BOSTON -- Automated external defibrillators, stationed in public places to resuscitate patients in cardiac arrest, had a 20% chance of being recalled for potential malfunction over the past decade, researchers reported.
BOSTON, Aug. 8 -- Automated external defibrillators, stationed in public places to resuscitate victims of cardiac arrest, had a 20% chance of being recalled for potential malfunction over the past decade, researchers reported.
From 1996 through 2005, during 2.78 million device-years of observation, 52 safety alerts and recalls, so-called advisories, were issued for potential malfunction (median 4.5 per year). A total of 385,922 defibrillators and device accessories were affected, according to a study in the Aug. 9 issue of the Journal of the American Medical Association.
The mean annual number of devices receiving an FDA advisory was 5.1 (SD 1.5) devices per 100 device-years. Over the past decade, 21.2% of the devices were recalled, most often because of electrical or software problems, according to data from weekly FDA Enforcement Reports, said William Maisel, M.D., and co-author Jignesh Shah, M.D., of Harvard's Beth Israel Deaconess Medical Center here.
In a second analysis of actual adverse events reported to the FDA, the researchers found that confirmed fatal device-related malfunctions, during sustained ventricular arrhythmias, occurred in 370 patients.
On the other hand, the authors cited "innumerable" lives saved, and a press release talked of "thousands of lives saved." But the authors provided only these rough estimates, with no hard data, on how well the public external defibrillator program has worked.
Hardware malfunctions were the most common type of problem, resulting in the failure of the device to turn on, to charge, or to successfully deliver a shock. The devices are simple to use, but highly complex, Dr. Maisel and colleagues said, so it is not surprising that they may occasionally malfunction. "But a recall rate of one in five over the past decade is too high," he said.
During the period studied, the annual number of defibrillators distributed increased almost 10-fold, from fewer than 20,000 in 1996 to nearly 200,000 in 2005, the researchers said. Yet despite increasing design complexity, the overall FDA advisory rate did not increase: 1996-2000 (P for trend=0.11); 2001-2005 (P for trend=0.19); 1996-2005 (P for trend=0.33). However, from 1996 through 2005 there was a significant increase in the annual number of automated external defibrillators advisories (P for trend = 0.02) and in the annual number of automated external defibrillators advisory devices (P for trend=0.01).
The devices are now found in many public places, such as airports, casinos, sports arenas, school, and churches.
The defibrillators were recalled in nine of the 10 study years, and device accessories were recalled in seven of these years. The actual number of defibrillators affected by advisories varied from a low of zero in 1998 to a high of 53,323 in 2005, the researchers reported.
"Every major AED [automated external defibrillator] manufacturer recalled products during the study, suggesting that this is an industry-wide issue and not specific to a single device or manufacturer," Dr. Maisel said.
It is often impossible to predict who the actual end user of the device will be in an emergency. Although a patient's implantable defibrillator is routinely registered with the manufacturer at the time of implantation, no such process reliably occurs with the external devices, Drs. Maisel and Shah wrote. Although recalls for these devices occur frequently, the actual number of observed malfunctions is small compared with the estimated number of lives saved, they emphasized.
As the number of external defibrillators increases, so, too, will the number of recalls, they said. Efforts should be directed toward developing a reliable system to locate and repair potentially defective devices in a timely fashion, and to better notify owners when their devices are recalled, they advised.
Dr. Maisel wrote that he is an FDA consultant and chairs the FDA Circulatory System Medical Device Advisory Panel.
In an editorial in the same JAMA issue, N.A. Mark Estes III, M.D., at the New England Medical Center here, emphasized that the study should be carefully considered in the context of benefits and risks of the devices. The recalls represent potential, not actual malfunction, he noted.
No manufactured product can ever be completely free of flaws, he said, but considering that malfunction might result in failure to deliver a life-saving therapy, strategies should aim to achieve a malfunction risk that is as low as possible.
Therefore, he wrote that despite the cost, efforts to develop rigorous mechanisms to accurately monitor these devices are essential. "Device manufactures and the federal government should allocate the funds required to make this effort successful," he said. Initial steps should be guided by the knowledge that many recalled devices remain in service and have not been appropriately evaluated.
Dr. Estes also recommends additional measures to track those who use these devices. Subsequent measures, he said, will required the best efforts of health care professionals, regulators, manufacturers, and the public "using the best practices of evidence-based medicine in post-marketing surveillance."
During cardiac arrest, he added, "when each minute really matters for survival, all stakeholders share the duty of ensuring the highest possible standards of [device] reliability."
Dr. Estes reported that he has served in the speaker's bureau and has received honoraria from Medtronic, Guidant, and St Jude Medical and has served as an expert witness in Stone vs Frontier.