Cardiac arrest survival greatly increases when bystanders use an automated external defibrillator


Study Highlights:

Survival from cardiac arrest doubled when bystanders stepped in to use a publicly-available automated external defibrillator rather than wait until emergency responders arrived.


The study showed that the longer it takes emergency personnel to arrive, the greater the benefit of a bystander using an AED to shock the victim.

Victims who received a defibrillator shock from a bystander had far greater chances at survival and being discharged from the hospital than those who did not.


Embargoed until 4 a.m. CT / 5 a.m. ET Monday, February 26, 2018

DALLAS, Feb. 26, 2018 — Survival from cardiac arrest doubled when a bystander stepped in to apply an automated external defibrillator (AED) before emergency responders arrived, according to new research in the American Heart Association’s journal Circulation.


According to the American Heart Association, of the more than 350,000 out-of-hospital cardiac arrests that occur in the United States each year, more than 100,000 happen outside the home. Less than half (45.7 percent) of cardiac arrest victims get the immediate help they need before emergency responders arrive, in part because emergency medical services take, on average, between four and ten minutes to reach someone in cardiac arrest.


An international team of researchers looked at 49,555 out-of-hospital cardiac arrests that occurred in major U.S. and Canada cities. They analyzed a key subgroup of these arrests, those that occurred in public, were witnessed and were shockable.


The researchers found that nearly 66 percent of these victims survived to hospital discharge after a shock delivered by a bystander. Their findings emphasized that bystanders make a critical difference is assisting cardiac arrest victims before emergency responders can get to the scene.


Among the study’s results:

Bystanders used an AED in 18.8 percent of these cases.

Cardiac arrest victims who received a shock from a publicly-available AED had far greater chances of survival and being discharged from the hospital than those who did not; 66.5 percent versus 43 percent.


Cardiac arrest victims who received a shock from a publicly-available AED that was administered by a bystander had 2.62 times higher odds of survival to hospital discharge and 2.73 times more favorable outcomes for functioning compared to victims who first received an AED shock after emergency responders arrived.


Victims who received an AED shock from a bystander (57.1 percent) using a publicly-available device instead of having to wait for emergency responders (32.7 percent) had near normal function and better outcomes.


Without a bystander using AED shock therapy, 70 percent of cardiac arrest patients either died or survived with impaired brain function.

“We estimate that about 1,700 lives are saved in the United States per year by bystanders using an AED,” said senior study author Myron Weisfeldt, M.D. “Unfortunately, not enough Americans know to look for AEDs in public locations, nor are they are trained on how to use them despite great and effective efforts of the American Heart Association.


According to the American Heart Association (AHA), use of an AED is the third step in the cardiac arrest chain of survival. The first two steps in a witnessed, out-of-hospital cardiac arrest are to 1) call 9-1-1 and 2) begin immediate cardiopulmonary resuscitation (CPR).