title: Low- and medium-molecular-weight hydroxyethyl starches: comparison of their effect on blood coagulation.
abstract: BACKGROUND
  High-molecular-weight hydroxyethyl starch (HES) compromises blood coagulation more than medium-molecular-weight HES. The authors compared medium molecular weight HES (200 kd [HES200]) and low-molecular-weight HES (70 kd [HES70]).
  
  
  METHODS
  In a prospective, double-blind, randomized-sequence crossover study, 22 male volunteers received 15 ml/kg HES200 and HES70. Blood samples were taken before and 5 min, 30 min, 1 h, 2 h, 4 h, 8 h, and 24 h after infusion. The following parameters were analyzed at all time points: prothrombin time, activated partial thromboplastin time, fibrinogen, factor VIII, antigenetic and functional von Willebrand factor, platelets, Thrombelastograph analysis parameters (reaction time, coagulation time, maximum amplitude, angle alpha, and clot lysis 30 and 60 min after maximum amplitude), ionized calcium, hematocrit, HES plasma concentration, molecular weight (weight average and number average), molar substitution, and polydispersity (weight average/number average). Repeated-measures analysis of variance (P < 0.05) was used to compare the response of the aforementioned parameters to the infusion of HES70 and HES200.
  
  
  RESULTS
  Both HES solutions had a significant impact on all parameters. A slightly greater compromise with HES200 was found in activated partial thromboplastin time (P = 0.010), factor VIII (P = 0.009), antigenetic von Willebrand factor (P = 0.041), functional von Willebrand factor (P = 0.026), maximum amplitude (P = 0.008), and angle alpha (P = 0.003). No difference was established with the other parameters. HES concentration (P < 0.001), weight average (P < 0.001), number average (P < 0.001), and polydispersity (P < 0.001) were higher with HES200. There was no difference with molar substitution (P = 0.091).
  
  
  CONCLUSIONS
  Low-molecular-weight hydroxyethyl starch (70 kd) compromises blood coagulation slightly less than HES200, but it is unclear whether this is clinically relevant.
authors.affiliation: Institute of Anesthesiology, University Hospital, Zurich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Jamnicki
authors.forename: T
authors.initials: T
authors.lastname: Bombeli
authors.forename: B
authors.initials: B
authors.lastname: Seifert
authors.forename: A
authors.initials: A
authors.lastname: Zollinger
authors.forename: V
authors.initials: V
authors.lastname: Camenzind
authors.forename: T
authors.initials: T
authors.lastname: Pasch
authors.forename: D R
authors.initials: DR
authors.lastname: Spahn
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008970:Molecular Weight; D010952:Plasma Substitutes / Q000494:pharmacology*; D011446:Prospective Studies; D011517:Prothrombin Time; D013916:Thrombelastography
chemical_list: D006454:Hemoglobins; D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes