Drone-Delivery of Defibrillators Reduces Time to Defibrillation in a Ski Resort: A Randomised Simulation-Based Trial

Background: Out-of-hospital cardiac arrest (OHCA) is the leading cause of sudden, non-traumatic death in ski resorts. Early defibrillation is essential, yet access to automated external defibrillators (AEDs) is often delayed. Drone-based AED delivery has shown promise in urban settings, but its feasibility and performance under winter alpine conditions remain largely unknown. Methods: In this randomised, simulation-based cross-over trial, three methods of AED delivery were compared: (1) automated drone delivery to bystanders, (2) snowmobile-equipped ski patrol, and (3) simulated helicopter emergency medical service (HEMS) flights. Thirty-six simulations involving 12 bystanders, 2 ski patrollers, and 2 physicians were planned. The simulations took place at distances of up to 2,500 m at four locations at 2,275 m altitude in a highly visited ski resort in the Alps. The primary outcome was time to defibrillation (TTD). Secondary outcomes included bystanders’ perceived workload, physical effort, and handling difficulty. Results: Thirty (83%) simulations were completed; six (17%) were cancelled due to severe snowfall. Drone-delivered AEDs achieved significantly shorter TTD compared with snowmobile ski patrol [5.6 (95% CI 4.9–6.3) min vs. 6.7 (95% CI 6.1–7.3) min; p=0.019] and compared with HEMS [15.3 (95% CI 14.6–16.0) min; p<0.001]. Bystanders correctly applied AED pads in all scenarios and reported low median workload (NASA-TLX 7.3/20) and low median handling difficulty and physical effort (VAS 13 and 22 mm on a 100-mm scale). Conclusions: Automated drone delivery of AEDs in a mountainous ski resort is feasible under winter conditions and could reduce TTD compared with conventional rescue responses.