WEDNESDAY, June 4 (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.
More information
To learn more about traumatic brain injury, visit the
U.S. Centers for Disease Control and
Prevention.
