Medical Gases
Lynn Morrison
Regional QA Pharmacist
NHS Greater Glasgow and Clyde
Medical Gases
Introduction and session objectives
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To describe the different medical gases found within
a hospital
To understand the design and construction of a
medical gas pipeline system (MGPS)
To be aware of the system of controls applied to
facilitate the safe and secure operation of a medical
gas pipeline system
To understand the roles and responsibilities of key
personnel involved in medical gases
To understand the role of the Quality Controller
(MGPS)
To have an awareness of medical gas testing
To appreciate the role of the EDC pharmacist in an
emergency situation
Medical Gases – what gases are
found in hospitals?
Oxygen
 Nitrous oxide
 Medical Air
 Surgical Air
 Oxygen / Nitrous oxide mixture 50:50
“Equanox” or “Entonox”
 Vacuum
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What are the medical gases used
for?
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Oxygen – used to sustain life
Medical air – used to drive ventilators
Surgical air – used to operate surgical tools
Nitrous oxide – used in theatres for
anaesthetic purposes
Equanox / Entonox – used as an analgesic,
home delivery
Vacuum - suction
What other gases could you find?
Carbon dioxide
 Helium / oxygen mixtures
 Nitric oxide
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What are these gases used for?
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Carbon dioxide – clinical and physiological
investigations
Helium/oxygen mixtures – respiratory assessment
and treatment e.g. COAD
Nitric oxide – aids oxygen exchange in respiratory
distress conditions
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How are the gases supplied to
the hospital?
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Oxygen – delivered as a liquid via a tanker to
a liquid oxygen tank compound with vacuum
insulated evaporators - VIE
Nitrous oxide – cylinders
Medical air – cylinders or compressors
Equanox / Entonox – cylinders
Other gases – cylinders
NHS Scotland - national contracts for supply
of medical gases
Where are the gases stored?
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Liquid Storage Tank with VIE – oxygen
Cylinder store – various gases
Manifold rooms – e.g. medical air, nitrous oxide,
Equanox/ Entonox
Medical and surgical air compressor systems and
receiver tanks
Other locations – e.g. ready use stores
ambulances
patient transport
Oxygen tank – VIE tank
“Duty” tank and a “stand by” tank
 Vacuum insulated evaporator
 Valve box (with test point)
 Alarm panel
 Copper pipework – medical gas pipeline
system - connecting tanks to the
hospital pipeline system
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Oxygen tank and VIE
Oxygen tank – control panel
Cylinder store
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Visit the cylinder store on site
Cylinder stores should be :separate from other buildings
no “naked flames”
clean, tidy, locked
full cylinders should be stored separately from empty
each gas type to be stored separately
etc
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Can you think of any other storage requirements?
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separate cylinders by size
temperature control
log of issue and return
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Cylinders
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Currently :Oxygen – black body / white shoulders
Nitrous oxide – blue
Medical air – grey body / black and white shoulders
Equanox / Entonox – blue body / blue and white
shoulders
Heliox – black body / brown and white shoulders
Carbon dioxide - grey
Future :EU Directive – all cylinders will have white body and
colour coded shoulders as above
Implementation to be completed by 2025
Manifold rooms
A manifold is defined as a set of
pipework to which a series of cylinders
is attached.
 “Duty” and “stand by” bulk supply to the
hospital
 Must be in date
 Must be checked regularly
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Oxygen manifold
Medical air manifold
Medical / Surgical air
compressors
How do the gases get to the
patient ?
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Medical Gas Pipeline System (MGPS)
Copper pipelines
Pressure reducing valves
AVSU – area valve service unit
Terminal outlets
Flow meter and tubing
Mask / nasal canulae
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Cylinders – valve and flowmeter
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Area Valve
Service
Units
Terminal Units
Safety issues
Medical gases
 Oxygen – supports combustion – patient’s
clothing and bedding can become saturated
 Nitrous oxide – causes headaches,
drowsiness, cumulative effects, teratogenic
effects, can cause asphyxia in confined
spaces
also supports combustion
 Equanox / Entonox – combination of the
above
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Safety issues
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Cylinder handling
Never carry a cylinder by its neck
Use correct trolleys
Protective equipment
Never roll cylinders!!
