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home_oxygen

home oxygen

adult domiciliary oxygen therapy

indications

  • continuous oxygen (ideally > 19hrs/day):
    • is indicated to improve longevity & quality of life if either:
      • stable daytime PaO2 is < 55 mmHg at rest
      • stable daytime PaO2 is 55-59 mmHg and there is evidence of hypoxic organ damage (incl. RVF, pulm. HT or polycythaemia)
    • flow rate should be set to maintain PaO2 > 60mmHg (SaO2 > 90%) during waking rest. This will usually need to be increased by 1L/min during sleep, exertion or air travel.
  • intermittent oxygen therapy:
    • is indicated for:
      • nocturnally to relieve demonstrated sleep desaturation to an SaO2 < 88% (PaO2 <55mmHg)
        • oxygen concentrator may be most economic method for this
      • a small cylinder of oxygen for emergency use by pt with severe asthma who is prone to sudden life-threatening episodes
      • for relief of symptoms in terminally ill pts who will usually have a life expectancy of < 3months
        • oxygen use may become continuous as symptoms progress
      • provision to extend exercise capacity but this has not been shown to prolong life except in pts awaiting lung transplants, etc where physical fitness levels in a rehab. program may be beneficial, thus this indication has the lowest priority when considering demands for home oxygen provision.

contraindications

  • lung dysfunction where main complaint is SOB, but who maintain PaO2>60mmHg & show no secondary effects of chronic hypoxia
  • smokers who continue to smoke - fire risk
  • pts who have not received adequate medical Rx
  • inadequate motivation to undertake the discipline required in oxygen Rx

dangers

  • serious hypercapnia may occasionally develop esp. if:
    • acute exacerbations of disease
    • sedatives, alcohol, narcotics
  • fire risk if smokers

methods of oxygen delivery

compressed oyxgen cylinders

  • 100% oxygen at outlet, reliable, simple maintenance, no background noise
  • heavy, expensive, small capacity
  • sizes:
    • traveller - 0.257-0.682cu.m
    • C - 0.55cu.m lasts 3h at 2L/min
    • D - 1.5cu.m lasts 11h at 2L/min
    • E - 3.8-5.2cu.m lasts ~30h at 2l/min
    • G - 7.6-8.8cu.m - hospital use only

oxygen concentrator

  • molecular filter removes nitrogen allowing 90-95% oxygen at outlet but only at 2L/min usually
  • cheap, safe, convenient, not portable, needs electricity, noisy & vibrates, risk of mechanical failure
  • can be wheeled but weigh 21-26kg
  • cannot be used for nebulisation as pressure too low (35-63kPa cf 140kPa for neb. pumps)
  • cheaper than compressed if use is equivalent to 3 E size cylinders/mth but depends on electricity supply costs
  • if use for > 2 years, cheaper to buy than rent, although rental cost not affected by amount of usage & includes maintenance costs (~$180/yr 1997)
  • requires regular maintenance - changing & cleaning of filters, checking alarm systems

liquid oxygen systems

  • conserve space by storing at -183deg.C (30L then equiv. to 25800L of gaseous oxygen)
  • 2 tanks needed - a large storage tank of 30L (equiv. to 7 E size compressed cylinders) & a portable unit filled from the larger tank for portable use
  • oxygen delivered through coils, where it vaporises
  • light weight, high capacity, reliable, simple maintenance, high cost, small risk of frost bite

authorised prescribers as per Program of Aids for Disabled People

  • respiratory physicians
  • cardiologists
  • any medical practitioner if patient meets cost

references and resources

home_oxygen.txt · Last modified: 2014/07/29 15:09 (external edit)