A Cooling Approach to Stroke Treatment
Hypothermia may help in severe cases, study shows
THURSDAY, Aug. 2, 2001 (HealthDayNews) -- Desperate medical situations sometimes call for desperate remedies.
That why doctors at the Cleveland Clinic Foundation are trying hypothermia -- dropping body temperature below 90 degrees -- for patients who suffer the most severe kind of strokes.
The results of the first small trial of the technique offer "a glimmer of hope that it might influence the outcome," says Dr. Derk Krieger, the Cleveland Clinic staff physician who started the trial.
Krieger says something new is needed because the clot-dissolving drugs that are standard therapy for stroke don't do much in very severe cases. Hypothermia might help by inhibiting the inflammatory reactions that increase brain damage, he says.
"The most powerful protection I could think of was hypothermia," he says.
So in a pilot study, nine of 19 patients who suffered severe strokes received only clot-dissolving drugs, while hypothermia was induced in the 10 others after clot-dissolving treatment showed little or no improvement. The patients were sedated to prevent shivering, and a combination of cooling blankets and ice water baths lowered their body temperatures to 89.6 degrees Fahrenheit.
It took an average of three and a half hours to reach that temperature, which was maintained for 12 to 72 hours.
Some outcomes were bleak. Four of the cooled patients had critical complications, including heart abnormalities and hemorrhaging, compared with two of the non-cooled patients. Three hypothermia patients died within three months, compared with two of the non-cooled patients. But Krieger says a closer look at the results makes hypothermia look better.
"In the hypothermia group there were three deaths, one case of severe disability, one case of moderate disability, with the rest of the patients showing no deficit," he says. "So 50 percent of the patients had a good outcome. In the other group, there were two deaths, three patients in a vegetative state, one patient with severe disability, two with inhibitive disabilities and just one good outcome."
The findings, which are reported in the August issue of Stroke, a journal of the American Heart Association, will lead to a larger study involving 40 patients, Krieger says.
The new study will involve another method to achieve hypothermia. Instead of external cooling, body temperature will be lowered by internal catheters in about 30 minutes. That could improve the effectiveness of the treatment, Krieger says.
Hypothermia definitely is an experimental treatment, says Dr. Mark J. Alberts, director of the stroke program at Northwestern University School of Medicine in Chicago and a spokesman for the American Heart Association.
"While the general approach is promising, this is preliminary work that needs to be further studied and expanded," Alberts says. "The number of patients treated was very small, the benefits were marginal at best, and there were significant complications associated with hypothermia."
"Hypothermia has been studied before for several difficult disorders, such as stroke and head trauma," Alberts says. "It seems to work well in laboratory studies, but in humans you run into side effects, and the benefits in humans don't seem to be as great as predicted by the laboratory studies."
Krieger looks at the bright side: "This was a small trial, not a randomized trial, but it works."
What To Do
Prevention of stroke is infinitely better than treatment, so attention to preventive measures, such as controlling high blood pressure, is wise.
For information on stroke and its prevention, consult the American Heart Association or the National Institute of Neurological Disorders and Stroke.