Abstract 01: Dispatching Lay Rescuers Through a Smartphone Application is Associated With Increased Bystander Defibrillation in Out-of-Hospital Cardiac Arrest

Introduction: Survival after out-of-hospital cardiac arrest (OHCA) is dependent on early defibrillation. To increase bystander defibrillation in OHCAs, a first-responder program dispatching lay rescuers (Heart Runners) through a smartphone application (Heart Runner-app) was implemented in the Capital Region of Denmark. We investigated the proportion of Heart Runners arriving prior to the Emergency Medical Services (EMS) and rates of bystander defibrillation. Methods: The Capital Region of Denmark comprises 1.8 mil. inhabitants and 19,048 Heart Runners were registered. In cases of suspected OHCA, the Heart Runner-app was activated by the Emergency Medical Dispatch Center. Up to 20 Heart Runners < 1.8 km from the OHCA were dispatched to either start cardiopulmonary resuscitation (CPR) or to retrieve and use a publicly accessible automated external defibrillator (AED). Through an electronic survey, Heart Runners reported if they arrived before EMS and if they applied an AED. OHCAs where at least one Heart Runner arrived before EMS were compared with OHCAs where EMS arrived first. All OHCAs from September 2017 to May 2018, where Heart Runners had been dispatched, were included. Results: Of 399 EMS treated OHCAs, 78% (n=313/399) had a matching survey. A Heart Runner arrived before EMS in 47% (n=147/313) of the cases, and applied an AED in 41% (n=61/147) of these cases. Rate of bystander defibrillation was 2.5-fold higher compared to cases where the EMS arrived first (Table 1). Conclusions: By activation of the Heart Runner-app, Heart Runners arrived prior to EMS in nearly half of all the OHCA cases. Bystander defibrillation rate was significantly higher when Heart Runners arrived prior to EMS.