The relationship between cardiopulmonary resuscitation duration and prognosis in patients with out-of-hospital cardiac arrest due to asphyxiation.

Aim: Asphyxial out-of-hospital cardiac arrest (OHCA) is associated with poor outcomes and may have a narrower time window for favourable outcomes compared to cardiac-origin OHCA. However, studies examining cardiopulmonary resuscitation (CPR) duration in OHCA due to asphyxiation are limited. Hence, this study aimed to investigate the relationship between CPR duration and prognosis in patients who experienced OHCA due to asphyxiation.

Methods: This retrospective study used data from the Japanese Association for Acute Medicine's OHCA registry for June 2014 to December 2021. The study population comprised adult patients who received CPR by emergency medical service personnel and achieved return of spontaneous circulation. The primary outcome was one-month survival; the secondary outcome was favourable neurological outcome at one month (cerebral performance category 1 or 2). The influence of CPR duration was examined using logistic regression analysis after adjusting for multiple confounding factors.

Results: The analysis included 2594 patients of asphyxiation-induced OHCA. The median CPR duration was 26 min (interquartile range, 17-35 min). At one month, 515 patients (19.9%) survived and 62 (2.4%) achieved favourable neurological outcomes. Increasing CPR duration was associated with lower chances of one-month survival and favorable neurological outcome (aOR per minute: 0.88 and 0.78, respectively; 95% CI: 0.86-0.90 and 0.71-0.85, respectively). The probability of favorable neurological outcome and survival dropped below 1% after 4 and 31 min of CPR, respectively.

Conclusions: Prolonged CPR was associated with poor outcomes in patients with asphyxiation-related OHCA and may be futile in these cases.