OXYGEN DEVICES
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RT 210A
Oxygen Therapy – Indications*
• Documented hypoxemia (PaO2 and/or SaO2
decreased below patients baseline)
• An acute care situation in which hypoxemia is
suspected (cardiopulmonary arrest, stroke,
Pneumo…)
• Severe trauma
*From the AARC Clinical Practice Guideline
Oxygen Therapy – Indications*
• Acute myocardial infarction
• Short term therapy or surgical intervention
*From the AARC Clinical Practice Guideline
Indications
• When a patient exhibits signs, symptoms or situations that indicate
oxygen therapy there are very few contradictions.
A patient may need oxygen to keep the workload of the heart and
lungs at a normal level. If an asthmatic patient has an asthma attack
and their airways are becoming restrictive they won't be able to
bring in as much air to their lungs. In this case you want the air that
they are able to bring into their lungs to have higher levels of oxygen
than what room air alone can provide.
One indication for oxygen is short-term therapy. In many of these
situations a patient may have normal SaO2 values but are in a
situation where hypoxia may be common. Some of these may be
postoperative patients, CO2 poisoning, cyanide poisoning, shock,
trauma, acute MI or some premature babies. Oxygen
can sometimes be better used as a preventative than a treatment.
Hypoxemia
• When the a patient develops hypoxemia their breathing rate
will begin to rise proportionally along with their heart rate to
compensate for the demand of oxygen.
• Pulmonary vasoconstriction and hypotension develop. This in
turn will increase the workload on the right side of the heart
and over time can lead to heart failure.
• Tachypnea, tachycardia, dyspnea, lethargy/confusion develop
with severe hypoxemia
• Other visual symptoms include restlessness and headaches.
Oxygen Therapy – Contraindications*
• There are no specific contraindications to
oxygen therapy when indications are judged to
be present
*From the AARC Clinical Practice Guideline
Oxygen Therapy – Hazards and
Complications*
• Ventilatory depression (if you supersede a
patients need)
• Absorption atelectasis
• Oxygen toxicity
*From the AARC Clinical Practice Guideline
Oxygen Therapy – Hazards and
Complications*
• Fire hazard (combustible)
• Retinopathy of prematurity
• Bacterial contamination (when using humidity
or aerosol)
*From the AARC Clinical Practice Guideline
Ventilatory Depression
• Patients at risk:
• COPD patients with hypercapnea, again only if the
patient receives more PaO2 than they require, the
FIO2 does not necessarily matter during an
exacerbation, always give them enough to support
appropriate tissue oxygenation.
Ventilatory Depression
• Mechanism of action
• Patient has “normal” PaCO2 > 60 mmHg (chronic
hypercapnea)
• Response of central chemoreceptors blunted
• PaO2 decreases to < 55 mmHg
Ventilatory Depression
• Mechanism of action
• Decrease in oxygen level triggers response by
peripheral chemoreceptors, if they
• Rate and depth of breathing increase
Ventilatory Depression
• Mechanism of action
• When supplemental oxygen administered, PaO2 can
rise to > 55 mmHg, removing stimulus to
peripheral receptors
• Hypoventilation results
Absorption Atelectasis
• Two contributing factors
• FIO2 > 0.50
• Air trapping
What are the types of
atelectasis?
• Passive
• From hypoventilation, typically post surgical pain, weakness,
diaphragm weakness
• Resorptive
• When there is endobronchial obstruction, there is no more
ventilation and air gets absorbed from alveoli. Alveoli collapse with
significant loss of lung volume. Example: Lobar atelectasis from
endobronchial lung cancer.
• Relaxation
• Normally lungs are held close to chest wall by the negative pressure
in pleura. In pneumothorax or pleural effusion the negative pressure
in pleura is lost. Lung relaxes to its resting position.
• Adhesive
• Surfactant is necessary for keeping the alveoli open. In ARDS and
Pulmonary embolism there is loss of surfactant and alveoli collapse.
