As the recent death of Michael Jackson has shown, few patients in cardiac arrest survive, even when given CPR by a trained health professional. Now, a large analysis shows that survival rates for seniors in cardiac arrest have not improved much in the last decade.
The study, published in Thursday’s New England Journal of Medicine, looked at almost 435,000 U.S. seniors treated for cardiac arrest. Only about 18 percent of the patients lived long enough to leave the hospital, researchers found.
“Although significant efforts have been made to improve CPR, we found… no significant change in survival,” said the study’s lead author, Dr. William Ehlenbach, a senior fellow at the University of Washington in Seattle.
Cardiac arrest occurs when the heart stops beating entirely or only quivers uselessly, because of a heart attack or other cause such as a drug overdose.
Cardiopulmonary resuscitation, which involves rhythmic chest compressions, can help maintain blood pressure and flow until more advanced treatments can be tried. Those might involve using a defibrillator to shock the heart back into a normal rhythm.
When patients are otherwise healthy, CPR can often be successful. Indeed, survival rates for out-of-hospital cardiac arrest have improved in recent years because of more widespread use of CPR by bystanders, and the use of automated external defibrillators.
But this study found that rates of in-hospital cardiac arrest are not improving.
Researchers led by Dr. William Ehlenbach at the University of Washington in Seattle analyzed the care of 433,985 Medicare patients over the age of 65 treated from 1992 through 2005. Survival odds did not substantially change over time, they found.
Blacks had survival rates about one-quarter lower than whites. Men, older patients, and people admitted from nursing homes also had lower survival rates after CPR.
“Some, but not all, of the racial difference in survival appears to be attributable to the hospitals where patients receive care, since black patients more often receive care at hospitals where patients of all races have lower odds of survival after CPR,” the authors note.
The researchers suggest there could be a number of reasons for the findings. For one, they note there have been changes in the severity of the underlying illnesses that cause cardiac arrest.
“Although all patients who require CPR have severe acute illness by virtue of needing CPR, there may be differences in the type or severity of the acute illness leading to CPR that could influence outcomes,” they write.
They also suggest it’s possible that more patients who are poor candidates for resuscitation are being given CPR. They note that while do-not-resuscitate (DNR) orders became more common during the 1980s, they have either become less common since then or have not effectively decreased the use of CPR to patients who are unlikely to benefit.
One other factor that may have affected their findings was that many people who survive CPR may not be discharged home and may be instead transferred to longer-term care facilities.
Source: Epidemiologic Study of In-Hospital Cardiopulmonary Resuscitation in the Elderly, William J. Ehlenbach, M.D., M.Sc., Amber E. Barnato, et. a., NEJM, Vol. 361:22-31, July 2, 2009