Guidelines Suggest When Resuscitation Works for Cardiac Arrest

Only about 1 percent of victims survive an attack, study says

WEDNESDAY, Aug. 2, 2006 (HealthDay News) -- Guidelines to help emergency-medical technicians (EMTs) decide whether or not to end resuscitation efforts for patients having cardiac arrest outside of a hospital have been devised by Canadian researchers.

"This clinical decision rule would help with guiding physicians and paramedics on which patients had the greatest chance for surviving out-of-hospital cardiac arrest," said study lead author Dr. Laurie Morrison, associate professor of emergency medicine at the University of Toronto.

"Most people die in out-of-hospital cardiac arrest," she said. "The survival rate is very low, and we want to be able to identify where further resuscitation is futile and where we could instead support the family.

"For those that survival is a possibility, we want to get them to the emergency department," Morrison added.

The guidelines, published in the Aug. 3 issue of the New England Journal of Medicine, aren't the final word, said Dr. Jose Martinez, assistant professor of clinical medicine at the University of Miami Miller School of Medicine. "As technical and medical knowledge evolve, we are modifying guidelines on how to proceed," he said. "This adds a bit more to our armamentarium."

Practically speaking, guidelines depend on a number of factors, including cost and geographic region.

Cardiac arrest is the sudden, abrupt loss of heart function. The victim may or may not have diagnosed heart disease, according to the American Heart Association.

According to an accompanying editorial in the journal by Dr. Gordon A. Ewy, of the University of Arizona Health Sciences Center, overall survival of out-of-hospital cardiac arrest in large U.S. cities is only about 1 percent, the rate "that has been suggested to define medical futility."

Guidelines are currently already in place for advanced-level paramedics, but not for emergency-medical technicians (EMTs) trained in the use of automated external cardiac defibrillators, which shock a heart back into a normal rhythm. As a result, many patients who have little or no chance for survival are nevertheless taken to emergency departments.

The new study states that several cities in the United States have emergency medical services systems that consisted entirely or partially of EMTs trained in this way.

According to the study, three factors identified patients who did not survive out-of-hospital cardiac arrest:

  • no return of spontaneous circulation before transportation began;
  • no shock given before transportation;
  • the cardiac arrest was not witnessed by EMS personnel.

The suggested guidelines would recommend termination of resuscitation if these three factors were in place.

The researchers looked at the records from 24 emergency medical systems in Ontario, Canada. All patients aged 18 and older who had presumed cardiac arrest and were treated by EMTs trained in the use of an automated external defibrillator were included.

Follow-up data was available for all 1,240 patients.

The guidelines recommended termination of life-saving efforts for 776 patients, four of whom (0.5 percent) survived. The rule was correct 90.2 percent of the time in recommending that a patient be transported to the emergency room. It correctly predicted death 99.5 percent of the time when termination was recommended.

"There's still a small percentage of survivors not protected by the rule, so ethical and social issues come into play," Martinez pointed out. "Is it worthwhile to miss a possible opportunity?"

If the rule were implemented, only 37.4 percent of patients would be transported to an emergency room, as opposed to 100 percent now.

Morrison outlined several arguments in favor of implementing the guidelines.

"If the situation is futile, you want to turn resources towards the family," she said.

Also, if "futile resuscitations" are transported to an emergency room, emergency staffers have to divert their attention from more viable cases. In the meantime, families who have raced to the hospital behind the ambulance end up having to grieve in a very public and busy place.

High-speed transport is also risky. It puts pedestrians, other drivers and the ambulance staff at risk for motor vehicle accidents. Paramedics also run the risk of exposing themselves to HIV or hepatitis while trying to perform invasive procedures in a vehicle going up to 100 mph, the researchers said.

More information

For more on cardiac arrest, visit the American Heart Association.

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