Metabolic measurements during mechanical ventilation in the pediatric intensive care unit.

The metabolism of critically ill infants and children is significantly influenced by their underlying diseases, and standard predictive equations result in inappropriate nutritional support in most of these patients. Furthermore, significant day-to-day variability in energy expenditure may be present in individual patients. Inadequate or excessive energy supply can adversely affect the clinical course of many critically ill patients. For these reasons, serial measurements of energy expenditure should be considered whenever accurate determination of energy needs is deemed necessary. With the wide availability of proprietary metabolic carts suitable for use in mechanically ventilated pediatric patients, serial metabolic measurements via indirect calorimetry are feasible in most critically ill infants and children. The use of indirect calorimetry should also be considered in this population to assess changes in oxygen consumption and the relationship of oxygen consumption to oxygen delivery in response to changes in therapy, such as manipulation of cardiac output using vasoactive medications, or during weaning of mechanical ventilation.