Automated external defibrillators delivered by drones to patients with suspected out-of-hospital cardiac arrest

Abstract

Background: Early defibrillation is critical for the chance of survival in in out-of-hospital cardiac arrest (OHCA). Drones, used to deliver automated external defibrillators (AEDs), may shorten time to defibrillation, but this has never been evaluated in real-life emergencies. Purpose: The aim of this study was to investigate the feasibility of AEDdelivery by drones in real-life cases of OHCA. Methods: In this prospective clinical trial, three AED-equipped drones were placed within controlled airspace in Sweden, covering approximately 80,000 inhabitants (125km2). Drones were integrated in the emergency medical services for automated deployment in beyond-visual-line-of-sight flights in; a) consecutive real-life suspected OHCAs b) test-flights from 06-01-20 to 09-30-20. Primary outcome was the proportion of successful AED-deliveries when drones were dispatched in cases of suspected OHCA. Among secondary outcomes were the proportion of cases where AED-drones arrived prior to ambulance and time benefit vs. ambulance. Results: Totally 14 cases were eligible for dispatch during the study period in which AED-drones took off in 12 alerts to suspected OHCA; with a median distance to location 3,1 km (IQR:2,8-3,4). AED-delivery was feasible within 9 meters (IQR:7,5-10,5) from the location and successful in 11 alerts, 92%. AED-drones arrived prior to ambulances in 64%, with a median time benefit of 01:52 minutes (IQR:01:35-04:54). In an additional 61 test-flights the AED-delivery success rate was 90% (55/61). Conclusion: In this pilot study, we have shown that AED-delivery by drones in real-life cases of OHCA is feasible with a substantial time benefit and a successful delivery rate of 92%. Further technological improvements are needed to increase dispatch rate and time gains.