A prospective, observational clinical trial of fever reduction to reduce systemic oxygen consumption in the setting of acute brain injury.
BACKGROUND
Fever after acute brain injury appears to be a detrimental factor, associated with impaired neurological outcomes. This study assessed physiological changes in systemic oxygen consumption (VO2) during cutaneous cooling after severe brain injury.


METHODS
This prospective, observational, clinical study evaluated ten, critically ill, brain-injured patients requiring mechanical ventilation with a core body temperature of greater or equal to 38 degrees C. Febrile patients failing to defervesce after acetaminophen underwent indirect calorimetry for a 1-hour baseline period followed by a 4 h cooling period. The Arctic Sun(R) Temperature Management System (Medivance) directed core temperature to a goal of 36 degrees C.


RESULTS
The patients had a mean age of 32 years (95% CI 23, 40), Glasgow Coma Scale of 6 (95% CI 5,7), and APACHE 2 score of 19 (95% CI 15, 22), with 8 of 10 patients suffering traumatic brain injuries. The baseline 1-h core temperature was significantly reduced from 38.6 degrees +/- 0.9 to 36.3 degrees +/- 1.2 degrees C (P < 0.0001) over 4 h. Two cohorts were identified based upon the presence or absence of shivering. Within the non-shivering cohort, systemic VO2 was significantly reduced from 415 +/- 123 to 308 +/- 115 ml/min (-27 +/- 18%) (P < 0.05). In contrast, those with shivering showed no significant reduction in VO2, despite significantly decreasing core temperature. The overall percentage change of VCO2 correlated with VO2 (r (2) = 0.91).


CONCLUSIONS
Fever reduction in acute brain injury appears to significantly reduce systemic VO2, but is highly dependent on shivering control.
Hata
J Steven
JS
The Division of Critical Care, Department of Anesthesia, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA. steven-hata@uiowa.edu
Shelsky
Constance R
CR
Hindman
Bradley J
BJ
Smith
Thomas C
TC
Simmons
Jonathan S
JS
Todd
Michael M
MM
D018806:APACHE; D000082:Acetaminophen / Q000627:therapeutic use; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000627:therapeutic use; D001831:Body Temperature / Q000187:drug effects; D001930:Brain Injuries / Q000378:metabolism* / Q000628:therapy*; D003131:Combined Modality Therapy; D003422:Critical Care; D005260:Female; D005334:Fever / Q000188:drug therapy* / Q000378:metabolism*; D015600:Glasgow Coma Scale; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use; D007036:Hypothermia, Induced; D008297:Male; D010101:Oxygen Consumption; D011446:Prospective Studies; D012121:Respiration, Artificial; D012768:Shivering / Q000187:drug effects
D018712:Analgesics, Non-Narcotic; D006993:Hypnotics and Sedatives; D000082:Acetaminophen