Abstract 296: Relationship Between Emergency Medical Service Response Time And Bystander Cardiopulmonary Resuscitation In Children With Out-of-hospital Cardiac Arrest: A Nationwide, Population-based Observational Study

Abstract

Introduction: Bystander cardiopulmonary resuscitation (CPR) and a short response time for emergency medical services (EMSs) are important determinants of survival after out-of-hospital cardiac arrest (OHCA). As asphyxia cardiac arrest is more common than cardiac arrest from a primary cardiac event in children, effective ventilation is vital during pediatric OHCA. Hypothesis: There would be no difference in post-pediatric OHCA between standard bystander CPR (S-CPR) with rescue breaths and chest-compression-only bystander CPR (CC-CPR) before EMS arrival if EMS response time is extremely short. Methods: The study included 13,719 Japanese children (aged <18 years) from an All Japan Utstein-style registry who received bystander CPR post-OHCA between 2005 and 2019. Patients were divided into two groups: S-CPR (n = 5,369) and CC-CPR (n = 8,350). After propensity score matching, we compared the outcomes between the groups according to EMS response time. EMS response times were categorized into 13 groups: ≤2, 3-4, 5-6, 7-8, 9-10, 11-12, 13-14, 15-16, 17-18, 19-20, 21-22, 23-24, and ≥25 min. The primary study endpoint was 1-month neurologically intact survival, defined as a cerebral performance category score of 1 or 2 (CPC 1-2). Results: Propensity score matching was achieved for 4,639 of 5,369 patients with S-CPR (86,4%) and 4,639 of 8,350 patients with CC-CPR (55.6%). Overall 1-month CPC 1-2 rate in S-CPR was significantly higher than that of CC-CPR: 17.0% (788/4,639) vs. 9.3% (429/4,639, P <0.0001). There were no significant differences in 1-month CPC 1-2 rate between S-CPR and CC-CPR groups when EMS response times were ≤2 min ( P = 0.17), 17-18 min ( P = 0.55), 19-20 min ( P = 0.14), 21-22 min ( P = 0.23), 23-24 min ( P = 1.00), and ≥25 min ( P = 0.07). However, the rate of 1-month CPC 1-2 was significantly higher with S-CPR than with CC-CPR when the EMS response time ranged 3-4 min ( P < 0.01) to 15-16 min ( P < 0.01). Conclusions: CC-CPR for children with OHCA before EMS arrival had a similar association with S-CPR for 1-month neurologically intact survival when EMS response time was ≤2 min and ≥17 min onward. However, 1-month neurologically intact survival in S-CPR was superior to CC-CPR when EMS response time was outside this range.