathing by assisting those spontaneous
breaths that occur within each synchronisation window while limiting the occurrence of such
assistance to no more than at the set rate
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5. With any Group 1 or Group 2 mode selected, in the absence of a patient-trigger event, the operator is
assured that the ventilator will deliver the next primary-inflation after the maximum expiratory time
that is determined solely by the set rate. These breaths are entirely dependent upon the ventilator’s
primary inflation-type and its settings and are therefore designated as controlled breaths.
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Figure .
iagram showing the concepts of the relationship betweenISO/19223:2016(E)
breath and inflation related terms in the vocabulary of this
International Standard
68
Primary inflation
(Assured
delivery)
Support inflation
Demand
flow
Unspecified
delivery
Patient trigger
event
Time
Patient trigger
event
Synchronisation
Window
Assisted
Synchronised
Patient
demand
Supported
Inspiratory
Breath
Unassisted
Controlled
Ventilator delivery functions
Means of delivery initiation
Outcome
Assured rate
> Assured rate
Connections showing the relationship for modes where the patient
is able to increase the primary-inflation delivery rate above that set
Unscheduled
Connections showing the relationship for modes where patient trigger events
do not increase the average primary-inflation delivery rate above that set
NSJ Iss 6d: 15/11/2015
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Figure E.1 — Diagram showing the concepts of the relationship between breath and inflation
related terms in the vocabulary of the International Standard
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Annex F
Concepts Relating to Baseline Airway Pressures
and PEEP as Used in this Standard
(informative)
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Inherent in the concept of a ventilation-pattern that determines how and when inflations are delivered is the
determination of what happens between inflations. Typically there are clinical requirements to ventilate
patients with an elevated baseline airway-pressure and this requires the use specific control elements and
appropriate algorithms, particularly when provision is made for unrestricted, unassisted breathing, both
between, and concurrent with, primary-inflations. Figures F.19 – F.27 illustrate the application of the
terminology in this vocabulary that relate to this phase.
Figures F.19 – F.22 show the typical expiratory-phase waveforms that could be expected with four specific
usage scenarios. These were chosen to illustrate the effects of settings, patient parameters and control
algorithms on pressures during, and at the end of, time-terminated expiratory phases. For the purposes of
these explanations the figures all use the same basic CMV-PC mode setting.
As the pressure at the patient-connection port falls during an expiration, there is an unavoidable dynamic lag
in the corresponding rate of fall of the alveolar pressure. This is mainly due to airway-resistance and flow
limitation factors. Normally, the effects of this lag will have fully dissipated by the end of the expiratory phase,
but with shorter expiratory times or with diseased lungs, the average alveolar pressure may still be above
the measured expiratory pressure at the end of the expiratory phase. The amount by which this average
alveolar pressure exceeds the measured positive end-expiratory pressure, PEEP, cannot be measured directly
but its presence and order of magnitude is commonly ascertained by the use of an expiratory-hold procedure.
The airway pressure measurement at the end of this procedure is the average of that of the pressurised gas
in the alveoli that has been able to distribute uniformly throughout the lung during the expiratory-hold time,
but it may not fully include the contribution of any trapped gas to the true average pressure.
Figure F.19 illustrates the normal situation where the alveolar pressure does lag the expiratory pressure
while there is expiratory flow but once the expiratory pressure reaches a constant value at the set BAP level
and expiratory flow has ceased an expiratory hold procedure would show that the alveolar gas had ceased
distributing and that the average pressure of the gas that had distributed, total PEEP, was at the measured
PEEP level.
Figure F.20 illustrates a typical situation that may occur when ventilating a diseased lung with airflow
obstruction and flow limitation. In this case, the expiratory pressure has reached a constant value at the set
BAP but the effects of the dynamic lag have not fully dissipated by the end of the expiratory phase. An
expiratory hold procedure would show that the alveolar gas had not ceased distributing and that the average
pressure of the gas, designated as total PEEP (tPEEP), was greater than the measured PEEP by the amount
designated as dynamic PEEP (dPEEP).
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Figure F.21 again illustrates a typical situation that may occur when ventilating a diseased lung with airflow
obstruction and flow limitation. However, in this case an expiratory-control algorithm has been used to
determine an optimum expiratory pressure waveform on a ventilator with the ability to maintain such a
waveform by means of an ACAP or ACAPL adjunct, or an equivalent function. The waveform has been initially
taken below the set BAP level in order to discharge gas from the ventilator breathing system and the patient’s
upper airways as quickly as possible before bringing it back up to the set level while the pressure in the lower
airways is still declining. The effect is to decrease the dynamic lag in the later stages of the expiration and to
thereby reduce the dynamic PEEP.
Figure F.22 illustrates a typical situation that may occur if the set expiratory time is too short such that there
is insufficient time for the gas in the lung to fully discharge before the next inflation is initiated. This is more
likely to occur at the higher set rates as may be appropriate for younger patients or if there is excessive
resistance in the expiratory limb of the ventilator breathing system. In this case, the measured PEEP does not
reach the baseline pressure level leading to an increase in the measured total PEEP. Although it could be said
that this portion of total PEEP is also a dynamic factor, it is not included in the dynamic PEEP measurement
because, unlike dynamic PEEP, it is unlikely to be a good indicator of lung impairment.
