Duke medical researchers are trying to prove that maintaining hypothermia in certain brain injury patients might increase the patients' chances of recovery.
The Duke Medical Center is one of nine sites nationwide taking part in the National Acute Brain Injury Study: Hypothermia II, a $15.6 million project sponsored by the National Institutes of Health. The investigation, led by Dr. Guy Clifton, a University of Texas at Austin researcher, is considering how low body temperature in brain injury patients might aid recuperation.
The study will involve about 500 hypothermic head-injury patients aged 16 to 45 who enter the emergency room with a closed head injury, in a comatose state and with no other major injuries. Temperature-controlled suits will maintain a low body temperature of about 91.4 degrees Fahrenheit in half of the patients during their first 48 hours at the clinic. Doctors will then gradually warm them over the next 18 hours. The remaining half of the patients will be allowed to warm naturally to about 98.6 degrees Fahrenheit.
"About one-third of patients are a little cool when they come in, because when you suffer a brain injury, your body cools immediately as your brain's temperature controls begin to fail," said Dr. Carmelo Graffagnino, an assistant clinical professor of neurology and lead investigator of the study at Duke.
Following a major brain injury, the brain swells and releases excretory amino acids that cause secondary neuron injury.
"[Cooling the brain] reduces swelling in the brain, and probably directly protects neurons by reducing their metabolic demand," said Dr. Daniel Laskowitz, assistant professor of neurology. "It's been known for about a decade that cooling animal brains can improve their outcome. The treatment has a strong laboratory rationale based on animal data. It is an intuitive and straightforward approach to try with people."
In the United States each year, almost 50,000 people die and about 80,000 become permanently brain-damaged as a result of brain injuries. Laskowitz noted that currently, there is no treatment available for improving a patient's final outcome.
The study is groundbreaking for another reason��it will be the first Triangle-area study to use community consent. Because the research involves patients who are unresponsive, doctors will waive the patient's or family's right to consent if an immediate relative or a patient's legal representative cannot be contacted within one hour of the patient's arrival.
By both federal law and the standards of Duke's Internal Review Board, Medical Center researchers must gain consent to conduct research from members of the community--in this case, through surveys distributed at public forums in the Triangle area. The next educational session the researchers will hold at Duke will take place Nov. 6 at 6 p.m. in Duke Hospital North's Auditorium 2001.
To be eligible for community consent, Graffagnino said, a study must involve a life-threatening condition for which there is no other treatment, a time-sensitive emergency situation and the development of groundbreaking and safe treatments.
"The risk is very minimal," Graffagnino added. "Smaller studies have shown little difference in bleeding, heart rhythm, infection rate or blood problems in hypothermic patients. The studies done to date do not indicate any increased risk for the temperatures we're going at."
A similar study, the 1994 NABIS, found that inducing hypothermia in most brain injury patients did not have therapeutic value. However, of the 30 percent of patients who were already hypothermic upon hospital admittance and cooled by doctors, 48 percent showed significant recovery, while only 24 percent of patients who were allowed to warm naturally showed equal progress.
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