Media Releases

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

August 15, 2016

Toron­to, ON –  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 device 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 car­diac arrest 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.


For more infor­ma­tion:

Liz Do
Depart­ment of Mechan­i­cal & Indus­tri­al Engi­neer­ing
Uni­ver­si­ty of Toron­to
416–978-4036 (office)