Clinical question: Does targeted hypothermia (33°C) after cardiac arrest confer benefits compared with targeted temperature management at 36°C?
Background: Therapeutic hypothermia is a current recommendation in resuscitation guidelines after cardiac arrest. Fever develops in many patients after arrest, and it is unclear if the treatment benefit is due to hypothermia or due to the prevention of fever.
Study design: RCT.
Setting: ICUs in Europe and Australia.
Synopsis: The study authors randomized 950 patients who experienced out-of-hospital cardiac arrest to targeted temperature management at either 36°C or 33°C. The goal of this trial was to prevent fever in both groups during the first 36 hours after cardiac arrest. No statistically significant difference in outcomes between these two approaches was found. In the 33°C group, 54% died or had poor neurologic function, compared with 52% in the 36°C group (risk ratio 1.02; 95% CI 0.88 to 1.16; P=0.78).
Given the wide confidence interval, a trial with either more participants or more events might be able to determine whether a true difference in these management approaches exists.
Bottom line: Therapeutic hypothermia at 33°C after out-of-hospital cardiac arrest did not confer a benefit compared with targeted temperature management at 36°C.
Citation: Nielsen N, Wetterslev J, Cronberg T, et al. Targeted temperature management at 33°C versus 36°C after cardiac arrest. N Engl J Med. 2013;369(23):2197-2206.