DALLAS (AP) - The American Heart Association and other experts are recommending doctors chill comatose victims of cardiac arrest to help prevent brain damage.
An endorsement published this week in the heart association journal Circulation cites recent studies that showed that cooling the body just a few degrees - to between 89.6 and 93.2 - improves the patient's chances of recovery.
The cooling can be done through such means as ice packs and cold air.
"It's a very big breakthrough," said Dr. Robert Hickey, a co-author of the endorsement and an emergency medicine pediatrician at Children's Hospital of Pittsburgh. "For every six or seven patients treated with hypothermia, there will be one more survivor and one more person living at home and returning to work than would have occurred if hypothermia were not used."
People who suffer cardiac arrest can often be saved if the heart is restarted with an electric shock. But the challenge is how to arrest the brain damage that begins minutes after blood flow stops.
Cooling reduces the brain's need for oxygen while suppressing the chemical processes that kill brain cells.
Doctors have known for a long time that reducing a person's body temperature before the heart stops, such as when open-heart surgery is performed, can help prevent brain damage.
In fact, cooling for cardiac arrest - though at much lower temperatures - was tried in the 1950s. But it was abandoned because of serious side effects. Even the milder cooling carries a slightly increased risk of bleeding, infection and abnormal heart rhythms.
Studies by researchers in Europe and Australia - reported last year in the New England Journal of Medicine - prompted the endorsement by the International Liaison Committee on Resuscitation's Advanced Life Support Task Force. The task force includes the heart association.
"What is so exciting about these new studies is that they showed that even if we cooled the brain after the oxygen supply had been cut off, people did better," said Dr. Jerry P. Nolan, the group's lead author. He is a consultant in anesthesia and critical care medicine at the Royal United Hospital in Bath, England.
The cooling should be started as soon as possible after successful resuscitation and continued for 12 to 24 hours, Nolan said.
In the European study of 275 patients, half were chilled with circulating cold air and ice packs from a normal 98.6 degrees to between 89.6 and 93.2 degrees for 24 hours. Fifty-five percent of the cooled group had a favorable outcome compared with 39 percent of the group that did not get the treatment. The death rate at six months was 41 percent in the cooled group and 55 percent in the group that was not cooled.
In Australia, researchers used ice packs, and cooling was started by paramedics. Forty-three of 77 patients were chilled to 91.4 degrees for 12 hours. Forty-nine percent of the treated group recovered well enough to go home or to a rehabilitation center, compared with 26 percent of the patients who were not chilled.
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American Heart Association: www.americanheart.org
