July 16, 2012
Post Cardiac-Arrest Deaths On The Decline
Brett Smith for redOrbit.com - Your Universe Online
Patients who arrive at a hospital in a state of cardiac arrest have a better chance for survival than a decade ago, according to a new study in the journal Circulation.
While the report was unable to identify a particular reason for the improvement, researchers suspect a combination of changes, including the way hospitals treat cardiac arrest and the increased awareness of those witnessing someone suddenly collapse from the attack.
Using the 2001-2009 U.S. National Inpatient Sample (NIS), a national hospital discharge database, researchers found that the death rate among Americans hospitalized after cardiac arrest was just under 58 percent, down from almost 70 percent in 2001.
The study noted that because the numbers account only for patients who survive long enough to be admitted to the hospital, the figures reflect hospital treatment and not overall survival rates. Of the more than 300,000 Americans who have a heart attack outside of a hospital each year, less than 8 percent survive.
"But the study does have a clear message," senior researcher Alejandro A. Rabinstein, of the Mayo Clinic told Reuters Health. "If you have a cardiac arrest and you get to be hospitalized, your chances of surviving the hospitalization are getting better."
One of the few advances that has been made in treating cardiac arrest over the course of the study is that experts now recommend that bystanders do "hands-only" CPR. The new way of performing the life-saving technique does not involve mouth-to-mouth breathing and is believed to be easier for the average person to perform; increasing the odds that they will perform CPR on a stranger.
The proliferation of automated external defibrillators (AEDs) along with the proper training surrounding their use may have also contributed to increased survival rates, according to the study.
In addition to increased awareness by potential by-standers, several treatments adopted by hospitals may have also played a role in survival rates.
The increased use of angioplasty soon after patients arrive at the hospital, which has become a more common practice in recent years, may be helping, according to Rabinstein.
He also suspects that a revolutionary treatment for people who remain comatose after cardiac arrest is making a difference. Notably, the rising survival rate for cardiac arrest victims in the study occurred at the same time hospitals started using therapeutic hypothermia.
Therapeutic hypothermia involves cooling the patient's body using cold IV saline, cooling blankets or ice packs and returning the patient´s core temperature to normal a day later.
When a cardiac arrest stops circulation, the brain is the first organ to require oxygen. While a lack of oxygen endangers the brain, the real trouble starts when the heart is shocked back to life and starts flooding the brain with fresh oxygen. The brain´s cells respond by firing up their activity so much it becomes toxic. This electrochemical chain reaction overloads and destroys many cells in the process.
"The effect of therapeutic hypothermia is mainly improving survival with (brain) function, rather than survival itself," Rabinstein told Reuters reporter Amy Norton.
Despite evidence pointing to the success rate of the new treatment, hospitals have not been quick to adopt therapeutic hypothermia.