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Resting energy expenditure after Fontan surgery in children with single-ventricle heart defects
Nilesh M Mehta1, John M Costello, Lori J Bechard
1Division of Critical Care Medicine/Anesthesia, Department of Anesthesiology, Pain and Perioperative Medicine, Children's Hospital Boston, Harvard Medical School, Bader 634, MSICU Office, 300 Longwood Ave, Boston, MA 02115, USA. nilesh.mehta@childrens.harvard.edu
Insights
Children after Fontan surgery rarely show hypermetabolism. Measured resting energy expenditure (REE) did not correlate well with estimated energy needs, impacting nutritional support after pediatric cardiopulmonary bypass.
Area of Science:
- Pediatric Cardiology
- Metabolic Research
- Critical Care Medicine
Background:
- Accurate resting energy expenditure (REE) and oxygen consumption (VO2) data are crucial for optimizing nutrient prescriptions in children post-pediatric cardiopulmonary bypass (CPB).
- Understanding post-operative metabolic states is essential for managing single-ventricle physiology after complex cardiac surgeries.
Purpose of the Study:
- To measure resting energy expenditure (REE) and oxygen consumption (VO2) in children immediately after Fontan surgery.
- To compare measured REE with standard equation-estimated energy expenditure (EEE) and classify metabolic status (hyper-, normo-, hypometabolic).
- To identify factors correlating with metabolic status post-Fontan surgery.
Main Methods:
- Continuous indirect calorimetry (IC) was used to measure REE and VO2 in 30 children post-Fontan surgery.
- Measured REE at 8 hours post-surgery was compared to EEE using the World Health Organization equation.
- Patients were categorized based on the ratio of measured REE to EEE.
Main Results:
- Mean REE was 57 ± 20 kcal/kg/d and mean VO2 was 110 ± 35 mL/min in 26 patients.
- No significant changes in VO2 or REE were observed within 24 hours post-surgery.
- A majority of patients (73%) were normometabolic or hypometabolic, with poor correlation between measured and estimated REE (r = 0.32).
- Lack of hypermetabolism correlated with higher intraoperative lactate and positive fluid balance.
Conclusions:
- Children with single-ventricle defects exhibit a low prevalence of hypermetabolism after Fontan surgery.
- Measured REE showed poor correlation with equation-estimated energy expenditure in most patients.
- The findings suggest that current energy prescriptions may need adjustment due to the absence of increased energy expenditure post-CPB.
Background:
Data on resting energy expenditure (REE) and oxygen consumption (VO(2)) after pediatric cardiopulmonary bypass (CPB) will facilitate optimal nutrient prescription.
Methods:
The authors measured continuous REE and VO(2), using an in-line indirect calorimetery (IC) in 30 consecutive children with single-ventricle physiology immediately after Fontan surgery. REE during steady state at 8 hours after surgery was compared with standard equation-estimated energy expenditure (EEE). Patients were classified into 3 groups: hypermetabolic (measured REE [MREE]/EEE ratio >1.2), hypometabolic (MREE/EEE ratio <0.8), and normometabolic (MREE/EEE ratio 0.8-1.2). Demographic, anthropometric, and perioperative clinical characteristics were examined for their correlation with metabolic status.
Results:
In 26 of 30 patients with completed IC, mean REE at 8 hours after surgery was 57 ± 20 kcal/kg/d, and mean VO(2) was 110 ± 35 mL/min. Mean values of VO(2) and REE did not change within the first 24 hours after surgery. There was poor correlation between MREE at 8 hours and the EEE using the World Health Organization equation (r = 0.32, P = .11). Most patients (n = 19, 73%) were either normometabolic or hypometabolic. Lack of hypermetabolism was significantly associated with higher intraoperative serum lactate level and positive fluid balance compared with the rest of the group.
Conclusions:
The authors report a low prevalence of hypermetabolism in children with single-ventricle defects after Fontan surgery. Measured REE had poor correlation with equation-estimated energy expenditure in a majority of the cohort. The absence of increased energy expenditure after CPB will influence energy prescription in this group.
