title: Comparative effects on glucose absorption of intragastric and post-pyloric nutrient delivery in the critically ill.
abstract: BACKGROUND
  Studies in the critically ill that evaluate intragastric and post-pyloric delivery of nutrient have yielded conflicting data. A limitation of these studies is that the influence in the route of feeding on glucose absorption and glycaemia has not been determined.
  
  
  METHODS
  In 68 mechanically ventilated critically ill patients, liquid nutrient (100 ml; 1 kcal/ml containing 3 g of 3-O-Methyl-D-glucopyranose (3-OMG), as a marker of glucose absorption), was infused into either the stomach (n = 24) or small intestine (n = 44) over six minutes. Blood glucose and serum 3-OMG concentrations were measured at regular intervals for 240 minutes and the area under the curves (AUCs) calculated for 'early' (AUC60) and 'overall' (AUC240) time periods. Data are presented as mean (95% confidence intervals).
  
  
  RESULTS
  Glucose absorption was initially more rapid following post-pyloric, when compared with intragastric, feeding (3-OMG AUC60: intragastric 7.3 (4.3, 10.2) vs. post-pyloric 12.5 (10.1, 14.8) mmol/l.min; P = 0.008); however, 'overall' glucose absorption was similar (AUC240: 49.1 (34.8, 63.5) vs. 56.6 (48.9, 64.3) mmol/l.min; P = 0.31). Post-pyloric administration of nutrients was also associated with greater increases in blood glucose concentrations in the 'early' period (AUC60: 472 (425, 519) vs. 534 (501, 569) mmol/l.min; P = 0.03), but 'overall' glycaemia was also similar (AUC240: 1,875 (1,674, 2,075) vs. 1,898 (1,755, 2,041) mmol/l.min; P = 0.85).
  
  
  CONCLUSIONS
  In the critically ill, glucose absorption was similar whether nutrient was administered via a gastric or post-pyloric catheter. These data may have implications for the perceived benefit of post-pyloric feeding on nutritional outcomes and warrant further investigation.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Di Bartolomeo
authors.forename: Marianne J
authors.initials: MJ
authors.lastname: Chapman
authors.forename: Antony
authors.initials: A
authors.lastname: V Zaknic
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Summers
authors.forename: Karen L
authors.initials: KL
authors.lastname: Jones
authors.forename: Nam Q
authors.initials: NQ
authors.lastname: Nguyen
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Rayner
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Adam M
authors.initials: AM
authors.lastname: Deane
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D016638:Critical Illness / Q000628:therapy*; D004750:Enteral Nutrition / Q000379:methods*; D005260:Female; D065570:Gastric Absorption / Q000502:physiology*; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism*; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011708:Pylorus / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: D001786:Blood Glucose; D005947:Glucose