Home Oxygen Therapy

Article Author:
Eman Shebl
Article Editor:
Terry Cates
Updated:
10/27/2018 12:31:37 PM
PubMed Link:
Home Oxygen Therapy

Introduction

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:

  • Long-term oxygen therapy (LTOT) in which oxygen is delivered for patients with chronic hypoxemia, for at least 15 hours daily.
  • Ambulatory oxygen therapy (AOT): Oxygen supplementation during exercise and daily activities for patients who are not hypoxemic at rest but who develop hypoxemia on exercise.
  • Nocturnal oxygen therapy (NOT) in which oxygen administered overnight alone with no oxygen therapy during daytime hours
  • Short burst oxygen in which a brief and intermittent oxygen supplementation used as needed, in the absence of hypoxemia.
  • Palliative oxygen therapy (POT): The use of oxygen for relieving of breathlessness in advanced or life-limiting disease in the absence of known hypoxemia

These methods of oxygen delivery at home have different degrees of supporting evidence.[1]

Indications

Indications for Long-term oxygen therapy (LTOT)

Chronic Obstructive Pulmonary Disease (COPD)

LTOT is indicated for patients with chronic obstructive pulmonary disease (COPD) when:

  • A resting PaO2 = 7.3 kPa (55 mm Hg) or SaO2 88% or less while being at rest in a stable clinical condition
  • A resting PaO2 = 8.0 kPa (59 mm Hg) or SaO2 89% or less if there is evidence of cor pulmonale, right heart failure or polycythemia (hematocrit greater than 55%) while being  in a stable clinical condition[2]

Many previous studies showed survival benefit of LTOT in COPD patients with chronic hypoxemia.[3][4] 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.[4]

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.[2]

Pulmonary Hypertension

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.[2]

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.[5][2]

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.[5]

Contraindications

Home oxygen therapy is not indicated in patients who continue smoking cigarettes because of the significant risk of fire.[6]

Equipment

 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:

  • The low-flow nasal cannula which is used to supply a low flow of oxygen (1 to 6 liter per minute). For each liter per minute of oxygen flow about 3% to 4% is added to the oxygen concentration. Oxygen delivered by nasal cannula to the nasopharynx mixes with room air. Consequently, the concentration of oxygen by nasal cannula varies depending upon the patient's respiratory rate, tidal volume, oxygen flow rate, and extent of mouth breathing.[7]
  • Simple oxygen masks used to supply a flow of oxygen rates between 6 and 10 L per minute with oxygen concentrations between 35% and 50%, and this depends on the patient's respiratory rate and the mask fit.[8] In a simple mask, oxygen is delivered through a small-bore tube connected at the base of the mask. Exhaled gas escapes through holes on each side of the mask. Room air enters through these holes and mixes with oxygen, an oxygen flow rate greater than 5 L per minute is needed to prevent CO2 rebreathing.[9]
  • Venturi masks, which allows for a fixed O2%, are available for delivery of controlled oxygen concentrations of 24%-40%. May benefit patients with hypercapnic respiratory failure requiring LTOT.[9]
  • There are other interfaces which allow minimal head contact but no facial contact.[7]

Preparation

Patient screening for LTOT requirement

A pulse oximeter is widely available and can be used[5] 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.[10][5]

Follow-up of LTOT Patients

  • Follow-up at 3 months after LTOT has been initiated, to ensure LTOT is still indicated.
  • Patients receiving LTOT should have follow-up at 6 to 12 months after the first 3-month follow-up.[1]

Complications

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.[11]

Enhancing Healthcare Team Outcomes

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[10] 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.[1] (Level IV)