Comparison of liquid and gaseous oxygen for domiciliary portable use.

BACKGROUND Liquid oxygen is available for portable use and may have advantages over gas cylinders. METHODS The use and acceptability of liquid and gaseous oxygen was compared in 15 patients with chronic lung disease who had shown an improvement of at least 10% in assessments of exercise tolerance and breathlessness with standard portable oxygen. Gaseous and liquid portable oxygen were provided in random order for two eight week periods, and assessments consisted of six minute walking tests, lung function tests, chronic respiratory disease index questionnaires, and diary cards. RESULTS The walking distance was not significantly affected by the weight of the equipment with either system. Patients used the liquid oxygen for significantly longer (23.5 hours a week) than the gas cylinder (10 hours a week). When using liquid oxygen patients went out of the house on average for 19.5 hours a week, compared with 15.5 hours a week with gaseous oxygen. The liquid oxygen system was preferred because the oxygen lasted longer, filling was easier, and the canister was easier to carry. CONCLUSIONS Liquid oxygen for portable treatment may be of benefit in selected patients with chronic lung disease.