New emergency treatment for out-of-hospital cardiac arrest found to significantly improve patient's chance of survival

Wednesday, March 12, 2008

SCOTTSDALE, Ariz. – For more than 250,000 Americans each year, it's the worst possible scenario. While simply walking down the street, without any warning sign, you suddenly collapse to the ground and begin uncontrollable shaking and gasping for air. You are experiencing cardiac arrest, and even worse, you are stricken far from a hospital or doctor.

How serious is the danger? According to a study published in the March 12 issue of the Journal of the American Medical Association (JAMA), your fears are well grounded. Cardiac arrest experienced outside a hospital setting is now a major public health concern, and survival is uncommon. In 2004, an estimated 97 percent of people suffering cardiac arrest in Arizona did not survive.

Fortunately, the study strikes a more optimistic note for the future. Authored by Bentley J. Bobrow, M.D., Mayo Clinic Department of Emergency Medicine, the study examined a new life-saving procedure taught to emergency medical services (EMS) providers. The procedure is called Minimally Interrupted Cardiac Resuscitation, also known as Cardiocerebral Resuscitation (CCR), and is not only easy to train and administer, it is significantly more likely to save your life.

The JAMA paper reports the results of EMS providers trained in CCR, compared with those receiving standard advanced life support in Arizona. The survival-to-hospital discharge rate tripled, from 1.8 percent in the control group, to 5.4 percent in the CCR-trained group. Further, in a subgroup of patients with ventricular fibrillation where chances of success are highest, the survival rate increased from 4.7 percent to 17.6 percent.

"Cardiac arrest is a disease where we have not seen an improvement in survival in more than 25 years, and CCR has shown it can triple the current rate," confirms Dr. Bobrow, principal investigator of the study and Medical Director of the Arizona's Bureau of Emergency Medical Services and Trauma System.

CCR involves delivering a series of rapidly applied chest compressions — without pausing for mouth-to-mouth resuscitation. In most occurrences of witnessed cardiac arrest, over-ventilation is common and decreases the chance of successful resuscitation.

The advantage of CCR over traditional CPR is that it better maintains steady blood flow to the heart and brain during resuscitation. This is important to survival, as well as obtaining a favorable neurological outcome. It also minimizes the danger of over-ventilation, which increases intra-thoracic pressure in the chest that can endanger critical blood flow back to the heart.

"During cardiac arrest, the hands of the EMS provider become the patient's heart," said Dr. Bobrow.

CCR was developed years ago by the Resuscitation Research Group at the University of Arizona Sarver Heart Center in Tucson, Ariz., led by Gordon A. Ewy, M.D., who co-authored the JAMA study.

"This was truly a collaboration among public health, emergency medical providers and medical researchers" said Dr. Bobrow. "One of the missions of Mayo Clinic is to save lives, and this is one of the ways we do it. If we can get the survival rate to 20 percent, we could save tens of thousands of lives a year."

For the study, EMS personnel were trained to administer an initial series of 200 uninterrupted chest compressions over a period of approximately two minutes, then perform standard rhythm analysis and administer a single electrical shock, if indicated. Another 200 compressions are immediately performed, and the cycle is repeated three times. EMS workers also administered Epinephrine intravenously as soon as possible and with each cycle of chest compressions.

The study analyzed reports from 886 patients treated by trained EMS professionals over two and a half years. The data came from 62 EMS agencies in Arizona that covered 75 percent of the state. The study excluded children and cardiac arrests secondary to trauma, drowning or other non-cardiac causes.

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Mayo Clinic is the first and largest integrated, not-for-profit group practice in the world. As a leading academic medical center in the Southwest, Mayo Clinic focuses on providing specialty and surgical care in more than 65 disciplines at its outpatient facility in north Scottsdale and at Mayo Clinic Hospital. The 244 licensed-bed hospital is located at 56th Street and Mayo Boulevard (north of Bell Road) in northeast Phoenix, and provides inpatient care to support the medical and surgical specialties of the clinic, which is located at 134th Street and Shea Boulevard in Scottsdale.

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