The difference between the measured PEEP and the set BAP is designated in this vocabulary by the term
ΔPEEP. Typically there will be no difference between PEEP and the set BAP, but where a difference arises
the operator should be aware of the possible implications. A positive difference may indicate too short an
expiration time or a restriction in the expiratory pathway of the ventilator breathing system (for example, a
contaminated filter). A negative difference may indicate that the pressure in the lungs is being allowed to
drop below the intended minimum level due to uncompensated leakage from the ventilator breathing circuit
or at the connections of an airway device.
Figures F.23 illustrates a typical expiratory phase of a primary-inflation in a Group 2 ventilation-mode, which
may be alternatively referred to as a BAP phase. This alternative name is not only more concise and less
ambiguous but leads naturally into the terminology of bi-level ventilation (the two levels of which are
indicated by orange broken lines).
Figures F.24 – F 27 illustrate the function of an expiratory-control algorithm.
F.24 shows its function during the BAP phase of the primary inflation of a Group 2 ventilation-mode when
each patient inspiration is supported by a pressure support inflation, whereas F. 25 shows the same BAP
phase but with either no support of with the support reduced to its ‘off’ or ‘zero’ level.
F.26 shows its function when spontaneous breathing is enabled during a primary inflation phase, which may
be alternatively referred to as a BAP-high phase.
F.27 shows the function of the expiratory-control algorithm in a CSV mode with and without pressure support.
In each of these illustrations the expiratory-pressure waveforms are determined by the expiratory-control
algorithm and maintained by the in-built functionality of either an ACAP adjunct that is active at the BAP level,
or an equivalent pressure-regulation function. The range of waveforms and how closely they are maintained
may be impaired with the use of some equivalent pressure-regulation functions.
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148
3
Airway
pressure,
pAW
1
Typical, measured
expiratory-pressure
waveform
4
Dynamic lag of
alveolar pressure
5
2
Ambient
pressure
Typical, estimated
alveolar pressure
waveform
7 PEEP
(measured)
6 BAP
(setting)
8 total
PEEP
©NSJ
9 Expiratory phase
149
a) Typical ideal expiratory-airway-pressure waveforms
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3
1 Airway
pressure,
pAW
Typical, measured
expiratory-pressure
waveform
4 Dynamic lag of
alveolar pressure
5 Typical, estimated
alveolar-pressure
waveform in impaired
lung
10 dynamic
PEEP
2
Ambient
pressure
7 PEEP
(measured)
6 BAP
(setting)
©NSJ
9 Expiratory phase
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8 total
PEEP
b) Typical expiratory-airway-pressure waveforms with an impaired lung
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Figure F.1 (1 of 2) — Illustrations of the application of BAP and PEEP terminology
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3
Airway
pressure,
pAW
1
Typical, algorithmgenerated, expiratorypressure waveform
4
Typical, estimated
alveolar pressure
waveform
5
Dynamic lag of
alveolar pressure
10
dynamic
PEEP
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7 PEEP
(measured)
6 BAP
(setting)
2
Ambient
pressure
8
total
PEEP
©NSJ
9 Expiratory phase
a) Typical expiratory-airway-pressure waveforms with an impaired lung but with an expiratory-control
algorithm programmed to enhance initial evacuation of the gas in the upper airways by increasing
the initial pressure differential.
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3
Airway
pressure,
pAW
1
Typical, measured
expiratory-pressure
waveform
4
5
Typical, estimated alveolar
pressure waveform
10
dynamic
PEEP
Dynamic lag of
alveolar pressure
2
Ambient
pressure
11 ΔPEEP
6 BAP
(setting)
9 Expiratory phase
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7 PEEP
(measured)
8
total
PEEP
©NSJ
c) Typical expiratory-airway-pressure waveforms on a basic ventilator with inadequate set expiratory
time or excessive expiratory-limb resistance (e.g., due to kinked tube or increased resistance filter).
Figure F.1 (2 of 2) — Illustrations of the application of BAP and PEEP terminology
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3
Typical displayed
expiratory-pressure
waveform
1
Airway
pressure,
pAW
4
Inspiratory
pressure, pI
or BAP-high
2
Ambient
pressure
5 PEEP
6 BAP
7 BAP time, tL
or expiratory time
9 Expiratory phase
8 Inflation
phase
10 Support-inflation cycle
BAP phase
11
or primary expiratory phase
Spontaneous
inspiration with
pressure-support
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12
Inspiratory
flow
0
13
Expiratory
flow
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14
Unassisted
spontaneous
inspiration
©NSJ
Figure F.2 — The BAP/Expiratory phase
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1 Airway
pressure,
pAW
1
2
2
1
PEEP
3 BAP
4 PEEP
PEEP
2 Ambient pressure
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5 BAP (or Expiratory) time
a) Function of the expiratory-control algorithm during a BAP (or primary expiration) phase
with supported breaths
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1 Airway
pressure,
pAW
2
Ambient
pressure
1
3
4 PEEP
PEEP
3 BAP
PEEP
5 BAP (or Expiratory) time
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b) Function of the expiratory-control algorithm during a BAP (or primary expiration) phase with
unassisted breaths
Notes to Figures F.6a) and F.6b):
Typical expiratory-pressure
waveforms, following a primary1
inflation, as may be determined
by the expiratory-control
algorithm
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2
Pressure-support
inflation to assist
spontaneous
inspirations
3
The expiratory-control algorithm also generates
the constant pressure portion of the intended
primary expiratory pressure waveform, which the
ACAPL adjunct acts to maintain in order to enable
unrestricted breathing when pressure-support is
absent or turned off, and to compensate for
leakage.