Absorption Atelectasis
• Mechanism of action
• At higher FIO2, nitrogen in alveolus is replaced by
oxygen
• With obstruction of the airway, oxygen is rapidly
absorbed into the capillary without replacement
in the alveolus
Absorption Atelectasis
• Mechanism of action
• Removal of oxygen causes decrease in volume of
alveolus, resulting in alveolar collapse or atelectasis
Absorption Atelectasis
• Mechanism of action
• May also occur in patients with low tidal volumes as a
result of sedation, pain, or CNS dysfunction
• Oxygen is absorbed faster than it can be replaced
• Alveoli gradually decrease in volume
• May eventually lead to complete collapse
• May occur even without supplemental oxygen
Oxygen Toxicity
• Two contributing factors
• FIO2 > 0.50
• Time of exposure
Oxygen Toxicity
• Pathophysiological changes
• Damage to capillary epithelium
• Interstitial edema
• Thickening of alveolar capillary membrane
Oxygen Toxicity
• Pathophysiological changes
• Destruction of type I alveolar cells
• Proliferation of type II alveolar cells
• Formation of exudate
Oxygen Toxicity
• Pathophysiological changes
• Decrease in ventilation/perfusion ratio
• Physiologic shunting
• Hypoxemia
Oxygen Toxicity
• Mechanism of action
• Overproduction of free radicals
• Safe level: FIO2 ≤ 0.50
Oxygen Toxicity
Fire Hazard
• Risk increases as oxygen level increases
• Greatest risks include operating rooms and
selected procedures
• Laser bronchoscopy may cause intratracheal
ignition in presence of increased FIO2
Retinopathy of Prematurity (ROP)
• Occurs in premature and low birth weight infants
• Causative factor
• Increased PaO2 usually greater than 80 mmHg
• Covered in neonatal section of curriculum
• http://www.youtube.com/watch?v=BVYwo-RmDNE
Bacterial Contamination
• Associated with equipment
Assessment of the Hypoxemic Patient
• Clinical signs of hypoxemia
• Tachypnea
• Tachycardia
• Anxiety
Assessment of the Hypoxemic Patient
• Clinical signs of hypoxemia
• Cyanosis
• Present when there are 5 grams of desaturated
hemoglobin
• May not be present in instances of severe anemia
• May be present in absence of hypoxemia in presence of
polycythemia
Assessment of the Hypoxemic Patient
• Clinical signs of hypoxemia
• Confusion
• Lethargy
• Coma
Assessment of the Hypoxemic Patient
• Laboratory data
• Arterial blood gas results (PaO2)
• Saturation (SpO2)
• Increased levels of lactic acid may indicate hypoxia
• O2 delivery in COPD patients:
• http://www.youtube.com/watch?v=XFieSB3TzK
4
Assessment of the Hypoxemic Patient
• Specific clinical conditions
• Myocardial infarction
• Generally given 100% oxygen, especially in ED
• Recent research may show that high FIO2 may cause
vasoconstriction of the coronary arteries, contributing to
cardiac ischemia
Assessment of the Hypoxemic Patient
• Specific clinical conditions
• Trauma
• Overdose
Monitoring the Physiologic
Effects of Oxygen
• The symptoms of hypoxia are cognitive
impairment, cardiac rhythm and conduction
dysfunction, and renal dysfunction.
• Monitoring arterial blood gas analysis is standard
for documenting oxygenation, ventilation, and
acid–base balance.
• Pulse oximetry is the most common form of
continuously monitoring oxygen saturation.
• Oxygen analyzers are used to measure the
concentration of oxygen administered to
patients.
Oxygen Devices
• http://www.youtube.com/watch?v=OWLkJv61eo&feature=related
• Low flow systems
• High flow systems
• Positive pressure (vents, IPPB, resuscitation bags)
• Hyperbaric chamber
Low Flow Oxygen Systems
• Deliver flows at less than the patient’s
inspiratory flow rate, diluting the inspired
oxygen with room air
• FIO2 varies dependent upon the specific
device and the patient’s inspiratory flow
Low Flow Oxygen Systems
• Conditions required for low flow systems
• VT between 300 and 700 mL
• f < 25 breaths per minute
• Regular breathing pattern
Nasal Cannula
•
•
•
•
Used on adults pediatrics and neonates
Adult flows: 0.5-6L
Infant/neonatal flows: typically less than 1 L
Typically a low flow device but may be high flow if given as a
high flow nasal cannula
• Add humidity for flows over 4L or anytime a infant/neonate or
pediatric is on any amount of O2
Delivery Devices – Nasal Cannula
• Advantages
• Economical
• Comfortable – better patient compliance
• Patient able to eat, speak, and cough with cannula
in place
• Mouth breathing not a significant factor
Estimating FiO2
Nasal Cannula flow rate
FIO2
1L
.24
2L
.28
3L
.32
4L
.36
5L
.40
6L
.44
O2 mask flow rate
FIO2
5-6 L
0.4
6-7 L
0.5
7-8 L
0.6
NC
•
•
•
•
•
0.5 LPM = 22%
1 LPM = 24%
2 LPM = 28%
3 LPM = 32%
4 LPM = 36% starting at 4 LPM a bubble humidifier is required
to prevent
• 5 LPM = 40% irritating the nasal mucosa which can cause nose
bleeds or
• 6 LPM = 44% drying of mucus.
Delivery Devices – Nasal Cannula
• Disadvantages
• Imprecise concentration of oxygen delivered
• May fluctuate according to patient’s
breathing pattern
• May cause irritation to nares, nasal airway, or
ears (around ear), may use cushion around ear
• Easily dislodged
Delivery Devices – Nasal Cannula
• Flows generally not greater than 6 L/min
• May use with very low flows, less than
L/min
• Flows ≤ 4 L/min do not require use of
humidifier
¼
Figure 16-9A: Nasal cannula with elastic strap.
(A) Adapted from Scanlan CL, et al. Egan’s Fundamentals of Respiratory Care. 7th ed. Mosby; 1999.
Figure 16-9B: Over-the-ear style nasal cannula.
Figure 16-9C: Various styles of nasal prongs.