Never eat/smoke while handling cylinders
Etc!!
Training vital!!!
Control systems - Documentation
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HTM 02-01
Part A ;
Design, installation,
validation and
verification
Part B ;
Operational
Management
In Scotland (s)HTM
02-01
Control systems - Documentation
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Permit to work system
controls any engineering work to be carried out on the MGPS
safeguards the integrity of the MGPS and patient safety
4 part documentation signed by all those involved in the work
activity
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Operational policies
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Controlled document
Scope
Responsibilities and training for staff
Record drawings and accompanying documentation
Description of MGPS, valves, alarms etc
Medical gas committee
Emergency procedures
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Control systems - Documentation
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Health and Safety at Work legislation
Manufacturer / supplier product
material safety data sheets
C11
CHIP
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SPQAG testing protocols
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Control systems – defined roles
and responsibilities
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Designated Medical Officer or
Nursing Officer
Authorised Person
Competent Person
QUALITY CONTROLLER
(MGPS)
Control systems – defined roles
and responsibilities
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QUALITY CONTROLLER (MGPS)
responsible for the quality control of medical
gases as terminal units and plant
accepts professional responsibility for the
last independent check of a MGPS
must be able to provide evidence of training,
competence
registered - QC (MGPS) register
Your involvement with medical gases
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Clinical function
Clinical need
Equipment
Understand operation of MGPS
Understand safety considerations for
cylinders
Regulators, flowmeters and associated tubing
etc
Emergency situations
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Must be aware of day to day operational
aspects of MGPS / cylinder management to
ensure have fundamental knowledge to cope
with emergency situation
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Examples
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Procedure to be followed
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Operational policy documents and
emergency information cards
Emergency situations
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YOUR ROLE
to ensure back up supply is made available and
additional cylinders sourced as required
to contact suppliers and arrange delivery
Must ensure you know :where back up supply (cylinders / tank) stored on site
how to contact suppliers (cylinders or liquid supply)
how many cylinders to ask for
the size of cylinder to ask for
the delivery location
BEFORE AN EMERGENCY OCCURS !!
Medical gases
Testing
Medical gas testing
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RQAS Med Gas test team
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Tests carried out – commissioning new installations
modifications to existing systems
de-commissioning of systems
routine compressor testing
Medical gas testing
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Tests completed
Identity / purity
Particulate contamination
Non specific contamination
Water vapour
Carbon Dioxide
Carbon Monoxide
Oil
Sulphur dioxide
Nitrous fumes
Line pressure
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Vacuum pressure
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Acceptance criteria (Ph. Eur.)
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Identity and purity – acceptance criteria
oxygen - > or equal to 99.5%
(absence of nitrous oxide)
oxygen in medical / surgical air –
20.4% to 21.4%
nitrous oxide - >98%
(absence of oxygen)
oxygen / nitrous oxide mixture
48% to 52% of each component
Particles – absence of particles e.g. copper oxide,
copper, “verdigris”
Non- specific contamination – polytest tube –
absence of colour change in crystals
Water vapour – not more than 0.05mg/L / 67vpm
Acceptance criteria (Ph. Eur.)
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CO2 – not more than 500ppm / 300ppm
CO – not more than 5ppm
Oil – not more than 0.1mg/L – medical /
surgical air to ensure no carry over from
compressor motors
Sulphur dioxide – not more than 1ppm
Nitrous fumes – not more than 2ppm
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Vacuum – not less than 400mmHg
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Visit to Medical Gas storage
facilities and wards/ departments
Visit the following : Oxygen tank and VIE plant
 Medical air compressor plant
 Nitrous oxide manifold
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Visit a ward :What gases are supplied via a piped system?
- look out for terminal units, area valve
service units (AVSU)
What gases are supplied in cylinder form?
Quiz
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Please complete multiple choice
questions