The effect of hyperoxia on mortality in critically ill patients: a systematic review and meta analysis

BACKGROUND: Studies investigating the role of hyperoxia in critically ill patients have reported conflicting results. We did this analysis to reveal the effect of hyperoxia in the patients admitted to the intensive care unit (ICU). METHODS: Electronic databases were searched for all the studies exploring the role of hyperoxia in adult patients admitted to ICU. The primary outcome was mortality. Random-effect model was used for quantitative synthesis of the adjusted odds ratio (aOR). RESULTS: We identified 24 trials in our final analysis. Statistical heterogeneity was found between hyperoxia and normoxia groups in patients with mechanical ventilation (I(2) = 92%, P < 0.01), cardiac arrest(I(2) = 63%, P = 0.01), traumatic brain injury (I(2) = 85%, P < 0.01) and post cardiac surgery (I(2) = 80%, P = 0.03). Compared with normoxia, hyperoxia was associated with higher mortality in overall patients (OR 1.22, 95% CI 1.12~1.33), as well as in the subgroups of cardiac arrest (OR 1.30, 95% CI 1.08~1.57) and extracorporeal life support (ELS) (OR 1.44, 95% CI 1.03~2.02). CONCLUSIONS: Hyperoxia would lead to higher mortality in critically ill patients especially in the patients with cardiac arrest and ELS. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12890-019-0810-1) contains supplementary material, which is available to authorized users.