Long term oxygen therapy is indicated when a patient in a stable phase of their condition, has a low blood oxygen level (hypoxaemia). The oxygen level must be below a certain limit PaO2=55mmHg or PaO2<60mmHg when there is evidence of hypoxic organ damage. This is measured by an arterial blood gas test. It is recommended that people who qualify for long term oxygen therapy use the oxygen for 16 or more hours each day.
Exertional oxygen may be provided if a person has exercise induced hypoxaemia. Oxygen saturations must fall below 88% on room air and a person must show significant improvement on oxygen to qualify for exertional oxygen.
A sleep study must be performed to determine if nocturnal oxygen is required. Nocturnal oxygen is indicated if a patient has oxygen desaturation to SpO2≤88% for more that a third of the night. Some causes of desaturation (obstructive sleep apnoea or obesity hypoventilation) may require other forms of therapy such as nocturnal ventilation or continuous positive airway pressure.
Indicated in terminally ill patients with a limited life expectancy and evidence of hypoxaemia.