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33 Cards in this Set
- Front
- Back
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LTOT Study (1980) |
Long Term Oxygen Therapy
1. No oxygen = 20% survival @ 5 y |
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Physiological Criteria |
• Blood oxygen level <60 mmHg (n 80-100) or oxygen saturation < 90% (n 96-100)
PLUS |
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Funding |
Ministry of Health: |
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Funding |
Private Insurance:
Other: |
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Responsibilities of RT |
• Assess physiological criteria to qualify patient
• Assess type of therapy/equipment (ex: concentrator /LOX / portability)
• Assess physical aspects of patient’s home |
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Responsibilities of RT |
• Initial set-up & patient/caregiver education
• Ongoing assessment/troubleshooting
• Liaison with health care team |
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Systems Available |
• Molecular Sieve Oxygen Concentrators
• Liquid Reservoir Systems – LOX
• Electronic Oxygen Conserving Devices
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Molecular Sieve Oxygen Concentrators |
• Separates gases by passing ambient air through a bed of sodium-aluminum silicate pellets (Zeolite)
• Pellet size traps N2, CO2and water vapour while O2 molecules pass through
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Molecular Sieve Oxygen Concentrators How does it work? |
1. Pump compressor draws ambient air in and |
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Molecular Sieve Oxygen Concentrators How does it work? |
2. 4-way solenoid switch determines direction of airflow accumulator every 15seconds |
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Molecular Sieve Oxygen Concentrators How does it work? |
3. Sieve canister pressurized @ 20 psi
4. Every 15 seconds the air flow direction switches to alternate canister so trapped gases can be purged out through depressurization of first canister |
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Molecular Sieve Oxygen Concentrators How does it work? |
5. 80% of concentrated O2
6. 20% of concentrated O2 collected into an accumulator reservoir for patient use |
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Molecular Sieve Oxygen Concentrators How does it work? |
7. At oxygen accumulator the internal pressure reduced to 8-10 psi
8. Thorpe tube flowmeter calibrated at 0-5 LPM (compensated to internal pressure)
9. Air filtered for particulate dust and bacteria prior to exiting @ DISS connection |
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Molecular Sieve Oxygen Concentrators Efficiency |
• Can never achieve 100% purity of oxygen
• Inert gases too small to get trapped and continue into accumulator, so dilute purity
• FiO2 range to patient is 0.22 to 0.40
• At flows >2 LPM gas is humidified (comfort) |
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Molecular Sieve Oxygen Concentrators Safety |
1. Audible/visual high pressure alarm if internal pressure >25 psi
2. Audible/visual low pressure alarm if internal pressure <5 psi |
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Molecular Sieve Oxygen Concentrators Safety |
3. Battery-operated audible alarm if electrical power failure
4. DISS threading at outlet
5. Low O2percent alarm –optional feature |
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Molecular Sieve Oxygen Concentrators Portability/Patient Motility |
• Rely on back-up cylinders
• E, D or smaller sized cylinders
• Some models enable cylinders to be transfilled through concentrator itself |
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Molecular Sieve Oxygen Concentrators Advantages |
• Very cost efficient for partial and continuous use
• Safe: low pressure system, alarms in place
• Little maintenance required; sieve pellets replaced when purity < 85% |
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Molecular Sieve Oxygen Concentrators Disadvantages |
• Pump motor noisy and generates heat
• Requires electrical power, need back-up cylinders for power interruptions
• Low O2 percentages only: FiO2 <0.40
• Cylinders required for out-of-home mobility |
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Liquid Home Oxygen Systems (LOX) |
• Miniature version of liquid bulk supply
• Pure oxygen stored in liquid state; below its critical temperature
• 1 cu ft LOX = 860 cu ft gaseous O2 |
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Liquid Home Oxygen Systems (LOX) |
• Liquid molecules continuously changing to vapour & gas within reservoir base
• 20-40 L reservoir base canisters or “dewars”
• Double steel-walled, separated by a vacuum to minimize heat exchange |
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Liquid Home Oxygen Systems (LOX) |
• Pressurized above liquid @ 20 psi; “head pressure”
• Rotary needle valve or Thorpe tube flowmeter adjusts flows 0-8 LPM |
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Liquid Home Oxygen Systems (LOX) How it works |
1. To conserve liquid, gaseous O2 also used for patient (liquidmolecules always vaporizing) |
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Liquid Home Oxygen Systems (LOX) How it works |
3. Liquid passes through vaporizing or warming coils to enable conversion to vapour -> gas
4. SINCE molecules within canister continually change from liquid to gas, head pressure re-accumulates to 20 psi |
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Liquid Home Oxygen Systems (LOX) How it works |
5. Economizer valve re-opens and gaseous O2
6. Refilled from truck once or twice per week depending on usage (LPM prescription)
7. Weight scales used to indicate amount |
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Liquid Home Oxygen Systems (LOX) Safety |
Primary Pressure Relief
• Weighted pop-off set at 2 psi above head pressure |
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Liquid Home Oxygen Systems (LOX) Safety |
Secondary Pressure Relief
• Weighted pop-off set at 10 psi above head pressure |
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Liquid Home Oxygen Systems (LOX) Safety |
Vent-to-Fill Valve
• Manually operated DISS threaded outlet connection |
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Liquid Home Oxygen Systems (LOX) Portable System |
• 0.5-2 L sized canisters
• Transfill directly from home reservoir base
• Filled by patient as needed, just prior to use
• Operate as base canister EXCEPT do not employ an economizer valve |
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Liquid Home Oxygen Systems (LOX) Portable System |
• Primary & secondary pressure relief as for base canister • Nipple connection, no DISS
• Vent-to-fill valve to facilitate liquid transfer from base unit into portable container (manually operated) |
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Liquid Home Oxygen Systems (LOX) Advantages |
• Large volumes for high usage situations
• Low pressure system
• Compact and lightweight portable canisters transfilled as needed
• Pure oxygen - increased percent to patient |
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Liquid Home Oxygen Systems (LOX) Disadvantages |
• High waste due to venting -> for continuous use only
• High overhead -> product, truck, manpower
• Risk of frost (cryogenic burn) |
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Liquid Home Oxygen Systems (LOX) Calculate Duration of Flow |
• 1L of LOX = 2.5 lb
• 1 lb of LOX = 344 L gaseous O2 (860 cuft/2.5 lb)
• Divide weight by flow to get duration |
