title: In vitro effects of 3% hypertonic saline and 20% mannitol on canine whole blood coagulation and platelet function.
abstract: BACKGROUND
  Hyperosmolar therapy, using either mannitol or hypertonic saline (HTS), is considered the treatment of choice for intracranial hypertension. However, hyperosmolar agents may impair coagulation and platelet function, limiting their use in patients at risk for hemorrhage. Despite this, studies evaluating the effects of mannitol compared to other hyperosmolar agents in dogs are largely lacking. The aim of this study was to compare the in vitro effects on global hemostasis and platelet function of 20% mannitol and 3% HTS on canine blood.
  
  
  METHODS
  Citrated whole blood from 15 healthy dogs was diluted with 0.9% saline, 20% mannitol and 3% HTS in ratios of 1:16 and 1:8. Rotational thromboelastometry (ROTEM) was used to assess clotting time (CT), clot formation time (CFT) and maximal clot firmness (MCF) following extrinsic activation (Ex-tem) and after platelet inhibition (Fib-tem). A platelet function analyzer (PFA-100) was used to assess closure time (Ct(PFA)).
  
  
  RESULTS
  No significant differences were observed between untreated whole blood and samples diluted with saline. Samples diluted with both mannitol and HTS were hypocoagulable compared to untreated whole blood samples. At a dilution of 1:16, no significant differences were found between any measured parameter in samples diluted with saline compared to mannitol or HTS. At a 1:8 dilution, Ct(PFA) was prolonged in samples diluted with mannitol and HTS compared to saline, and Ct(PFA) was prolonged more with mannitol than HTS. Ex-tem CT was increased at a 1:8 dilution with mannitol compared to HTS. Ex-tem CFT was prolonged at a 1:8 dilution with both agents compared to saline, and was prolonged more with mannitol than HTS. Ex-tem MCF was reduced at a 1:8 dilution with both agents compared to saline.
  
  
  CONCLUSIONS
  Data in this study indicate that both mannitol and HTS affect canine platelet function and whole blood coagulation in vitro in a dose-dependent fashion. The most pronounced effects were observed after high dilutions with mannitol, which impaired platelet aggregation, clot formation time, clot strength, and fibrin formation significantly more than HTS. Further in vivo studies are necessary before recommendations can be made.
authors.affiliation: Division of Emergency and Critical Care, Small Animal Clinic, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Laenggassstrasse 128, 3012, Bern, Switzerland. katja.adamik@vetsuisse.unibe.ch.
authors.forename: Katja-Nicole
authors.initials: KN
authors.lastname: Adamik
authors.affiliation: Division of Emergency and Critical Care, Small Animal Clinic, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Laenggassstrasse 128, 3012, Bern, Switzerland. emmanuelle.butty@bluewin.ch.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Butty
authors.affiliation: Clinical Diagnostic Laboratory, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Laenggassstrasse 124, 3012, Bern, Switzerland. judith.howard@vetsiusse.unibe.ch.
authors.forename: Judith
authors.initials: J
authors.lastname: Howard
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects*; D001792:Blood Platelets / Q000187:drug effects; D004285:Dogs / Q000097:blood*; D008353:Mannitol / Q000494:pharmacology*; D010979:Platelet Function Tests / Q000662:veterinary*; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D014914:Whole Blood Coagulation Time / Q000662:veterinary*
chemical_list: D012462:Saline Solution, Hypertonic; D008353:Mannitol