The following is a summary of “Association Between Number of Volunteer Responders and Interventions Before Ambulance Arrival for Cardiac Arrest,” published in the February 2023 issue of Cardiology by Gregers, et al.

Worldwide, volunteer responder (VR) programs have been implemented to mobilize laypeople in out-of-hospital cardiac arrest (OHCA) cases, but the ideal number of VRs to send out remains unknown. For a study, researchers sought to determine whether there was a correlation between the quantity of VRs that arrived before the arrival of emergency medical personnel (EMS) and the percentage of bystander CPR and defibrillation.

For the Capital Region (September 2, 2017, to May 14, 2019) and the Central Region of Denmark, we included OHCAs not observed by EMS with VR activation (November 5, 2018, to December 31, 2019). According to how many VRs arrived before EMS, they divided the population into 4 groups: 0, 1, 2, and 3 or more. They looked at correlations between the number of VRs arriving before EMS and bystander CPR and defibrillation using a logistic regression model adjusted for EMS response time.

906 OHCAs were included. The adjusted ORs for bystander CPR were 2.40 (95% CI: 1.42-4.05), 3.18 (95% CI: 1.39-7.26), and 2.70 (95% CI: 1.32-5.52) when 1, 2, or 3 or more VRs arrived before EMS (reference), respectively, when EMS arrived before 1 (1.97 [95% CI: 1.12-3.52], 2 (2.88 [95% CI: 1.48-5.58], 3 or more (3.85 [95% CI: 2.11-7.01] VRs), or more (3.85 [95% CI: 2.11-7.01] VRs, the adjusted OR for bystander defibrillation rose (reference). When ≥3 VRs arrived before 1 VR, the adjusted OR of bystander defibrillation rose to 1.95 (95% CI: 1.18-3.22) as opposed to when one VR came first (reference).

When one or more VRs arrive before the EMS, they identified a correlation between higher bystander CPR and defibrillation, with a trend toward increased bystander defibrillation as the number of VRs coming first rises.

Reference: jacc.org/doi/10.1016/j.jacc.2022.11.047