American Heart Association guidelines recommend that patients receive the shocks within two minutes. In a study of medical records from 6,789 patients at 369 hospitals around the country, researchers found that hospital staff failed to administer the shocks quickly enough 30.1 percent of the time.
The delays made a difference -- 39 percent of people who got the treatment quickly survived, compared with only 22.2 percent of those whose treatment was delayed. Overall, 34 percent of the patients in the study survived to leave the hospital.
That's less than the 50 percent survival rate of people who go into cardiac arrest in an airport, casino or other location where portable defibrillators are available, according to an editorial that accompanied the study.
That difference in survival rate may be partially attributable to the fact that patients in hospitals are generally weaker or sicker than those who go into cardiac arrest outside of hospitals. However, it's also because doctors and public health officials have focused for several years on making the automated defibrillators -- which can be used even by bystanders with very little training -- available in public areas.
"Most patients assume -- unfortunately, incorrectly -- that a hospital would be the best place to survive a cardiac arrest," wrote Dr. Leslie Saxon, of the University of Southern California, in the editorial. "Surely we can do better to fulfill this expectation by better using existing technology."
The researchers, led by Dr. Paul Chan of St. Luke's Mid America Heart Institute in Kansas City, Mo., also found that delays were more likely among patients who had been admitted for non-cardiac illnesses; in hospitals of less than 250 beds; and when the cardiac arrests happened at night and on weekends, when fewer doctors were on duty.
Black patients were also more likely to get delayed treatment, although the researchers said that difference was probably due to differences in the types of hospitals where black and white patients were admitted.
Dr. Charles Pozner, director of pre-hospital care at Brigham and Women's Hospital in Boston, told Bloomberg News that many delays occur when nurses and other staff members must wait for a doctor to arrive before administering the shocks. The defibrillators available in hospitals are often not the automated kind available in public areas, and require training to use.
"The worst problem is when you have a patient in with a sprained ankle in some part of the clinic where you have no expectation of something happening," W. Frank Peacock, vice chief of emergency medicine at the Cleveland Clinic, told Bloomberg News.
Nationwide, the problem may be even worse than the study indicates, study author Chan told the New York Times, because the hospitals in the study had all joined a national registry on cardiac arrest and were making a specific effort to meet cardiac resuscitation guidelines.
Chan told the Wall Street Journal that he hopes the article will encourage discussion on the best ways for hospitals to improve their statistics. Possible measures include allowing nurses to administer shocks with manual defibrillators, installing automatic defibrillators in all hospital rooms, and creating centralized systems that automatically monitor patients' heart rates.