Many life-saving defibrillators behind locked doors during off-hours, study finds

August 15, 2016
An automated external defibrillator (AED) is pictured. Research led by U of T Engineering Professor Tim Chan showed that up to 30 per cent of the time, AEDs are locked inside closed buildings when someone suffers cardiac arrest in a public place. Credit: Liz Do - U of T Engineering

When a person suffers cardiac arrest, there is a one in five chance a potentially life-saving Automated External Defibrillator (AED) is nearby. But up to 30 per cent of the time, the device is locked inside a closed building, according to a study led by U of T Engineering researchers, published today in the Journal of the American College of Cardiology.

The work was conducted by Professor Timothy Chan of the Department of Mechanical & Industrial Engineering at the University of Toronto, in collaboration with Rescu, led by Dr. Laurie Morrison at Li Ka Shing Institute of St Michael's Hospital in Toronto.

Currently, AED placement in Canada does not necessarily consider accessibility of the during an emergency. Many AEDs are located within office buildings, schools and recreation facilities, which tend to be open for a limited set of hours during the daytime.

Toronto had 2,440 cases of out-of-hospital cardiac arrests in a public place during the study period, and 767 AED locations. Of these AED locations, 73.5 per cent were not open 24-hours a day, and 28.6 per cent were closed on weekends. Of the total number of out-of-hospital cardiac arrests, 451 were located near an AED but only 354 were located near an AED when the AED was accessible, resulting in a coverage loss of 21.5 per cent.

When researchers looked at cardiac arrests during evenings, nights and weekends, which is when the majority of all out-of-hospital cardiac arrests occur, coverage diminished to 31.6 percent.

The researchers concluded that a significant proportion of out-of-hospital cardiac arrests occur close to a public AED that is inaccessible at the time of the arrest, and a model that accounts for both location and availability when determining AED placement has the potential to significantly increase the likelihood of accessing an AED when needed.

"Our research has shown AED availability for cardiac arrests is overestimated when time factors, such as building access and time of day, are not considered," said Chan. "The model considers time of day, building access and location information to optimize AED availability. Using the model, we found an average 25 per cent improvement in AED accessibility for cardiac arrests at all times of day."

Government legislation mandating all AEDs be registered with emergency medical services dispatch centers and accessible to the public 24/7 would also improve access to AEDs.

But coverage is only one issue, according to the study's authors: AED coverage does not necessarily equal survival, because the existence of an AED still doesn't necessarily mean the AEDs are being used.

"Accessibility is only one piece of the larger puzzle in optimizing public defibrillator use and bystander response in an emergency," said Chan, who is also director of the Centre for Healthcare Engineering at the University of Toronto.

In an accompanying editorial comment, Robert J. Myerburg, a professor of medicine at the University of Miami Miller School of Medicine, said the study is important and should be included in planning strategies for AED locations, but society would benefit more by both achieving better outcomes after out-of-hospital and reducing the number that occur in the first place.

"Now we need a parallel effort to develop a roadmap for improving prediction and prevention of out-of-hospital cardiac arrest," he said.

Explore further: Ensuring defibrillators are accessible when heart attacks are most likely to happen

Related Stories

Ensuring defibrillators are accessible when heart attacks are most likely to happen

November 11, 2015
Walking through an office building on St. George Street, Engineering's Christopher Sun quickly spots a portable automated external defibrillator (AED) conveniently tucked near the side of the entrance.

Sudden cardiac arrest? Can't find an AED? There may be an app for that

November 7, 2015
The earlier bystanders can deliver shocks with an automated external defibrillator (AED) to people who have cardiac arrest outside the hospital, the better their chances are for survival. Although it may be difficult to find ...

Researchers determine where best to place defibrillators

May 2, 2013
TORONTO: Prompt use of an automated external defibrillator, or AED, can greatly increase the survival rates of people who suffer a cardiac arrest. And MIE Professor Tim Chan, working with Dr. Laurie Morrison at St. Michael's ...

Efforts to improve AED usage increase bystander defibrillation in public but not at home

August 30, 2015
Efforts to improve automated external defibrillator (AED) usage increase bystander defibrillation in public places but not at home, reveals a study of more than 25 000 cardiac arrest patients presented at ESC Congress today ...

Study shows public access defibrillators are increasing survival but are not being used enough

June 1, 2015
New research presented at this year's Euroanaesthesia shows that use of public access defibrillation on people suffering cardiac arrest is associated with a large increase in chances of survival. However, despite the great ...

Statewide initiative associated with improved cardiac arrest outcomes

March 23, 2016
Statewide efforts to equip family members and the general public with the know-how and skills to use cardiopulmonary resuscitation (CPR) and automated external defibrillators (AEDs) in the home or in public coincide with ...

Recommended for you

Low-salt and heart-healthy dash diet as effective as drugs for some adults with high blood pressure

November 22, 2017
A study of more than 400 adults with prehypertension, or stage 1 high blood pressure, found that combining a low-salt diet with the heart-healthy DASH diet substantially lowers systolic blood pressure—the top number in ...

Stroke patients may have more time to get treatment, study finds

November 22, 2017
Patients and doctors long have relied on a simple rule of thumb for seeking care after an ischemic stroke: "Time is brain."

Cases of heart failure continue to rise; poorest people worst affected

November 22, 2017
The number of people being diagnosed with heart failure in the UK continues to rise as a result of demographic changes common to many developed countries, new research by The George Institute for Global Health at the University ...

Some cancer therapies may provide a new way to treat high blood pressure

November 20, 2017
Drugs designed to halt cancer growth may offer a new way to control high blood pressure (hypertension), say Georgetown University Medical Center investigators. The finding could offer a real advance in hypertension treatment ...

Could this protein protect people against coronary artery disease?

November 17, 2017
The buildup of plaque in the heart's arteries is an unfortunate part of aging. But by studying the genetic makeup of people who maintain clear arteries into old age, researchers led by UNC's Jonathan Schisler, PhD, have identified ...

Raising 'good' cholesterol fails to protect against heart disease

November 16, 2017
Raising so-called 'good' cholesterol by blocking a key protein involved in its metabolism does not protect against heart disease or stroke, according to a large genetic study of 150,000 Chinese adults published in the journal ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.