Domiciliary oxygen.

Major studies have shown that LTOT improves survival in patients with COPD, although the precise mechanism remains unclear. There are established guidelines for prescription, but these are often disregarded. This is perhaps partly because oxygen concentrators and cylinders are prescribed by general practitioners unable to carry out a full assessment of patients' suitability for oxygen therapy. Patients who are thought to be suitable for oxygen therapy should be referred to a respiratory physician with the facilities to carry out a full evaluation of their needs. It is important not to neglect other aspects of treatment when assessing a patient for domiciliary oxygen. Bronchodilator therapy should be maximised with or without inhaled steroids, and patients will often also benefit from a moderate amount of regular exercise as part of the overall pulmonary rehabilitation programme.