For patients with chronic pulmonary and/or cardiac diseases, there is often a need for oxygen therapy to continue after discharge from hospitalization. Providing oxygen for patients at home has many benefits when given appropriately.
Oxygen supplementation at home includes:
These methods of oxygen delivery at home have different degrees of supporting evidence.
Indications for Long-term oxygen therapy (LTOT)
Chronic Obstructive Pulmonary Disease (COPD)
LTOT is indicated for patients with chronic obstructive pulmonary disease (COPD) when:
Many previous studies showed survival benefit of LTOT in COPD patients with chronic hypoxemia. Also with COPD, LTOT may improve patient outcome measures other than survival benefit including quality of life, depression, cognitive function, exercise capacity, and hospital admission rate.
Interstitial Lung Disease (ILD)
Patients with severe ILD may develop chronic hypoxemia which may lead to poor tissue oxygenation with many subsequent complications and worsen prognosis. The use of LTOT in patients with ILD may improve survival and prevent complications. There are no randomized controlled trials (RCTs) reporting the LTOT effects in ILD, and so, recommendations for LTOT are extrapolated from evidence in COPD patients.
There is no evidence of LTOT survival benefits in patients with pulmonary hypertension, except pulmonary hypertension due to COPD. But LTOT in pulmonary hypertension may improve tissue oxygenation and prevent complications due to chronic hypoxemia.
Cystic Fibrosis (CF)
Severe CF patients may develop chronic hypoxemia. LTOT in patients with CF may lead to survival improvement and prevent complications caused by chronic hypoxemia, but no studies examined the use of LTOT in CF patients. Recommendations for LTOT in these patients are extrapolated from evidence in COPD patients.
Advanced Cardiac Failure
There are no studies on the effects of LTOT in patients with chronic heart failure. Using LTOT in patients with advanced cardiac failure and resting hypoxemia may lead to improvement in tissue oxygenation and preventing complications due to hypoxemia.
Home oxygen therapy is not indicated in patients who continue smoking cigarettes because of the significant risk of fire.
Many types of devices are available for home oxygen use. These include concentrators, liquid systems, cylinders, and generators.
The choice of an oxygen delivery system depends on the clinical status of the patient and the needed concentration of inspired oxygen and patient tolerance to the device used.
Common routes for home oxygen therapy include:
Patient screening for LTOT requirement
A pulse oximeter is widely available and can be used for screening patients who might be indicated for LTOT. Studies showed that using SpO2 level equal to 92% has 100% sensitivity and specificity of only 69% for identifying patients with a PaO2 less than 7.3 kPa. Stable patients with oxygen saturation (SpO2) equal to 92% at rest should be referred for a blood gas evaluation, and assessment for LTOT need. Stable patients with clinical evidence of peripheral edema, hematocrit equal to 55% or pulmonary hypertension with oxygen saturation (SpO2) equal to 94% at rest should be referred for a blood gas evaluation, and assessment for LTOT need.
Follow-up of LTOT Patients
There are potential toxicities in patients administered oxygen in high concentrations (above 50%) for long periods like atelectasis, oxidative stress, and peripheral vasoconstriction, but the benefits outweigh the risks. Uncontrolled oxygen delivery may lead to a worsening of hypercapnia in patients with chronic obstructive pulmonary disease.
It is advised to target the SpO2 to 90% to 92% to prevent tissue hypoxia while minimizing any side effects, which might be associated with excessive oxygen supplementation.
Patients should be made aware of the dangers of using home oxygen in the presence of any naked flame such as cookers and candles.
Oxygen cylinders should be at least 5 feet away from naked flames, a heat source, or electrical devices.
There is a significant risk of fire associated with smoking while using home oxygen therapy. Smoking cessation should be advocated.
And a written education should be given to patients before ordering home oxygen.
A respiratory therapist can evaluate and assist patients with their home oxygen needs. The respiratory therapist can provide expertise in the various types of home oxygen delivery devices and provide ongoing assessment of the patient. Patient compliance can be maximized by selecting the appropriate device. Before, referring patients to home oxygen evaluation services, written and verbal information should be given to patients. (Level IV)