Recent experimental studies have demonstrated that mild
hypothermia at about 34 degrees C can be effective in the control of
intracranial hypertension. A randomized controlled study of mild
hypothermia was carried out in 33 severely head-injured patients. All patients fulfilled the following criteria: 1) persistent intracranial pressure (ICP) greater than 20 mm Hg despite fluid restriction,
hyperventilation, and high-dose
barbiturate therapy; 2) an ICP lower than the mean arterial blood pressure; and 3) a Glasgow Coma Scale score of 8 or less. The patients were divided into two groups: one received mild
hypothermia (16 patients) and one served as a control group (17 patients). Mild
hypothermia significantly reduced the ICP and increased the cerebral perfusion pressure. Eight patients (50%) in the
hypothermia group and three (18%) in the control group survived (p < 0.05), while five (31%) in the
hypothermia group and 12 (71%) in the control group died of uncontrollable
intracranial hypertension (p < 0.05). In five patients in the
hypothermia group, cerebral blood flow was measured by the
hydrogen clearance method and arteriojugular venous
oxygen difference was evaluated before and during mild
hypothermia. Mild
hypothermia significantly decreased the cerebral blood flow, arteriojugular venous
oxygen difference, and cerebral metabolic rate of
oxygen (p < 0.01). The results of this preliminary investigation suggest that mild
hypothermia is a safe and effective method to control traumatic
intracranial hypertension and to improve mortality and morbidity rates.