Figure F.3 (1 of 2) —Illustrations of the function of the expiratory-control algorithm on ventilators
with an ACAPL adjunct (or an equivalent function) during BAP phases
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1
1 Airway
pressure,
pAW
2
Ambient
pressure
6
BAP-high
(or Inspiratory
pressure)
1
3 BAP
5 BAP-high time (or inspiratory time)
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c) Function of the expiratory-control algorithm during a primary inflation phase
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2
1 Airway
pressure,
pAW
3
1
1
PEEP
4 PEEP
3 BAP
2 Ambient pressure
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d) Function of the expiratory-control algorithm in CSV modes
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Notes to Figures F.6c) and F.6d):
1
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Typical expiratory-pressure waveforms,
following a support-inflation, at either
BAP levels, as may be determined by the
expiratory-control algorithm
2
Pressure-support
inflation to assist
spontaneous
inspirations
3
The expiratory-control algorithm also generates the constant
pressure portion of the intended primary expiratory pressure
waveform, which the ACAPL adjunct acts to maintain in order
to enable unrestricted breathing when pressure-support is
absent or turned off, and to compensate for leakage.
Figure F.3 (2 of 2) — Illustrations of the function of the expiratory-control algorithm on ventilators
with an ACAPL adjunct (or an equivalent function) during BAP phases
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Annex G
Conventions followed in this International Standard
(Informative)
G.1 Avoidance of repetition
In order to avoid the repetition of ‘in this International Standard’ in the text of the sub-clauses of this
International Standard, the expressions ‘is used’ and ‘in this vocabulary’ are to be read as being in reference
to the vocabulary of this International Standard.
G.2 Post-coordinated terms
The notes to some definitions make reference to post-coordinated terms. These are terms formed by the
combination of two defined terms, or of a defined term with a natural language word, to form a new
compound term. Usually, the additional term or word qualifies the base term by reference to an alternative
site, pressure level or point of occurrence within a respiratory cycle. It may place a restriction on the
applicability of the base term. Some of the most commonly used post-coordinated terms are defined in their
own right but users of the vocabulary are free to create other post-coordinated terms providing the
combination does not conflict with the meaning of the defined term.
G.3 Use of hyphens
Where hyphens are used in compound terms in the vocabulary of this International Standard their use is
considered to be good practice in the interests of readability and the minimisation of possible ambiguity but
their use is not normative.
G.4 Flows and pressures
In natural language, the word ‘flow’ denotes a steady movement of a body of fluid in the same general
direction. In order to denote a quantified flow the addition of the word ‘rate’ is necessary.
Similarly, the word ‘pressure’ in reference to a gas denotes a continuous physical force exerted against
something that the gas is in contact with. In order to denote it as a quantity the addition of a term such as
‘level’ is necessary
In practice, when used as artificial-ventilation terms these additions seldom add meaning because the context
makes it clear when they are being used to represent a value. Because of the need for brevity, particularly
when used on user interfaces and in instructions for use, in the vocabulary of this International Standard, the
term ‘flow’ is taken to encompass the concept of a rate of flow and the term ‘pressure’ is taken to encompass
the concept of the pressure level. Where this is seen to create an ambiguity, or in applications where the use
of correct English is considered to be the priority, the terms ‘rate’ or ‘level’ may be added, respectively, where
appropriate.
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G.5 Measurements
References to measured values in this vocabulary are to be taken as referring to values obtained from
measurement devices of systems, with the understanding that the actual measurement signal(s) may have
been appropriately processed to remove artefacts such as result from transients and ‘noise’ while
maintaining a declared accuracy; also that the site(s) of measurement may be away from the site to which
the measurement is referenced.
As a measurement, without further qualification or context, a recorded or displayed discrete value of a
quantity is that of a measurement at any point in time relative to a respiratory cycle or a specified elapsed
time. As the actual value of a quantity generally varies with time, even if regulated to a set value, a displayed
or recorded measured value has no meaning unless related to a specific point(s) in a respiratory cycle(s),
either by a qualifying term or by the context of use. An example of context is a displayed waveform, which is
clearly a continuous display of the actual measured value with progress of time. An example of a qualified
term is peak inspiratory pressure where the displayed value is the maximum measured value recorded during
a specified interval.
Although the definition of many terms relating to quantities in the vocabulary of this International Standard
specify a site at which it applies, there is no requirement that measurements are made at that site. In practice,
the site of actual measurement(s) may be anywhere in the ventilator breathing system providing the indicated
value is referenced to the specified site. The displayed or recorded measured value may be a calculated value
based on the results of more than one measurement at different sites.
As stated in sub-clause 4.0, the terms relating to quantities in this vocabulary are conceptual and are
independent of any specific system of units of measurement. It is for particular standards to specify any
requirements regarding measurement accuracy, the applicability and appropriateness of the measurement
methods that might be adopted, and units of measurement.
G.6 Multiplicity of terms
Artificial-ventilation may be described in many levels of granularity, depending on the objective of the
description. This vocabulary is based on a comprehensive conceptual model of such ventilation, which can
lead to an apparently confusing multiplicity of terms relating to certain aspects of that function when listed
in an all-encompassing vocabulary. It is to be emphasised that there is no requirement for manufacturers to
adopt every one of these terms, nor be required to provide their own equivalent to every one, in the labelling
of any specific ventilator.
