Community first-responders in cardiac arrest. Effect on survival? A comprehensive Danish study of 29,445 out-of-hospital cardiac arrests

AIM: Since 2018, Denmark has implemented a national community first-responder system, activated by the emergency dispatch centre, to supplement local first-responder programs. The responders are dispatched to all out-of-hospital cardiac arrests (OHCA). This study aimed to investigate the effect of community first-responders on survival following OHCA. METHODS: A manual review of prehospital medical records for all 29,445 OHCA cases in Denmark from 2018 through 2023. The type of responder who initiated resuscitative efforts was stratified into three main groups: bystanders present at the incident, community first-responders, or ambulance personnel. The primary outcome was survival at 30 days and 365 days. RESULTS: After exclusions, 21,413 patients were analysed, of which initial resuscitation efforts were provided by on-scene bystanders (12,613), community first-responders (2155), or emergency medical service (EMS) personnel (6140). In 505 cases, the provider of the initial CPR was unclear. Provision of initial resuscitative efforts by on-scene bystanders before ambulance arrival was associated with odds ratios of 2.42 for 30-day survival and 2.51 for 365-day survival, compared with patients whose first resuscitation was not initiated before EMS arrival. There was no significant difference in outcome when first resuscitation efforts were provided by community first responders or delayed until EMS arrival. CONCLUSION: In OHCA, basic life support initiated by bystanders was associated with a survival rate more than twice that of OHCA patients whose first resuscitation was provided by community first-responders or ambulance personnel. Our findings support early resuscitation, but we found no evidence to support dispatching community first-responders to OHCA.