Influence of body temperature, with or without sedation, on energy expenditure in severe head-injured patients.
OBJECTIVE
To quantify the effect of body temperature and sepsis on energy expenditure in head-injured patients.


METHODS
Prospective, nonrandomized, observational study.


METHODS
Neurosurgical intensive care unit.


METHODS
Severe head-injured patients.


METHODS
Use of an indirect calorimeter to measure energy expenditure.


RESULTS
Mean arterial pressure (MAP), heart rate (HR), body temperature, and mean hourly energy expenditure were recorded. Twenty-four patients had 1,919 hourly measures of the above parameters. The measurement periods were divided into four groups, according to the anesthetic agents used for sedation: fentanyl and midazolam (group FM); fentanyl, midazolam, and curarization (group C); thiopental (group T); and no sedation (group NS). The energy expenditure/basal energy expenditure ratio (EE/BEE) was significantly lower in group T (1.20 +/- 0.15) than in group FM (1.32 +/- 0.24) or group C (1.32 +/- 0.20) and was significantly higher in group NS (1.60 +/- 0.33). There was a significant correlation between body temperature and EE/BEE (p < .0001, r2 = .27) only in sedated patients. Using the equation of the regression line to correct energy expenditure for differences in body temperatures between groups, the difference in energy expenditure between groups with sedation disappeared. This finding suggested that the low energy expenditure under thiopental was due only to hypothermia. Sepsis significantly increased energy expenditure independently of fever. There was a weak but statistically significant correlation between energy expenditure and HR (p<.01, r2 = .13) but not between energy expenditure and MAP.


CONCLUSIONS
Sedation had a major effect on energy expenditure. In sedated patients, body temperature was the main determinant of energy expenditure; the anesthetic agent used had little influence on the level of energy expenditure. Sepsis increased energy expenditure independently of fever, probably through hormonal changes.
Bruder
N
N
Département d'Anesthésie-Réanimation, CHU Timone, Marseille, France.
Raynal
M
M
Pellissier
D
D
Courtinat
C
C
François
G
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000777:Anesthetics; D001831:Body Temperature; D001930:Brain Injuries / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D002153:Calorimetry, Indirect; D016292:Procedural Sedation; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018805:Sepsis / Q000150:complications / Q000503:physiopathology
D000777:Anesthetics