Energy expenditure: how much does it matter in infant and pediatric chronic disorders?

A sound understanding of energy needs during chronic illness is necessary to avoid imbalances in energy intake and requirements. Failure to accurately estimate energy needs results in both underfeeding and overfeeding in chronically ill children. Suboptimal energy and protein intake may lead to deterioration in body composition, particularly lean body mass loss, which eventually impacts functional outcomes in these vulnerable groups. Furthermore, infants and children with chronic illnesses have a high prevalence of malnutrition and can ill afford further nutritional deterioration from suboptimal nutrient delivery. On the other hand, unintended delivery of excessive energy in patients with chronic respiratory insufficiency results in increased respiratory burden and poor outcomes. Hence, awareness of the energy requirements and attention to energy and protein balance are important when caring for children with chronic illnesses. The basic concepts of the metabolic stress response, measurement of energy expenditure, and the impact of energy imbalance on clinical outcomes in children with chronic illness are reviewed.