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(Circulation. 2000;102:e9028.)
© 2000 American Heart Association, Inc.
Cardiovascular News |
Cardiovascular News
Defibrillator Disagreement
The issue of automated external defibrillators (AEDs), how many there should be and who should have them, sparked controversy in the pages of the September 20, 2000 issue of the Journal of the American Medical Association. On one side of the issue is Mickey Eisenberg, MD, PhD, director of the emergency medicine service at the University of Washington Medical Center in Seattle, who calls for widespread dissemination of AEDs—to the point that he thinks consideration should be given to selling them to consumers for use in their own homes (Eisenberg M. Dissemination of defibrillators—medical vs consumer scenarios. JAMA. 2000;284(11):1435–1438). On the other side of the issue are Arthur Kellerman, Jr., MD, MPH, and Jeremy Brown, MD, who pose the question: Have AEDs been oversold? (Brown J, Kellerman, Jr. A. The shocking truth about automated external defibrillators. JAMA. 2000;284(11);1438–1441).
Dr. Eisenberg compares AEDs with cardiopulmonary resuscitation (CPR). He states that CPR was restricted to the surgical suite for years, then it went to emergency departments and hospital rooms, and now it is taught to thousands of people each year. "CPR has become a lay procedure—anybody can learn it, and it is assumed that bystanders will use it in emergency situations." He thinks that AEDs are very similar.
In his editorial, Dr. Eisenberg estimates that survival of out-of-hospital cardiac arrest is probably between 2% and 3%, despite sophisticated emergency medical services programs and community CPR. According to Dr. Eisenberg, this is because the four links in the chain of survival—quick access to emergency care, cardiopulmonary resuscitation, defibrillation, and advanced care—rarely happen quickly.
"Approximately 60% of cardiac arrests in the home are directly witnessed." Most such cardiac arrests result from ventricular defibrillation, which can be treated with defibrillation. Dr. Eisenberg says that the answer to this problem can be either medically or consumer driven.
If the answer is medical, AEDs will remain in the control of physicians, who must "prescribe" them. Insurance companies will not pay for them without studies that prove their value. Dr. Eisenberg asks, "Should AEDs be prescribed for everyone older than a certain age, for everyone with ischemic heart disease, for everyone with a certain number of coronary risk factors, or for everyone with a decreased ejection fraction?" Medical studies are needed to determine how widespread the use of AEDs should be, and those will take many years. He says that an early study of AEDs did not show benefit, although the machines used were heavy and first generation, and "Furthermore, as long as AEDs require prescriptions, it is likely the cost will remain high."
If the consumer model is used, AEDs could be purchased over-the-counter by the public. Dr. Eisenberg thinks this would drive the cost down to as little as $250. He expects AEDs will come packaged with a training video and be available through a variety of consumer outlets. He further states that the public must also accept that defibrillation is something the man on the street can do. Groups such as the American Heart Association, the American Red Cross, and the American Safety and Health Institute have supported the concept of public access to AEDs. Although the machines have been disseminated in public places, Dr. Eisenberg warns that success will be limited by the fact that only 16% of cardiac arrests occur in public.
Dr. Eisenberg says that some might wonder if such a scenario is cost-effective, but reducing the cost of AEDs through mass production will help achieve that goal. "Dissemination of AEDs is currently the only practical means to ensure rapid defibrillation. The crucial issue is how to best achieve widespread dissemination."
In their opposing editorial, Drs. Brown and Kellerman say that, despite widespread enthusiasm for the technology, there is little "evidence" to support the concept of universal access to AEDs. Studies of the use of the machines have been had varying results.
Providing AEDs to emergency medical services makes sense in light of current information, they write, but this is only valuable if the ambulances can reach patients within 8 minutes or less. "It does not make sense to promote public access defibrillation when there is insufficient evidence that this strategy results in higher community rates of cardiac arrest survival."
In fact, they state that it is unclear where to put AEDs so the public can have access to them because most locations have no more than one cardiac arrest per year. They call for studies to determine whether widespread use of AEDs is cost-effective in reducing mortality. They say the ongoing Public Access Defibrillation Community Trial, funded by the National Heart, Lung and Blood Institute, may answer some of the questions. Until those data are available, they call for a moratorium on further dissemination of the technology.
They agree that, given the current enthusiasm for AEDs, over-the-counter sales might seem the next logical step. However, they warn that this means that only the wealthy will have the technology. "Early defibrillation is but one link in the chain of survival," they warn. "The best way to reduce deaths from heart disease is through prevention."
In an interview, Dr. Kellerman said, "We should slow down the bandwagon to figure out how many we need. This technology, although wonderful, has been grossly oversold, and the scientific evidence (of its worth in a public setting) is non-existent."
Quest for Early Detection
The National Heart, Lung and Blood Institute has launched a $68 million multi-center study to find new ways of detecting heart disease before symptoms become evident. The 10-year study involves 6 centers, which will recruit 6500 participants between the ages of 45 and 84 years. The study group will be split equally between men and women.
Forty percent of the participants in the Multi-Ethnic Study of Atherosclerosis (MESA) will be white, 30% will be African-American, 20% Hispanic, and 10% Asian. None of the participants will have known heart disease when they enroll.
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