Impact of Emergency Medical Services Call–to–Hospital Arrival Time on Outcomes of Cardiac Arrest: A Nationwide Prospective Cohort

Abstract

Objective: To investigate the effect of emergency medical services (EMS) call-to-hospital arrival time on clinical outcomes in patients with out-of-hospital cardiac arrest.

Patients and methods: This retrospective analysis of a nationwide, population-based prospective cohort of out-of-hospital cardiac arrest cases in South Korea was conducted from January 1, 2016, to December 31, 2021. Of 182,508 patients, 76,505 with out-of-hospital cardiac arrest who received cardiopulmonary resuscitation were evaluated. Patients were categorized according to quartiles (Qs) of the time elapsed from the EMS call to hospital arrival (Q1, ≤25 minutes; Q2, 26-30 minutes; Q3, 31-39 minutes; Q4, ≥40 minutes). The primary outcome was in-hospital mortality; secondary outcomes included mortality within 24 hours of admission and poor neurologic outcomes at discharge.

Results: The in-hospital mortality rate was the lowest in the shortest EMS call-to-hospital arrival time quartile (Q1) at 78.7% compared with 87.7% in Q3, with poor neurologic outcomes most frequent in Q4 (P<.001). After adjusting for confounders, the odds ratios in Q1 were 0.30 for in-hospital mortality, 0.37 for 24-hour mortality, and 0.32 for poor neurologic outcomes. Subgroup analysis showed lower in-hospital mortality in Q1 than in Q4, regardless of bystander cardiopulmonary resuscitation, prehospital return of spontaneous circulation status, residence, place of arrest, initial rhythm, or use of an automated external defibrillator.

Conclusion: Shorter EMS call-to-hospital arrival times were significantly associated with lower in-hospital mortality rates and better neurologic outcomes in patients with out-of-hospital cardiac arrest.