Signs of Life During Out-of-Hospital Cardiac Arrest: A Retrospective Cohort Study

Signs of life are observed during out-of-hospital cardiac arrest (OHCA) resuscitation, but their frequency, timing relative to return of spontaneous circulation (ROSC), and prognostic significance remain incompletely described. We evaluated the prevalence of signs of life during resuscitation and their association with survival.

We performed a retrospective observational cohort study of all OHCAs treated by a single urban emergency medical services system from January 1 through December 31, 2022. Data were abstracted from prospectively maintained OHCA and airway management registries. Signs of life include respiratory effort, eye opening or tracking, body movement, and verbal response. Each sign was classified as occurring before or after initial ROSC. We used descriptive statistics, binomial confidence intervals, and unadjusted and adjusted logistic regression to evaluate associations between signs of life, OHCA etiology, and survival.

Among 617 treated OHCAs, 156 patients (25.3%) had at least one sign of life. Respiratory effort was most common (148 patients, 24.0%), followed by any body movement (69, 11.2%), eye opening (55, 8.9%), and any verbal response (43, 7.0%). Most documented signs occurred after ROSC, although 44 patients (7.1%) had at least one pre-ROSC sign of life. Patients with signs of life were more likely to have witnessed arrest and initial shockable rhythm and were less likely to receive intra-arrest epinephrine or prehospital advanced airway management. Survival occurred in 91 of 156 patients (58.3%) with signs of life compared with 25 of 461 patients (5.4%) without signs of life. In adjusted analysis, any sign of life was associated with survival (adjusted odds ratio [aOR] 10.3, 95% confidence interval [CI] 5.4-19.9); this relationship held when restricted to signs of life after ROSC (aOR 6.7, 95% CI 3.4-13.3). Among overdose-related OHCA, any body movement (aOR 2.44, 95% CI 1.05-5.67) and any verbal response (aOR 8.06, 95% CI 2.71-24.01) were more frequent than in the non-overdose OHCA cohort.

One in four treated OHCA patients displayed at least one sign of life during resuscitation. Signs of life, particularly those after ROSC, were strongly associated with survival and may provide clinically useful information during prehospital resuscitation.