title: Microcirculatory effects of intravenous fluid administration in anesthetized dogs undergoing elective ovariohysterectomy.
abstract: OBJECTIVE
  To assess the microcirculatory effects of IV fluid administration in healthy anesthetized dogs undergoing elective ovariohysterectomy.
  
  
  METHODS
  49 client-owned dogs.
  
  
  METHODS
  Dogs were sedated, and anesthesia was induced with propofol and diazepam and maintained with isoflurane in oxygen. Dogs received lactated Ringer's solution (LRS) IV at rates of 0, 10, or 20 mL/kg/h. Videomicroscopy was used to assess and record effects of LRS administration on microcirculation in the buccal mucosa. Measurements of microcirculatory (total vessel density, proportion of perfused vessels, microcirculatory flow index, and perfused vessel density by vessel size [< 20 μm, ≥ 20 μm, and all diameters]) and other physiologic variables (heart rate, Doppler-measured blood pressure, oxygen saturation as measured by pulse oximetry, capillary refill time, and body temperature) were compared among groups at baseline (immediately after anesthetic induction), 30 and 60 minutes afterward, and overall.
  
  
  RESULTS
  Neither the proportion of perfused vessels nor microcirculatory flow index varied among treatment groups at any time point, regardless of vessel size. For vessels < 20 μm in diameter and for all vessels combined, total and perfused vessel density were similar among groups. For vessels ≥ 20 μm in diameter, total vessel density was significantly greater in the 20 mL/kg/h group than in other groups, and perfused vessel density was significantly greater in the 20 mL/kg/h group than in the 0 mL/kg/h group, when all time points were considered. Other physiologic variables were similar among groups.
  
  
  CONCLUSIONS
  Total and perfused vessel density of vessels ≥ 20 μm in diameter (mostly venules) were greatest in dogs that received 20 mL of LRS/kg/h. Further research is required to evaluate clinical importance of these findings.
authors.affiliation: Department of Clinical Studies, Matthew J. Ryan Veterinary Hospital, University of Pennsylvania, Philadelphia, PA 19104.
authors.forename: Deborah C
authors.initials: DC
authors.lastname: Silverstein
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Cozzi
authors.forename: Amber S
authors.initials: AS
authors.lastname: Hopkins
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Keefe
mesh_terms: D061605:Administration, Intravenous; D000758:Anesthesia / Q000662:veterinary; D000818:Animals; D001783:Blood Flow Velocity; D001794:Blood Pressure; D004285:Dogs / Q000502:physiology* / Q000601:surgery; D005260:Female; D005440:Fluid Therapy / Q000662:veterinary; D006339:Heart Rate / Q000187:drug effects; D007044:Hysterectomy / Q000662:veterinary; D007530:Isoflurane / Q000494:pharmacology; D007552:Isotonic Solutions / Q000494:pharmacology*; D008833:Microcirculation / Q000187:drug effects*; D009061:Mouth Mucosa / Q000098:blood supply*; D010052:Ovariectomy / Q000662:veterinary; D015742:Propofol / Q000494:pharmacology; D000077325:Ringer's Lactate
chemical_list: D007552:Isotonic Solutions; D000077325:Ringer's Lactate; D007530:Isoflurane; D015742:Propofol