WEDNESDAY, June 4, 2008 (HealthDay News) -- Cooling the brain after a traumatic brain injury may not help improve neurological outcomes and might even increase mortality.
That's the conclusion of a randomized trial of 225 children with brain injuries, but the authors and other experts suspect that by changing the cooling and re-warming protocol, other researchers may have more success with this therapy.
"Our hypothesis was that hypothermia would improve the outcome," said study author Dr. Jamie Hutchison, a critical care physician and director of the acute care research unit at the Hospital for Sick Children in Toronto.
"Children were randomized to receive 24 hours of cooling, to 32 degrees Celsius. They had to be enrolled within eight hours of their injury and, after cooling, we re-warmed an average of 0.5 degree Celsius every two hours. To our surprise, we didn't see any benefit," said Hutchison.
He said the study was designed to assess neurological outcomes, and that there was no difference between those who were cooled and those who received standard treatment. Additionally, the researchers saw a trend toward increased mortality in the cooled group. But, Hutchison said, the study wasn't designed to assess mortality and that those findings were not statistically significant.
Results of the study are in the June 5 issue of the New England Journal of Medicine.
Youngsters up to age 4 are among those most likely to suffer a traumatic brain injury, according to the U.S. Centers for Disease Control and Prevention. About 435,000 American children visit emergency rooms with traumatic brain injuries each year, and as many as 2,685 children die from traumatic brain injuries in the United States annually, according to the CDC.
Common causes of traumatic brain injuries are motor vehicle accidents, falls, assaults and collisions, like those that might occur during sports, reports the CDC. About 75 percent of traumatic brain injuries are mild, but more serious injuries can cause lifelong disability, creating problems with thinking, reasoning, the senses, language and emotions.
Hutchison said there may be a number of reasons why they didn't see an effect from cooling in the current trial. "Possibly, we may need to keep it going longer after a brain injury, because the brain keeps swelling for days after an injury. Perhaps 24 hours is too short a duration," he theorized.
Also, he said that there was a significantly higher incidence of low blood pressure during re-warming, and that the re-warming period may have been too quick.
The bottom line, said Hutchison, is that cooling for brain injury in children should not be used in the same context it was for this trial: 24 hours of cooling with re-warming occurring over 18 hours.
He said that several other studies of hypothermia for pediatric brain injury are already under way, but they're cooling for longer periods and re-warming more slowly.
Dr. P. David Adelson, director of neurotrauma at Children's Hospital of Pittsburgh, is leading one of the newer trials. He said this was a well-done study, and that other researchers have learned from it, but that "the jury is still out" on hypothermia for brain injury.
In his current study, Adelson said they are starting the cooling sooner, cooling for a longer period of time and re-warming at a far slower pace.
"This is a promising therapy that's going through an evolution. I think this study shows the difficulty of looking at complex disease processes [like traumatic brain injury], and trying to look at interventions. No one therapy will be the end-all treatment for brain trauma," said Adelson.
To learn more about traumatic brain injury, visit the U.S. Centers for Disease Control and Prevention.