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.

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