Jacob Hollenberg and his colleagues at the Karolinska Institute have conducted a study looking at whether drones could be used to get a defibrillator to the scene of an emergency more quickly than an ambulance (New Scientist, 2017).

Having a bystander perform chest compressions while improve the chances of someone surviving a cardiac arrest, but a shock from a defibrillator must be applied quickly to restart the heart. Defibrillators are designed to give spoken instructions so that anyone can use them, and many are available in public places.

Jacob Hollenberg, director of the centre for resuscitation science at the Karolinska Institute, said “Cardiac arrest is one of the major killers in the western world (The Guardian, 2017). Every minute is crucial; I would say every second is crucial. Every minute that passes from collapse to [cardiopulmonary resuscitation] or defibrillation, the chances of survival goes down by 10%. That’s why survival after 10 to 12min is basically zero. There’s a huge difference in using the defibrillator within the first few minutes. Even if you improve the timing of the ambulances in these type of situations, it’s too late – only one in 10 victims survive”.

He said “If we can decrease the time in cardiac arrest from collapse to defibrillation by a few minutes, hundreds of lives would be saved each year.”

The 5.7kg drone was developed by the Swedish Transportation Agency to carry a 763g automated external defibrillator (AED). The eight rotor unmanned aerial drone, with a maximum cruising speed of 75km/h, was stationed at a fire station in Norrtälje, a rural location near Stockholm. Over a seventy two hour period in October 2016, it was dispatched eighteen times by two licensed pilots using GPS coordinates to out of sight locations within a ten kilometre radius where cardiac arrests had occurred between 2006 and 2014.

The results, published in the Journal of the American Medical Association, found that the median time from call to dispatch of the emergency services was three minutes compared to three seconds for the drone. The median time from dispatch to arrival of the drone was five minutes twenty one seconds, compared with twenty two minutes for the emergency services. The drone arrived more quickly than the emergency services in all cases with a median reduction in response time of sixteen minutes thirty nine seconds over a median flight distance of about two miles.

Limitations of the study included the small number of flights over short distances in good weather and the possibility of changes in traffic patterns from the period between 2006 and 2014 to the present day. Additionally, the outcomes between those who receive resuscitation from the emergency services and from a bystander using an AED were not compared by the study, although Jacob Hollenberg said the defibrillators are “easier to use than a fire extinguisher.”

His team is working with emergency services, preparing to dispatch the drone in real emergencies and test whether it improves outcomes. He said “Hopefully we will be up and running within a year or two.” A larger scale trial will be carried out and agreement needs to be reached with the aviation authorities. Currently, laws in Sweden, as in the UK, require drones to be operated within sight.

Jacob Hollenberg said future trials could look at use of drones for other health emergencies, such as allergic reactions and road traffic accidents. He said “I am all about saving lives. We have to work together with the authorities and air traffic control systems.” His team has already tested drones to search for people who are drowning. He said “I’m convinced that the possibility of using drones in medical emergencies is enormous.”

Adrian Boyle of the Royal College of Emergency Medicine, London said the approach is interesting, but making sure more people can do CPR would probably have more benefit. He said “One of the things we are bad at in the UK is teaching bystanders CPR, which would arguably be a much lower tech, more useful intervention than this.”

Stockholm, London and other cities have trialled mobile apps that alert CPR-trained people if someone has a cardiac arrest nearby.

NHS England is planning to use drones to assist hazardous area response teams, who deal with medical emergencies involving chemical, biological or nuclear materials. Christian Cooper of the National Ambulance Resilience Unit said it is also looking at the possibility of using drones to deliver blood and organs for transplant.