To determine the changes in resting energy expenditure (REE), body temperature and jugular bulb oxygen saturation (SjVO₂) of the patients with brain injury or brain death.

Fifty-two patients with Glasgow Coma Scale score < 6 admitted to our intensive care unit between October 2002 and November 2003 were included in the study. Among these patients Group 1 (n = 26) included patients with brain death. This group was divided into two subgroups later. Group 1a (n = 13) consisted of the patients with brain death when they were included in the study and Group 1b (n = 13) consisted of patients who progressed to brain death during their intensive care unit stay although they were initially not brain dead. Group 2 (n = 26) consisted of the patients with brain injury but no brain death. REE using indirect calorimetry, SjVO₂ and body temperature was recorded daily and simultaneously during the first 5 days of the study. REE values were expressed as the percentage of basal metabolic rate (BMR%) calculated using the Harris–Benedict equation.

There were no differences in terms of age, APACHE II score at admission, reason for coma and BMR between Group 1 and Group 2 (P > 0.05). Mean body temperatures were 35.6 ± 0.9°C and 37 ± 0.6°C (P < 0.01), mean SjVO2 values were 90.3 ± 9.9% and 77.9 ± 10% (P < 0.01) and mean REE values were 1542 ± 580 kcal (97 ± 26.8% of mean BMR) and 1963 ± 600 kcal (117 ± 29.2% of mean BMR) (P < 0.05) in Group 1 and Group 2, respectively. In Group 1b, the mean body temperature was lower and the mean SjVO₂ was higher than the values before brain death (P < 0.05). In this group, although the mean REE was lower than the value before brain death, this difference was not statistically significant (P = 0.07).

In this study, we found that the mean value of REE was 17% higher than the BMR in the patients with brain injury. The mean REE and body temperature was lower and the mean SjVO₂ was higher in the brain-dead patients than in the patients with no brain death.