X-Message-Number: 12707 Date: Wed, 03 Nov 1999 20:53:39 -0500 From: Jan Coetzee <> Subject: Hypothermia does not help Guy Clifton NIH Trial Says Cooling Therapy Is of No Benefit for Brain Injury by Pete Moore In recent years, there has been some suggestion that inducing hypothermia in people with brain injury may enhance their recovery. At the National Neurotrauma Society's 17th Annual Symposium, held October 22-23, 1999 in Miami, Florida, researchers presented new data that indicated that this idea needs to be treated with severe caution. Cooling patients who were over the age of 45, or those with severe trauma, decreased their chance of a successful recovery from the injury, while younger patients who had more minor injuries appeared to gain only marginal benefit. In 1994, Guy Clifton from the University of Texas at Houston established a research project in which he and his collaborators started randomly allocating patients to standard management or standard management with additional hypothermia. The idea was to study whether early induction of hypothermia for a 48-hour period improved the outcome of patients with severe brain injury. Patients were excluded from the trial if cooling could not be started within six hours of the injury, and the cooled group were given Vecuronium (5-10 mg/hr) to prevent them from shivering. Cooling was initiated in the emergency room and the body temperature was held at around 33 C for 48 hours. At the end of the hypothermic period the patient was re-warmed slowly, over a period of 16-18 hours. Clifton explained that pilot studies had taught them that if you increase body temperature rapidly, you get a severe increase in intracranial temperature. Eighty percent of the patients were admitted to hospitals in Sacremento, Houston, St. Louis, and Pittsburgh, with the remaining 20 percent being cared for in a variety of different centers. Seventy percent were from car acccidents, and 11 percent were pedestrians who had been hit by cars. Sadly, when Clifton began analyzing the data in May, he found no difference in overall mortality between the patients held at normal temperatures and those who were cooled. Intriguingly, there was a difference in the cause of mortality. In the most severely injured patients in the hypothermic group, the problem was low blood pressure combined with high intracranial pressures, which happened because the brain became loaded with fluid and swelled inside the skull. "We have got to figure out how to manage the fluid balance of these patients," says Clifton. When he analyzed the cooled group in more detail, Clifton found that there was about a 5 percent positive effect in the less severely injured patients who were less than 45 years old. "The take-home message is that in patients with very severe injuries and in elderly patients there is probably no indication for the use of hypothermia. In those that are younger and with lesser injuries, which accounts for some 70 percent of patients in coma with brain injury, there could be a beneficial effect, but it was not statistically significant, so one would not recommend its routine use at all at the moment," explains Clifton. "However, we are now in a position to focus on giving the treatment to the most likely group of people who could benefit and may then see greater effects." Pete Moore is a freelance science writer at The Lancet. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=12707