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

Abstract

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 ,90% for >30% of the night on either of two consecutive nights. HRQL was evaluated with the SF-36 Health Survey Questionnaire, Chronic Respiratory Questionnaire, and the Pittsburgh Sleep Quality Index. Results: Thirty eight patients (63% men) of mean (SD) age 73.5 (8.04) years and mean (SD) forced expiratory volume in 1 second 0.77 (0.35) l were evaluated. Overnight desaturation occurred in six (16%; 95% CI 4 to 27). Desaturators had mean (SD) resting oxygen saturation on room air of 88 (4.2)% compared with 90 (4.1)% in non-desaturators (p = 0.15), and corrected saturations of 93 (2.0)% versus 94 (2.0)% (p = 0.18). HRQL and sleep quality were poor but did not differ between desaturators and nondesaturators. Conclusions: Most patients did not exhibit overnight desaturation despite not increasing their LTOT prescription overnight. These results challenge the recommendation of routinely increasing overnight oxygen flow in patients receiving LTOT.

British Thoracic Society guidelines for home oxygen use in adults: accredited by NICE

“…Several studies have suggested that a flow rate established from resting ABGs while awake may not allow adequate oxygenation overnight with patients spending only between 72% and 77% of the time with SpO 2 >90% overnight 46 49 50. Patients with more severe COPD and worse daytime ABGs spent a significantly greater proportion of the night with hypoxaemia 51.…”

Sleep hypoventilation due to increased nocturnal oxygen flow in hypercapnic COPD patients

“…Nisbet et al. 21 reported that, in the majority of COPD patients, supplemental oxygen delivered at the same rate as that used during the daytime, adequately corrected nocturnal SpO 2 with only 15.8% experiencing an overnight SpO 2 < 90%. Our current results are similar to those of Nisbet et al.…”

Supplemental Oxygen Needs During Sleep. Who Benefits?

“…This latter recommendation is implemented with great regional variability around the world, 109 and has been the subject of various studies examining the need to increase supplemental oxygen during the night. 110,111 At least one study has shown a slightly higher degree of hypercapnia with increasing oxygen supplementation per the NOTT guidelines, although the clinical importance is not known. 112,113 Based on the physiological consequences of NOD, and the results of NOTT and MRC trials, it seems intuitive that the treatment for NOD alone (without daytime hypoxemia) should also be supplemental oxygen, and that there should be some measureable impact on health.…”