Automatic External Defibrillators in the Sports Arena: The Right Place, the Right Time
John D. Cantwell, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 26 - NO. 12 - DECEMBER 2021
At first glance, the idea of having automatic external defibrillators (AEDs) at sports events may seem curious, since spectator sports are the domain of young, healthy athletes. Yet athletes are not entirely free of cardiac risk. More important, there are many other people at sports events—officials, coaches, fans—who are at risk for cardiac arrest. In just one example, baseball umpire John McSherry suffered a fatal heart attack before a national TV audience during the Cincinnati Reds' home opener in April 1996.
Sizing Up the Need
The vast majority of cardiac arrest cases occur, of course, in nonathletes. The American Heart Association (AHA) estimates that about 350,000 people die of cardiac arrest each year. An average of 16 sudden cardiac deaths occur annually among US high school and college athletes (1), though additional deaths may go unreported. The cause of death in athletes is usually ventricular fibrillation associated with underlying cardiovascular disease or as a result of blunt impact to the chest wall (commotio cordis).
The use of on-site AEDs to treat cardiac arrest is rising because traditional emergency medical service (EMS) is unavoidably too slow. The single most important determinant of survival is the time from collapse to defibrillation: Each minute of delay decreases the chance of survival by 7% to 10%. Most patients will survive if defibrillation is achieved in less than 3 minutes; few will if the delay is 16 minutes or longer, despite CPR administration (2).
The AHA estimates that 100,000 deaths could be prevented each year with rapid defibrillation. In the outpatient cardiac rehabilitation program that I have directed for 25 years, we have had seven cardiac arrests. All seven patients were successfully defibrillated, thanks to the immediate availability of a defibrillator (3).
In large sports settings, AEDs can supplement standby EMS services. At sports events in small towns or venues, the AED might be the only means available to effect early defibrillation.
How AEDs Operate
The AED is easily used by athletic trainers, security guards, and other lay people. The devices are small (the size of a book), light (4 to 7 lb), and relatively inexpensive ($3,500). Four companies market such devices, which are of high quality and reliability, according to initial field testing.
Nonphysicians can learn to use an AED in about an hour. The user simply applies the two electrodes to the left apex and the right base of the chest. With most devices one pushes the "on" button and listens for a voice on the machine to direct whether or not to push the defibrillator button. In monophasic models, the electric current travels from the positive electrode pad to the negative pad. The current in biphasic models travels in both directions.
Maintenance is minimal on AEDs. The devices are equipped with long-life batteries and have features that notify the users when battery replacement is needed.
Who's Using Them?
Most professional football and basketball teams have AEDs on the sidelines, according to AED manufacturers, and the devices are becoming more common in professional baseball dugouts. A number of college teams, including at least 12 schools in the Southeastern Conference, have purchased AEDs, and I expect use to increase in high school sports. The school board in Jackson County, West Virginia, purchased AEDs for the county's two high schools after a baseball player in an adjacent county died following a hit in the chest by a baseball.
AEDs are also showing up in other sports settings, according to AED industry sources, including golf courses and ski hills. Health clubs that cater to cardiac rehabilitation patients already have defibrillators.
Though the use of AEDs in the sports setting is growing, several issues related to their use have not been fully resolved.
Efficacy. Because no efficacy study addresses sports-related AED use, such use is not yet part of any group's official recommendations.
One of the larger efficacy studies to date comes from an airline experience (4). In 1991 Quantas Airlines installed AEDs in its international terminals and on all aircraft flying its 55 international routes. Over a span of 64 months, the AEDs were used in 46 cardiac arrests—27 on aircraft and 19 in terminals. All arrests in terminals were witnessed. Ventricular fibrillation occurred in 17 cases, and defibrillation was successful in 16.
Of 6 aircraft passengers who had cardiac arrests that were witnessed, all were in ventricular fibrillation; 5 were successfully defibrillated. In witnessed cardiac events, the time from collapse to defibrillation averaged just 38 seconds. The patients in this study who were in ventricular fibrillation would have died without defibrillation. Unwitnessed cardiac arrest on airplanes may occur when the individual is thought to be sleeping. These prolonged asystolic conditions do not respond to defibrillation.
In an analysis of AED efficacy in 12 EMS systems (5), 44 instances of ventricular fibrillation occurred over 8 months. A single 150-joule biphasic shock defibrillated the patient in 39 cases. Four others responded to three or fewer shocks. These results were impressive, considering the time from the 911 call to the first shock averaged 8.2 minutes.
The Rochester, Minnesota, police department has placed AEDs in all squad cars. Among patients with ventricular fibrillation who underwent early defibrillation by police, 58% survived to discharge, vs 26% who survived after defibrillation by later-arriving paramedics (6).
Safety. The potential side effects of defibrillation include cell membrane damage, postshock arrhythmias, and postdefibrillation ST-segment depression on the electro-cardiogram. Any of these side effects is minor compared to the benefit of a life saved. The risk of side effects is expected to be less with biphasic AEDs because they achieve defibrillation with less energy (150 joules vs 200 to 360 joules). More studies are needed to determine if the biphasic device is as effective as the monophasic device and has fewer adverse effects.
Obviously, the laypeople who use the device need proper AED and CPR training to avoid inappropriate resuscitation attempts. In February 1999 the AHA and the National Safety Council will launch a new cardiopulmonary resuscitation (CPR) program—Heartsaver FACTS (first aid, automatic external defibrillator, CPR training system)—that incorporates AED training. An inappropriate shock from an AED could trigger ventricular fibrillation, though this can be reversed with a second shock. To prevent human error, all machines have computers that evaluate heart rhythm and decide if deployment is appropriate. AED users will also need yearly training on use of the device and on CPR.
Another concern might be machine malfunction, but the literature does not appear to report instances of misfiring.
Cost-effectiveness. Are AEDs cost-effective? Only future randomized, controlled trials—for example, a study involving office buildings with and without on-site AEDs—can say, and cost-effectiveness studies in a sports setting have not been done. One estimate, using a decision model, suggested that AED use by lay personnel had a median incremental cost of under $50,000 per additional quality-adjusted life-year saved (7), putting it in the range of some commonly accepted diagnostic and therapeutic cardiovascular procedures. Cost-effectiveness data may come from the Buckhead Coalition, an Atlanta business group that has placed at least 40 AEDs in large office buildings throughout Atlanta and has trained security guards to use them.
Liability issues. A recent AHA report on AED use by laypeople encourages states to address liability concerns by incorporating defibrillation into "Good Samaritan" laws (8). At present, 22 states have done so.
A Worthwhile Clinical Leap
Clearly, some questions about the use of AEDs remain to be settled. Nonetheless, given my own experience and that reported by others, I believe that AEDs should be in the medical bags of team physicians and athletic trainers and in sports arenas, health clubs, large office and apartment buildings, homes of certain high-risk cardiac patients, and maybe even in physicians' cars. If the cost can be reduced and field tests remain impressive, AEDs might become as common as fire extinguishers.
In medicine you can never have absolute certainty that treatment will prolong a patient's life. Yet there have been developments, such as penicillin, that through the years were immediately and obviously effective, even without the backing of efficacy studies. I believe the AED is one of those developments.
Dr Cantwell is a cardiologist at Cardiology of Georgia, PC, and clinical professor of medicine at Morehouse School of Medicine, both in Atlanta. He is an editorial board member of The Physician and Sportsmedicine. Address correspondence to John D. Cantwell, MD, Cardiology of Georgia, PC, 95 Collier Rd NW, Suite 2075, Atlanta, GA 30309.
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