The Association Between Signs of Life and Outcomes in Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis.

Aim: Out-of-hospital cardiac arrest (OHCA) carries a poor prognosis despite advances in cardiopulmonary resuscitation (CPR). Traditional prognostic factors have limited accuracy, and "signs of life," including gasping, pupillary light reflex (PLR), and CPR-induced consciousness (CPRIC), have been proposed as prognostic markers. We conducted a systematic review and meta-analysis to evaluate the association between signs of life and outcomes in OHCA. Methods: PubMed, MEDLINE, and Web of Science were systematically searched. Eligible studies included adult patients with OHCA of presumed medical origin reporting survival or neurological outcomes in relation to signs of life. Study quality was assessed using the Newcastle-Ottawa Scale. Pooled odds ratios with 95% confidence intervals were calculated using a random-effects model. Results: Eight cohort studies, including 4,862 patients, were analyzed. All studies were of good methodological quality. The presence of signs of life was associated with higher survival and favorable neurological outcomes within 30 days after cardiac arrest (CA). Similar associations were observed for longer-term survival, although evidence for longer-term neurological outcomes was limited. Conclusion: Signs of life during CA or CPR were consistently associated with improved survival and favorable neurological outcomes in patients with OHCA, both within 30 days and beyond 90 days. These findings suggest that signs of life may have prognostic value; however, their applicability may vary depending on clinical context. Systematic documentation of signs of life may be considered in standardized reporting frameworks.