Doctor Deters Death With Drone-Delivered Defibrillator

By Gene Emery

May 19, 2022

NEW YORK (Reuters Health) - Talk about on-time delivery.

Rescue workers in Sweden say they have used a drone to convey an automated external defibrillator (AED) to the scene of a cardiac arrest in just over three minutes, potentially saving the patient's life.

The case, reported in the New England Journal of Medicine, documents how an airdropped AED could improve the odds for people whose hearts have stopped in a place where no defibrillator is readily available.

It "has the potential to be a relevant and important part in the chain of survival in the future," researchers from Karolinska Institutet in Stockholm conclude in a letter to the journal

The resuscitation occurred December 9 where a 71-year old man collapsed while shoveling snow outside his home.

His wife found him, and an emergency physician who happened to pass by began chest-compression resuscitation.

As part of a study where five drones equipped with AEDs are based at two airports, one drone was dispatched to the scene. The craft are remotely piloted by humans.

The 673-meter (0.4-mile) flight took 3 minutes 19 seconds. A neighbor retrieved the AED from the drone.

The first cardiac shock was administered by the emergency physician just before the arrival ambulance workers at the patient's side, 5 minutes 30 seconds after the drone was dispatched.

The man ultimately required three more shocks, regained consciousness, was discharged after receiving an implantable cardioverter defibrillator, and had a full neurologic recovery.

The researchers, led by Dr. Andeas Claesson, who chairs the Swedish Resuscitation Council, acknowledged that "it is uncertain whether the earlier delivery of the AED by the drone (rather than waiting for the arrival of EMS) affected the patient's outcome" and the fortuitous appearance of the doctor may have been a major factor as well.

But the "drone delivery made it possible to perform defibrillation shortly before EMA arrived," they said.

The full study, begun April 21, 2021, is hoping to use the drones in 80 cases to see if they improve outcomes when a cardiac arrest occurs in the community.

"The idea came up in 2013 due to an increase in EMS response times seen in Sweden over the last 10 years. Response times were increasing and survival was still dismal - around 10%," Dr. Claesson told Reuters Health by email. "Technology was evolving and had the potential to facilitate early defibrillation prior to EMS arrival."

The drones are dispatched between 8 a.m. and 10 p.m. when it is not raining and wind speeds are below 8 meters/second (18 mph). An AED is delivered about three or four times per week.

Part of the test is designed to see if the drones and their AEDs can get to the scene before ambulance workers.

The drones fly at an altitude of 60 to 80 meters (about 200 to 260 feet), have a maximum speed of 70 km/h (43 mph) and a maximum one-way range of 6 km (3.7 miles). The AEDs are lowered from the drone so "no rotors can come in contact with eager stressed bystanders," said Dr. Claesson, who is also an associate professor at the Karolinska Institute.

The test is scheduled to end May 31.

SOURCE: The New England Journal of Medicine, online May 18, 2022.