Oxygen in interstitial lung diseases.

Domiciliary oxygen is essential in the care of hypoxaemic interstitial lung disease (ILD) patients. Guidelines concur in advising prescription of long-term oxygen therapy (LTOT) for ILD patients with severe hypoxaemia at rest, in view of its beneficial impact on breathlessness/disability and extrapolating potential survival benefits seen in COPD patients. A less severe hypoxaemia threshold for initiation of LTOT is recommended for patients with pulmonary hypertension (PH)/right heart failure, requiring careful evaluation in all ILD patients. In light of evidence suggesting a link between nocturnal hypoxaemia, development of PH and poor survival, studies assessing the impact of nocturnal oxygen are urgently needed. Severe exertional hypoxaemia is frequent in ILD patients, with impact on exercise tolerance, quality of life and mortality. Ambulatory oxygen therapy (AOT) has been associated with improvement in breathlessness and quality of life in ILD patients with exertional hypoxaemia. However, given the paucity of evidence, not all current AOT guidelines are in agreement. Ongoing clinical trials will provide further useful data. Despite its beneficial effects, supplemental oxygen imposes burdens and challenges to patients. A key unmet area of need is the development of less cumbersome and more efficient oxygen delivery systems to reduce the negative impact of AOT on patients' lives.