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Published on: April 29, 2013
Challenge of predicting resting energy expenditure in children undergoing surgery for congenital heart disease
Barbera De Wit1, Rosan Meyer, Ajay Desai
1Paediatric Intensive Care Unit, The Royal Brompton Hospital, London, UK.
Insights
Children with congenital heart disease need more energy after open heart surgery, especially if they had cardiopulmonary bypass or were malnourished. Current equations inaccurately predict their energy needs.
Area of Science:
- Pediatric cardiology
- Critical care medicine
- Nutritional science
Background:
- Children with congenital heart disease (CHD) often require open heart surgery.
- Accurate assessment of energy expenditure is crucial for postoperative nutritional management in these vulnerable patients.
- Current predictive equations for energy expenditure may not be accurate for children with CHD post-surgery.
Purpose of the Study:
- To identify predictors of energy expenditure in children with CHD before and after open heart surgery.
- To compare measured resting energy expenditure (REE) with values predicted by existing equations.
Main Methods:
- Prospective study involving 21 mechanically ventilated children post-CHD surgery.
- Resting energy expenditure measured using indirect calorimetry.
- Comparison of measured REE with preoperative/postoperative clinical variables and standard predictive equations (Schofield, WHO, PICU-specific).
Main Results:
- Mean measured REE was 67.8 kcal/kg/day; most children received inadequate nutrient delivery.
- Cardiopulmonary bypass significantly increased postoperative REE (73.6 kcal/kg/day vs. 58.3 kcal/kg/day without bypass).
- Preoperative malnutrition was linked to higher postoperative REE. Measured REE differed significantly from all tested predictive equations (p < .006).
Conclusions:
- Preoperative nutritional status and the use of cardiopulmonary bypass are key factors influencing postoperative energy expenditure in children with CHD.
- Existing predictive equations lack the clinical accuracy needed for estimating energy requirements in this population.
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.