The study's lead investigator, Children's Hospital of Pittsburgh neurosurgeon P. David Adelson, MD, and fellow researchers determined that induced moderate hypothermia initiated after severe traumatic brain injury (TBI) is a safe therapeutic intervention for children.
TBI initiates several metabolic processes that can exacerbate the injury. Adult research has produced evidence that hypothermia may limit some of these deleterious metabolic responses.
The trial, which is the only multi-center clinical trial involving children underway in the United States, was conducted to determine whether moderate hypothermia (32-33 degrees Celsius) begun in the early period after severe TBI and maintained for 48 hours is safe compared with normal body temperature (36.5-37.5 degrees Celsius). By inducing hypothermia in pediatric patients down to 32 degrees Celsius, doctors found that hypothermia tended to reduce mortality, lower the severity of intracranial hypertension during the cooling phase and has the potential to improve the functional outcome of young patients.
Therefore, it was determined that hypothermia is likely a safe therapeutic intervention for children after severe TBI up to 24 hours after injury
Study results are published in the April issue of the journal, Neurosurgery. A total of 75 patients were involved in the trial, which was funded by the National Institutes of Health.
"Traumatic brain injury causes more children's deaths in this country than all other causes of death combined," said Dr. Adelson, who is the director of the Pediatric Neurotrauma Center at Children's Hospital of Pittsburgh. "There is no one thing that can effectively treat all cases of traumatic brain injury, but our hope is that with the cooling from hypothermia, we may block or slow down the brain's delet erious biochemical mechanisms following an injury and also be able to develop other more effective treatments."
Lowering body temperature can help control brain swelling and intracranial pressure, which can also exacerbate secondary injury if left unchecked. Induced hypothermia can be accomplished using several methods. Surface cooling methods such as cooling blankets placed under and on top of patients and ice packs placed in the groin and armpit areas are effective in decreasing temperature.
In addition to safety, mortality and complications during the treatment protocol and during hospitalization, the study also assessed functional and cognitive outcome in these children with severe traumatic brain injury.
After severe TBI, 48 children less than 13 years of age admitted within six hours of injury were randomized by age to moderate hypothermia treatment in conjunction with standardized head injury management versus normal body temperature.
An additional 27 patients were entered into a parallel trial of those patients who were excluded because there was a delay in transfer of greater than six hours following injury but within 24 hours of admission, or unknown time when the injury occurred (i.e. child abuse) or were an adolescent (13-18 years old).
Assessments of safety included mortality, infection, coagulopathy (blood clotting), arrhythmias and hemorrhage as well as ability to maintain target temperature, mean intracranial pressure (ICP), and percent time of ICP less than 20 mm Hg during the cooling and subsequent rewarming phases. Additionally, assessments of neurocognitive outcomes were obtained at three and six months of follow-up. Researchers will conduct further studies to determine the effect of moderate hypothermia on functional outcome and intracranial hypertension.