If you go into cardiac arrest while you’re out shopping for groceries or watching your child’s Little League game, your odds of survival are low. But there’s something that can help – widespread deployment of automated external defibrillators.
The latest evidence comes from Japan, where the country’s Fire and Disaster Management Agency tracked 312,319 out-of-hospital cardiac arrests that occurred between January 2005 and December 2007. In 12,631 of those cases, the arrest was of cardiac origin, involved ventricular fibrillation and was witnessed by a bystander.
At the beginning of the study, when there were 0.11 public-access AEDs per square kilometer of inhabited area, only 1.2% of the victims got a shock from a bystander. By the end of the study, there were 0.97 AEDs per inhabited square kilometer, and bystanders gave shocks 6.2% of the time.
And how did those patients do? Nearly 32% of those who received shocks from bystanders using public-access AEDs were alive and had “minimal neurologic impairment” after one month. That may not sound very high, but it’s much better than the 14.4% rate for all patients who had a cardiac arrest in the presence of a bystander but didn’t get a shock until emergency medical crews arrived on the scene.
The researchers found that as more AEDs were deployed at schools, offices, sports facilities and other public venues throughout the country, the average time it took for someone to administer a shock or begin CPR fell from 3.6 minutes to 2.9 minutes.
Previous studies, including one from the United States, have shown that stationing defibrillators in the community is helpful to victims of cardiac arrest. But the Japanese study is the first to show that those results hold up when AEDs are distributed throughout an entire country, not just in select areas.
The Japanese researchers said they hoped their study would “encourage other countries or communities to promote public-access-defibrillation programs.”
The results were published Thursday in the New England Journal of Medicine.
-- Karen KaplanPhoto: AEDs, such as this one on a commuter train in Boston, improve the odds of surviving a cardiac arrest. Credit: Darren McCollester / Chicago Tribune/MCT