Courtesy of Teleflex Incorporated. Unauthorized use prohibited
Nasal Cannula
Keep flange against
upper lip
NC should be adjusted
below chin, do not place
behind head, choking risk;
unless applying to
neonates/small peds. On
infants, tape to face
Nasal Cannula
• Insert the nasal cannula into your nose and breathe through
your nose normally.
• If you’re not sure whether oxygen is flowing, place the cannula
in a glass of water. Bubbles mean that oxygen is flowing.
• Patients may use extension tubing for increased mobility
Simple Mask/O2 mask
© Corbis/age fotostock
Figure 16-10B: Simple O2 mask.
Simple Oxygen Mask
• Typically given for short term use, during
deliveries, in the ER
• Flows begin at 5-6L at least to prevent
rebreathing exhaled CO2
• Max flow is around 10-12L
• DO not add a bubble humidifier
• Not used regularly by RT’s
Simple Mask
• Used for patients in need of oxygen in the range of 35% to
50%.
• Again this is a estimation since it is a low flow device. This
mask is used on children through adults but not neonates. The
mask can be uncomfortable and needs to be removed to eat.
Used for short term or emergency use requiring moderate O2
use such as CHF, Pulmonary Emboli, Pulmonary Fibrosis, Labor,
Surgery, Heart attack, and a multitude of other diseases. Not
for CO2 retainers.
Delivery Devices – Simple Oxygen Mask
• Advantages
• Can deliver moderate concentrations (FIO2
between 0.35 and 0.55 at flows of 5 to 10 L/min)
• Economical
• Mouth breathing not a factor
Delivery Devices – Simple Oxygen Mask
• Disadvantages
• Uncomfortable for most patients
• Must be removed for eating, speaking,
expectorating
• May allow vomitus to be aspirated
Delivery Devices – Simple Oxygen Mask
• Disadvantages
• May allow accumulation of CO2 and rebreathing if
flow is inadequate
• Can irritate skin and cause pressure sores
• http://www.youtube.com/watch?v=tBUjR5HDqNs&feature
=related
Aerosol Mask
• Used for the delivery of aerosol. Either by:
• Small volume nebulizer or Large volume
nebulizer
• Can be a face or trach mask
• FIO2 dependent on device in
• it is used
Partial Rebreathing Mask
• No one way valves
• Otherwise looks identical to a non rebreathing mask
Partial Rebreathing Mask
• Originally used in anesthesia; currently used for short-term therapy
requiring moderate to high FIO2, Not a commonly used mask
• Has a reservoir bag that fills with oxygen but also exhaled CO2.
Delivers up to 60% O2 with flows of 10-15 LPM. The bag should not
deflate on inspiration, if it does INCREASE THE FLOW. Used for the
delivery of moderately high FIO2’s and is given for the same reasons a
simple mask is given. Usually seen in emergency rooms. Not for CO2
retainers. This is a low flow oxygen device, the patient should be
breathing adequately and simply need an increased FIO2.
Partial Rebreathing Mask
• Advantages
• Able to deliver moderate concentrations of oxygen
(FIO2 between 0.40 And 0.70)
• Economical
• Mouth breathing not a factor
Partial Rebreathing Mask
• Disadvantages
• Uncomfortable for many patients
• Must be removed for eating, speaking,
expectorating
Partial Rebreathing Mask
• Disadvantages
• May allow vomitus to be aspirated
• Possible suffocation hazard if anti-entrainment
valves in place and the oxygen source fails
Non Rebreathing mask (NRB)
• Looks similar to the partial rebreathing mask except this one
has 3 one way valves that prevents the patient from exhaling
CO2 into the reservoir bag.
• Instead the bag is filled with 100% O2 that the patient inhales.
This device is set at flows of 10-15 LPM and is similar to the
partial rebreathing mask in that the bag should not deflate on
inspiration.
• This device can deliver 55% to 95% oxygen depending on how
many one way valves are present. This mask is given in all
emergencies, for nitrogen washout, ARDS, heart attack,
pulmonary embolism, CHF, pnemothorax, pneumonia, and a
multitude of other diseases in which the patient is
spontaneously breathing but requires high FIO2’s. This is not
for CO2 retainers unless it is an emergency situation.
Non-Rebreathing Mask
• Used primarily in emergencies and for shortterm administration of high concentrations of
oxygen
One way valves
Non-Rebreathing Mask
• Differentiated from partial rebreathing mask by
presence of valve between mask And reservoir
bag
• http://www.youtube.com/watch?v=VV5w4qer
BDg
• http://www.youtube.com/watch?v=fyg5FnGk0z
A
Non-Rebreathing Mask
• Sufficient flow must be maintained;
evidenced by reservoir bag always being at
least partially inflated
• Usually has anti-entrainment valve on only
one side of mask; precaution against
suffocation in the event of oxygen source
failure
Non-Rebreathing Mask
• Advantages
• Able to deliver relatively high concentrations of
oxygen (FIO2 between 0.60 and 0.80)
• Theoretically able to deliver up to FIO2 of 1.00
• Economical
• Easy to apply
Non-Rebreathing Mask
• Disadvantages
• Uncomfortable for many patients
• Must be removed for eating, speaking,
expectorating
Non-Rebreathing Mask
• Disadvantages
• May allow vomitus to be aspirated
• Possible suffocation hazard if anti-entrainment
valves in place and the oxygen source fails
Reservoir (Oxygen Conserving) Cannula
• Uses a reservoir to trap and build up oxygen
that the patient inspires. Uses up to 4 LPM of
oxygen, and is worn in the same manor as a
nasal cannula.
