LOS ANGELES -- People who suffer cardiac arrest are more likely to survive if they are in a casino or airport than if they are in a hospital, researchers said today.
Doctors already knew that more than half of those who suffer such attacks in airports and casinos survive. But a new study shows that only a third of victims in hospitals survive -- primarily because patients do not receive life-saving defibrillation within the recommended two minutes.
Nearly 40% of hospital patients who received defibrillation within two minutes survived, compared with 22% of those for whom the response took longer, researchers reported in the New England Journal of Medicine.
As many as 750,000 people suffer such attacks in hospitals every year in the United States, and a quarter of a million suffer them outside hospitals.
"It is probably fair to say that most patients assume -- unfortunately, incorrectly -- that a hospital would be the best place to survive a cardiac arrest," USC cardiologist Leslie Saxon wrote in an editorial accompanying the report.
People who suffer cardiac arrest in the middle of an airport or casino -- where defibrillators are widely available -- are typically noticed immediately, whereas a lone patient suffering an attack in a hospital room may not be noticed for much of the crucial window of opportunity during which defibrillation is most effective.
The odds of survival are even lower in hospitals with fewer than 250 beds, and on nights and weekends, according to the study by Dr. Paul S. Chan of Saint Luke's Mid-America Heart Institute in Kansas City, Mo., and Dr. Brahmajee K. Nallamothu of the University of Michigan.
At least part of the apparent discrepancy arises because hospital patients are sicker to begin with, whereas those who suffer attacks in airports and casinos generally don't have underlying illnesses or symptoms, said UCLA cardiologist Gregg C. Fonarow, who was not involved in the study.
Nonetheless, he said, hospitals can do more to shorten the time before defibrillation is administered.
Defibrillation is used when patients suffer either ventricular fibrillation or ventricular tachycardia. In the first case, the heart beats abnormally or intermittently; in the second, it beats extremely rapidly. In both cases, the result is the same: an inability to pump blood through the body effectively.
Applying a shock to the heart often restores normal heart rhythm. Devices found in public places, called automated external defibrillators, can be used by trained laypeople to quickly treat the condition.
Guidelines developed by major heart organizations call for defibrillation within two minutes after the onset of an attack, but there is little hard data to support the need for a rapid response, the authors wrote.
To obtain such data, they used information from the National Registry of Cardiopulmonary Resuscitation, a voluntary registry in which 369 U.S. hospitals -- about 15% of the total -- report all attempts at in-hospital resuscitation and their outcomes.
Excluding patients who were undergoing surgery or other procedures, as well as those with implanted defibrillators, researchers identified 6,789 patients who were candidates for defibrillation.
About half received defibrillation within one minute, but a full 30% of cases took at least two minutes, with some patients going as long as six minutes before receiving treatment. The longer the time that elapsed before treatment, the less likely the patient was to survive, they reported.
"We found that delayed defibrillation was common, and that rapid defibrillation was associated with sizable survival gains in these high-risk patients," Chan said.
In addition to the size of the hospital and time of day, patient characteristics played a role.
For reasons that are not clear, black patients were less likely to receive the treatment within the two-minute window. Patients who were not attached to a heart monitor and those admitted for conditions not involving heart disease were also less likely to receive the quickest treatment.
The problem may actually be understated, researchers added, because only the best hospitals are likely to be participating in the registry.
Several things can be done to improve the chances of a good outcome, experts said. Wider use of automated external defibrillators in hospitals, for instance, would allow nurses to begin the procedure rather than waiting for physicians, Saxon said. Increased use of wireless heart telemetry would also speed up detection of attacks.
Some cures may be even simpler, Fonarow said, such as storing defibrillators in more accessible locations and reconfiguring hospital rooms so the devices can be more readily email@example.com