Association between the first post-resuscitation partial pressure of arterial carbon dioxide and neurologic outcomes in children with out-of-hospital cardiac arrest: a multicenter retrospective cohort study.

Abstract

The prognostic significance of the first post-ROSC PaCO₂ in pediatric out-of-hospital cardiac arrest (OHCA) remains uncertain. We evaluated its association with 30-day outcomes. We conducted a multicenter retrospective cohort study using the Japanese OHCA registry (2014-2022). Pediatric patients aged <18 years with return of spontaneous circulation (ROSC) were included, and the primary analysis was restricted to patients with first post-ROSC blood gas sampling within 60 minutes. Patients were categorized as hypocapnia (<35 mmHg), normocapnia (35-45 mmHg), or hypercapnia (>45 mmHg) according to the first post-ROSC PaCO₂ measurement. The primary outcome was favorable neurologic outcome at 30 days, defined as a Pediatric Cerebral Performance Category score of 1-3. The secondary outcome was 30-day survival. Associations were evaluated using multiple propensity score-based overlap weighting and hospital-clustered weighted generalized estimating equation models, with normocapnia as the reference. Among 215 patients, 27 had hypocapnia, 39 normocapnia, and 149 hypercapnia. Favorable neurologic outcome at 30 days occurred in 41 (19.1%), and 30-day survival in 92 (42.8%). After adjustment, we found no clear evidence that either hypocapnia or hypercapnia was associated with favorable neurologic outcome (hypocapnia: adjusted odds ratio [aOR], 0.83; 95% confidence interval [CI], 0.13-5.14; hypercapnia: aOR, 1.46; 95% CI, 0.25-8.68) or 30-day survival (hypocapnia: aOR, 1.46; 95% CI, 0.26-8.01; hypercapnia: aOR, 0.36; 95% CI, 0.09-1.46). In this multicenter study of pediatric OHCA, we found no clear evidence of an independent association between first post-ROSC PaCO₂ category and 30-day outcomes, although estimates were imprecise.