Arrest Chilling Lessens Brain Damage of Cardiac

Two new major studies have shown that cooling the body temperature to below normal can help prevent brain damage after cardiac arrest. The findings were announced in an advisory statement published by the American Heart Association (AHA, Dallas, TX, USA) in the July 8, 2003, issue of Circulation.

Patients who survive a cardiac arrest that lasts more than a few minutes often suffer brain damage because no oxygen is reaching the brain. The idea of cooling the body to help prevent this damage is not new, but until recently there was no firm evidence of a benefit. In the new studies, cardiac arrest patients were "self-selected,” meaning there was no other cause, and they had to have been comatose but not for more than an hour, with good blood pressure restored by defibrillation.

A European study involving 273 patients showed that 55% of unchilled patients died following cardiac arrest, compared to 41% who received the chilling treatment. The results of a study in Australia showed even better results. In a study of 67 patients, 68% of unchilled patients died, compared to only 51% of those treated. Doctors in the European study used a special mattress with a cover that blew air over the body and used ice bags, if necessary, to cool the victims for 24 hours. In the Australian study, paramedics applied ice packs to patients' heads and torsos.

The cooling procedure, which aims to lower the body temperature to 89.6-93.2 O F, should be started as soon as possible after successful resuscitation and continued for 12-24 hours, according to Jerry P. Nolan, M.D., lead author of the statement. "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.”

Cooling therapy results in a slightly increased risk of bleeding, infection, and abnormal heart rhythms, noted Dr. Nolan. Further studies are needed to determine what other groups of cardiac arrest patients might benefit from the cooling treatment. The new recommendations are based on the findings of the Advanced Life Support Task Force of the International Liaison Committee on Resuscitation (ILCOR), of which Dr. Nolan is co-chairman.




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