Association between agonal breathing and outcomes after out-of-hospital cardiac arrest: a retrospective study

Out-of-hospital cardiac arrest (OHCA) in patients remains associated with poor survival and neurologic outcomes. Agonal breathing is associated with improved outcomes but lacks a standardized definition or timing for assessment. The aim of this study was to examine the association between agonal breathing and favorable neurologic outcome in patient with OHCA, focusing on its pattern at emergency medical services (EMS) contact and hospital arrival.

This prospective cohort study collected data from patients with OHCA in Japan between 2019 and 2021, using the SOS-KANTO registry. Agonal breathing was assessed at EMS arrival and hospital arrival and categorized into 3 groups: no agonal breathing, prehospital or hospital agonal breathing, and prehospital and hospital agonal breathing. The primary outcome was favorable neurologic outcome (cerebral performance category of 1 or 2). Multivariable logistic regression was performed to examine the association between agonal breathing and outcomes.

After multiple imputation for missing data, 9909 patients with OHCA were categorized: no agonal breathing (n = 8956, 90.4%), prehospital or hospital agonal breathing (n = 860, 8.7%), and prehospital and hospital agonal breathing (n = 93, 0.9%). Favorable neurologic outcomes were observed in 1.8%, 13.0%, and 19.4% of patients, respectively. Compared with patients with no agonal breathing, patients with prehospital or hospital agonal breathing had higher odds of favorable neurologic outcome (odds ratio, 2.91 [95% CI, 2.08-4.08]), as did patients with prehospital and hospital agonal breathing (odds ratio, 4.63 [95% CI, 2.26-9.49]).

Agonal breathing was associated with higher odds of a favorable neurologic outcome in patients after OHCA, particularly when observed both at EMS contact and on hospital arrival.