oxygen therapy rhonda contant, bsch, rrt. let’s start with the basics! how much o2 is in room...
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Oxygen TherapyRhonda Contant, BScH, RRT
Let’s Start with the Basics! How much O2 is in room air?
How much O2 comes out of a flowmeter?
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Oxygen TherapyO2 delivery systems: design and
performance
Three basic designs exist1. Low-flow systems
2. Reservoir systems
3. High-flow systems
We need to answer 2 key questions…1. How much O2 can the system deliver?
What is the FiO2 or FiO2 range of the device?
2. Does the FiO2 vary or remain fixed with changing pt demands?
Fixed or Variable FiO2? Depends on how much of the pt’s
inspired gas the device delivers
Fixed or Variable FiO2? Fixed FiO2
The device is designed to deliver ALL the pt’s inspired gas FiO2 is constant or fixed
Fixed or Variable FiO2? Variable FiO2
The device provides only SOME of the inspired gas
The pt must draw the rest from the surrounding environment (room air)
What happens if we mix O2 with room air? Dilutes the delivered O2 lowers FiO2
The result = variable FiO2 from breath to breath depending on pt demands
Low Flow Systems: Uses low flows (< 8 Lpm)
They are variable systems therefore the pts demands will affect the FiO2
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Low Flow Systems:Nasal cannula Delivers an FIO2 of 0.24 to 0.40
Used with flow rates of ¼ to 8 L/min
FIO2 depends on how much room air the patient inhales in addition to the O2.
Device is usually well tolerated.
Humidifier should be used with flows > 4 Lpm
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Nasal Prongs / Cannula
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How to Estimate the FiO2 for Nasal Cannula:
FiO2 = 21% + (4 x #Lpm)
Example: What is the approximate FiO2 when the flow meter is set at 2 Lpm?
FiO2 = 21% + ( 4 x Lpm) FiO2 = 21% + ( 4x 2) FiO2 = 29%
Reservoir Systems Incorporate a mechanism to gather and
store O2 between pt breaths
Pts draw from this reservoir when their inspiratory flows exceed the oxygen flow delivered by the device
Instead of diluting with room air, they dilute with O2 results in a higher FiO2
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Reservoir SystemsReservoir cannula Designed to conserve oxygen
Nasal reservoir Pendant reservoir
Can reduce oxygen use as much as 50% to 75%
Humidification usually not needed
Moustache Reservoir Cannula
Pendant Reservoir Cannula
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Reservoir SystemsReservoir masks Most commonly used reservoir systems
Three types Simple mask Partial rebreathing mask Nonrebreathing mask
Inc.
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Simple Mask
Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
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Partial and Non - Rebreathers
Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc.
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High Flow Systems Supply a given (or fixed) O2 concentration at a
flow equaling or exceeding the patient’s peak inspiratory flow
Use air-entrainment or blending system to mix air and oxygen at very specific ratios to determine a specific oxygen concentration
Can ensure a fixed FIO2
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Air Entrainment or Venti Mask
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High Flow Jet Nebs
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Equipment for Aerosol Therapy
Airway appliances Aerosol mask Face tent T-tube Tracheostomy mask
All used with large-bore tubing
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Equipment for Bland Aerosol Therapy
Equipment for Bland Aerosol Therapy
How do we know what to use? Nasal Cannula
Uses: Stable pts requiring low FiO2 Home care pts requiring long term O2
Advantages Adults, peds and infants Easy to apply Disposable, inexpensive Well tolerated Can eat with them in place
How do we know what to use? Nasal Cannula
Disadvantages Easily dislodged High flows uncomfortable Can cause dryness and bleeding Variable FiO2s
How do we know what to use? Reservoir (NRBR)
Uses Emergencies Unstable pts (MI) Acute hypoxemia Smoke inhalation / CO poisoning CHF
How do we know what to use? Reservoir (NRBR)
Advantages High FiO2 Adults and peds Quick and easy to apply Disposable and inexpensive
Disadvantages Uncomfortable Can’t eat with mask on Risk of aspiration if pt vomits Potential suffocation hazard
How do we know what to use? Venti mask
Uses: Unstable pts requiring precise low FiO2 Pts with variable RR and Tidal Volume
Advantages: Easy to apply Disposable and inexpensive Stable, precise FiO2
Disadvantages: Uncomfortable Can’t eat with mask on Noisy Risk of aspiration if pt vomits
How do we know what to use? Large Volume (Jet) Nebulizers
Uses: Pts with artificial airways Pts with supraglottic swelling To help mobilize secretions
Advantages: Provides humidification Provides fixed FiO2
Disadvantages: FiO2 varies with back pressure (ie condensation in
tubing) Increased risk for infection
FYIs O2 is a prescribed drug
For every connection there is a possibility for a leak
Vasoline and O2 don’t mix use a water based lubricant to treat nasal and lip dryness
When in doubt, call RT, we are there to help!!
Questions?