Oxygen should be used to support oxygen saturation in arterial blood in the target range for the patient.[4]

Long-term oxygen therapy may cause respiratory depression but is likely to be needed for very severe airflow obstruction, where the FEV1 is predicted to be below 30%. It should also be considered if the FEV1 is severe, between 30-49%.

Other signs and symptoms to consider oxygen therapy include:

• cyanosis (skin taking on a blue tone);
• a high level of red blood cells (polycythaemia);
• peripheral swelling/oedema;
• raised blood pressure in the jugular vein;
• an oxygen saturation level of 92% or lower breathing air.

If supplemental oxygen is required long-term, then it should be used for at least 15 hours per day, ideally provided by an oxygen concentrator. Ambulatory oxygen supply may be considered after specialist assessment of how desaturated blood oxygen levels can become on exercise, and also to determine the appropriate oxygen flow rate.[4]

Practical safety recommendations for oxygen use include advising on the risk of tripping over equipment, and the potential for burns and fires especially in homes where someone smokes or uses e-cigarettes.