G.7 Use of the terms expiration and exhalation
The use of terms relating to gas entering and leaving the patient’s lungs is fundamental to a vocabulary of
artificial ventilation. In normal speech in English, terms such as inspire, inhale, exhale and expire in their
various inflected forms are used for that purpose but each has connotations that makes it less than ideal in
at least one of its forms. In particular, inhalation has become associated with drug abuse and many clinicians
consider it to be inappropriate to speak of the patient expiring, in the presence of the patient or those close
to them. However, one of the basic objectives of a terminology standard is, wherever possible, to have only
one term to represent each concept. After much discussion the terms inspiration and expiration were
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selected for this vocabulary but with the recognition that the use of alternative terms may be more
appropriate in potentially sensitive situations.
G.8 The use of symbols to represent defined terms
It is not a primary objective of this International Standard to specify requirements for symbols to be used as
alternatives to a defined terms. Symbols are typically used where space is limited, such as on a user interface,
but for many terms, currently used symbols are very diverse. Some manufacturers attempt to follow the
guidance and examples for mathematical signs and symbols to be used in natural sciences and technology
given in ISO 80000 but this guidance is not comprehensive.
Symbols have only been included as alternative preferred terms in this International Standard where there
appears to be a general consensus relating to their use in representing the main terms used when setting a
ventilator. Their use in product labelling is recommended but, as stated in Clause 2, not a requirement.
Where reproduced, this may be in fonts and styles to suit the application, except for letters designating
quantities. These should always in an italic style in accordance with the relevant parts of ISO 80000 &
ISO/IEC Directives Part 2: 2011, which specify that:
Symbols for quantities are generally single letters from the Latin or Greek alphabet, sometimes
with subscripts or other modifying signs. The quantity symbols are always written in italic
(sloping) type, irrespective of the type used in the rest of the text. No recommendation is made
or implied about the font of italic type in which symbols for quantities are to be printed. When,
in a given context, different quantities have the same letter symbol or when, for one quantity,
different applications or different values are of interest, a distinction can be made by use of
subscripts. A subscript that represents a physical quantity or a mathematical variable, such as
a running number, is printed in italic (sloping) type. Other subscripts, such as those
representing words or fixed numbers, are printed in roman (upright) type.
G.9 Bi-level terminology
The terminology in this vocabulary has been developed taking account of the additional functionality of
ventilators incorporating an ACAP adjunct. This is an advanced regulation function that, unlike conventional
pneumatic regulators, maintains a set airway pressure, irrespective of the direction of the airway flow. It is
used not only to enhance the regulation of the airway pressure during pressure-control inflations but also to
maintain the required pressure between primary inflations. This makes it possible for the patient to breathe
at any time, both concurrently with a primary inflation and during primary expiratory phases, with a minimal
imposed addition to the patient’s work of breathing. The set pressure for this regulation function may be
continuously constant, as when used with a CPAP mode, or in the form of a varying pressure waveform with
constant portions as is typically generated by either the inflation-type algorithm during inflation phases or
the expiratory-control algorithm during BAP (or expiratory) phases. During BAP phases it maintains a
constant pressure when there is no pressure-support, available or selected, and in the presence of any leakage.
On ventilators with this increased functionality, manufacturers have either labelled their modes as bi-level
modes, with corresponding terminology for the settings and displays, or have retained the classical
terminology for their modes, settings and displays, accompanied by a statement indicating that the patient is
free to breathe at any time.
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310
