The association between the type of bystander and survival after an out-of-hospital cardiac arrest: A French nationwide study.

Background: Early bystander interventions are associated with more favorable outcomes after out-of-hospital cardiac arrest (OHCA). The objective of the present study was to determine whether the type of bystander-patient relationship was associated with survival and neurological outcomes after OHCA in France. Methods: We analyzed data registered in the French National Cardiac Arrest Registry (RéAC) between July 1st, 2011, and April 30th, 2023. The study population comprised bystander-attended cases of OHCA managed by the emergency medical services. Bystanders were categorized as family members, other laypersons, off-duty professional first responders, or off-duty healthcare professionals. The primary outcome was 30-day survival with a favorable neurological outcome (Cerebral Performance Category 1 or 2). The secondary outcomes included the bystander cardiopulmonary resuscitation (CPR) initiation rate, return of spontaneous circulation, and survival upon admission to the hospital. Our statistical analyses were based on bivariate and multivariable logistic regressions analyses. Results: Among the 89,861 OHCA cases analyzed, family members constituted the largest group of bystanders (69.2%). Compared with non-family-member bystanders, family bystander status was associated with a lower CPR initiation rate, a longer no-flow time, and lower 30-day survival rates. Specifically, cases of OHCA with non-family-member bystanders were 32% more likely to survive with a CPC of 1-2 at day 30 than cases with family member bystanders. Medically trained bystander status (off-duty professional first responders and healthcare professionals) was associated with higher CPR initiation and 30-day survival rates, relative to nontrained laypersons. Conclusions: Survival after an OHCA appears to be associated with the type of bystander. Although family members were the most common bystanders, they were less likely to initiate CPR and less likely to see the OHCA patient survive. Efforts to increase the post-OHCA survival rate should include targeted interventions (such as public education and training programs) that emphasize the importance of early CPR and automated external defibrillator use by family members.