Oxygenation and ventilation targets after cardiac arrest: A systematic review and meta-analysis

Aim: To perform a systematic review and meta-analysis of the literature on oxygenation and ventilation targets after successful resuscitation from cardiac arrest in order to inform an update of international guidelines. Methods: The review was performed according to PRISMA and registered on PROSPERO (ID: X). Medline, EMBASE, and the Cochrane Library were searched on August 22, 2019. The population included both adult and pediatric patients with cardiac arrest. Two investigators reviewed abstracts, extracted data, and assessed the risk of bias. Meta-analyses were performed for studies without excessive bias. Certainty of evidence was evaluated using GRADE. Results: We included 7 trials and 36 observational studies comparing oxygenation or ventilation targets. Most of the trials and observational studies included adults with out-of-hospital cardiac arrest. There were 6 observational studies in children. Bias for trials ranged from low to high risk, with group imbalances and blinding being primary concerns. Bias for observational studies was rated as serious or critical risk with confounding and exposure classification being primary sources of bias. Meta-analyses including two trials comparing low vs high oxygen therapy and two trials comparing hypercapnia vs no hypercapnia were inconclusive. Point estimates of individual studies generally favored normoxemia and normocapnia over hyper- or hypoxemia and hyper- or hypocapnia. Conclusions: We identified a large number of studies related to oxygenation and ventilation targets in cardiac arrest. The majority of studies did not reach statistical significance and were limited by excessive risk of bias. Point estimates of individual studies generally favored normoxemia and normocapnia.