JOURNAL OF NEUROTRAUMA Volume 19, Number 3, 2002 © Mary Ann Liebert, Inc. Hypothermia on Admission in Patients with Severe Brain Injury GUY L. CLIFTON, 1 EMMY R. MILLER, 1 SUNG C. CHOI, 2 HARVEY S. LEVIN, 3 STEPHEN MCCAULEY, 3 KENNETH R. SMITH, JR., 4 J. PAUL MUIZELAAR, 5 DONALD W. MARION, 6 and THOMAS G. LUERSSEN 7 ABSTRACT Data from the “National Acute Brain Injury Study: Hypothermia” were examined to identify the impact of hypothermia on admission. In all patients, temperature was measured at randomization using bladder catheters with thermistors. Patients assigned to hypothermia were cooled using fluid- circulating pads. Outcome was assessed at 6 months using the dichotomized Glasgow Outcome Scale (good outcome 5 good recovery/moderate disability; poor outcome 5 severe disability/vegetative/ dead). One-hundred and two patients (hypothermia, 62; normothermia, 40) were hypothermic on admission (#35.0°C). Hypothermia-on-admission patients assigned to normothermia (n 5 40) had a 78% poor outcome, and normothermia-on-admission patients assigned to normothermia had a 52% poor outcome (p , 0.004). Hypothermia-on-admission patients assigned to hypothermia had a lower percentage of poor outcomes than those assigned to normothermia (hypothermia, 61%; nor- mothermia, 78%; p 5 0.09). Patients over 45 years of age had an adverse effect of hypothermia re- gardless of admission temperature due to medical complications. Patients who were hypothermic on admission, age # 45 years (n 5 81), and assigned to hypothermia had a significantly lower per- centage of poor outcomes than those assigned to normothermia (hypothermia, 52%; normothermia, 76%; p 5 0.02). Factors associated with hypothermia on admission were increased age, prehospital hypotension, smaller size, positive blood alcohol, larger volume of pre-hospital fluids, slightly higher injury severity, and winter enrollment The treatment effect was found in all of the four centers, which randomized the majority (80%) of the patients. It is unclear whether the improved outcome when hypothermia is maintained is a beneficial effect of very early hypothermia induction or an ad- verse effect of permitting the patients to rewarm passively. Key words: hypothermia on admission; maintenance of hypothermia; outcome; severe brain injury 293 1 Vivian L. Smith Center for Neurologic Research, Department of Neurosurgery, University of Texas–Houston Medical School, Houston, Texas. 2 Departments of Biostatistics and Neurosurgery, Medical College of Virginia/Virginia Commonwealth University, Richmond, Virginia. 3 Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, Texas. 4 Department of Neurosurgery, St. Louis University, St. Louis, Missouri. 5 Department of Neurological Surgery, University of California, Davis, Sacramento, California. 6 Brain Trauma Research Center, Department of Neurosurgery, University of Pittsburgh, Pittsburgh, Pennsylvania. 7 Division of Neurosurgery, Indiana University, Indianapolis, Indiana.