Sweden uses drones to fight cardiac arrest

Flying drones with defibrillators to help cardiac arrest patients is faster than ambulances in two out of three cases, a new Swedish study published in The Lancet Digital Health found.

The survival rate of patients with cardiac arrests in Sweden is the same as it was ten years ago, and although thousands of automated external defibrillators have been installed in public spaces such as shopping centres and libraries, it has made little difference.

“Most cardiac arrests happen at home. If we want to help more people survive, we need to help them more quickly on the spot”, Andreas Claesson, a paramedic for 25 years and an associate professor of emergency medicine at the university Karolinska Institutet in Stockholm, told Euractiv.

The solution might just come from the sky. A new Swedish research study shows that drones are faster than ambulances in two out of three cases, or in 67 % of the occasions when deployed.

Drones vs ambulances

The novel approach was tested from April 2021 to May 2022 in real-world circumstances in five semi-urban areas in the western region of  Västra Götaland in Sweden, home to some 200,000 people.

In the event of an emergency call, the drone received the alert at the same time as two ambulances. It flew in an automated fashion to the reported address, delivering a basket containing a defibrillator. In almost all cases (91%), this life-saving device was winched down within 15 meters of the door of the building or the patient.

However, the drones used by the operator Everdrone could not be used or deployed in windy, rainy or snowy weather and were sometimes hampered by flying restrictions.

Drones were used in 72 out of 211 cases of suspected cardiac arrests during the study period. Of these, a defibrillator was safely delivered in 58 cases (in the remaining 14, the drones were recalled by the dispatch centre).

Of these 58 cases, the drone outpaced the ambulances 37 times (67%), with a median time of 3 minutes and 14 seconds.

Moreover, in 25 % of the cases, the drone was almost eight minutes ahead, says Claesson, who describes the response time as a crucial factor.

Of the 37 cases, 18 were true out-of-hospital cardiac arrests, and bystanders attached the defibrillators to 6 of those patients, one of whom survived for over 30 days, according to the results recently reported in The Lancet Digital Health.

The next steps

Now, Andreas Claesson is digging deeper into the research statistics and listening to the alarm calls to find out why bystanders did not use the defibrillator more often.

“I believe six out of 18 cases could be considered good because there may be people who don’t understand what to do or simply can’t do it”, he explains.

When the defibrillator is switched on, an automated voice guides the bystander and dispatcher on what to do. Once the defibrillator is appropriately attached to a patient, it uses an ECG electrocardiogram to analyse the heart’s electrical signals and detect any heart problems.

“Sometimes the heart may have stopped beating, with no activity. Then, there is no point in using the defibrillator. Instead, the device can advise bystanders on how to perform chest compressions”, says Claesson, emphasising that the study is a feasibility study.

“We now know that we have a transport system that works. It can also be used for other medical purposes, to deliver an auto-injector of adrenaline in case of an allergic reaction, a naloxone spray in the case of a drug overdose or a trauma dressing in the case of a shooting or a traffic accident”, he added.

The drones are still flying defibrillators in the five areas, and both the researchers and the Västra Götaland region see a lot of potential in the model.

One opportunity is to link the drone system to the Sms-livräddare network (mobile SMS rescuers), where volunteer responders trained in heart and lung rescue – can be alerted when someone calls 112 and the call centre suspects a cardiac arrest.

According to the network, around 350,000 people in Europe suffer from out-of-hospital cardiac arrest every year, and only around 10% of them survive.

A unique system

Magnus Kristiansson, the region’s project manager, told Euractiv that, to his knowledge, the drone system is unique in Europe.

“In the region, we are now looking at different approaches on how to use the drones in pre-hospital care”, he says.

Another drone test is now being carried out by the region and Norway, funded by the EU Interreg programme.

“The drones that have cameras fly out to traffic or other accidents where the emergency centre needs to film and monitor the situation”, Kristiansson tells Euractiv.

Everdrone, the operator, is planning to invest in the next generation of drones, which can fly in rainy weather and over longer distances.

“We see this as a technical element that we can use in many future scenarios. Not only to deliver defibrillators but also to create equal care, even for those who live on islands near our costs, for example”, Magnus Kristiansson says.

Additionally, EENA, the European Emergency Number Association, has been proactively involved in developing drone use for emergencies, including testing the use of AED-equipped UAV in Sweden in 2021”, according to its Executive Director Gary Machado.

“We concluded that UAV AED delivery is showing great potential as a way to improve OHCA survival rates, and we are pleased to see this technology expanded to other life-saving medical treatments and look forward to the possibilities this will bring for public safety in Europe”, he added in a comment to Euractiv.

[By Monica Kleja, Edited by Vasiliki Angouridi |]


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