Ice Slows Brain Damage in Heart Patients

Putting patients on ice after they suffer cardiac arrest helps to prevent brain damage caused by the drop in blood circulation, an international team of researchers reported Monday.

Cardiac arrest -- the trembling heart malfunction that can be reversed using a defibrillator -- can not only kill, but it can leave a survivor with dead brain cells.

Two studies published in the journal Circulation show that cooling the body temperature to below the normal 98.6 degrees can help prevent that damage.

A mild reduction in body temperature, to between 89.6 degrees and 93.2 degrees, lasting 12 to 24 hours, is needed, said Dr. Jerry Nolan, who helped lead the International Liaison Committee on Resuscitation’s Advanced Life Support Task Force.

Nolan, of Royal United Hospital in Bath, England, and colleagues used a special mattress with a cover that blew air over the body and ice bags to cool patients for 24 hours after they arrived at the hospital.

In an Australian study, paramedics put ice packs against the heads and torsos of patients.

Patients who were cooled suffered less brain damage, both teams found.

The principle is not surprising -- reducing a person’s body temperature before the heart stops, such as before open-heart surgery, has been shown to prevent brain damage.

“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,” Nolan said in a statement released by the American Heart Assn., which publishes Circulation.

When brain cells die, they set off a cascade of reactions that can kill neighboring cells, even if they are healthy.

“Cooling slows down the chemical reactions, thereby lowering inflammation,” Nolan said.