General points about oxygen therapy in chronic obstructive pulmonary disease

There is strong evidence of survival benefit of long-term oxygen therapy (LTOT) in patients with COPD and severe chronic hypoxaemia when used for at least 15 hours daily.

Therefore, oxygen therapy in COPD must be used with care in the acute setting but it can have distinct benefits in the long term. Chronic hypoxaemia causes slowly progressive pulmonary hypertension with the development of right ventricular hypertrophy and possible cor pulmonale with secondary polycythaemia. Secondary polycythaemia increases blood viscosity and hence resistance to flow. There is also sludging and a tendency to thrombosis.

Assess the need for oxygen therapy in people with any of the following:

Very severe airflow obstruction - forced expiratory volume in one second (FEV1) less than 30% predicted.

Cyanosis.

Polycythaemia.

Peripheral oedema.

Raised jugular venous pressure.

Oxygen saturation 92% or below when breathing air.

Consider assessment for people with severe airflow obstruction (FEV130-49% predicted).