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Icing down patients to avoid brain damage

/ Source: The Associated Press

For 24 hours, Hamilton Loeb lay unconscious inside a cold blue suit that put his brain on ice.

Four times, his heart had stopped beating and he was shocked back to life. Then doctors essentially refrigerated him,in a bid to avert the brain damage that too often cripples survivors of cardiac arrest.

Today, the 53-year-old Washington lawyer is back to normal, and he credits the cold with protecting his brain.

Chilling the sick may sound counterintuitive, but research shows mild hypothermia — cooling the body just a few degrees — can significantly improve the odds of a full recovery after cardiac arrest. Now scientists are trying to prove whether a cool-down can protect against some of the damage from other disorders, too:

  • Last month, a study of 75 children with head injuries concluded that inducing hypothermia reduced the dangerous brain swelling that accompanies these injuries — and there were signs that it may also help the youngsters’ cognitive function.

“Similar to icing your ankle when you twist it, we’re trying to think about cooling your brain,” explains lead researcher Dr. P. David Adelson of the Children’s Hospital of Pittsburgh, who is planning a larger study to prove the benefit.

  • For stroke victims, the National Institutes of Health is funding new research to see if chilling extends the narrow window of time they have to get a lifesaving treatment that restores blood flow in their brains.

Yet while medical guidelines already urge inducing hypothermia in cardiac-arrest survivors like Loeb, few hospitals routinely offer it, laments neurologist Dr. George Lopez of the Baylor College of Medicine.

Perhaps the biggest hurdle is how to chill people: The body fights mightily, by shivering, to stay at 98.6 degrees, and packing ice or old-fashioned cooling blankets into hospital beds is a messy and hard-to-control way to overcome that resistance. Newer technology may make hypothermia more feasible.

Cold reduces need for oxygen

But Loeb’s heart kept stopping on the way to the hospital, and doctors didn’t know how many minutes without oxygen had added up.

Only about 5 percent of people survive cardiac arrest, where the heart’s electrical system goes haywire and the heartbeat abruptly stops. And they often have lasting neurologic damage; brain cells start dying within three to six minutes of oxygen loss.

Without chilling, “we’re helpless” to protect their brains, says Dr. Julio Panza, Washington Hospital Center’s coronary intensive care chief. “All of us have gone through the experience of a patient resuscitated ... but the brain’s not there.”

So once Loeb’s heartbeat finally stabilized, Panza and cardiologist Dr. Howard Cooper encased him in the Arctic Sun suit — special pads that look like a bright blue vest and shorts and are stuck to the skin with a gel. Cold water rushes through tiny channels in the pads, simulating immersion in water.

Within about an hour, the padded suit made by Medivance Inc. had dropped Loeb’s body temperature to 91 degrees.

Studies show that cardiac-arrest survivors treated with hypothermia were up to 40 percent more likely to avoid lasting brain damage. Chilled patients were also slightly more likely to live.

First, the cold reduces the brain’s need for oxygen.

However, once blood flow resumes, a vicious chemical chain reaction continues to kill brain cells, as harmful proteins spewed by dying neurons in turn take out their neighbors. Just as fruit lasts longer in the fridge, hypothermia slows that process, allowing injured brain cells to recover.

Speed is key

That latter action suggests hypothermia could help with stroke and adult head injuries, too, but so far early-stage studies haven’t panned out. Scientists aren’t yet sure exactly how cold patients must be or for how long, and methods ranging from ice packs to threading icy catheters deep inside patients’ veins vary in their precision, notes Baylor’s Lopez.

But for cardiac arrest, chilling by any method helps, he says. Because speed is key, Lopez is working to get Houston’s paramedics to bring cardiac-arrest survivors straight to one of the three city hospitals that offer hypothermia even if it means bypassing a closer emergency room.

In Washington, Loeb’s doctors can’t say for sure if the chilling saved his brain or he was just extra lucky. But today the only lingering sign of his brush with death is a little amnesia — no memory of the weeks surrounding his collapse.

“All my instincts tell me that having the chilling treatment easily could have been the thing that made the difference,” Loeb says.

His wife is more emphatic: “As far as I’m concerned, a miracle has happened.”