Heart Stop: Subway Stations Among Best AED Sites In Paris

Marlene Busko

September 05, 2014

BARCELONA, SPAIN — In addition to placing automated external defibrillators (AEDs) in fitness clubs, hockey arenas, and airports, what other type of public facilities are the best sites for these devices, and how many devices would provide the best return on investment? A new geographic optimization model from researchers in Paris provides some clues.

In an abstract presented here at the European Society of Cardiology (ESC) 2014 Congress and in a press briefing, Dr Benjamin Dahan (Paris Sudden Death Center, INSERM, France) reported that based on locations where out-of-hospital cardiac arrests occurred in the past decade in Paris, it would be best to place AEDs in the city's 302 subway stations[1].

"If we spend money on AEDs, it will be very valuable if we use a rational approach to choose the optimal placement," since each defibrillator costs about €1000 plus maintenance, Dahan told the press.

"We know we have to place AEDs in sports facilities, transportation facilities (train stations and airports), high-school sports facilities, and casinos," Dahan further explained to heartwire . "Our strategy is more about the thousands of [people] who have a cardiac arrest anywhere in the street."

The group of experts—which includes EMS first responders, emergency-room physicians, cardiologists, epidemiologists, geographers, and mathematicians—is selling this service of determining optimal placement of AEDs to other cities, as explained on their website. "Considering it will improve drastically the cost-effectiveness of their AED program, this should be an excellent investment," he noted.

Session cochairperson Prof Kenneth Dickstein (University of Bergen, Norway) said the study addresses an important issue—where to put expensive defibrillators so that they will be readily available to help save lives. However, people also need to know where to find a defibrillator when the need arises and how to use it. Dahan agreed, noting that in their model, they specifically considered a few familiar public locations.

Urgent Need for Defibrillators in Public Places

Dr Benjamin Dahan

Each year, an estimated 500 000 people in Europe and 350 000 people in the US have out-of-hospital sudden cardiac arrest, but fewer than 5% survive, Dahan noted. Furthermore, EMS first-responder teams take at least 10 minutes to reach a cardiac-arrest victim; most cases start with ventricular fibrillation, and every minute of delay before defibrillation decreases chances of survival by 10%.

Thus, there is an urgent need for accessible defibrillators in public places. North American guidelines recommend placing AEDs at sites with a high likelihood of witnessed cardiac arrest, and European guidelines suggest locations where out-of hospital cardiac arrests occur at least once every two years.

However, until now, there has been no standardized approach for optimal placement of AEDs in cities, Dahan said.

Based on data from emergency medical services, they identified out-of-hospital cardiac arrests of patients in Paris from 2000 to 2010 and calculated the median distances from these events to a few types of potential public locations for defibrillators.

During the decade, there were 4176 cardiac arrests in Paris, and of these, 34% (1415 cases) occurred outside the home, with precise locations available for 1355 cases.

The researchers calculated the median distances between the out-of-hospital cardiac arrests and the city's 20 city council-district buildings, 195 post offices, 302 subway stations, 957 bike-sharing stations, and 1466 pharmacies.

The cardiac arrests occurred a median distance of 324 m from the nearest post office, 239 m from the closest subway station, and, not surprisingly, 1052 m from a city-council building.

However, although there are far more pharmacies than bike-sharing stations in the city, the cardiac arrests occurred within 142 m of a pharmacy vs within 137 m of a bike-sharing station. Thus, since the many pharmacies are not distributed evenly, they would not provide ideal coverage of the population, according to Dahan.

The model showed that "in Paris, a distribution of 350 AEDs at subway stations would provide a good coverage of the population and . . . additional AEDs wouldn't be as cost-effective as the first 350 AEDs," he summarized.

The team is poised to determine optimal AED placement in other cities.

The Paris Sudden Death Expertise Center (SDEC), the French Institute of Health and Medical Research (INSERM), Paris Descartes University, and the Assistance Publique-Hôpitaux de Paris (APHP) collaborated in this study. Dahan has no disclosures.

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