Meta-Analysis Comparing Hypothermia Versus Normothermia in Patients After a Cardiac Arrest

The current American Heart Association 2022 guidelines recommend actively preventing fever by targeting a temperature ≤37.5°C for comatose patients after cardiac arrest. Contemporary randomized controlled trials (RCTs) show conflicting results regarding the benefit of targeted hypothermia (TH). We performed this updated meta-analysis of RCTs to evaluate the role of hypothermia in patients after a cardiac arrest. We searched Cochrane, MEDLINE, and EMBASE from inception to December 2022. Trials with patients randomly allocated for targeted temperature monitoring and reported neurologic and mortality outcomes were included. Statistical analysis was performed using Cochrane Review Manager using the random-effects model and calculated the pooled risk ratios of outcomes using the Mantel-Haenszel method. A total of 12 RCTs and 4,262 patients were included in the review. Compared with normothermia, the TH group had significantly improved neurologic outcomes (risk ratio 0.90, 95% confidence interval 0.83 to 0.98). However, no significant difference in mortality was observed (risk ratio 0.97, 95% confidence interval 0.90 to 1.06) between the groups. This meta-analysis supports the role of TH in patients after a cardiac arrest, especially secondary to improvement in neurologic outcomes.