• There are two types: pendant and nasal pillow.
The pendant cannula hangs down to chest and
forms a pendant reservoir for oxygen. The nasal
pillow is a mustache reservoir the sits on the
upper lip. Both types are unattractive for the
patient but saves money by using less flows 0.25
LPM to 4 LPM.
• Primary use in home care and/or ambulatory
patients
Reservoir Cannula
• Oxymizer and Oxymizer Pendant brand reservoir cannulas
store oxygen in a reservoir during exhalation and deliver a
bolus of 100% oxygen upon the next inhalation. These devices
were originally designed for portable home oxygen therapy.
However, they are finding increasing use in acute care settings
for patients who are difficult to supply oxygen via standard
nasal cannulas and as high-delivery alternatives to oxygen
delivery via a face mask
Nasal Pillow and
Pendant
Reservoir Cannula
• Reservoir cannula
• Pendant reservoir
cannula
Reservoir (Oxygen Conserving) Cannula
• Advantages
• Lowers oxygen usage, thereby lowering
cost
• Allows greater mobility secondary to
longer duration of cylinder
Reservoir (Oxygen Conserving) Cannula
• Disadvantages
• Unattractive (many home care cannulas are now
hidden into hats, visors…)
• Must be replaced regularly (See manufacturer’s
specifications), increasing cost
• Breathing pattern affects performance
Transtracheal Catheter
• Teflon catheter surgically inserted between
second and third trachea rings
• Increases the anatomic reservoir during
expiration providing greater bolus of oxygen
to be inspired
Transtracheal Catheter
• Used primarily in home care and for ambulatory
patients who will not accept nasal oxygen
• Not commonly used. Surgically inserted into the
trachea by MD. Uses less flow than a nasal cannula or
a nasal catheter. Good for long term oxygen use on
patients that do not tolerate nasal cannulas and need
increased mobility. Needs a humidifier at any flow.
Needs to be changed and clean periodically to prevent
mucus plugs.
Transtracheal Catheter
• Advantages
• Able to deliver very low flows of oxygen (1/4 to
4 L/min.)
• Uses less oxygen, lowering costs
Transtracheal Catheter
• Advantages
• Improvement in compliance with therapy
• Humidification not required because of low flows
Transtracheal Catheter
• Disadvantages
• High initial cost (surgical procedure)
• Possibility of infection
Transtracheal Catheter
• Disadvantages
• Easily plugged by mucus
• If removed for replacement, tract may close
Transtracheal Catheter
Nasal Catheter
• Less commonly used. Long term nasal cannula that bypasses
the upper airway.
• Used during bronchoscopys and for long term use in children.
Soft and smooth open distal end facilitates non-traumatic
insertion, Proximal end is fitted with color coded funnel shape
connector for easy connection to oxygen source. Uses less
flow than a nasal cannula but delivers the same oxygen
concentration. Requires a humidifier at any flow. Hard to
insert and may cause gagging and aspiration if inserted to
deeply. Changed every 8 hours!
Nasal Catheter
Figure 16-8: Nasal catheter for oxygen administration.
Adapted from Scanlan CL, et al. Egan’s Fundamentals of Respiratory Care. 7th ed. Mosby; 1999.
OxyMask
• Developed in 2005
• Open mask design, FIO2 based on flow inputted into mask as
indicated on package.
• Not considered a high flow device, as the % may vary
• Ranges from 25-90% O2
Oxygen Devices
• Venturi Mask Setup
• http://www.youtube.com/watch?v=qJ9ZIAYAKBY&feature=rel
ated
• Large Volume Nebulizer
• http://www.youtube.com/watch?v=0HUJs0FgkoY&feature=rel
ated
• Simple Mask
• http://www.youtube.com/watch?v=fIdioyC4Bjc&feature=relat
ed
•
• Overall:
• http://www.youtube.com/watch?v=OWLkJv61eo&feature=related
High Flow Oxygen Systems
• Provide a flow of oxygen equal to or
exceeding the patient’s peak inspiratory
flow
• Use either air entrainment or blending to
provide precise concentrations of oxygen
High Flow Oxygen Systems
• Conditions that may require high flow systems
• VT > 700 ml
• f > 25 breaths per minute
• Irregular breathing pattern
• Need for delivery of precise concentration of
oxygen
High Flow Oxygen Systems
• Delivery devices
• Air entrainment (Venturi) mask
• Air entrainment nebulizer
• Blending systems
Venturi Mask
• Set flow dependent upon final concentration of
oxygen desired
• Concentrations available between 24% and 50%
• As the FIO2 is increased the total flow decreases
• The device depends on the venturi entrainment
size, the input flow and obstructions
• http://www.youtube.com/watch?v=zdIXQVVuLs4
3 designs. Two change the
entrainment window size
to increase/decrease FIO2,
the other has colored
adapters. The flow
required is indicated on
the device
Venturi Mask
• Calculation of total flow to the patient
• 2 ways (memorizing ratios or magic box)
• Both methods give you the ratio. Add the ratio together
then multiply by the flow the patient is set on. To
determine if you are meeting a patients total flow take
this total flow and compare it to a patients (Ve x3)
Figure 16-12: Magic box to determine oxygen-to-air ratio when mixing O2
and air. Examples are shown for 40% and 60% O2.
