Association Between the Number of Emergency Medical Services and the Chest Compression Quality in Out-of-Hospital Cardiac Arrest

Sang A Yoon; Ki Hong Kim; Jeong Ho Park; Tae Han Kim; Stephen Gyung Won Lee; Ki Jeong Hong; Young Sun Ro; Kyoung Jun Song; Sang Do Shin

doi:10.1016/j.jemermed.2025.05.021

Association Between the Number of Emergency Medical Services and the Chest Compression Quality in Out-of-Hospital Cardiac Arrest

J Emerg Med. 2025 Jun 6:75:89-98. doi: 10.1016/j.jemermed.2025.05.021. Online ahead of print.

Authors

Sang A Yoon¹, Ki Hong Kim², Jeong Ho Park³, Tae Han Kim⁴, Stephen Gyung Won Lee⁴, Ki Jeong Hong³, Young Sun Ro³, Kyoung Jun Song⁴, Sang Do Shin³

Affiliations

¹ Seoul Metropolitan Fire and Disaster Headquarters, Seoul, South Korea.
² Department of Emergency Medicine, Seoul National University Hospital, Seoul, South Korea; Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, South Korea; Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea. Electronic address: emphysiciankkh@gmail.com.
³ Department of Emergency Medicine, Seoul National University Hospital, Seoul, South Korea; Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, South Korea; Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea.
⁴ Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, South Korea; Laboratory of Emergency Medical Services, Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea; Department of Emergency Medicine, Seoul National University Boramae Medical Center, Seoul, South Korea.

PMID: 40628143
DOI: 10.1016/j.jemermed.2025.05.021

Abstract

Background: Out-of-hospital cardiac arrest (OHCA) is a critical public health issue worldwide, and the quality of cardiopulmonary resuscitation (CPR) is essential for patient outcomes.

Objectives: The aim of this study was to evaluate the association between the number of emergency medical services (EMS) personnel and the quality of CPR in OHCA patients.

Methods: This retrospective study utilized data from a metropolitan EMS cardiac arrest registry. Adult cardiac arrest patients who visited emergency departments (EDs) from December 2020 to October 2022 were included. The primary outcome was the proportion of cardiac compressions that achieved an adequate rate (100-120 beats/min) and depth (5-6 cm) for more than 40% of the CPR duration, and flow time for more than 80%. The number of EMS personnel in the first-arrived ambulance was categorized into two- or three-member groups. Multivariate logistic regression was used to calculate adjusted odds ratios (AORs) and 95% confidence intervals (CIs).

Results: In total, 2777 patients were included. Compared with two-member EMS groups, three-member EMS personnel groups had a higher probability of achieving an adequate chest compression rate: AOR 1.43, 95% CI 1.15-1.77. There was no significant association with achieving an adequate chest compression depth, or chest compression flow time: AOR 1.00, 95% CI 0.80-1.24 and AOR 1.12, 95% CI 0.92-1.35, respectively.

Conclusion: Compared with a two-member EMS group, a three-member EMS group in the first-arrived ambulance was more likely to provide adequate chest compression rates. There were no significant differences in adequate chest compression depth or flow time.

Keywords: cardiopulmonary resuscitation; emergency medical services; out-of-hospital cardiac arrest; total quality management.