Study Supports Public Health Policies that Increase Access to AEDs
November 5, 2007–ORLANDO–Researchers now have evidence that at least 522 lives can be saved annually in the United States and Canada by the widespread placement of automated external defibrillators (AEDs).
Results of the study, “Bystander-administered AED shock improves survival from out-of-hospital cardiac arrest in the U.S. and Canada,” were presented today at the American Heart Association’s annual Scientific Sessions in Orlando. The findings are among the first conclusions to emerge from a landmark series of studies, known as the Resuscitation Outcomes Consortium (ROC) Trial, designed to reveal the best lifesaving techniques for cardiac emergencies.
According to the ROC team, use of AEDs by random bystanders more than doubled survival rates among victims felled by sudden cardiac arrest (SCA) due to a heart attack or errant heart rhythm. SCA victims treated immediately by bystanders with cardiopulmonary resuscitation (CPR) and an AED were more likely to survive to hospital discharge than victims whose access to defibrillation was delayed until emergency medical services providers could arrive at the scene. Previous research has shown that time is critical in saving SCA victims: For treatment to be effective, it must be provided as rapidly as possible—within five minutes of SCA.
“Our results were emphatically clear,” said principal investigator, Myron “Mike” L. Weisfeldt, M.D., a cardiologist at The Johns Hopkins University School of Medicine. “Good Samaritans, when given access to automated defibrillators in potentially fatal emergencies, save lives.”
The study encompassed 11 urban and rural sites in the U.S. and Canada, covering a population of about 20 million. The analysis included 9,897 non-traumatic, out-of-hospital cardiac arrests that occurred over a one-year period and were evaluated by emergency medical services personnel. If results from the study population of 20 million are extrapolated to the general population of the United States and Canada (roughly 360 million), an estimated 522 lives are saved.
About a third of study subjects (30.4 percent) received CPR from a bystander. For 2.5 percent of the patients (249), the bystander used an AED whether a shock was administered or not. The people using the defibrillator typically had received training of some sort. The largest proportion (42 percent) consisted of health care workers, 30 percent were lay volunteers, and 23 percent were on- or off-duty police officers.
About half of the incidents occurred in public places. These included:
26% in public buildings.
24% in places of recreation.
12% in industrial settings.
10% on the highway, which were almost certainly performed by police officers.
29% in other public places.
Locations where cardiac arrest rescues occurred in private spaces included:
42% in homes, condos, or apartment buildings.
30% in nonhospital health care facilities.
25% in residential institutions, such as nursing homes.
Although no data were available on the neurological condition of patients at hospital discharge, broader experience suggests 95 percent of patients who survive leave the hospital in good to excellent neurological condition, Weisfeldt added.
The findings support broad deployment of AEDs in public spaces where large gatherings occur, such as senior care facilities, hospitals, sports stadiums, community centers, shopping malls, airports, and the lobbies of large hotels and office buildings.
“This is a serious matter of public health policy and similar to previous discussions about placing fire extinguishers near building exits, wearing seat belts while driving, or manufacturing cars with airbags,” said Weisfeldt, the William Osler Professor of Medicine at Hopkins and past president of the American Heart Association (AHA). “Government, community and business leaders need to carefully consider increased access to automated external defibrillators when making healthy public policy.”
“This research is the closest thing to the real-world experience of life-threatening, sudden cardiac death that we have,” says Weisfeldt. “There is no downside risk to using the defibrillators,” Dr. Weisfeldt concluded.
The ROC study, set to continue through 2010, is funded by the U.S. National Heart and Lung and Blood Institute, a member of the National Institutes of Health.
Other researchers involved in this study were Tom Terndrup, M.D., at the University of Alabama in Birmingham; Ahamed Idris, M.D., at the University of Texas Southwestern Medical Center in Dallas; Richard Kerber, M.D., at the University of Iowa Carver College of Medicine in Iowa City; Tom Aufderheide, M.D., at the Medical College of Wisconsin in Milwaukee; Ian Stiell, M.D., at the University of Ottawa in Ontario, Canada; Jim Christenson, M.D., at the University of British Columbia in Vancouver, Canada; Cliff Callaway, M.D., Ph.D., at the University of Pittsburgh Medical Center; Jerris Hedges, M.D., M.S., at Oregon Health & Science University in Portland; David Hoyt, M.D., at the University of California, San Diego; Peter Kudenchuk, M.D., at the University of Washington in Seattle; and Arthur Slutsky, M.D.; Laurie Morrison, M.D.; and Paul Dorian, M.D., at the University of Toronto in Ontario, Canada.
For more information, visit (https://roc.uwctc.org).
Sources: American Heart Association, The Johns Hopkins University School of Medicine