Defibrillators badly placed to save lives
Machines too far from cardiac arrest hot spots, researchers find
When someone suffers cardiac arrest, speed matters. But defibrillators in public places in Toronto are not in the best locations to help cardiac arrest victims, a new study has found. Researchers at the University of Toronto and St. Michael’s Hospital have identified cardiac arrest “hot spots” not close enough to automated external defibrillators (AEDs). The corner of Jarvis and Gerrard topped the list, with 11 cardiac arrests in a five-year period. Queen and Bay and Jarvis and Dundas followed with six cardiac arrests each, while Dundas and Spadina saw four. All were more than100 metres from an AED. One hundred metres is the approximate distance a bystander can carry a defibrillator in one and a half minutes, the maximum time recommended by the American Heart Association. “Seconds count,” said Andrew Lotto, manager of resuscitation programs at the Heart and Stroke Foundation of Ontario. If a defibrillator is used in the first few minutes, chances of survival can increase up to 75 per cent. But with each passing minute, those chances fall by 10 per cent, he said.
“The longer the delay in CPR, in the emergency response, in calling 911, that will lower the chances of survival,” said Lotto. University of Toronto engineering professor Timothy Chan teamed up with emergency medicine specialists at St. Michael’s Hospital to create a mathematical model for placing defibrillators around the city. Chan compared the locations of all 1,310 public cardiac arrests between 2005 and 2010 with the locations of the 1,699 public defibrillators registered with Toronto Emergency Medical Services. He found that less than one in four cardiac arrests had a public defibrillator within100 metres. On average, the distance was closer to 300 metres. Eight of the top 10 cardiac hot spots were in the downtown core. The two outliers were Eglinton and Warden, and Brimley and Progress, with the latter being the furthest from an AED at 560 metres. While researchers did not examine why cardiac arrests were more common in the hot spots, Chan said it was likely a combination of foot traffic and socioeconomic factors. “Certain people who are homeless or may be drug users could be more susceptible to cardiac arrest,” he said. “Some of these areas are more likely to be where these individuals would congregate in the city.”
His mathematical model based on previous cardiac arrests is more precise than the current methodology used by Toronto EMS and the Heart and Stroke Foundation, he said.
Currently, AEDs are placed in high-traffic areas like transit hubs, shopping malls and recreation centres. But Lotto said Chan’s research will help his team choose locations in the future.
“We know AEDs save lives,” he said. “We want them to be as commonplace as fire extinguishers. But before (they can be that commonplace), we have to . . . strategically deploy to those high-risk places.”
It’s unknown how many defibrillators are in the city because registering them with Toronto EMS is optional.
Businesses are urged to register so that emergency dispatch can tell callers there’s an AED nearby.
Toronto residents should learn where AEDs are located and how to use them, said St. Michael’s critical care physician Dr. Natalie Wong.
The devices are meant to be easy for untrained people to use and have picture-based instructions printed on them. Most sports facilities and subway stations have them, she said.
“Time is the most important thing,” she said. “If they know where (a defibrillator) is and they see something happen, they can immediately run and grab it.”