IntroductionResponse to medical incidents in mountainous areas is delayed due to the remote and challenging terrain. Drones could assist in a quicker search for patients and can facilitate earlier treatment through delivery of medical equipment. We aim to assess the effects of using drones in search and rescue (SAR) operations in challenging terrain. We hypothesize that drones can reduce the search time and treatment-free interval of patients by delivering an emergency kit and telemedical support. MethodsIn this randomized controlled trial with a cross-over design two methods of searching for and initiating treatment of a patient were compared. The primary outcome was a comparison of the times for locating a patient through visual contact and starting treatment on-site between the drone-assisted intervention arm and the conventional ground-rescue control arm. A linear mixed model (LMM) was used to evaluate the effect of using a drone on search and start of treatment times. ResultsTwenty-four SAR missions, performed by six SAR teams each with four team members, were analyzed. The mean time to locate the patient was 14.6 min (95% CI 11.3–17.9) in the drone-assisted intervention arm and 20.6 min (95% CI 17.3–23.9) in the control arm. The mean time to start treatment was 15.7 min (95% CI 12.4–19.0) in the drone-assisted arm and 22.4 min (95% CI 19.1–25.7) in the control arm (p < 0.01 for both comparisons). ConclusionThe successful use of drones in SAR operations leads to a reduction in search time and treatment-free interval of patients in challenging terrain, which could improve outcomes in patients suffering from traumatic injuries, the most commonly occurring incident requiring mountain rescue operations.