Drone Delivery of AEDs to Patients With Suspected OHCA
- In a pilot study performed in Sweden, an AED was successfully delivered by drone in 11 of 14 eligible cases and in 11 of 12 (92%) drone take-offs.
- Of 11 successful cases of AED drone delivery, the AED arrived prior to the ambulance in seven cases, with a small time-benefit (mm:ss) of 01:52 in those seven cases and 00:49 overall.
- It remains to be seen whether early and reliable AED delivery by drone can be translated into improved survival of OHCA either in urban or more rural regions.
What is the feasibility of delivering automated external defibrillators (AEDs) for out-of-hospital cardiac arrest (OHCA)?
In a prospective clinical trial, three AED-equipped drones were placed within controlled airspaces in Sweden covering approximately 80,000 inhabitants (125 km2). After an initial 4-month test interval with simulations, both test flights and flights in response to emergency calls were performed during a 4-month interval from June 1–September 30, 2020. When dispatch centers indicated a suspected OHCA during an emergency call, an automatic alert was sent to a drone pilot; followed by pre-flight checks, route-planning, telephone permission from air-traffic control, autonomous drone flight to the coordinates of the suspected OHCA, and pilot-initiated AED delivery. Inclusion criteria included hours between 08:00 and 22:00; post-alert exclusion criteria included darkness, rainy conditions or any rain, wind ≥8 m/s, buildings >5 stories (20 m), no-fly zones, and alerts outside the designated administrative area. The primary outcome measure was the proportion of successful and accurate AED deliveries once the drone took off. Secondary outcome measures were the proportion of cases in which the drone arrived prior to the ambulance and the time difference between drone and ambulance arrivals.
A total of 53 alerts of suspected OHCA occurred during the study period, of which 39 (74%) met exclusion criteria. Of the remaining 14 cases eligible for drone dispatch, an AED drone took off in 12 (86%), with a median distance to location of 3.1 km (interquartile range [IQR], 2.8–3.4 km). AED delivery was feasible within 9 m (IQR, 7.5–10.5 m) from the location and successful in 11 of 12 flights (92%). The AED drone arrived before the ambulance in 7 of 11 (64%) successful cases, with a difference in arrival time (mm:ss) in those seven cases of 01:52 (IQR, 1:35–4:54), and an overall time benefit for all 11 drone arrivals of 00:49 (IQR, 00:00–01:52). During the same study interval, there were either 61 or 62 test flights with either 55 or 56 (90%) successful AED deliveries (inconsistent data reported).
In this pilot study, AEDs were carried by drone to cases of OHCA with a successful delivery rate of 92% and a small time-benefit compared to emergency medical services in cases where the drone arrived first. The authors concluded that further improvements are needed to increase dispatch rate and time benefits.
Early application of AED use is associated with improved survival in OHCA. This interesting pilot study (pun intended) showed that, in certain highly controlled circumstances, it is feasible to deliver an AED by drone, and outlines the methodology for doing this. The study did not address the time to implement the AED (which might be longer for bystanders than for trained paramedics) or any clinical outcomes. It remains to be seen whether early and reliable AED delivery by drone can be translated into improved survival of OHCA either in urban or more rural regions.
Keywords: Arrhythmias, Cardiac, Cardiopulmonary Resuscitation, Defibrillators, Emergency Medical Services, Heart Arrest, Outcome Assessment, Health Care, Out-of-Hospital Cardiac Arrest, Pilot Projects, Secondary Prevention, Survival
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