March 12, 2008

New CPR Technique Triples Survival Rates

Researchers in Arizona reported that three times as many people survived a cardiac arrest when a new method of resuscitation, which involves a series of 200 chest compressions followed by defibrillator shock, was implemented.   

"Cardiac arrest is incredibly common and survival is poor," said Dr. Bentley Bobrow, medical director for emergency services for the state of Arizona and a researcher at the Mayo Clinic in Scottsdale.   

The new resuscitation method, which is not intended for bystanders, increases blood flow to the heart and brain after cardiac arrest stops the heart from pumping blood.

"Even if you could improve survival by a few percentage points, you will save thousands of people across the country," said Bobrow, the study's lead author.

Experts say the most helpful thing bystanders can do for someone suffering a cardiac arrest is to give chest compressions while awaiting an ambulance.

Cardiac arrest occurs when the heart stops circulating blood.  People with cardiac arrest typically have ventricular fibrillation, a deadly heart rhythm in which the heart quivers but does not pump blood. It is during this phase that old-fashioned chest compressions can help push blood back into the heart, making it more likely to restart.  If shock is not delivered within the first four minutes, the heart may stop altogether and resuscitation becomes much more difficult.

Since most emergency teams do not arrive on scene within four minutes, the new resuscitation approach calls for a round of 200 chest compressions within the first two minutes to increase the odds the heart will restart.

"Traditionally, we've told them to defibrillate right away. When they do that, the patient dies frequently," Bobrow said in a Reuters telephone interview.

Only 3 percent of people in Arizona who had a cardiac arrest outside of a hospital survived in 2004. Bobrow wanted to improve the statistics. He and his team studied the use of minimally interrupted cardiac resuscitation, also known as cardio cerebral resuscitation, a highly sequenced form of CPR performed by emergency medical workers.

After the first 200 compressions, the patient gets a shock, then a different worker provides another 200 chest compressions. At that point, shots of epinephrine may be given to stimulate the heart, followed by a tube insertion into the trachea to ventilate the lungs.

The method aims to continuously pumping blood to the heart and brain.

During the study, Bobrow's team trained emergency workers in two Arizona city fire departments, then compared the survival data from 2005 to 2007 for 886 cardiac victims before and after the procedure was implemented.

The analysis showed the rate of people who lived long enough to be discharged from the hospital was 1.8 percent before the training and 5.4 percent after the new procedure began being used.  The benefit was greatest for those who had ventricular fibrillation with a shockable rhythm, with survival rates jumping from 4.7 percent to 17.6 percent among the group.

In a commentary to the study's report, Dr. Mary Ann Peberdy of Virginia Commonwealth University in Richmond said the findings suggest the need for a back-to-basics approach to cardiopulmonary resuscitation.

"We are learning more and more that we can't get sloppy on how we do CPR," she wrote.


On the Net:

The study was reported in the Journal of the American Medical Association

Mayo Clinic