Recovery from postoperative hypothermia predicts survival in extensively burned patients.

To clarify the cause of postoperative hypothermia in extensively burned patients, factors affecting postoperative hypothermia were studied in 16 extensively burned adult patients (8 survivors and 8 nonsurvivors) with a burn index greater than 35. Body temperature was monitored continuously in either the urinary bladder or rectum. Hypothermia of less than 35 degrees C occurred in 89% (66 of 74) of the total operations performed in these 16 patients. The rate of temperature rise (RTR) was significantly lower in nonsurvivors (0.4 +/- 0.2 degrees C/h) than in survivors (1.7 +/- 0.9 degrees C/h; p < 0.001). Continuous indirect calorimetry performed in seven patients (four survivors and three nonsurvivors) demonstrated that RTR was determined primarily by heat production. The measured energy expenditure reached only 1.7 +/- 0.2 times the basal energy expenditure during rewarming in nonsurvivors, whereas it was 2.7 +/- 0.9 times the basal energy expenditure in survivors (p < 0.01). Surprisingly, in nonsurvivors, the RTR was significantly decreased even during the first 2 weeks. These findings suggest that those who cannot generate heat well in postoperative hypothermia are unable to produce the additional energy required to overcome sepsis.