Respiratory quotient changes in full term newborn infants within 30 hours from birth before start of milk feeding

Abstract

Objective: To evaluate substrate utilization in full-term newborn infants, fed every 3–4 h with glucose 10% solution, within 30 h from birth.

Design: Random.

Setting: Full term newborn infants at the Paediatric Division City Major Hospital, Chair of Paediatrics, Verona University.

Subjects: Forty-six newborn infants, 24 females and 22 males of 39±2 weeks gestational age.

Methods: Oxygen consumption (VO₂) and CO₂ production (VCO₂) were measured. Permitting the computation of the respiratory quotient (RQ), which expresses substrate oxidation, at 6 and 30 h from birth. An indirect calorimeter (Deltratrac TMII-MBM-200-DATEX) was used to measure components of energy-balance.

Results: Energy expenditure calculated at 6 h was 8.130 (±1.5757) kJ/kg/h. At 30 h the value changed to8.858 (±1.483) kJ/kg/h. Statistical evaluation (t-student) showed a significant (P=0.000) variation in RQvalues (6 h: RQ=0.94; 30 h: RQ=0.88).

Conclusions: Respiratory quotient suggests an increase of energy derived from fat metabolism at 30 h from birth. Our data confirm that early breast feeding or formula milk feeding could represent a physiological approach to nutritional regimen of the newborn infant.

Sponsorship: University of Verona, Italy.