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As both approaches appear to have advantages and disadvantages, and as there is not yet any clear consensus
as to which is better from a human factors perspective, this vocabulary includes terms suitable for both
approaches. These terms are in most cases presented as alternatives but it is expected that they will always
be used consistently and in context, according to the mode designation adopted by the manufacturer.
It is expected that in future editions of this International Standard more specific guidance will be given on
the application of such terms.
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Annex H
Terminology — Alphabetized index of defined terms
(Normative)
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NOTE
The ISO Online Browsing Platform (OBP) provides access to terms and definitions. 1
Term
Source
Term
Source
A/CV
ISO 19223, —4.8.7
ACAP
ISO 19223, —4.9.2
ACAPH
ISO 19223, —4.9.4
ACAPL
ISO 19223, —4.9.3
accompanying documents
ISO 19223, —4.13.28
IEC 60601-1:2005, —3.4,
modified
actual value
ISO 19223, —4.13.22
additional breath
ISO 19223, —4.1.8
additional minute volume
ISO 19223, —4.7.12
additional primary-inflation
ISO 19223, —4.2.13
additional primary-inflation rate
ISO 19223, —4.4.2.14
additional-breath rate
ISO 19223, —4.4.2.7
adjunct
ISO 19223, —4.9.1
adjustable airway pressure limit
ISO 19223, —4.12.1.9
adjustable pressure limit
ISO 19223, —4.12.1.9
airway
ISO 19223, —4.13.2
airway device
ISO 19223, —4.13.3
airway leak
ISO 19223, —4.6.13
airway pressure
ISO 19223, —4.5.1
airway pressure limit
ISO 19223, —4.12.1.1
airway pressure release ventilation
ISO 19223, —4.8.12
airway resistance
ISO 19223, —4.13.4
alarm condition
IEC 60601-1-8, —
ISO 19223, —4.12.2.1
1 Available at: https://w w w .iso.org/obp/ui/#home
© ISO 2016 – All rights reserved
143
ISO/DIS 19223:2016(E)
Term
144
Source
alarm condition
ISO 19223, —4.12.2.1
IEC 60601-1-8 2006+A1:2012
Clause 3.1, modified
alarm limit
ISO 19223, —4.12.3.1
IEC 60601-1-8 2006+A1:2012
Clause 3.3, modified
alternative mode name
ISO 19223, —4.8.17
alternative ventilation mode name
ISO 19223, —4.8.17
anaesthesia breathing system
ISO 19223, —4.13.18
APL
ISO 19223, —4.12.1.9
apnoea ventilation
ISO 19223, —4.8.14
APRV
ISO 19223, —4.8.12
artificial ventilation
ISO 19223, —4.13.7
assist/control ventilation
ISO 19223, —4.8.7
assisted breath
ISO 19223, —4.1.14
assisted breath rate
ISO 19223, —4.4.2.3
assured constant airway pressure
ISO 19223, —4.9.2
assured constant airway pressure,
high
ISO 19223, —4.9.4
assured constant airway pressure,
low
ISO 19223, —4.9.3
assured delivery
ISO 19223, —4.2.14
assured minute volume
ISO 19223, —4.7.11
assured ventilation
ISO 19223, —4.8.5
auto trigger
ISO 19223, —4.10.10
automatic ventilation
ISO 19223, —4.13.8
backup ventilation
ISO 19223, —4.8.15
BAP
ISO 19223, —4.11.1
BAP phase
ISO 19223, —4.3.3
BAP phase
ISO 19223, —4.9.7
BAP pressure-low
ISO 19223, —4.9.7
BAP time
ISO 19223, —4.3.4
BAP-high
ISO 19223, —4.9.10
BAP-high phase
ISO 19223, —4.9.11
© ISO 2016 – All rights reserved
ISO/19223:2016(E)
Term
Source
baseline airway-pressure
ISO 19223, —4.11.1
bias flow
ISO 19223, —4.6.8
bi-level PAP
ISO 19223, —4.9.6
bi-level ventilation
ISO 19223, —4.9.5
breath
ISO 19223, —4.1.1
breath stacking
ISO 19223, —4.10.11
breath synchronization
ISO 19223, —4.10.7
breathe
ISO 19223, —4.1.2
breathing therapy mode
ISO 19223, —4.8.19
CMV continuous mandatory
ventilation
ISO 19223, —4.8.6
concave declining-flow pattern
ISO 19223, —4.6.11
concurrent breath
ISO 19223, —4.1.9
concurrent supported-breath rate
ISO 19223, —4.4.2.9
concurrent unassisted-breath rate
ISO 19223, —4.4.2.10
continuing airway pressure alarm
condition
ISO 19223, —4.12.2.3
continuous flow
ISO 19223, —4.6.9
continuous mandatory ventilation
ISO 19223, —4.8.6
continuous positive airway pressure
ISO 19223, —4.8.13
continuous spontaneous ventilation
ISO 19223, —4.8.10
controlled breath
ISO 19223, —4.1.16
controlled breath rate
ISO 19223, —4.4.2.5
CPAP
ISO 19223, —4.8.13
CSV
ISO 19223, —4.8.10
cycle time
ISO 19223, —4.3.19
declining-ramp (flow pattern)
ISO 19223, —4.6.10
delivered minute volume
ISO 19223, —4.7.7
delivered volume
ISO 19223, —4.7.2
delta PEEP
ISO 19223, —4.11.6
Δ delta
ISO 19223, —4.5.6
Δ inspiratory pressure
ISO 19223, —4.5.7
Δp
ISO 19223, —4.5.7
Δ PEEP
ISO 19223, —4.11.6
© ISO 2016 – All rights reserved
145
ISO/DIS 19223:2016(E)
Term
146
Source
Δ pressure
ISO 19223, —4.5.7
demand flow
ISO 19223, —4.6.12
dPEEP
ISO 19223, —4.11.5
dual-control
ISO 19223, —4.2.5
dynamic PEEP
ISO 19223, —4.11.5
emergency air intake port
ISO 19223, —4.14.3
end-expiratory flow
ISO 19223, —4.6.7
end-inspiratory flow
ISO 19223, —4.6.4
