BOSTON - A new study shows that automated external defibrillators (AEDs), the devices used to resuscitate victims of sudden cardiac arrest, had a greater than 20 percent chance of being recalled for potential malfunction over the past decade.
The findings, reported in the August 9 issue of The Journal of the American Medical Association (JAMA), suggest the need for a more reliable system to locate and repair potentially defective devices in a timely fashion.
"Though they are simple to use, AEDs are, in fact, complex medical devices," explains the study's senior author William Maisel, MD, MPH, director of the Pacemaker and Defibrillator Service at Beth Israel Deaconess Medical Center (BIDMC) and Assistant Professor of Medicine at Harvard Medical School. "It is therefore not surprising that they may occasionally malfunction. An AED recall rate of 1 in 5 over the past decade, however, is too high."
The portable units provide voice commands, automated heart rhythm analysis, and if necessary, shock delivery to resuscitate victims of cardiac arrest. Their ease of operation -- coupled with their clinically proven ability to improve the survival of cardiac arrest victims -- has resulted in their widespread use in recent years.
"During the period we followed - between 1996 and 2005 - the annual number of AEDs distributed increased almost 10-fold, from fewer than 20,000 in 1996 to nearly 200,000 in 2005," says Maisel. Many public areas such as airports, sports arenas, casinos, schools and churches are now routinely outfitted with AEDs, and certain AED models have even been approved by the U.S. Food and Drug Administration (FDA) for use without a prescription, enabling consumers to purchase them more easily.
In their study, Maisel and coauthor Jignesh Shah, MD, of BIDMC's Cardiovascular Division determined the number and rate of AED safety alerts and recalls (collectively referred to as "advisories") as well as the number of actual AED malfunctions by analyzing weekly FDA Enforcement Reports and reports of AED-related adverse events. (The FDA routinely issues such "advisories" to notify the public about potentially defective medical devices.)
Their comprehensive analysis showed that between 1996 and 2005, a total of 52 advisories affecting 385,922 AEDs or critical AED accessories were issued. They also found that device malfunctions occurred during attempted resuscitation in 370 patients. Device recalls were most often issued due to hardware malfunctions, which may result in a failure of the AED to power on, to charge, or to successfully deliver a shock.
"AEDs are responsible for saving thousands of lives," notes Maisel. "Time to defibrillation is the most important determinant of survival for patients who have suffered a cardiac arrest." However, he adds, as AED distribution continues to increase, the number of devices prone to malfunction can also be expected to increase.
"Unlike implantable cardiac defibrillators (ICDs) which are routinely registered with the manufacturer at the time of implantation, no such process reliably occurs with AEDs," Maisel explains. "Our study demonstrates that there is an urgent need to develop a more reliable system to identify and repair potentially defective AEDs in a timely fashion and to better notify AED owners when their devices are recalled."
Maisel is an FDA consultant and chair of the FDA Circulatory System Medical Device Advisory Panel. The opinions expressed herein are the personal views of the authors and do not necessarily represent the policies, practices, positions or opinions of the FDA.
Beth Israel Deaconess Medical Center is a patient care, teaching and research affiliate of Harvard Medical School and ranks fourth in National Institutes of Health funding among independent hospitals nationwide. BIDMC is clinically affiliated with the Joslin Diabetes Center and is a research partner of the Dana-Farber/Harvard Cancer Center. BIDMC is the official hospital of the Boston Red Sox. For more information visit www.bidmc.harvard.edu.