title: Effects of Posture and Meal Volume on Gastric Emptying, Intestinal Transit, Oral Glucose Tolerance, Blood Pressure and Gastrointestinal Symptoms After Roux-en-Y Gastric Bypass.
abstract: BACKGROUND
  The purpose of this study is to determine the effects of posture and drink volume on gastric/pouch emptying (G/PE), intestinal transit, hormones, absorption, glycaemia, blood pressure and gastrointestinal (GI) symptoms after gastric bypass (Roux-en-Y gastric bypass (RYGB)).
  
  
  METHODS
  Ten RYGB subjects were studied on four occasions in randomized order (sitting vs. supine posture; 50 vs. 150 ml of labelled water mixed with 3 g 3-O-methyl-D-glucose (3-OMG) and 50 g glucose). G/PE, caecal arrival time (CAT), blood glucose, plasma insulin, glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), peptide YY (PYY), 3-OMG, blood pressure, heart rate and GI symptoms were assessed over 240 min. Controls were ten volunteers with no medical condition or previous abdominal surgery, who were studied with the 150-ml drink in the sitting position.
  
  
  RESULTS
  Compared to controls, PE (P < 0.001) and CAT (P < 0.001) were substantially more rapid in RYGB subjects. In RYGB, PE was more rapid in the sitting position (2.5 ± 0.7 vs. 16.6 ± 5.3 min, P = 0.02) and tends to be faster after 150 ml than the 50-ml drinks (9.5 ± 2.9 vs. 14.0 ± 3.5 min, P = 0.16). The sitting position and larger volume drinks were associated with greater releases of insulin, GLP-1 and PYY, as well as more hypotension (P < 0.01), tachycardia (P < 0.01) and postprandial symptoms (P < 0.001).
  
  
  CONCLUSIONS
  Pouch emptying, blood pressure and GI symptoms after RYGB are dependent on both posture and meal volume.
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, North Terrace, Adelaide, SA, 5000, Australia, quoc.nguyen@health.sa.gov.au.
authors.forename: Nam Q
authors.initials: NQ
authors.lastname: Nguyen
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Debreceni
authors.forename: Carly M
authors.initials: CM
authors.lastname: Burgstad
authors.forename: Judith M
authors.initials: JM
authors.lastname: Wishart
authors.forename: Max
authors.initials: M
authors.lastname: Bellon
authors.forename: Chris K
authors.initials: CK
authors.lastname: Rayner
authors.forename: Gary A
authors.initials: GA
authors.lastname: Wittert
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects*; D005746:Gastric Emptying / Q000502:physiology*; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000209:etiology*; D005772:Gastrointestinal Transit / Q000502:physiology*; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D062407:Meals / Q000502:physiology*; D008875:Middle Aged; D009767:Obesity, Morbid / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D019518:Postprandial Period; D011187:Posture / Q000502:physiology*; D011897:Random Allocation
chemical_list: D001786:Blood Glucose; D007328:Insulin