end-inspiratory pressure
ISO 19223, —4.5.8
exhaust port
ISO 19223, —4.14.4
expiration
ISO 19223, —4.1.11
expiratory flow
ISO 19223, —4.6.5
expiratory hold
ISO 19223, —4.3.8
expiratory pause
ISO 19223, —4.3.6
expiratory phase
ISO 19223, —4.3.2
expiratory pressure
ISO 19223, —4.5.9
expiratory pressure-relief
ISO 19223, —4.5.10
expiratory time
ISO 19223, —4.3.1
expiratory-control algorithm
ISO 19223, —44.11.3
expiratory-flow time
ISO 19223, —4.3.5
expiratory-hold time
ISO 19223, —4.3.9
expiratory-pause time
ISO 19223, —4.3.7
expiratory-termination flow
ISO 19223, —4.6.6
expired minute volume
ISO 19223, —4.7.9
expired tidal volume
ISO 19223, —4.7.4
flow trigger
ISO 19223, —4.10.3
flow-regulation
ISO 19223, —4.2.9
flow-termination
ISO 19223, —4.10.15
gas input port
ISO 19223, —4.14.7
gas intake port
ISO 19223, —4.14.2
gas output port
ISO 19223, —4.14.5
gas return port
ISO 19223, —4.14.6
hazard
ISO 14971:2007, 2.2
© ISO 2016 – All rights reserved
ISO/19223:2016(E)
Term
Source
high airway pressure limit
ISO 19223, —4.12.1.5
high airway-pressure alarm limit
ISO 19223, —4.12.3.2
high airway-pressure-relief limit
ISO 19223, —4.12.1.6
high airway-pressure-termination
limit
ISO 19223, —4.12.1.7
high-airway-pressure alarm
condition
ISO 19223, —4.12.2.2
high-pressure-relief limit
ISO 19223, —4.12.1.6
high-pressure-termination limit
ISO 19223, —4.12.1.7
I:E ratio
ISO 19223, —4.3.21
IMV
ISO 19223, —4.8.8
intermittent mandatory ventilation
ISO 19223, —4.8.8
inflation
ISO 19223, —4.2.1
Inflation Initiation and Termination
ISO 19223, —4.10
inflation phase
ISO 19223, —4.3.17
inflation-type
ISO 19223, —4.2.2
initiate
ISO 19223, —4.1.10
Inspiratory minute volume (external
monitor)
ISO 19223, —4.7.8
inspiration
ISO 19223, —4.1.10
inspiratory effort
ISO 19223, —4.1.7
inspiratory flow
ISO 19223, —4.6.1
inspiratory hold
ISO 19223, —4.3.15
inspiratory pause
ISO 19223, —4.3.13
inspiratory phase
ISO 19223, —4.3.11
inspiratory pressure
ISO 19223, —4.5.2
inspiratory time
ISO 19223, —4.3.10
inspiratory time fraction
ISO 19223, —4.3.22
inspiratory volume
ISO 19223, —4.7.3
inspiratory-flow time
ISO 19223, —4.3.12
inspiratory-hold time
ISO 19223, —4.3.16
inspiratory-pause time
ISO 19223, —4.3.14
inspiratory-pressure relief
ISO 19223, —4.5.5
inspiratory-termination flow
ISO 19223, —4.6.3
© ISO 2016 – All rights reserved
147
ISO/DIS 19223:2016(E)
Term
148
Source
intended purpose
ISO 19223, —4.13.25
ISO 14971:2000, — 2.5
intended use
ISO 19223, —4.13.25
ISO 14971:2000, — 2.5
ISO spontaneous breath rate
ISO 19223, —4.4.1.3
leakage minute volume
ISO 19223, —4.7.10
leakage tidal volume
ISO 19223, —4.7.5
limit
ISO 19223, —4.13.23
low inspiratory-pressure alarm
condition
ISO 19223, —4.12.2.4
low inspiratory-pressure alarm limit
ISO 19223, —4.12.3.3
low PEEP alarm condition
ISO 19223, —4.12.2.5
lung
ISO 19223, —4.13.14
lung compliance
ISO 19223, —4.13.5
lung ventilator
ISO 19223, —4.13.1
ISO 80601-2-12:2011, —
201.3.222 modified
lungs
ISO 19223, —4.13.15
mandatory
ISO 19223, —4.10.9
mandatory ventilation
ISO 19223, —4.8.5
maximum deliverable airway
pressure
ISO 19223, —4.12.1.4
maximum deliverable pressure
ISO 19223, —4.12.1.4
maximum limited airway pressure
ISO 19223, —4.12.1.3
ISO/IEC 80601-2-12: 2011, —
201.3.214 modified by the
addition of semantic notes
maximum limited pressure
ISO 19223, —4.12.1.3
maximum settable inspiratory
pressure
ISO 19223, —4.12.1.8
measured
ISO 19223, —4.13.20
mechanical ventilation
ISO 19223, —4.13.9
minute volume
ISO 19223, —4.7.6
MMV
ISO 19223, —4.8.11
minimum minute volume
ISO 19223, —4.8.11
© ISO 2016 – All rights reserved
ISO/19223:2016(E)
Term
Source
natural breathing
ISO 19223, —4.1.4
negative-pressure ventilation
ISO 19223, —4.13.11
NIV
ISO 19223, —4.13.12
non-concurrent unassisted-breath
rate
ISO 19223, —4.4.2.11
non-invasive ventilation
ISO 19223, —4.13.12
normal condition
ISO 19223, —4.13.26
IEC 60601-1:2005, —3.70]
normal use
ISO 19223, —4.13.24
IEC 60601-1:2005, —3.71
NPV
ISO 19223, —4.13.11
patient-connection port
ISO 19223, —4.14.8
patient-trigger event
ISO 19223, —4.10.6
patient-triggered inflation rate
ISO 19223, —4.4.2.12
patient-triggered primary inflation
rate
ISO 19223, —4.4.2.8
PC
ISO 19223, —4.2.4
peak inspiratory flow
ISO 19223, —4.6.2
peak inspiratory pressure
ISO 19223, —4.5.3
PEEP
ISO 19223, —4.11.1
pES
ISO 19223, —4.2.7
phase time ratio
ISO 19223, —4.3.21
plateau inspiratory pressure
ISO 19223, —4.5.4
plateau pressure
ISO 19223, —4.5.4
pLim
ISO 19223, —4.12.1.2
port
ISO 19223, —4.14.1
positive end-exhalation pressure
ISO 19223, —4.11.2
positive pressure inflation
ISO 19223, —4.2.1
positive-pressure ventilation
ISO 19223, —4.13.10
