Overnight prescription of oxygen in long term oxygen therapy: time to reconsider the guidelines?

Background: Guidelines for long term oxygen therapy (LTOT) recommend increasing oxygen flow by 1 l/min overnight. A study was undertaken in patients with COPD on LTOT to determine the prevalence of overnight desaturation if the usual oxygen flow rate is not increased at night, whether resting oxygen saturation predicts overnight desaturation, and whether overnight desaturation correlates with health related quality of life (HRQL) and sleep quality. Methods: A cross sectional prospective study was performed on consecutive patients with COPD on LTOT attending our regional outpatient oxygen service. All patients fulfilled standard criteria for LTOT, had been established on LTOT at a flow to achieve resting oxygen saturations >90%, but had not been instructed to increase oxygen flow overnight. Overnight desaturation was defined as