MONDAY, Nov. 15 (HealthDay News) -- Although automated external
defibrillators have been found to reduce heart attack death rates
in public places such as restaurants, malls and airplanes, they
have no benefit and, paradoxically, seem to increase the risk of
death when used in hospitals, a new study suggests.
The reason may have to do with the type of heart rhythms
associated with the heart attack, said researchers publishing the
study in the Nov. 17 issue of the
Journal of the American Medical Association, who are also scheduled to present their findings Monday at the American Heart Association (AHA) annual meeting in Chicago.
And that may have to do with how sick the patient is.
The authors only looked at hospitalized patients, who tend to be
sicker than the average person out shopping or attending a sports
event. In those settings, automated external defibrillators (AEDs),
which restore normal heart rhythm with an electrical shock, have
been shown to save lives.
"You are selecting people who are much sicker, who are in the hospital. You are dealing with heart attacks in much more sick people and therefore the reasons for dying are multiple," said Dr. Valentin Fuster, past president of the AHA and director of Mount Sinai Heart in New York City. "People in the street or at a soccer game are much healthier."
In this analysis of almost 12,000 people, only 16.3 percent of
patients who had received a shock with an AED in the hospital
survived versus 19.3 percent of those who didn't receive a shock,
translating to a 15 percent lower odds of surviving.
The differences were even more acute among patients with the
type of rhythm that doesn't respond to these shocks. Only 10.4
percent of these patients who were defibrillated survived versus
15.4 percent who were not, a 26 percent lower rate of survival,
according to the report.
For those who had rhythms that do respond to such shocks,
however, about the same percentage of patients in both groups
survived (38.4 percent versus 39.8 percent).
But over 80 percent of hospitalized patients in this study had
non-shockable rhythms, the study authors noted.
In public settings, some 45 percent to 71 percent of cases will
respond to defibrillation, according to the study authors.
The disparity in survival is quite possibly due to the fact that
valuable time that could have been spent resuscitating the patient
with other methods is instead wasted on deploying an AED.
"The more time you waste during resuscitation using ineffective procedures, the more likely you are to have adverse outcomes," said Dr. Jeffrey S. Borer, chair of the department of medicine and of cardiovascular medicine at the State University of New York Downstate Medical Center in New York City.
"The importance of chest compression to maintain circulation has gained greater importance in the view of researchers in the field recently, and training in resuscitation has just begun to incorporate these new concepts," he continued. "The capacity to perform efficient resuscitations is not universally available among hospital personnel and the use of AEDs therefore might be expected to be less efficient among most hospital personnel. Even if an AED could be effectively used by an appropriately trained person, it could be ineffectively used by everyone else."
Hospitals across the nation are installing these portable AED
heart-shockers intending to boost survival rates among heart attack
According to background information in the study, upwards of
50,000 AED units were sold to U.S. hospitals between 2003 and 2008
with market growth expected to continue shooting up. More than
one-third of the 550 hospitals included in this study had AEDs.
"A lot of money is being spent and the resuscitation rate is truly significantly lower among patients in whom AEDs are deployed in hospitals," Borer said. "We have to rethink seriously the way resuscitations are being carried out in hospitals, who uses what when. The study certainly is of sufficient concern so that it should lead to studies that are designed to evaluate this issue in a more appropriate, comprehensive way."
American Heart Association has more on automated
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
Copyright © EBSCO Publishing. All rights reserved.