preset value
ISO 19223, —4.13.21
pressure limit
ISO 19223, —4.12.1.1
pressure limited
ISO 19223, —4.12.1.2
pressure trigger
ISO 19223, —4.10.4
pressure-control
ISO 19223, —4.2.4
© ISO 2016 – All rights reserved
149
ISO/DIS 19223:2016(E)
Term
150
Source
pressure-high
ISO 19223, —4.9.10
pressure-high phase
ISO 19223, —4.9.11
pressure-low phase
ISO 19223, —4.9.8
pressure-regulation
ISO 19223, —4.2.10
pressure-support
ISO 19223, —4.2.6
pressure-termination
ISO 19223, —4.10.16
primary inflation rate
ISO 19223, —4.4.2.1
primary-inflation
ISO 19223, —4.2.12
primary-inflation cycle
ISO 19223, —4.3.20
proportional effort support
ISO 19223, —4.2.7
PS
ISO 19223, —4.2.6
rate
ISO 19223, —4.4.1.1
remote inflation-initiation
ISO 19223, —4.10.13
respiratory activity
ISO 19223, —4.1.6
respiratory cycle
ISO 19223, —4.3.18
respiratory cycle time
ISO 19223, —4.3.19
respiratory system
ISO 19223, —4.13.16
respiratory system coefficients
ISO 19223, —4.13.17
rise time
ISO 19223, —4.2.11
RR
ISO 19223, —4.4.1.2
RRspont
ISO 19223, —4.4.1.3
RRv ent
ISO 19223, —4.4.1.4
S/T
ISO 19223, —4.2.8
set
ISO 19223, —4.13.19
SIMV
ISO 19223, —4.8.9
single fault condition
ISO 19223, —4.13.27
IEC 60601-1:2005, —3.116
spontaneous breath
ISO 19223, —4.1.3
spontaneous rate
ISO 19223, —4.4.1.3
spontaneous respiratory rate
ISO 19223, —4.4.1.3
spontaneous/timed pressure-control
ISO 19223, —4.2.8
superordinate mode
ISO 19223, —4.8.18
supported breath
ISO 19223, —4.1.13
© ISO 2016 – All rights reserved
ISO/19223:2016(E)
Term
Source
support-inflation
ISO 19223, —4.2.15
support-inflation rate
ISO 19223, —4.4.2.2
Supralaryngeal airway
ISO 11712, —3.10
synchronisation window
ISO 19223, —4.10.8
synchronised breath
ISO 19223, —4.1.15
synchronised breath rate
ISO 19223, —4.4.2.4
synchronised intermittent mandatory
ventilation
ISO 19223, —4.8.9
systematic ventilation-mode name
ISO 19223, —4.8.16
tB
ISO 19223, —4.3.4
TC
ISO 19223, —4.13.13
termination
ISO 19223, —4.10.14
ti
ISO 19223, —4.3.10
tI :tTOT
ISO 19223, —4.3.22
tidal volume
ISO 19223, —4.7.1
time-high
ISO 19223, —4.9.12
time-low
ISO 19223, —4.14.5
time-low
ISO 19223, —4.9.9
time-termination
ISO 19223, —4.10.17
tL
ISO 19223, —4.14.5
total inflation rate
ISO 19223, —4.4.2.13
total PEEP
ISO 19223, —4.11.4
total rate
ISO 19223, —4.4.1.2
total respiratory rate
ISO 19223, —4.4.1.2
tPEEP
ISO 19223, —4.11.4
trigger
ISO 19223, —4.10.2
trigger event
ISO 19223, —4.10.6
trigger level
ISO 19223, —4.10.5
tube compensation
ISO 19223, —4.13.13
unassisted breath
ISO 19223, —4.1.12
unassisted breath rate
ISO 19223, —4.4.2.6
unrestricted breathing
ISO 19223, —4.1.5
© ISO 2016 – All rights reserved
151
ISO/DIS 19223:2016(E)
Term
Source
VBS
ISO 19223, —4.13.18
ISO 4135:2001, —3.1.6 and
4.1.1, modified
IEC 80601-2-12:2011, —
201.3.221, modified
VBS leak
ISO 19223, —4.6.14
VC
ISO 19223, —4.2.3
V DEL
ISO 19223, —4.7.2
ventilation
ISO 19223, —4.13.6
ventilation mode
ISO 19223, —4.8.2
ventilation-mode Group 1
ISO 19223, —4.8.4.1
ventilation-mode Group 1a
ISO 19223, —4.8.4.1.1
ventilation-mode Group 1b
ISO 19223, —4.8.4.1.2
ventilation-mode Group 2
ISO 19223, —4.8.4.2
ventilation-mode Group 2a
ISO 19223, —4.8.4.2.1
ventilation-mode Group 2b
ISO 19223, —4.8.4.2.2
ventilation-mode Group 3
ISO 19223, —4.8.4.3
ventilation-mode Group 3a
ISO 19223, —4.8.4.3
ventilation-mode Group 3b
ISO 19223, —4.8.4.3.2
ventilation-mode groups
ISO 19223, —4.8.4
ventilation-pattern
ISO 19223, —4.8.3
ventilator
ISO 19223, —4.13.1
ventilator breathing system
ISO 19223, —4.13.18
ISO 4135:2001, —3.1.6 and
4.1.1, modified
IEC 80601-2-12:2011, —
201.3.221, modified
152
ventilator breathing system leak
ISO 19223, —4.6.14
ventilator inspiration
ISO 19223, —4.2.1
ventilator mode
ISO 19223, —4.8.1
ventilator-initiated inflation rate
ISO 19223, —4.4.1.4
ventilator-initiated rate
ISO 19223, —4.4.1.4
ventilator-initiation
ISO 19223, —4.10.12
VI
ISO 19223, —4.7.3
VM
ISO 19223, —4.7.6
© ISO 2016 – All rights reserved
ISO/19223:2016(E)
Term
Source
Vmaddn
ISO 19223, —4.7.12
Vmassd
ISO 19223, —4.7.11
VMDEL
ISO 19223, —4.7.7
VME
ISO 19223, —4.7.9
VMI
ISO 19223, —4.7.8
VMLeak
ISO 19223, —4.7.10
volume targeted
ISO 19223, —4.2.16
volume-control
ISO 19223, —4.2.3
vt
ISO 19223, —4.2.16
VT
ISO 19223, —4.7.1
VT E
ISO 19223, —4.7.4
VT Leak
ISO 19223, —4.7.5
316
© ISO 2016 – All rights reserved
153
ISO/DIS 19223:2016(E)
Annex I
Index of figures
(Informative)
317
318
319
320
321
322
323
324
325
Annex C Figures
Figure C.1 - Format used in this International Standard for representations of ventilation patterns and
inflation-types
Figure C.2 (1 of 5) - Illustrations of the application of defined ventilation terms in designating key features of