Magic Box
• Set up magic box with given % O2 in the middle of box
• Place 100 and 21 and subtract from 40. This gives you the
ratio.
Memorizing
ratios:
.28
.30
.35
.40
.50
.60
Primary ratios
Venturi Mask
• Advantages
• Inexpensive
• Easy to apply
• Stable, precise concentration
• Ideal for COPD, as it gives high flow and also precise
FIO2
• Maybe adapter for Trach use
Venturi Mask
• Disadvantages
• Generally limited to adult use
• Uncomfortable, noisy
Venturi Mask
• Disadvantages
• Must be removed for eating, speaking,
expectorating
• FIO2 varies if entrainment port occluded or in the
presence of back pressure, or water in tubing if
using a LVN
• If port occluded FIO2 increases
Air Entrainment Nebulizer
• Generally no more than 15 L/min. input;
should maintain output of at least 60 L/min
• Used when aerosol is desired, e.g., patients
with artificial airways
Venturi Mask
Color adaptor type- Orifice size
changes
Venturi valve
Flow rate
Oxygen delivered
color
(l/min)
(%)
Blue
2
24
White
4
28
Yellow
6
35
Red
8
40
Green
12
60
Treatment with oxygen
60% or/>101 rebreathing
90-94
Figure 16-18C: Changes in air entrainment by changing jet size or
changing size of the entrainment port.
Air Entrainment Nebulizer
• Advantages
• Stable, precise concentration when FIO2 > 0.28 And
< 0.40
• Provides aerosol
• Inexpensive
• Easy to apply
LVN
• Used when upper airway is bypassed (ETT,
Trach)
• Used for croup, stridor
• Not used for Asthmatics
• Typically given- Bland aerosol with sterile
water
Figure 16-14B: Large-volume nebulizers.
Courtesy of Teleflex Incorporated. Unauthorized use prohibited
Figure 16-15A: Aerosol mask
(A) Adapted from Fink JR, Hunt GE. Clinical Practice of Respiratory Care. Lippincott Williams & Wilkins; 1999.
Figure 16-15B: Briggs T piece
(A) Adapted from Fink JR, Hunt GE. Clinical Practice of Respiratory Care. Lippincott Williams & Wilkins; 1999.
Figure 16-15C: Face tent
(A) Adapted from Fink JR, Hunt GE. Clinical Practice of Respiratory Care. Lippincott Williams & Wilkins; 1999.
Figure 16-15D: Tracheostomy collar
(A) Adapted from Fink JR, Hunt GE. Clinical Practice of Respiratory Care. Lippincott Williams & Wilkins; 1999.
Figure 16-17: Injection nebulizer, in which additional flow is injected at the
outlet of the nebulizer.
Courtesy Jeffrey J. Ward, R.R.T.
Figure 16-26: Equipment for heliox administration to spontaneously
breathing patients.
Figure 16-20: High-flow oxygen delivery system using two flow meters.
Courtesy of Dr. Dean Hess
Air Entrainment Nebulizer
• Disadvantages
• Increased risk of infection
• FIO2 varies if entrainment port occluded or in
the presence of back pressure
Components of an Air Entrainment Device
Aerosol Mask
Large Volume Nebulizer
• http://www.youtube.com/watch?v=0HUJs0FgkoY
• This also uses Bernoullis principle and has an adjustable FIO2.
The nebulizer provides cool mist to patients with stridor or
upper airway edema. Also used for patients with artificial
airways in need of humidification. It is also utilized for patients
with thick tenacious secretions. The flow is set between 8 and
15 LPM. The concentration of O2 is 28% to 100%. The higher
the concentration the lower the total flow due to the closing
of the venturi which adds or takes away air dilution. The
nebulizer sometimes requires two flow meters when using
higher FIO2 in order to achieve proper misting.
Blending Systems
• Generally used when high flows (> 60 L/min.)
required
• Separate pressurized air and oxygen sources
required
Blending Systems
• Manually blended system
• Each gas manually set with flowmeter
• Total flow and desired FIO2 must be calculated
Blending Systems
• To confirm proper operation of an O2 blending system there
are three major steps.
1.) Make sure that the inlet pressures of the air and O2
are within the specifications of the manufacturer.
2.) Test the alarms for low air and O2 by disconnecting
the sources seperately. Make sure that the safety bypass
system is working correctly.
3.) Make sure to analyze the O2 concentration at levels
of 100%, 21% and at desired FIO2.
