A new meta-analysis adds to the evidence that liberal use of supplemental oxygen may be harmful in acutely ill, hospitalized patients.

Authors performed a meta-analysis of 25 randomized trials of acutely ill patients (total n ~ 16,000) treated with strategies of either "low" or "high" supplemental oxygenation. Although the cutoffs varied between studies, patients receiving liberal oxygen most often had oxygen saturations at or above 96%.

There was a slight increase in risk of 30-day mortality (relative risk 1.14) in those randomized to receive higher doses of supplemental oxygen with higher target oxygen saturations.

Authors concluded,

Supplemental oxygen might become unfavourable above an SpO2 range of 94–96%. These results support the conservative administration of oxygen therapy.

Previous studies have suggested that targeting high oxygen saturation levels in blood (hyperoxemia) may be harmful in critical illness. High levels of blood oxygen have been associated with lower survival after cardiac arrest; worsened injury from myocardial infarction; and poorer outcomes from critical illness generally. Source:  Lancet