Modified hormonal effects on fat metabolism after severe head injury in children

Traumatic Brain Injury in the Pediatric Population

Traumatic brain injury (TBI) is a common injury among children. Most TBIs are mild and do not require hospitalization. However, whether or not the patients require acute hospitalization, TBIs may have long-lasting consequences. There is little research on the nutrient needs of these patients, and recommendations are frequently based on data from adults with TBI. It is clear that calorie and protein needs are elevated with acute TBI. However, calorie needs are also decreased by therapies such as sedation, chemical paralysis, and barbiturate coma. Long-term calorie needs may be lower for "comatose" patients. Enteral feeding is preferred and possible for patients with TBI, though gastric feeding may be problematic in some patients. In the acute phase, patients with TBI can also have dysregulation of fluid and electrolyte balance, which may require alterations in nutrition care. Dysphagia is common after moderately severe TBI and requires a multidisciplinary approach for treatment. Future opportunities for research on pediatric TBI are numerous and may include ongoing clarification of macronutrient needs, as well as investigation into the roles of specific nutrients such as zinc, antioxidants, and anti-inflammatory compounds.

Energy expenditure and substrate utilization in mechanically ventilated children

The objective of the study was to determine the value of indirect calorimetry and nitrogen balance (N balance) in order to evaluate the current feeding protocols of mechanically ventilated children. The study was designed as a cross-sectional prospective study. In 36 mechanically ventilated children energy expenditure was measured by indirect calorimetry, and total urinary nitrogen excretion (TUN) was determined. Substrate utilization and respiratory quotient (RQ) were calculated from the measured values of oxygen consumption (VO2), carbon dioxide production (VCO2), and TUN. The RQ was compared with the RQ of the macronutrients administered (RQmacr) according to the modified criteria of Lusk. In results, the total measured energy expenditure (TMEE) showed a wide variation (range 155-272 kJ.kg-1.d-1). The N balance was positive in 20 and negative in 16 patients. The ratio of caloric intake/TMEE was significantly higher in patients with a positive N balance (1.50 +/- 0.06) as compared with those with a negative N balance (0.8 +/- 0.1, P < 0.001). There was a significant relationship between the difference of RQ-RQmacr versus the ratio caloric intake/TMEE (r = 0.72, P < 0.001). Carbohydrate and fat utilization were not significantly different in patients with a positive or negative N balance. Protein utilization was significantly higher in those patients with a negative N balance. We concluded that measurement of TMEE with indirect calorimetry results in accurate determination of energy needs in critically ill mechanically ventilated children. Feeding according to or in excess of the TMEE is correlated with a positive N balance. A combination of the RQ and the RQmacr can be helpful in differentiating under- or overfeeding.