The use of a blender is for when O2 concentrations need to
be provided at a higher rate or flow. Flow meters have
limitations and therefore cannot provide these higher rates
like a blender can do.
Blending Systems
• Manually blended system
• Will deliver precise FIO2 if calculated correctly
• Deviation of either flow changes FIO2 and total
flow
Blending Systems
• Oxygen blender
• Able to deliver very precise concentrations
• Able to deliver high flows across a wide range of
concentrations
Blending Systems
• Oxygen blender
• Must check with analyzer periodically to confirm
proper operation and eliminate possibility of
blender failure
Oxygen Blending Device
Enclosure Systems
• One of the oldest approaches to oxygen
administration
• Provides patient with controlled
atmosphere
• Used primarily with infants and children
Enclosure Systems
• Oxyhood
• Used for neonates and infants that requires oxygen from
21% up to 100%. Flows must be set at a minimum of 7
LPM to prevent CO2 build up. A hood covers the infants
head without directly attaching to the patient. The hood
is comfortable but difficult to clean. The FIO2 is
measured at the bottom near the patients face with an
O2 analyzer due to layering affects of oxygen. The hood
amplifies sound, so minimize noise around the babies
sensitive ears. A humidifier is used instead of a nebulizer
due to the noise factor. Used for Nitrogen washout for
pneumothorax or as a weaning tool off nasal CPAP
Oxygen Hood
• Used with infants
• Minimum flow normally of 7 L/min
Oxygen Hood
• Disadvantages
• Noise level can cause auditory damage
• Difficult to clean and/or disinfect
Oxygen Hood
• Disadvantages
• Need to ensure neutral thermal environment is
maintained by using warmed gas, especially
with premature infants
Oxygen Hood
Enclosure Systems
• Delivery devices
• Oxygen tent
• Oxygen hood
• Incubator (isolette)
Oxygen Tent
• Generally uses 12 – 15 L/min
• Can produce FIO2 of 0.40 to 0.50
• Used with children/rare, Croup
Oxygen Tent
Oxygen Tent
• Advantage
• Simultaneously produces aerosol
• Allows child movement while maintaining FIO2
Oxygen Tent
• Disadvantages
• Expensive
• Cumbersome to use
• Limits access to patient
Oxygen Tent
• Disadvantages
• Fire hazard
• Difficult to clean and/or disinfect
Incubator
Incubator (Isolette)
• Used with infants to provide complete
control of environment
• Able to provide maximum FIO2 of 0.50 at 8 to
15 L/min
Incubator (Isolette)
• Advantages
• Provides complete environment
• Stable FIO2
Incubator (Isolette)
• Disadvantages
• Limited access to infant
• Expensive
• Difficult to clean and disinfect
Incubator (Isolette)
• Disadvantages
• Fire hazard
• Noise level can cause auditory damage
Hyperbaric Oxygen Therapy
• Therapeutic use of oxygen at pressures
greater than 1 atmosphere (expressed as
ATA or atmospheric pressure absolute)
Hyperbaric Oxygen Therapy
• Physiologic effects
• Hyperoxygenation of blood plasma and tissue
• Reduction in bubble size
• Vasoconstriction
• May be helpful in decreasing edema
Hyperbaric Oxygen Therapy
• Physiologic effects
• Neovascularization
• Creation of new capillary beds
• Enhanced immune function
• Aids in white blood cell function
Hyperbaric Oxygen Therapy
• Indications
• Air embolism
• Carbon monoxide poisoning
• Decompression sickness
• Acute traumatic ischemia
Hyperbaric Oxygen Therapy
• Indications
• Necrotizing soft tissue infection (gangrene)
• Ischemic skin graft
• Intracranial abscess
• Acute peripheral arterial insufficiency
Hyperbaric Oxygen Therapy
• Complications and hazards
• Barotrauma
• Pneumothorax
• Tympanic membrane rupture
• Gas embolism
Hyperbaric Oxygen Therapy
• Complications and hazards
• Oxygen toxicity
• Fire
• Decrease in cardiac output
Hyperbaric Oxygen Therapy
• Complications and hazards
• Sudden decompression
• Claustrophobia
Hyperbaric Oxygen Therapy
• Methods of administration
• Fixed hyperbaric chamber
• Capable of holding caregivers and patients
• Has airlock to allow entry and egress of
caregivers
Hyperbaric Oxygen Therapy
• Methods of administration
• Fixed hyperbaric chamber
• May be large enough to allow multiple patients
• Only patient receives supplemental oxygen
Fixed Hyperbaric Chamber
Hyperbaric Oxygen Therapy
• Methods of administration
• Monoplace chamber
• Large enough for single patient only
• Chamber kept at FIO2 of 1.0 during patient
treatment
Monoplace Chamber
Nitric Oxide (NO) Therapy
• Normally produced in the body
Figure 16-28A: INOmax delivery system.
Courtesy of IKARIA
Figure 16-28B: (B) INOvent delivery system.
Courtesy of IKARIA
Nitric Oxide (NO) Therapy
• Mechanism of action
• Activates guanylate cyclase which catalyzes
production of cGMP, leading to vascular smooth
muscle relaxation
Nitric Oxide (NO) Therapy
• Mechanism of action
• Improves blood flow to ventilated alveoli,
reducing intrapulmonary shunting
• Results in decrease in pulmonary vascular
resistance
Nitric Oxide (NO) Therapy
• Indications
• Treatment of neonates with hypoxic respiratory
failure with associated pulmonary
hypertension
Nitric Oxide (NO) Therapy
• Indications
• Potential uses
• RDS
• Primary pulmonary hypertension
• Cardiac transplantation, including pulmonary
hypertension following surgery
Nitric Oxide (NO) Therapy
• Indications
• Potential uses
• Acute pulmonary embolism
• COPD
• Sickle cell disease
• Pulmonary hypertension related to congenital
heart disease
Nitric Oxide (NO) Therapy
• Adverse effects
• In high concentrations (5000 to 20,000 ppm),
causes pulmonary edema that can be fatal
• Direct damage to cells
Nitric Oxide (NO) Therapy
• Adverse effects
• Impaired surfactant production
• Increase in left ventricular filling pressure
• Paradoxical response
• Methemoglobinemia
Nitric Oxide (NO) Therapy
• Dosage
• In neonates, initial dose is 20 ppm; continued
for up to 14 days or until underlying oxygen
desaturation is resolved
• Frequently can be reduced to 6 ppm at the end
of 4 hours
Administration of NO
• Patient preparation
• Stabilize the patient as much as possible
• Possibly sedate or paralyze patient
• Support blood pressure as needed
Administration of NO
• System features
• Delivery of precise, stable level of nitric oxide
• Capable of scavenging of nitric oxide
• Limited production of nitrogen dioxide (NO2)
Administration of NO
• Monitoring therapy
• Inhaled levels of NO and NO2
• Ventilatory status
Administration of NO
• Discontinuing therapy
• Monitor for rebound effect
• Patient must be able to maintain adequate
oxygenation
• Patient must be able to maintain hemodynamic
stability
Figure 16-28A: INOmax delivery system.
Courtesy of IKARIA
Figure 16-28B: (B) INOvent delivery system.
Courtesy of IKARIA
INOvent Delivery System
• For administration of
nitrous oxide to
mechanically
ventilated patients
Helium-Oxygen (Heliox) Therapy
• Used to decrease the work of breathing in
the presence of turbulent gas flow in the
large airways
Helium-Oxygen (Heliox) Therapy
• Used with bronchodilator therapy to treat
acute obstructive disorders (e.g., status
asthmaticus); must use correction factor
(multiply observed flow by 1.8) for
flowmeter
Helium-Oxygen (Heliox) Therapy
• Methods of administration
• Generally cannulas are not effective because of
high rate of diffusion
• Best method – snug fitting, non-disposable nonrebreathing mask
• May be administered through cuffed tracheal
airway with positive pressure
Helium-Oxygen (Heliox) Therapy
• Hazards
• Elevation of vocal pitch caused by low density gas
passing through vocal cords
• Cough less effective
• Hypoxemia secondary to using too low an oxygen
concentration
Oxygen Monitoring – Polarographic Analyzer
• Under ideal conditions of temperature,
pressure, and humidity, accurate to ± 2%
• Has a response time of 10 to 30 seconds
Oxygen Monitoring – Polarographic Analyzer
• Utilizes an electrochemical principle for
operation
• Blood or gas sample is separated from electrode
sample by oxygen permeable membrane
Polarographic Analyzer
Polarographic Analyzer
Electrochemical Principle for Operation
• Oxygen diffuses through the membrane
into the electrolyte solution where a
polarizing voltage causes electron flow
• Silver in the anode is oxidized and the flow
of electrons reduces oxygen and water of
the electrolyte to hydroxyl ions at the
platinum cathode
Figure 16-23: Oxygen analyzer.
