Challenge of predicting resting energy expenditure in children undergoing surgery for congenital heart disease

Objectives: To determine pre- and postoperative predictors of energy expenditure in children with congenital heart disease requiring open heart surgery; and to compare measured resting energy expenditure with current predictive equations. Design: Prospective resting energy expenditure data were collected, using indirect calorimetry, for ventilated children admitted consecutively to the pediatric intensive care unit after surgery for congenital heart disease. A 30-min steady-state measurement was performed in suitable patients. Resting energy expenditure was compared to pre- and postoperative clinical variables, and to predicted energy expenditure, using currently used predictive equations. Setting: Pediatric intensive care unit at the Royal Brompton Hospital, London. Patients: Children ventilated in the pediatric intensive care unit post surgery for congenital heart disease. Interventions: Measurement of energy expenditure by indirect calorimetry. Measurements and main Results: Twenty-one mechanically ventilated children (n = 17 boys, 4 girls) were enrolled in the study. Mean ± sd measured resting energy expenditure was 67.8 ± 15.4 kcal/kg/day. Most children had inadequate delivery of nutrients compared with actual requirements. Cardiopulmonary bypass had a significant influence on energy expenditure after surgery; in patients who underwent cardiopulmonary bypass during surgery, mean resting energy expenditure was 73.6 ± 14.45 kcal/kg/day vs. 58.3 ± 10.29 kcal/kg/day in patients undergoing nonbypass surgery. Children who were malnourished preoperatively had greater resting energy expenditure postoperatively. There was also a significant difference between measured energy expenditure and the Schofield (p = .006), World Health Organization (p = .002), and pediatric intensive care unit-specific formula (p < .0001). However, energy expenditure or a relative energy deficit in the early postoperative period was not associated with severity or duration of organ dysfunction. Conclusions: Poor nutritional status preoperatively and cardiopulmonary bypass were associated with a greater energy expenditure post cardiac surgery. None of the current predictive equations predicted energy requirements within acceptable clinical accuracy. Copyright

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