Feeding-Induced Changes in Energy Expenditure in Children With Cystic Fibrosis

Abstract

Seven children with cystic fibrosis (aged 7 to 12 years) were studied in the fasted and fed states. Using a primed, constant, intravenous infusion of NaH¹³CO₃, the rate of appearance of CO₂ (RaCO₂) was estimated. Net CO₂ excretion (VCO ₂) was also measured. Energy expenditure was calculated using the food quotient. RaCO₂ (mean ± SD) (μmol·kg^-1·min ^-1) in the fasted and fed states (297 ± 59 and 359 ± 67) was 117% and 105% of VCO₂ (259 ±48 and 352 ± 72). Feeding induced a 23% and a 37% increase in RaCO₂ and VCO₂, respectively, and respective 19% and 33% increases in energy expenditure (p < .05). Measurement of CO₂ production by isotopic dilution is a useful index of group changes in energy expenditure, including those induced by feeding. (Journal of Parenteral and Enteral Nutrition 18:497-502, 1994)