title: The effect of Hetastarch (670/0.75) in vivo on platelet closure time in the dog.
abstract: OBJECTIVE
  To evaluate the effect of 6% hydroxyethyl starch (HES) solution in vivo, with an average molecular weight of 670 kDa and degree of substitution of 0.75, on canine platelet function.
  
  
  METHODS
  Prospective, controlled-experimental study.
  
  
  METHODS
  University of California, Davis, Veterinary Medical Teaching Hospital.
  
  
  METHODS
  Seven healthy employee-owned dogs.
  
  
  METHODS
  Seven dogs were included in the treatment group. Four of these dogs also served as the control group. Platelet closure time (CT) was measured using a platelet function analyzer and collagen/ADP cartridges. Dogs were given 20 mL/kg of either sodium chloride 0.9% (control group, n=4) or HES (treatment group, n=7) IV over 1 hour. CT was measured before the infusion, and at 1, 3, 5, and 24 hours after the start of the infusion.
  
  
  RESULTS
  There was a significant change over time from 0 to 24 hours (P<0.001), a significant difference between groups across time (P<0.001), and a significant group-by-time interaction (P=0.007). At 3 hours, mean CT for the treatment group was 122.3+/-18.1 seconds, which was significantly different (P<0.001) from the control group (71.0+/-3.5 s). At 5 hours, mean CT for the treatment group was 142.7+/-33.9 seconds, which was significantly different (P=0.001) from the control group (75.0+/-8.6 s). Mean CT at 24 hours was within the reference interval for both the control and treatment group (66.0+/-2.9 and 81.8+/-11.9 s, respectively); however, CT in 3 individual dogs in the treatment group at this time point remained prolonged.
  
  
  CONCLUSIONS
  A clinically relevant dose of HES 670/0.75 prolongs CT in dogs for up to 24 hours. This may be due to platelet dysfunction in addition to the effects of hemodilution, and therefore, may increase the risk of bleeding.
authors.affiliation: William R Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA, USA. l.smart@murdoch.edu.au
authors.forename: Lisa
authors.initials: L
authors.lastname: Smart
authors.forename: Karl E
authors.initials: KE
authors.lastname: Jandrey
authors.forename: Philip H
authors.initials: PH
authors.lastname: Kass
authors.forename: Janelle R
authors.initials: JR
authors.lastname: Wierenga
authors.forename: Fern
authors.initials: F
authors.lastname: Tablin
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects*; D004285:Dogs / Q000097:blood*; D005260:Female; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology*; D008297:Male
chemical_list: D006895:Hydroxyethyl Starch Derivatives