Recently, the study "Mild hypothermia to improve the neurologic outcome after cardiac arrest" from the Hypothermia After Cardiac Arrest Study Group (New Engl J Med 2002;346:549-556) reported the results of a multicenter randomized controlled clinical trial that evaluated the effect of mild systemic hypothermia on mortality and functional outcome after resuscitation from out-of-hospital cardiac arrest due to ventricular fibrillation or tachycardia. Two hundred and seventy three patients were randomly assigned to standard normothermic or hypothermic management. Cooling to a target core body temperature of 32ºC to 34ºC was accomplished with the use of a specialized bed which delivers cold air over the entire body. Temperature was maintained in the target range for 24 hours after the start of cooling, followed by passive rewarming over 8 hours. Outcome was assessed at 6 months with a five point scale similar to the Glasgow Outcome Scale, dichotomized to classify independent patients with minimal or moderate disability to those who were dependent and severely disabled, vegetative, or dead. The results demonstrated a favorable neurological outcome in 55% of the 136 patients treated with hypothermia, compared to 39% of the 137 patients treated with normothermic management (risk ratio 1.40, 95% confidence interval 1.08 to 1.81, P=.009). . Mortality was also reduced with hypothermic management, from 41% in the hypothermia group to 55% in the normothermia group (risk ratio 0.74, 95% confidence interval 0.58 to 0.85, P=.02). In 19 patients (14%), the target temperature could not be reached. Complications did not differ significantly between the two groups, although there were trends toward increased rates of sepsis and bleeding with hypothermia.