title: Fluid balance, glomerular filtration rate, and urine output in dogs anesthetized for an orthopedic surgical procedure.
abstract: OBJECTIVE
  To determine fluid retention, glomerular filtration rate, and urine output in dogs anesthetized for a surgical orthopedic procedure.
  
  
  METHODS
  23 dogs treated with a tibial plateau leveling osteotomy.
  
  
  METHODS
  12 dogs were used as a control group. Cardiac output was measured in 5 dogs, and 6 dogs received carprofen for at least 14 days. Dogs received oxymorphone, atropine, propofol, and isoflurane for anesthesia (duration, 4 hours). Urine and blood samples were obtained for analysis every 30 minutes. Lactated Ringer's solution was administered at 10 mL/kg/h. Urine output was measured and glomerular filtration rate was estimated. Fluid retention was measured by use of body weight, fluid balance, and bioimpedance spectroscopy.
  
  
  RESULTS
  No difference was found among control, cardiac output, or carprofen groups, so data were combined. Median urine output and glomerular filtration rate were 0.46 mL/kg/h and 1.84 mL/kg/min. Dogs retained a large amount of fluids during anesthesia, as indicated by increased body weight, positive fluid balance, increased total body water volume, and increased extracellular fluid volume. The PCV, total protein concentration, and esophageal temperature decreased in a linear manner.
  
  
  CONCLUSIONS
  Dogs anesthetized for a tibial plateau leveling osteotomy retained a large amount of fluids, had low urinary output, and had decreased PCV, total protein concentration, and esophageal temperature. Evaluation of urine output alone in anesthetized dogs may not be an adequate indicator of fluid balance.
authors.affiliation: Department of Surgical & Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, USA. pboscan@colostate.edu
authors.forename: Pedro
authors.initials: P
authors.lastname: Boscan
authors.forename: Bruno H
authors.initials: BH
authors.lastname: Pypendop
authors.forename: Kristine T
authors.initials: KT
authors.lastname: Siao
authors.forename: Thierry
authors.initials: T
authors.lastname: Francey
authors.forename: Kristy
authors.initials: K
authors.lastname: Dowers
authors.forename: Larry
authors.initials: L
authors.lastname: Cowgill
authors.forename: Jan E
authors.initials: JE
authors.lastname: Ilkiw
mesh_terms: D000758:Anesthesia / Q000379:methods / Q000662:veterinary*; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001831:Body Temperature; D002302:Cardiac Output; D004231:Diuresis / Q000502:physiology*; D004283:Dog Diseases / Q000503:physiopathology / Q000601:surgery; D004285:Dogs / Q000502:physiology*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D007530:Isoflurane / Q000627:therapeutic use; D008297:Male; D016343:Monitoring, Intraoperative / Q000662:veterinary; D019637:Orthopedic Procedures / Q000662:veterinary*; D010111:Oxymorphone / Q000627:therapeutic use; D016119:Posterior Cruciate Ligament / Q000601:surgery*; D015742:Propofol / Q000627:therapeutic use; D012422:Rupture, Spontaneous / Q000601:surgery / Q000662:veterinary
chemical_list: D010111:Oxymorphone; D007530:Isoflurane; D015742:Propofol