Too Much Oxygen Is Harmful

Authors: Chu DK et al. 

Lancet 2018 Apr 28.

Supplemental oxygen can be a life-saving intervention for patients with hypoxemic respiratory failure; however, emerging evidence suggests that too much oxygen is harmful (NEJM JW Gen Med Dec 1 2016 and JAMA 2016; 316:1583). Small trials have shown excess cardiac arrhythmias, lung injuries, and other complications in hospitalized patients without demonstrated hypoxemia who receive oxygen or whose oxygen administration results in supra-normal partial pressures (i.e., hyperoxemia). Should we be doing more to turn down the oxygen when it’s not needed?

Investigators completed a meta-analysis of 25 randomized trials that included 16,000 acutely ill patients who were treated with either a liberal or a conservative oxygenation strategy. Oxygen targets and supplementation thresholds differed across studies. Median oxygen supplementation levels were fraction of inspired oxygen (FiO₂) 0.52 vs. 0.21 (liberal vs. conservative).

Relative risk for death at 30 days was significantly higher in patients who received liberal oxygen (RR, 1.14), although no association was evident between mortality and either peripheral saturation or FiO₂. Risk for disability, length of stay, and incidence of hospital-acquired infections, including pneumonia, were similar under both strategies.