title: The anabolic effect of perioperative nutrition depends on the patient's catabolic state before surgery.
abstract: OBJECTIVE
  We tested the hypothesis that the anabolic effect of hypocaloric, isonitrogenous nutrition in patients undergoing colorectal surgery depends on the patient's preoperative catabolic state.
  
  
  BACKGROUND
  Although there is evidence to suggest that total parenteral nutrition more effectively spares protein in depleted than in nondepleted cancer patients, the influence of preoperative catabolism on the anabolic effects of hypocaloric nutrition in patients undergoing elective surgery is unknown.
  
  
  METHODS
  Seventeen patients undergoing colorectal surgery received intravenous infusion of glucose with amino acids. Feeding was administered over 72 hours, from 24 hours before until 48 hours after surgery. Glucose provided 50% of the patient's measured resting energy expenditure. Amino acids provided 20% of the resting energy expenditure. Whole-body leucine balance (difference between the incorporation of leucine into protein = protein synthesis and endogenous leucine release = proteolysis) was determined using L-[1-(13)C]leucine kinetics before and 2 days after surgery. We analyzed the association between the postoperative increase in leucine balance and the following factors: preoperative leucine balance, protein breakdown, weight loss, oxygen consumption, circulating concentrations of glucose, free fatty acids, insulin, glucagon, cortisol, albumin, age, duration of surgery, and blood loss.
  
  
  RESULTS
  Of 6 potentially relevant variables, 4 (weight loss, protein breakdown, albumin, and cortisol) were removed because they were not significant during the stepwise linear regression procedure. Leucine balance and age were the remaining 2 factors that remained with the final regression model: Δleucine balance = 19.1 - (0.20 × age [years]) - (0.58) × leucine balance(preOP)).
  
  
  CONCLUSIONS
  We demonstrate a significant association between the degree of preoperative catabolism, the patient's age, and the anabolic effect of hypocaloric nutrition (ClinicalTrials.gov registration ID: NCT01414946).
authors.affiliation: Department of Anaesthesia, McGill University, Montreal, Quebec, Canada. thomas.schricker@mcgill.ca
authors.forename: Thomas
authors.initials: T
authors.lastname: Schricker
authors.forename: Linda
authors.initials: L
authors.lastname: Wykes
authors.forename: Sarkis
authors.initials: S
authors.lastname: Meterissian
authors.forename: Roupen
authors.initials: R
authors.lastname: Hatzakorzian
authors.forename: Leopold
authors.initials: L
authors.lastname: Eberhart
authors.forename: George
authors.initials: G
authors.lastname: Carvalho
authors.forename: Ari
authors.initials: A
authors.lastname: Meguerditchian
authors.forename: Evan
authors.initials: E
authors.lastname: Nitschmann
authors.forename: Ralph
authors.initials: R
authors.lastname: Lattermann
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D003082:Colectomy; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000601:surgery*; D017558:Elective Surgical Procedures; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007930:Leucine / Q000096:biosynthesis / Q000378:metabolism*; D016014:Linear Models; D008297:Male; D008660:Metabolism / Q000502:physiology*; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena; D009752:Nutritional Status / Q000502:physiology*; D010289:Parenteral Nutrition, Total; D019990:Perioperative Care; D011184:Postoperative Period; D057234:Preoperative Period; D014176:Protein Biosynthesis; D059748:Proteolysis; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D007930:Leucine