Over 15 years, 1,284 cardiac arrest deaths have been connected to the failure of automated external defibrillators (AEDs), according to a study published online last month in Annals of Emergency Medicine. One-quarter of those AED failures were due to battery failures.

“Survival from cardiac arrest depends on the reliable operation of AEDs,” lead study author Lawrence DeLuca of the University of Arizona Department of Emergency Medicine in Tucson, AZ, said in a release. “AEDs can truly be lifesavers but only if they are in good working order and people are willing to use them.”

Researchers analyzed reports to the Food and Drug Administration (FDA) about all adverse events connected to the use of an AED between January 1993 and October 2008. Of the 40,787 AED-related events reported to the FDA, 1,150 adverse events connected to fatalities were reported. Almost half (45 percent) of failures occurred during the attempt to charge and deliver a recommended shock to the person in cardiac arrest.

Battery power problems accounted for 23.2 percent of the failures The report noted that in 54 cases, the AED’s batteries were low. In 110 cases, the AED suddenly powered off while in 37 cases, the AED never came on at all. In 252 cases, the AED did not complete the rhythm analysis, and in 524 cases, the AED did not deliver the recommended shock.

Problems with pads and connectors accounted for 23.7 percent of the failures.

Sudden cardiac arrest is a leading cause of death in North America and Europe. Odds of survival decline 7 percent to 10 percent per minute of delay in defibrillation, according to the American College of Emergency Physicians, a national medical society that publishes the peer-reviewed scientific journal Annals of Emergency Medicine.

Many states require that fitness facilities have an AED on hand, but even as AEDs have proliferated in public places, bystanders often are reluctant to use them. An Annals of Emergency Medicine study published earlier this year found that less than half of people in public places reported being willing to use an AED, and more than half were unable to recognize one.

“AEDs are like any other piece of medical equipment: They can experience unexpected failures,” Deluca said. “I would recommend that people maintain AEDs as recommended by the manufacturer. If an unexpected device failure occurs, it is vitally important to promptly contact both the manufacturer and the FDA. Then, be sure to return the unit (and accessories, such as pads or batteries) to the manufacturer immediately so that it can be analyzed and a cause for the failure identified and fixed.”

The researchers also recommended having a backup AED on hand. Of the backup units mentioned in the reports studied by the researchers, three recommended shock but did not deliver the shock. However, 675 of the reports did not mention a backup unit, although that did not mean a backup unit was not on hand.