title: The effects on gastric emptying and carbohydrate loading of an oral nutritional supplement and an oral rehydration solution: a crossover study with magnetic resonance imaging.
abstract: BACKGROUND
  Preoperative administration of clear fluids by mouth has recently been endorsed as a way to improve postoperative outcomes. A carbohydrate-containing beverage supplemented with electrolytes or proteins may have additional benefits for patients' satisfaction. However, effects on gastric residual, nausea, and emesis and the effectiveness of these beverages for improving patients' hydration status have not been well defined.
  
  
  METHODS
  We evaluated changes in gastric volume over time by magnetic resonance imaging, as well as blood glucose levels, before and after administration of 500 mL oral rehydration solution (ORS) containing 1.8% glucose and electrolytes in 10 healthy volunteers. The same volume of an oral nutritional supplement (ONS) containing 18% glucose and supplemental arginine (545 mOsm/kg) was given to the same population using a crossover design.
  
  
  RESULTS
  The mean (median, 95% confidence interval) gastric fluid volume at 1 hour after oral ingestion was 55.0 (55.3, 39.0-70.9) mL in the ORS group, whereas 409.2 (410.9, 371.4-447.0) mL in the ONS group (P = 0.0002). The gastric fluid volume of all participants in the ORS group returned to <1 mL/kg at 90 minutes after ingestion, whereas none reached <1 mL/kg at 120 minutes in the ONS group. The ONS group showed a sustained increase in the blood glucose level after ingestion (P < 0.0001 to baseline at 30, 60, 120 minutes), while the ORS group showed an initial increase (P < 0.0001, P = 0.01, P = 0.205 at each time point).
  
  
  CONCLUSIONS
  ORS supplemented with a small amount of glucose showed faster gastric emptying, which may make it suitable for preoperative administration. In contrast, ONS supplemented with arginine with a relatively low osmolality was associated with a longer time for gastric emptying, although it showed a sustained increase in blood glucose level.
authors.affiliation: From the Departments of *Anesthesiology and Pain Relief Center and †Radiology, The University of Tokyo Hospital, Tokyo, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Nakamura
authors.forename: Kanji
authors.initials: K
authors.lastname: Uchida
authors.forename: Masaaki
authors.initials: M
authors.lastname: Akahane
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000328:Adult; D001120:Arginine / Q000008:administration & dosage / Q000627:therapeutic use; D001786:Blood Glucose / Q000378:metabolism; D016001:Confidence Intervals; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D023381:Endpoint Determination; D005440:Fluid Therapy / Q000379:methods*; D005746:Gastric Emptying; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D017060:Patient Satisfaction; D020250:Postoperative Nausea and Vomiting / Q000453:epidemiology / Q000517:prevention & control; D011300:Preoperative Care; D015532:Rehydration Solutions; D018401:Sample Size; D013270:Stomach / Q000033:anatomy & histology; D016896:Treatment Outcome
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D015532:Rehydration Solutions; D001120:Arginine