Association between intra- and post-arrest hyperoxia on mortality in adults with cardiac arrest: A systematic review and meta-analysis

Objectives: The association between intra-arrest and post-arrest hyperoxia and mortality in adults with cardiac arrest (CA) is widely debated. We therefore conducted a systematic review and meta-analysis to investigate the association between intra-arrest and post-arrest hyperoxia and mortality in adults with CA. Methods: We systematically searched MEDLINE and Cochrane databases to identify observational studies from January 2008 to December 2017 investigating the relationship between hyperoxia (either intra-arrest or post-arrest) and mortality in adults with CA. Results: We included 16 observational studies with a total of 40,573 adult patients. Six studies included patients only with out-of-hospital CA (OHCA), 2 studies included patients only with in-hospital CA (IHCA), and 8 studies included patients with both OHCA and IHCA. Two studies assessed intra-arrest hyperoxia while 14 studies examined post-arrest hyperoxia. Of the 10 studies included for quantitative analysis, intra-arrest hyperoxia was associated with a significantly lower mortality rate [odds ratio (OR) 0.25, 95% confidence interval (CI) 0.12–0.53, p < 0.001] while post-arrest hyperoxia was associated with higher mortality (OR 1.34, 95%CI 1.08–1.67, p = 0.008). Conclusions: In adults with CA, intra-arrest hyperoxia is associated with lower mortality while post-arrest hyperoxia is associated with higher mortality.