typical inflation waveforms
a)
b)
c)
d)
e)
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
Typical
Typical
Typical
Typical
Typical
airway pressure and flow waveforms for a pressure-control inflation
airway pressure and flow waveforms for a pressure-support inflation
airway pressure and flow waveforms for a flow-terminated pressure-control inflation
airway pressure and flow waveforms for volume-control inflation with an inspiratory pause
airway pressure and flow waveforms for a pressure-limited volume-control inflation
Figure C.3 - Typical airway pressure and flow waveforms for a CMV-PC mode
Figure C.4 - Typical airway pressure and flow waveforms for a CMV-PC <ACAPL> mode
Figure C.5 - Typical airway pressure and flow waveforms for a CMV- PC <ACAP> mode set with extended phase
times
Figure C.6 - Typical airway pressure and flow waveforms for a CMV- PC <ACAP> mode set with an extreme
inverse I:E ratio
Figure C.7 - Typical airway pressure and flow waveforms for an A/CV - PC mode
Figure C.8 - Typical airway pressure and flow waveforms for an A/CV – VC mode
Figure C.9 - Typical airway pressure and flow waveforms for an A/CV – PC <ACAP> mode
(No pressure-support inflation-type is permitted with this mode but it could be optionally labelled: Bi-level
ventilation (A/CV – PC <ACAP>).)
Figure C.10 - Typical airway pressure and flow waveforms for an SIMV- PC\PS mode
Figure C.11 - Typical airway pressure and flow waveforms for variations on an SIMV- PC\PS\PS <ACAP> mode
a) with typical settings for the simulation of Bi-level ventilation
b) with typical settings for the simulation of APRV
c) with a PC[S] primary inflation-type and optionally labelled as a ‘Bi-level ventilation’ mode
d) with a PC[S] primary inflation-type, no pressure-support at BAP level and optionally labelled as
intended for APRV (airway pressure release ventilation)
154
© ISO 2016 – All rights reserved
ISO/19223:2016(E)
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
Figure C.12 - Typical airway pressure and flow waveforms for a CSV - PS mode
Figure C.13 – Characteristics of a concurrent breath
Figure C.14 – Ventilation patterns
a)
b)
c)
d)
e)
f)
Key to symbols used in b) to f)
CMV ventilation-pattern
Assist/Control ventilation-pattern
IMV ventilation-pattern
SIMV ventilation-pattern
CSV ventilation-pattern
I.1 Annex E Figures
Figure E.1 — Diagram showing the concepts of the relationship between breath and inflation related terms
in the vocabulary of the International Standard
I.2 Annex F Figures
Figure F.1 Illustrations of the application of BAP and PEEP terminology
a) Typical ideal expiratory-airway-pressure waveforms
b) Typical expiratory-airway-pressure waveforms with an impaired lung
c) Typical expiratory-airway-pressure waveforms with an impaired lung but with an expiratory-control
algorithm programmed to enhance initial evacuation of the gas in the upper airways by increasing
the initial pressure differential.
d) Typical expiratory-airway-pressure waveforms on a basic ventilator with inadequate set expiratory
time or excessive expiratory-limb resistance (e.g., due to kinked tube or increased resistance filter).
Figure F.2 - The BAP/Expiratory phase
Figure F.3 Illustrations of the function of the expiratory-control algorithm on ventilators with an ACAPL
adjunct (or an equivalent function) during BAP phases
c) Function of the expiratory-control algorithm during a BAP (or primary expiration) phase with
supported breaths
d) Function of the expiratory-control algorithm during a BAP (or primary expiration) phase with
unassisted breaths
e) Function of the expiratory-control algorithm during a primary inflation phase
f) Function of the expiratory-control algorithm in CSV modes
© ISO 2016 – All rights reserved
155
ISO/DIS 19223:2016(E)
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
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ISO 10241, International terminology standards — Preparation and layout
[5]
ISO 31 (all parts), Quantities and units
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[11]
IEC 60601-1 Medical electrical equipment - Part 1: General requirements for basic safety and essential
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ISO 10651-4 Lung ventilators -- Part 4: Particular requirements for operator-powered resuscitator
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[17]
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ISO 23747 Anaesthetic and respiratory equipment -- Peak expiratory flow meters for the assessment of
pulmonary function in spontaneously breathing humans
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