Oxygen Delivery Devices
Oxygen. You need it. You love it. You take it for granted. What do you do when an illness takes your patient’s breath away?
Initial Troubleshooting of Oxygen Support
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A well-defined pleth waveform shows evenly spaced, equally wide waves of equal amplitude.
If you are not getting a good waveform, check to make sure your sensor has good contact with your patient’s skin. Consider moving the sensor to another limb (especially ones not distal to a BP cuff) or the earlobe.
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Ensure nasal cannula prongs are in the patient’s nares and/or that the prongs or face mask fits the patient’s face.
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Listen and look for increased secretions. Suction as needed to remove secretions obstructing the airway. Consider BVM suctioning if patient has a tracheostomy.
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Place patient in a sniffing position to better align the airways and prevent positional obstruction.
Head tilt-chin lift - flex neck forward while extending the head. Avoid hyperextending the neck as this may obstruct the airway.
In children <2 yo consider a shoulder toll. In children >2 yo, consider padding under the occiput.
Jaw thrust - place pinky along angle of mandible and lift forward and up.
How do oxygen flow rates affect FiO2?
For every liter of oxygen supplied, the FiO2 is assumed to increase by 4%.
FiO2 = 20% + (4 x oxygen litre flow)
Example: A nasal cannula set at:
1 L/min increases FiO2 to 24%
2 L/min increases FiO2 to 28%3 L/min increases FiO2 to 32%
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Nasal Cannula
1-4 L/min (24-36% FiO2)
Oxygen flowing into the nasopharynx mixes with room air. You can give 100% O2 but due to the dilution of oxygen the patient won’t receive the full oxygen concentration.
Flow rates >4L/min cause irritation to the mucosa unless it is humidified/heated
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Simple Face Mask
5-10 L/min (35-50% FiO2)
The mask acts as a reservoir for oxygen however holes on the side of the mask allow ambient air can enter the mask causing dilution of oxygen. When you exhale, CO2 is introduced in the mask resulting in rebreathing of a lower FiO2.
Do not use flow rates <5L/min as the patient could easily rebreathe air that has not been flushed from the mask.
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Non-Rebreather
10-15 L/min (80-100% FiO2)
The mask is connected to a reservoir system that allows for inhalation of highly concentrated oxygen. One-way valves allow CO2 to escape during exhaling so you don't rebreathe.
Do not go <10L/min otherwise the reservoir will not adequately fill and the disruption in airflow can lead to suffocation.
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High Flow Nasal Cannula
1.5-2 L/min/kg (max 40 L/min on Vapotherm®)
Set FiO2 25-100% (Avoid >50%, if reaching that then consider switching to BiPAP/intubation)
Large nasal cannula prongs and humidified, heated oxygen allows for increased flow rates and some degree of PEEP (up to 5 cm H2O).
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RAM Cannula
Initial settings: PIP 30, PEEP 10, Rate 30
(does not synchronize with patient breathing)RAM is a brand of nasal cannula with stiff, wide prongs that allow for better occlusion of the nares. It is the same cannula that is attached to a BiPAP machine (“essentially nasal BiPAP”) with slight loss of pressure compared to traditional BiPAP. Generally used in infants <6kg as typical BiPAP masks/prongs are too large.
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BiPAP
Initial settings:
0-1 yo: 10/5 | 5-12 yo: 14/7
1-5 yo: 12/6 | >12 yo: 16/8
Titrate based on tidal volume (goal 8-10 ml/kg)
Bi-level positive airway pressure provides inspiratory pressure and expiratory pressure. If not improving as expected, assess for leak (mask size, full face vs nasal), adjust the rate to improve patient synchronization, and add sedation for patient agitation.
Bag-Valve-Mask (BVM)
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The mask should provide a seal around the nose and mouth but not compress the eyes.
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Think about LIFTING the jaw to open the airway, not pushing down on the mask which can obstruct the airway.
Thum and index fingers in a C-shape to hold mask in place
Third, fourth, and fifth fingers in an E-shape along the boney mandible to lift it forward into the mask
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Rigid channels to prevent the tongue and soft tissue from obstructing the airway
Oropharyngeal airway - size based on measurement from mouth to angle of jaw.
Nasopharyngeal airway - size based on measurement from nasal opening to the angle of jaw.
Air-inlet valve allows room air to enter if fresh gas flow in inadequate
Pop-off valve allows oxygen to flow out if pressure is excessive
Expiratory (nonrebreather) valve directs oxygen to the patient and prevents rebreathing
PEEP valve can provide 5-20 cmH2O of PEEP
Can hold down the pop-off valve (releases at about 60 cmH2O) to give increased pressure in the circuit
