title: Energy expenditure and caloric and protein intake in infants following the Norwood procedure.
abstract: OBJECTIVE
  Cardiopulmonary bypass in infants results in a hypermetabolic response. Energy requirements of these patients have not been well studied. We assessed energy expenditure and caloric and protein intake during the first 3 days following the Norwood procedure.
  
  
  METHODS
  Clinical investigation.
  
  
  METHODS
  Children's hospital.
  
  
  METHODS
  Seventeen infants (15 boys, age 4-92 days, median 7 days).
  
  
  METHODS
  VO2 and VCO2 were continuously measured using respiratory mass spectrometry in 17 infants for the first 72 hrs following the Norwood procedure. The respiratory quotient was determined as VCO2/VO2. Energy expenditure was calculated using the modified Weir equation. Measurements were collected at 2- to 4-hr intervals. The mean values in the first 8 hrs, hours 8-32, hours 32-56, and the last 16 hrs were used as representative values for postoperative days 0, 1, 2, and 3. Total caloric and protein intakes were recorded for each day.
  
  
  RESULTS
  Energy expenditure, VO2, and VCO2 were initially high; declined rapidly during the first 8 hrs; and were maintained relatively stable in the following hours (p < .0001). Respiratory quotient showed a significant linear increase over the 72 hrs (p = .002). Energy expenditure on days 0, 1, 2, and 3 was 43 +/- 11, 39 +/- 8, 39 +/- 8, and 41 +/- 6 kcal/kg/day, respectively. Total caloric intake was 3 +/- 1, 14 +/- 5, 31 +/- 16, and 51 +/- 16 kcal/kg/day. Protein intake was 0, 0.2 +/- 0.2, 0.6 +/- 0.5, and 0.9 +/- 0.5 g/kg/day on days 0, 1, 2, and 3, respectively.
  
  
  CONCLUSIONS
  Infants exhibit a hypermetabolic response immediately following the Norwood procedure. Caloric and protein intake was inadequate to meet energy expenditure during the first 2 days after surgery. Further studies are warranted to examine the effects of caloric and protein supplementation on postoperative outcomes in infants after cardiopulmonary bypass.
authors.affiliation: Cardiac Program, the Hospital for Sick Children, Toronto, Ontario, Canada. jia.li@sickkids.ca
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Gencheng
authors.initials: G
authors.lastname: Zhang
authors.forename: Joann
authors.initials: J
authors.lastname: Herridge
authors.forename: Helen
authors.initials: H
authors.lastname: Holtby
authors.forename: Tilman
authors.initials: T
authors.lastname: Humpl
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Redington
authors.forename: Glen S
authors.initials: GS
authors.lastname: Van Arsdell
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D002315:Cardiopulmonary Bypass; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D013058:Mass Spectrometry; D008991:Monitoring, Physiologic / Q000379:methods; D009751:Nutritional Requirements; D009864:Ontario; D010101:Oxygen Consumption; D019990:Perioperative Care / Q000379:methods; D011506:Proteins / Q000008:administration & dosage*
chemical_list: D011506:Proteins; D002245:Carbon Dioxide