title: Delayed enteral feeding impairs intestinal carbohydrate absorption in critically ill patients.
abstract: OBJECTIVE
  Delay in initiating enteral nutrition has been reported to disrupt intestinal mucosal integrity in animals and to prolong the duration of mechanical ventilation in humans. However, its impact on intestinal absorptive function in critically ill patients is unknown. The aim of this study was to examine the impact of delayed enteral nutrition on small intestinal absorption of 3-O-methyl-glucose.
  
  
  METHODS
  Prospective, randomized study.
  
  
  METHODS
  Tertiary critical care unit.
  
  
  METHODS
  Studies were performed in 28 critically ill patients.
  
  
  METHODS
  Patients were randomized to either enteral nutrition within 24 hrs of admission (14 "early feeding": 8 males, 6 females, age 54.9 ± 3.3 yrs) or no enteral nutrition during the first 4 days of admission (14 "delayed feeding": 10 males, 4 females, age 56.1 ± 4.2 yrs).
  
  
  RESULTS
  Gastric emptying (scintigraphy, 100 mL of Ensure (Abbott Australia, Kurnell, Australia) with 20 MBq Tc-suphur colloid), intestinal absorption of glucose (3 g of 3-O-methyl-glucose), and clinical outcomes were assessed 4 days after intensive care unit admission. Although there was no difference in gastric emptying, plasma 3-O-methyl-glucose concentrations were less in the patients with delayed feeding compared to those who were fed earlier (peak: 0.24 ± 0.04 mmol/L vs. 0.37 ± 0.04 mmol/L, p < .02) and integrated (area under the curve at 240 mins: 38.5 ± 7.0 mmol/min/L vs. 63.4 ± 8.3 mmol/min/L, p < .04). There was an inverse correlation between integrated plasma concentrations of 3-O-methyl-glucose (area under the curve at 240 mins) and the duration of ventilation (r = -.51; p = .006). In the delayed feeding group, both the duration of mechanical ventilation (13.7 ± 1.9 days vs. 9.2 ± 0.9 days; p = .049) and length of stay in the intensive care unit (15.9 ± 1.9 days vs. 11.3 ± 0.8 days; p = .048) were greater.
  
  
  CONCLUSIONS
  In critical illness, delaying enteral feeding is associated with a reduction in small intestinal glucose absorption, consistent with the reduction in mucosal integrity after nutrient deprivation evident in animal models. The duration of both mechanical ventilation and length of stay in the intensive care unit are prolonged. These observations support recommendations for "early" enteral nutrition in critically ill patients.
authors.affiliation: Department of Gastroenterology & Hepatology, Royal Adelaide Hospital, School of Medicine, University of Adelaide, Adelaide, South Australia. quoc.nguyen@health.sa.gov.au
authors.forename: Nam Q
authors.initials: NQ
authors.lastname: Nguyen
authors.forename: Laura K
authors.initials: LK
authors.lastname: Besanko
authors.forename: Carly
authors.initials: C
authors.lastname: Burgstad
authors.forename: Max
authors.initials: M
authors.lastname: Bellon
authors.forename: Richard H
authors.initials: RH
authors.lastname: Holloway
authors.forename: Marianne
authors.initials: M
authors.lastname: Chapman
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Robert J L
authors.initials: RJ
authors.lastname: Fraser
mesh_terms: D019325:3-O-Methylglucose / Q000378:metabolism; D050260:Carbohydrate Metabolism; D016638:Critical Illness / Q000628:therapy*; D004750:Enteral Nutrition / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D008875:Middle Aged; D013997:Time Factors
chemical_list: D019325:3-O-Methylglucose