title: Systemic, renal, and colonic effects of intravenous and enteral rehydration in horses.
abstract: BACKGROUND
  Intravenous (IV) and intragastric (IG) administration of fluid therapy are commonly used in equine practice, but there are limited data on the systemic, renal, and enteric effects.
  
  
  OBJECTIVE
  IV fluid administration will increase intestinal and fecal hydration in a rate-dependent manner after hypertonic dehydration, but will be associated with significant urinary water and electrolyte loss. Equivalent volumes of IG plain water will result in comparatively greater intestinal hydration with less renal loss.
  
  
  METHODS
  Six Thoroughbred geldings.
  
  
  METHODS
  Experimental study. 6 by 6 Latin square design investigating constant rate IV administration at 50, 100, and 150 mL/kg/d over 24 hours in horses dehydrated by water deprivation. Equivalent volumes of IG plain water were administered by 4 bolus doses over 24 hours.
  
  
  RESULTS
  Water deprivation resulted in a significant decrease in the percentage of fecal water, and increases in serum and urine osmolality. IV fluids administered at 100 and 150 mL/kg/d restored fecal hydration, but increasing the rate from 100 to 150 mL/kg/d did not confer any additional intestinal benefit, but did result in significantly greater urine production and sodium loss. Equivalent 24-hour volumes of plain water resulted in greater intestinal water and less urine output.
  
  
  CONCLUSIONS
  IV polyionic isotonic fluids can be used to hydrate intestinal contents in situations where enteral fluids are impractical. IV fluids administered at three times maintenance are no more efficacious and might be associated with adverse physiological findings after withdrawal. Bolus dosing of IG water can be used to restore intestinal water with minimal adverse effects.
authors.affiliation: College of Veterinary Medicine, School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA, Australia. G.Lester@murdoch.edu.au
authors.forename: G D
authors.initials: GD
authors.lastname: Lester
authors.forename: A M
authors.initials: AM
authors.lastname: Merritt
authors.forename: H V
authors.initials: HV
authors.lastname: Kuck
authors.forename: J A
authors.initials: JA
authors.lastname: Burrow
mesh_terms: D000284:Administration, Oral; D000818:Animals; D003681:Dehydration / Q000188:drug therapy / Q000662:veterinary*; D005243:Feces / Q000737:chemistry; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007275:Injections, Intravenous; D008297:Male; D015532:Rehydration Solutions / Q000008:administration & dosage / Q000627:therapeutic use*; D013997:Time Factors; D014868:Water Deprivation
chemical_list: D015532:Rehydration Solutions