October 25, 2002

New study shows public defibrillators useful

Think defibrillators are only for use by professional medics, or at least television actors? Think again.

A new report co-authored by a University doctor tracked the placement and use of public defibrillators in Chicago airports and concluded that passers-by—including people unfamiliar with formal medicine—would use the machines to help resuscitate victims of cardiac arrest.

"A surprising number of people were saved by individuals with no formal training," said Lance Becker, a professor in clinical medicine. "Our national strategy has been to advise that no one is to touch these devices unless they are properly trained. This study rejects that widely—held notion."

The significance of the study lies in the fact that cardiac arrest is a time-sensitive killer; permanent brain damage begins about four minutes after an episode, and the chances of increased damage or death rise 10 percent with each passing minute a victim is not administered cardiopulmonary resuscitation (CPR) and defibrillation, or an electric shock, to jumpstart the heart.

Cardiac arrest, which is caused by heart attacks, heart disease, and accidents, is the leading cause of death in the United States with 250,000 deaths per year. Currently, about 95 percent of untreated cardiac arrest victims die before they reach the hospital.

According to the American Heart Association, a proliferation of external defibrillators, along with increased instances of bystander CPR, would save at least 40,000 lives each year.

The two-year study was the first of its kind. It monitored the use of multiple portable defibrillators placed in visible locations at regular distances from each other—close enough to be reached within a minute's walk—in O'Hare, Midway, and Meigs Field airports, which have a combined yearly flow of over 100 million passengers.

About the size of a laptop computer, the defibrillators carried both written and oral instructions, and were automated to decide, based on heart rate measurements, whether or not to administer shock treatment to the victims.

In the 18 cases of non-traumatic cardiac arrest during the study, 11 patients were successfully treated using the automated defibrillators, three were treated within five minutes of attack but died nonetheless, and four, who were not treated within the five-minute window, also died.

The defibrillators correctly refused to administer shock to four patients whose medical conditions were mistaken for cardiac arrest.

Six of the 11 bystanders who administered shock had no experience with defibrillators.

But the threat of lawsuits arising from misuse of the potentially life-altering machinery by inexperienced strangers is one of the reasons that defibrillators have yet to appear in every gas station, shopping center, and movie theater.

"Not every bystander is going to be able to use this device," Becker said.

"The real key is finding the optimal settings—those places that are probably going to have bystanders able to perform the process. If there are a hundred untrained people in an area, someone will be able to use the device correctly. But putting one in a supermarket might not work well."

Cost is another issue in determining placement of public defibrillators. In the airport study, the cost per life saved was $30,000 to $40,000 dollars, a reasonable figure in terms of the medical industry, but a cost only achievable by dint of the huge volume of human traffic circulating through the airports.

"At O'Hare it's cost-effective," Becker said. "It's not necessarily cost-effective to put a defibrillator in a 7-Eleven."

Even with all the debate over cost-effectiveness, automated defibrillators are beginning to spring up across America. The city of Anaheim just completed installation of the devices in all city buildings, and, as of October, CVS pharmacies began selling them online with a doctor's prescription.

The next step in the quest to maximize the number of lives saved by defibrillators, Becker said, is coming to understand how the devices can be brought into private homes, where 80 percent of cardiac arrest cases occur.

"The real question mark is going to be the home," he said. "Right now, our nation definitely just doesn't have strategy for putting defibrillators into the home."