Timing of the Adrenaline Administration in Witnessed Pediatric Out-of-Hospital Cardiac Arrest: Retrospective, National Cohort Study in Japan, Using a 2014–2020 Dataset

OBJECTIVES: We evaluated the association between the timing of initial adrenaline administration and outcomes in witnessed pediatric out-of-hospital cardiac arrest (OHCA). DESIGN: A multicenter, retrospective cohort study addressing resuscitation time bias by performing a risk-set matching analysis using time-dependent propensity scores. SETTING: Analysis of data from the Japanese Association for Acute Medicine OHCA (JAAM-OHCA) registry, which is a nationwide, multicenter, prospective collection of prehospital and in-hospital data involving Japanese patients with OHCA. PATIENTS: Pediatric patients (< 18 yr) with witnessed OHCA who received adrenaline, during the period June 2014 to December 2020. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We compared patients who received adrenaline in specific time intervals (1-10, 11-15, 16-20, 21-25, or 26-30 min) after first contact with emergency medical services with those who still had not received adrenaline during the same time. The primary and secondary outcomes were survival and favorable neurologic outcome at one month, defined as a Pediatric Cerebral Performance Category score of 1-3. We identified a total of 259 OHCA patients who had received adrenaline at 1-10, 11-15, 16-20, 21-25, 26-30, and 31 minutes or later; at each respective time point, there were 15, 39, 62, 55, 37, and 51 patients. Risk ratios (RRs) with 95% CIs for 1-month survival at each time group compared with patients at risk were: 1-10 minutes, RR, 2.94 (95% CI, 0.38-22.81); 11-15 minutes, RR, 0.97 (95% CI, 0.30-3.12); 16-20 minutes, RR, 1.00 (95% CI, 0.29-3.48); 21-25 minutes, RR, 1.35 (95% CI, 0.54-3.40); and 26-30 minutes, RR, 1.71 (95% CI, 0.27-10.78). We failed to identify an association between time interval and greater or lesser probability of survival or neurologic outcome. CONCLUSIONS: In the JAAM-OHCA registry, with pediatric data from 2014 to 2020, we failed to identify an association between earlier adrenaline administration and greater probability of 1-month survival or favorable neurologic outcomes.