Energy imbalance and the risk of overfeeding in critically ill children

Objective: To examine the role of targeted indirect calorimetry in detecting the adequacy of energy intake and the risk of cumulative energy imbalance in a subgroup of critically ill children suspected to have alterations in resting energy expenditure. We examined the accuracy of standard equations used for estimating resting energy expenditure in relation to measured resting energy expenditure in relation to measured resting energy expenditure and cumulative energy balance over 1 week in this cohort. Design: A prospective cohort study. Setting: Pediatric intensive care unit in a tertiary academic center. Interventions: A subgroup of critically ill children in the pediatric intensive care unit was selected using a set of criteria for targeted indirect calorimetry. Measurements: Measured resting energy expenditure from indirect calorimetry and estimated resting energy expenditure from standard equations were obtained. The metabolic state of each patient was assigned as hypermetabolic (measured resting energy expenditure/estimated resting energy expenditure >110%), hypometabolic (measured resting energy expenditure/estimated resting energy expenditure <90%), or normal (measured resting energy expenditure/estimated resting energy expenditure =90-110%). Clinical variables associated with metabolic state and factors influencing the adequacy of energy intake were examined. Main Results: Children identified by criteria for targeted indirect calorimetry, had a median length of stay of 44 days, a high incidence (72%) of metabolic instability and alterations in resting energy expenditure with a predominance of hypometabolism in those admitted to the medical service. Physicians failed to accurately predict the true metabolic state in a majority (62%) of patients. Standard equations overestimated the energy expenditure and a high incidence of overfeeding (83%) with cumulative energy excess of up to 8000 kcal/week was observed, especially in children <1 yr of age. We did not find a correlation between energy balance and respiratory quotient (RQ) in our study. Conclusions: We detected a high incidence of overfeeding in a subgroup of critically ill children using targeted indirect calorimetry The predominance of hypometabolism, failure of physicians to correctly predict metabolic state, use of stress factors, and inaccuracy of standard equations all contributed to overfeeding in this cohort. Critically ill children, especially those with a longer stay in the PICU, are at a risk of unintended overfeeding with cumulative energy excess. (Pediatr Crit Care Med 2011; 12:398-405)