Smartphone Activated Volunteer Responders and Bystander Defibrillation for Out-of-Hospital Cardiac Arrest in Private Homes and Public Locations


 
 
 To investigate the association between arrival of smartphone activated volunteer responders before the Emergency Medical Services (EMS) and bystander defibrillation in out-of-hospital cardiac arrest (OHCA) at home and public locations.
 
 
 
 A retrospective study (September 1, 2017–May 14, 2019) from the Stockholm Region of Sweden and the Capital Region of Denmark. We included 1271 OHCAs, of which 1029 (81.0%) occurred in private homes and 242 (19.0%) in public locations. Main outcome was bystander defibrillation. At least one volunteer responder arrived before EMS in 381 (37.0%) of OHCAs at home and 84 (34.7%) in public. More patients received bystander defibrillation when a volunteer responder arrived before EMS at home (15.5% vs 2.2%, P < 0.001) and in public locations (32.1% vs 19.6%, P = 0.030). Similar results were found among the 361 patients with an initial shockable heart rhythm (52.7% vs 11.5%, P < 0.001 at home and 60.0% vs 37.8%, P = 0.025 in public). The standardized probability of receiving bystander defibrillation increased with longer EMS response times in private homes. 30-day survival was not significantly higher when volunteer responders arrived before EMS (9.2% vs 7.7% in private homes, P = 0.41 and 40.5% vs 35.4% in public locations, P = 0.44).
 
 
 
 Bystander defibrillation was significantly more common in private homes and public locations when a volunteer responder arrived before the EMS. The standardized probability of bystander defibrillation increased with longer EMS response times in private homes. Our findings support activation of volunteer responders, and suggest that volunteer responders could increase bystander defibrillation, particularly in private homes.
