January 27, 2011

More Public Defibrillators Could Help Combat Cardiac Arrest

Researchers said Wednesday that devices to restore a normal heartbeat after cardiac arrest appear to be less useful at home than in public places.

The automatic external defibrillators (AED) are already present in airports and casinos across the U.S.  Some research hinted lately that more Americans' hearts are too far gone to be jolted back to life by an AED.

However, according to a new study published in the New England Journal of Medicine, those concerns are only partly justified.

A study based on data from the world's largest registry of cardiac arrests outside of hospitals government-funded researchers found an AED could have been used far more often in public settings than in private homes.

"AEDs are of tremendous value for people who have cardiac arrest in public locations," Dr. Myron L. Weisfeldt, of Johns Hopkins University in Baltimore, who led the new study, told Reuters. "It is not that they have no value at home, but they have less value there."

The researchers found that 60 percent of the people who collapsed in a public place while someone was watching had heart rhythms that allowed the use of an AED.

If the cardiac arrest took place at home, only 35 percent of the people might have been helped by an AED.

"Our guess is that people who have cardiac arrest at home are people who have chronic heart disease and are on medications," said Weisfeldt.

He said that in those cases, the heart might just stop completely instead of going through the weak flutter, where AEDs are still helpful.

Overall, a bystander used an AED with only 2 percent of the 13,000 patients the team studied, and just 7 percent left the hospital alive.

"One of the things that have been recognized for some time is that not enough members of the lay public perform CPR," Dr. Benjamin Abella, a resuscitation expert at the University of Pennsylvania in Philadelphia who was not involved in the study, told Reuters.

"It certainly also is striking just how few people had AEDs applied," he added. "There needs to be much more aggressive employment and education in use of AEDs."

He said the new findings suggest placing more of the devices in public locations rather than private residences would better spend public money.

Weisfeldt led a study last year that estimated AEDs save 474 lives annually in the U.S. and Canada.  About 300,000 Americans suffer cardiac arrest every year.

An editorial that questioned the new study written in the same journal said that small differences in how fast bystanders call 911 could explain why people do worse at home.

"The lone rescuer at home, who is probably less aware of the critical importance of speed, would lose the race to a public bystander," wrote Dr. Gust Bardy of the Seattle Institute for Cardiac Research.

Weisfeldt said that time did not seem to matter much, and more CPR education would probably be helpful in the private setting, where most cardiac arrests still occur.


On the Net: