Letter from the Editor

Call DAD! – Drone-Assisted Defibrillation

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

It is well-known that successful defibrillation of a patient suffering from an out-of-hospital cardiac arrest is critically dependent on prompt defibrillation. The conventional approach, in most countries at least, is to call 911 and wait for first responders to bring a defibrillator. To improve the time to cardiac defibrillation in the field, automatic external defibrillators (AEDs) have been positioned around the world in areas with high population densities where cardiac arrests are likely to occur, such as casinos, sporting event venues, shopping malls, etc. However, even public access to an AED can result in substantial time delays to defibrillation. When there is only one bystander, it requires the Good Samaritan to leave the victim to find an AED rather than deliver critical cardiopulmonary resuscitation (CPR). In many places, the closest AED is too far away to be useful.

There has been a lot of discussion in the past few years about using unmanned drones to quickly deliver an AED to the site of a cardiac arrest (Figure 1). To study this further, three researchers at the University of North Carolina (UNC) at Chapel Hill recently simulated a cardiac arrest on the UNC campus, comparing the time it would take for a bystander to locate an AED and bring it to the victim, to the time it would take to make a phone call and summon an AED by drone.1 (As a UNC alumnus, I was particularly interested to read this paper and find familiar landmarks on the campus map that showed the AED locations.) It appears that there are over 60 AEDs on the UNC campus. They identified 5 different zones on campus that had varying AED density. Zones were defined as a circular area with a 600-foot radius and contained anywhere from 1-8 AEDs. The investigators mimicked a cardiac arrest using a resuscitation manikin and asked the participant to simulate a 911 call, and then either hunt for an AED or stay by the manikin and await for delivery of an AED by a small drone. Multiple tests were performed in each zone. The drone that was used was a Matrice 600 Pro (DJI). It appears to be used commonly for aerial photography, but in this case was modified to carry a standard 2.5-pound HeartStart AED (Philips Healthcare). It departed from a launch site about 1000 feet from each arrest site and followed a strict legal protocol. “The drone flew autonomously using a preprogrammed flight path, flying over buildings and wooded areas where possible to reduce exposure to pedestrians. Per regulations stipulated from UNC’s Drone Policy, the UNC institutional review board, and the Federal Aviation Administration (FAA), a licensed drone pilot maintained visual contact with the drone at all times with the capacity to override the drone’s autonomous flight mode if necessary.”1

The drone was the victor. On average, the drone arrived sooner than the bystander was able to locate and retrieve an AED in 4 of the 5 zones. In one zone, where there were more AEDs close by, the drone could not arrive sooner than the bystander. However, there was one instance when the drone actually arrived 5.6 minutes sooner than the person.

This is an important study that shows that, on a college campus, an unmanned drone can usually deliver an AED to the site of a cardiac arrest faster than a bystander can hunt one down nearby. The study emphasizes how critical a few minutes are in defibrillation. It also highlights that when there is only one bystander, CPR can be delivered by the bystander while the drone is being delivered. If a drone can surpass the witness of a cardiac arrest to locate and deliver an AED on a college campus, it is likely to win the race in most other venues where AEDs are not so ubiquitous. This idea should be pursued. 

Stay safe,

Bradley P. Knight, MD, FACC, FHRS

@DrBradleyKnight
Editor-in-Chief, EP Lab Digest

Disclosures: Dr. Knight reports that he is a consultant, speaker, investigator, and offers fellowship support for Abbott, Baylis Medical, Biosense Webster, Inc., BIOTRONIK, Boston Scientific, Medtronic, and SentreHEART. He has received compensation for serving as a consultant to CVRx, Inc. 

References
  1. Arnold E, Cunningham CJ, Picinich M, et al. Drone delivery of an automated external defibrillator. N Engl J Med. 2020;383:1186-1188. doi: 10.1056/NEJMc1915956
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