Bystander cardiopulmonary resuscitation and outcomes of mass cardiac arrests caused by a crowd crush.

Introduction: A crowd crush can lead to respiratory arrest and result in multiple mass cardiac arrests (MCAs), which are often classified as Black Tag in disaster triage. Recently, many laypersons have been commonly trained in compression-only cardiopulmonary resuscitation (CPR) without ventilation support in various communities. This study aims to describe the characteristics of bystander CPR administered and the outcomes of MCAs during the Itaewon crowd crush incident.

Methods: An observational study was conducted on the CPR characteristics of MCAs during the Halloween Festival in 2022, utilizing two databases: (1) MCAs registered in the Korea Out-of-Hospital Cardiac Arrest Registry (KOHCAR) and (2) MCAs uploaded on social media platforms (Instagram and YouTube), identified through relevant keyword searches. Video clips with a minimum streaming time of 10 s and a clear view of bystander CPR were analyzed. General demographic findings were analyzed using the KOHCAR, while the type of bystander CPR (compression-only CPR with or without rescue breathing) was compared using the social media data.

Results: Of the 218 patients attended by EMS, 119 MCAs were registered in KOHCAR. The mean age of the victims was 24.5 years, with 10 (8.4%) being non-Korean. The median ambulance response time was 59 min. Among the victims, 22 (18.5%) received CPR (19 bybystanders, 2 by first responders, and 1 by a disaster medical assistant team), followed by EMS resuscitation, while 7 (5.9%) received CPR first by the EMS team. The remaining 90 victims (75.6%) were pronounced deceased by EMS providers. Three victims (2.5%) achieved return of spontaneous circulation (ROSC) in the field, and one (0.8%) survived to hospital discharge. From the social media database, 26 video clips containing CPR were identified (14 from 251 clips on Instagram and 12 from 187 on YouTube), excluding duplicates and non-CPR cases. In the 26 video clips containing CPR, a total of 228 bystander CPR cases were identified in the video clips. Of these, 217 (95.2%) involved compression-only CPR, while 11 cases (4.8%) included CPR with rescue breathing.

Conclusion: Most MCAs were pronounced deceased, likely due to their classification as Black Tag or delayed response times. Only a small percentage (4.8%) of bystander CPR cases included rescue breathing. An optimized resuscitation protocol for MCAs in crowd crush scenarios should be developed.