Courtesy of Amvex Corporation
Electrochemical Principle for Operation
• The greater the number of oxygen
molecules reduced, the greater the
electron flow between the anode and the
cathode
• The current generated is equivalent to the
partial pressure of oxygen and is displayed
as a percentage
Galvanic Analyzer
• Under ideal conditions of temperature,
pressure, and humidity, accurate to
± 2%
• Has a response time as long as 60 seconds
Galvanic Analyzer
• Utilizes an electrochemical principle for
operation
• Has a gold anode and lead cathode
• Current flow is generated by the chemical reaction
itself resulting in slower response time
Galvanic Analyzer
• When the chemicals in the sensor are
depleted, the sensor must be replaced
Galvanic Analyzer
Galvanic Analyzer
Oximetry
• Utilizes the principle of spectrophotometry
• Every substance has a unique pattern of light
absorption which varies predictably with the
amount of the substance present
Oximetry
• Each form of hemoglobin, e.g.,
oxyhemoglobin, carboxyhemoglobin,
methemoglobin, has a unique pattern
Oximetry
• Comparison of light transmitted through a blood
sample at two or more specific wavelengths
allows the measurement of two or more forms
of hemoglobin
• Oxyhemoglobin absorbs less red light and more
infrared light than reduced hemoglobin
• Comparison of light absorption yields %HbO2 and %Hb
CO-Oximetry
• Uses three different wavelengths of light
• Able to distinguish and measure Hb, HbO2,
HbCO, and metHb
• Results reported as SaO2 to distinguish
from pulse oximetry
CO-Oximeter
Pulse Oximetry
• Utilizes principle of spectrophotometry with
the principle of photoplethysmography
(utilization of light to detect tiny volume
changes in tissue during pulsatile blood flow)
• Uses only two wavelengths of light compared
to CO-oximeter
Pulse Oximetry
• Red and infrared LEDs alternately transmit
light through tissue to a receiver
Pulse Oximetry
• Does not distinguish between different forms
of hemoglobin, so can be inaccurate in cases
of carbon monoxide poisoning or with higher
levels of methemoglobin
• Results reported as SpO2
Pulse Oximetry
Transcutaneous Monitoring
• Used primarily with neonatal and pediatric
patients; changes in skin composition make
results less reliable for adults
• Skin sensor containing oxygen and carbon
dioxide electrodes is attached to the skin,
usually in the abdominal area
Transcutaneous Monitoring
• Sensor contains a heating element to heat
the skin
• Increases perfusion in the area of the sensor
• Allows diffusion of oxygen and carbon dioxide
more readily
Transcutaneous Monitoring
• Oxygen and carbon dioxide diffuse through
the skin into the electrolyte solution and are
analyzed by the two electrodes and reported
as mm Hg
• Results reported as PtcO2
Correlation of PtcO2 With PaO2
Age Group
PtcO2/PaO2 Ratio
Premature infants
1.14:1
Neonates
1.00:1
Children
0.84:1
Adults
0.79:1
Older adults
0.68:1
Factors Affecting Accuracy
• Poor perfusion
• Improper sensor application
• Use of vasodilator drugs
• Variation in skin characteristics
Factors Affecting Accuracy
• Hyperoxemia
• Inadequate heating of sensor
• Lack of contact between sensor and skin
Transcutaneous Monitor
Carbon Dioxide Monitoring – Severinghaus
Electrode
• Variation of Sanz electrode
• Used to measure pH
• Consists of two electrodes or half cells
• Measuring half cell contains silver-silver chloride
rod surrounded by solution of constant pH and
enclosed by pH-sensitive glass membrane
Carbon Dioxide Monitoring – Severinghaus
Electrode
• Variation of Sanz electrode
• Sample passes over glass membrane, changing
electrical potential of the measuring electrode
• Reference half cell of mercury-mercurous
chloride produces constant potential
Carbon Dioxide Monitoring – Severinghaus
Electrode
• Variation of Sanz electrode
• Difference in potential between electrodes is
proportional to H+ concentration and is
displayed as pH
Carbon Dioxide Monitoring – Severinghaus
Electrode
• Severinghaus electrode is Sanz electrode
that is exposed to an electrolyte solution in
equilibrium with the sample through a CO2
permeable membrane
Carbon Dioxide Monitoring – Severinghaus
Electrode
• CO2 diffuses through the membrane and
dissociates into H+ and HCO3- ions.
• The greater the concentration of CO2, the
greater the number of H+ ions
Carbon Dioxide Monitoring – Severinghaus
Electrode
• Change in pH of the solution proportional
to change in PCO2
• Used primarily in blood gas analyzer and
transcutaneous monitor
Carbon Dioxide Monitoring – Capnometry
• Used during mechanical ventilation and
general anesthesia
• Placed inline between ventilator circuit and
endotracheal or tracheostomy tube
• Infrared light is passed through a sample
chamber
Carbon Dioxide Monitoring – Capnometry
• Carbon dioxide absorbs infrared light
• The amount of infrared light passing through
the sample chamber is compared to a
reference chamber
Carbon Dioxide Monitoring – Capnometry
• The less infrared light, the greater the
concentration of carbon dioxide
• Result read out as PETCO2
Capnometry
Colorimetric Carbon Dioxide Analysis
• Uses an indicator that changes color when
exposed to different levels of carbon
dioxide
• Most units are either blue or purple in the
absence of carbon dioxide and change to
yellow when exposed to carbon dioxide
Colorimetric Carbon Dioxide Analysis
• Unit is disposable
• Placed on endotracheal tube following
intubation to confirm placement of ET tube
• May give false negative readings in states of
very low pulmonary perfusion
Colorimetric Carbon Dioxide Analysis
• May give false positive readings if large
volumes of carbonated drinks were
consumed prior to intubation
• Does not give a numeric result
Colorimetric Carbon Dioxide Analyzer
Nebulizers
• Hand Held Nebulizers/ also know as small volume nebulizers
may be given via aerosol mask, blow by, inline on the
vent/bipap or by mouth piece, given on air or oxygen
• Small volume nebulizers contain less than 200 ml of fluid
• Set flow 6-8 L, a typical treatment lasts 10-15 minutes, when
the neb starts to sputter, shake contents