title: The effect of clonidine on perioperative blood coagulation.
abstract: OBJECTIVE
  To evaluate the influence of perioperative stress protection by clonidine on blood coagulation.
  
  
  METHODS
  Prospective, randomized, double-blinded, placebo-controlled clinical trial.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  50 patients scheduled for elective gynecoabdominal surgery.
  
  
  METHODS
  Patients were randomly assigned to control (placebo) or clonidine group (single intravenous clonidine dose; 4 microg/kg(-1) or 3 microg/kg(-1) for age >65 years). Three measurement time points were defined: before administration of placebo/clonidine and anesthesia induction, (t1; baseline measurement); after surgery, before emergence of anesthesia (t2); and at the first postoperative day, 24 hours after anesthesia induction (t3). Blood coagulation was analyzed at all time points measuring international normalized ratio, platelets, thrombin-antithrombin complex, von Willebrand factor, soluble thrombomodulin, d-dimers, plasminogen activator inhibitor 1, and Thrombelastograph analysis.
  
  
  RESULTS
  In the postoperative period (t2, t3), hypercoagulability was present in all patients compared with baseline measurements (t1) but without differences between the control and clonidine group. Regarding hematologic, laboratory blood coagulation, and Thrombelastograph parameters, there was no statistically and clinically relevant difference throughout the study period between the 2 groups. No hemodynamic adverse events of clonidine were observed in the perioperative period. Until day of discharge, no thrombotic or thromboembolic events were reported in both groups.
  
  
  CONCLUSIONS
  Preoperative administration of a single dose of clonidine has no effect on perioperative blood coagulation.
authors.affiliation: Department of Anesthesiology, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Ganter
authors.forename: Christoph K
authors.initials: CK
authors.lastname: Hofer
authors.forename: Donat R
authors.initials: DR
authors.lastname: Spahn
authors.forename: Marcel
authors.initials: M
authors.lastname: Bruggisser
authors.forename: Thomas
authors.initials: T
authors.lastname: Bombeli
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Seifert
authors.forename: Thomas
authors.initials: T
authors.lastname: Pasch
authors.forename: Marco P
authors.initials: MP
authors.lastname: Zalunardo
mesh_terms: D000005:Abdomen / Q000601:surgery; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000328:Adult; D000768:Anesthesia, General; D001777:Blood Coagulation / Q000187:drug effects*; D001780:Blood Coagulation Tests; D003000:Clonidine / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D013509:Gynecologic Surgical Procedures; D006801:Humans; D007432:Intraoperative Period; D008875:Middle Aged; D013916:Thrombelastography
chemical_list: D000316:Adrenergic alpha-Agonists; D003000:Clonidine