Energy expenditure in children after severe traumatic brain injury.

Objective: To evaluate energy expenditure in a cohort of children with severe traumatic brain injury.

Design: A prospective observational study.

Setting: A pediatric neurotrauma center within a tertiary care institution.

Patients: Mechanically ventilated children admitted with severe traumatic brain injury (Glasgow Coma Scale < 9) with a weight more than 10 kg were eligible for study. A subset of children was co-enrolled in a phase 3 study of early therapeutic hypothermia. All children were treated with a comprehensive neurotrauma protocol that included sedation, neuromuscular blockade, temperature control, antiseizure prophylaxis, and a tiered-based system for treating intracranial hypertension.

Interventions: Within the first week after injury, indirect calorimetry measurements were performed daily when the patient's condition permitted.

Measurements And Main Results: Data from 13 children were analyzed (with a total of 32 assessments). Measured energy expenditure obtained from indirect calorimetry was compared with predicted resting energy expenditure calculated from Harris-Benedict equation. Overall, measured energy expenditure/predicted resting energy expenditure averaged 70.2% ± 3.8%. Seven measurements obtained while children were hypothermic did not differ from normothermic values (75% ± 4.5% vs 68.9% ± 4.7%, respectively, p = 0.273). Furthermore, children with favorable neurologic outcome at 6 months did not differ from children with unfavorable outcome (76.4% ± 6% vs 64.7% ± 4.7% for the unfavorable outcome, p = 0.13).

Conclusions: Contrary to previous work from several decades ago that suggested severe pediatric traumatic brain injury is associated with a hypermetabolic response (measured energy expenditure/predicted resting energy expenditure > 110%), our data suggest that contemporary neurocritical care practices may blunt such a response. Understanding the metabolic requirements of children with severe traumatic brain injury is the first step in development of rational nutritional support goals that might lead to improvements in outcome.