Related Experiment Video
Updated: Mar 27, 2026
Transuterine Fetal Tracheal Occlusion Model in Mice
Published on: February 5, 2021
Resting energy expenditure, macronutrient utilization, and body composition in term infants after corrective surgery
L Pereira-da-Silva1,2,3, L Rodrigues2, A C Moreira3
1Neonatal Intensive Care Unit, Hospital Dona Estefânia, Centro Hospitalar de Lisboa Central, Lisbon, Portugal.
Insights
Infants undergoing surgery showed unexpected fat loss during recovery, followed by fat gain. This suggests specific metabolic needs for catch-up growth, impacting body composition and energy expenditure.
Area of Science:
- Pediatric Metabolism
- Nutritional Science
- Surgical Recovery
Background:
- Limited understanding of infant metabolic changes and nutritional needs during the postsurgical anabolic phase.
- Investigating resting energy expenditure (REE) and macronutrient utilization in infants after major congenital anomaly surgery.
Purpose of the Study:
- To explore associations between REE, macronutrient utilization, and body composition in term infants during postsurgical catch-up growth.
- To characterize metabolic adaptations following corrective surgery for congenital anomalies.
Main Methods:
- Indirect calorimetry (Deltatrac II) to measure REE and respiratory quotient (RQ) for macronutrient utilization.
- Air displacement plethysmography (Pea Pod) to assess body composition (fat-free mass, fat mass, adiposity).
- Study included full-term infants post-weight gain after corrective surgery.
Main Results:
- Four infants (3-5 weeks postnatal) received standard nutritional intake.
- Median REE was 70.8 Kcal/Kg FFM/d, with a median RQ of 0.99.
- Weight and FFM gains correlated with initial fat mass and adiposity decrease, followed by an increase; low RQ preceded adiposity decrease.
Conclusions:
- Unexpected adiposity depletion observed during postsurgical weight gain in infants.
- Subsequent adiposity catch-up linked to high REE and RQ, indicating carbohydrate oxidation and lipid preservation for fat storage.
Introduction:
Knowledge on the metabolic changes and nutritional needs during the postsurgical anabolic phase in infants is scarce. This analysis explores the associations of resting energy expenditure (REE) and macronutrient utilization with body composition of full-term infants, during catch-up growth after corrective surgery of major congenital anomalies.
Methods:
A cohort of full-term appropriate for-gestational-age neonates subjected to corrective surgery of major congenital anomalies were recruited after gaining weight for at least one week. REE and macronutrient utilization, measured by respiratory quotient (RQ), were assessed by indirect calorimetry using the Deltatrac II Metabolic Monitor ®. Body composition, expressed as fat-free mass (FFM), fat mass (FM) and adiposity defined as percentage of FM (% FM), was measured by air displacement plethysmography using the Pea Pod ®.
Results:
Four infants were included at 3 to 5 postnatal weeks. Recommended energy and macronutrient intakes for healthy term infants were provided. Through the study, the median (min-max) REE (Kcal/Kg FFM/d) was 70.8 (60.6-96.1) and RQ was 0.99 (0.72-1.20). Steady increases in both body weight and FFM were associated with initial decrease in FM and adiposity followed by their increase. Low RQ preceded decrease in adiposity.
Conclusion:
The marked adiposity depletion, not expected during steady weight gain in the postsurgical period, prompts us to report this finding. The subsequent adiposity catch-up was associated with relatively high REE and RQ, suggesting preferential oxidation of carbohydrates and preservation of lipids for fat storage.
