The Brain Resuscitation Clinical Trial (BRCT) was established as a multi-institutional, clinical study of brain resuscitation. The BRCT was designed to test the hypothesis that the addition of thiopental loading to the protocol of standard therapy for cardiac arrest survivors, comatose at 10-50 minutes after restoration of spontaneous circulation, would significantly increase the number of patients recovering good cerebral function. Twelve hospitals in nine countries collaborated in this randomized, controlled clinical trial. The study was designed to take into account numerous problems including the reliability of information on complex events surrounding cardiac arrest, the difficulty of maintaining uniform treatment protocols, and the difficulty of obtaining informed consent within the constraints of the time the therapy was hypothesized to be effective. The major outcome measurements of the study were neurological status at the end of various time intervals following resuscitation and the best neurological performance ever attained during follow-up. Mortality and other untoward events were closely monitored to establish treatment safety. Of the 262 patients entered into the study between 1979 and 1982, 45% were over 65 years of age, and 75% were men. The majority of the arrests (74%) occurred out of hospital, and major pathology underlying arrest was cardiac. Arrest time was greater than 5 minutes in 36% of the patients. As a result of randomization, patient characteristics at entry as well as the characteristics associated with the brain insult in the standard group were similar to those in the thiopental group.