In a unique pilot project in Sweden, drones were used to deliver defibrillators to real-life alerts of suspected cardiac arrest. The drones were dispatched in more than a fifth of the emergencies and arrived on target and ahead of the ambulance in most cases.
”This is the first time in the world that a research group can report results from a study where drones flew defibrillators to location of real-life alerts of suspected cardiac arrest,” says lead researcher Andreas Claesson, associate professor at the Center for Resuscitation Science at the Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet.
With sudden cardiac arrest, every minute counts. Currently, the odds of surviving an out-of-hospital cardiac arrest are 10 percent. However, with early CPR and a shock from an automated external defibrillator (AED), the chances of survival could reach 50-70 percent but response time needs to improve. In 2019 the median response time from alert to ambulance arrival for out-of-hospital cardiac arrest (OHCA) in Sweden was 11 minutes.
To try and reach cardiac arrest victims sooner, researchers investigated using the rapid dispatch of drone-carried defibrillators in parallel with ambulances. Drones are already used in some countries to dispatch medicines and medical supplies to remote rural regions, The study, conducted in mid-2020 in western Sweden, describes an integrated method where emergency operators, drone pilots and air traffic control worked together to facilitate the dual response.
The drones took off in response to 12 out of 53 alerts of suspected cardiac arrest over a four-month period, successfully delivering an AED to the site in 11 of those cases. In seven of those cases, the drones arrived before the ambulance, with a median time benefit of 1 minute and 52 seconds. However, no drone-delivered defibrillators were attached to the patients before ambulances arrived.
“Even if none of the AEDs were used this time, our study shows that it is possible to use drones to transport defibrillators in a safe way and with target precision during real-life emergencies,” said first-author Sofia Schierbeck, PhD student at the Center for Resuscitation Science at the Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet. “A precondition for their future use is that the dispatcher takes initiative and instructs people on site to quickly collect and attach the AED in order to help the person with cardiac arrest.”
More work is needed to increase the dispatch rate and time benefits. For instance, in 2020 the drones were grounded if it was dark, rainy or the winds were too strong. The software system was also configured to avoid routes above densely populated areas, meaning that some alerts were too far out of range.
“Since this study was completed, we have identified several areas of improvement,” Andreas Claesson said. “In April this year, we began a follow-up study with a more optimised system. In that study, we want to test if we can use the drones in more alerts and reduce the response time further and thereby increase the time benefit as compared to the ambulance. Every minute without treatment in the early stages reduces the chance of survival by around 10 percent, and that is why we believe this new method of delivery has the potential to save lives.”
The results are published in the European Heart Journal.
Source: Karolinska Institute
