Lack of effect of induction of hypothermia after acute brain injury.

Background: Induction of hypothermia in patients with brain injury was show n to improve outcomes in small clinical studies, but the results were not d efinitive. To study this issue, we conducted a multicenter trial comparing the effects of hypothermia with those of normothermia in patients with acut e brain injury. Methods: The study subjects were 392 patients 16 to 65 years of age with co ma after sustaining closed head injuries who were randomly assigned to be t reated with hypothermia (body temperature, 33 degreesC), which was initiate d within 6 hours after injury and maintained for 48 hours by means of surfa ce cooling, or normothermia. All patients otherwise received standard treat ment. The primary outcome measure was functional status six months after th e injury. Results: The mean age of the patients and the type and severity of injury i n the two treatment groups were similar. The mean (+/-SD) time from injury to randomization was 4.3+/-1.1 hours in the hypothermia group and 4.1+/-1.2 hours in the normothermia group, and the mean time from injury to the achi evement of the target temperature of 33 degreesC in the hypothermia group w as 8.4+/-3.0 hours. The outcome was poor (defined as severe disability, a v egetative state, or death) in 57 percent of the patients in both groups. Mo rtality was 28 percent in the hypothermia group and 27 percent in the normo thermia group (P=0.79). The patients in the hypothermia group had more hosp ital days with complications than the patients in the normothermia group. F ewer patients in the hypothermia group had high intracranial pressure than in the normothermia group. Conclusions: Treatment with hypothermia, with the body temperature reaching 33 degreesC within eight hours after injury, is not effective in improving outcomes in patients with severe brain injury. (N Engl J Med 2001;344:556- 63.) Copyright (C) 2001 Massachusetts Medical Society.