Drones could help cut the time it takes to get a defibrillator to people experiencing cardiac arrests when not in hospital, researchers have suggested.
In the UK alone, there are more than 30,000 out-of-hospital cardiac arrests a year where emergency medical services attempt to resuscitate the individual, according to the British Heart Foundation. However, fewer than one in 10 people survive such an event, and some who do are left with neurological problems.
One important factor that can affect survival is how rapidly victims get access to treatment – every minute without CPR and defibrillation reduces the chance of survival by 10%.
“We have an objective as EMS [emergency medical service] organisations and EMS physicians to help cardiac arrest patients get defibrillated as early as possible,” said Matthieu Heidet, a professor of emergency medicine at Henri-Mondor university hospital in Créteil, France.
Work by Heidet and colleagues has suggested drones could be used to increase access to the life-saving devices.
To explore the issue, the team analysed the number and location of 28,349 out-of-hospital cardiac arrests that occurred between 2011 and 2024 in administrative areas within the Greater Paris area. Central Paris was excluded from the analysis.
The team cross-referenced these events with the location of fixed automated external defibrillators (AEDs).
The researchers found accessibility of the 1,893 AEDs varied considerably across the area.
“Only 30% of all [out-of-hospital cardiac arrest] cases occurred within the target 500-metre network distance of the nearest recorded fixed AED,” said Dr Hillary Minka, an emergency physician at the Lariboisière hospital in Paris and the first author of the work.
The team found an extra 910 fixed AEDs would be needed for 84.5% of the recorded cardiac arrest cases to have been within 500 metres of an AED, while 1,712 extra fixed AEDs would be needed for 100% coverage.
However, by using drones operating within a radius of 3,900 metres, coverage could be increased with fewer devices.
“As drone bases were introduced, the number of additional fixed AEDs required fell substantially,” said Minka, noting that with 100 drone bases and 26 additional fixed AEDs, more than 97% of the cardiac arrest cases would have been located either within 500 metres of a fixed AED or within approximately 4km (2.5 miles) of a drone base. The use of 200 drone bases and just four extra AEDs meant more than 99% of cases would have been covered.
The researchers also looked at the proportion of the cardiac arrest cases deemed close enough to an existing fixed AED that the device could be retrieved in a round trip within five minutes.
The results revealed only 30-40% of the cardiac arrest cases had access to current fixed AEDs within this time period using the ground transportation network.
Heidet added that this figure was optimistic. “In France, only 8% of out-of-hospital cardiac arrest patients benefit from the application of a public AED before the arrival of the [emergency services],” he said, noting one factor is that a large proportion of AEDs are inaccessible, for example because they are housed in enclosed private spaces that are not open at all times.
By contrast, Minka noted that in a scenario involving 200 drone bases, 871 existing fixed AED sites and four additional fixed AED sites, drone delivery reached virtually all of the cardiac arrest cases covered by the model within five minutes.
The team’s models were based on drones being housed at sites ranging from current AED locations to fire stations and mobile intensive care units, and did not look at real-world deployment of such tech.
Heidet noted it is not the first time drones have been considered for the delivery of AEDs; the approach is already being used in parts of Sweden and has saved lives.
In real-world systems, Heidet added, drones are operated by trained drone pilots.
“Once an emergency call is received and an [out-of-hospital cardiac arrest] is identified at the dispatch centre, the drone is activated by EMS dispatchers. It then takes off and follows an automated flight path, while the final approach and subsequent AED delivery are handled by the drone pilot. The entire process is conducted under the supervision of the emergency medical service,” he said. Once delivered, the AED can be used by members of the public at the scene.
Heidet added the cost of drones needed to be integrated into the evaluation of such technology, noting there may be a balance between the ideal model and the feasible economic model.
The study, which has not yet been peer-reviewed, is to be presented at the European Emergency Medicine Congress in Paris on Saturday.
