Comparison of continuous flow versus demand oxygen delivery systems in patients with COPD: A systematic review and meta-analysis.

Demand oxygen delivery systems (DODS) enable prolongation of liquid oxygen cylinder life compared to continuous oxygen flow (CONT) use. Evidence is lacking, however, regarding their efficacy. This study investigated the literature comparing liquid-based CONT to DODS in patients with chronic obstructive pulmonary disease (COPD). Four electronic databases were searched from 1980 until January 2018. Primary outcomes were oxyhaemoglobin saturation (SpO