title: Hydroxyethyl starch impairs in vitro coagulation.
abstract: BACKGROUND
  Artificial colloids affect haemostasis. Particularly hydroxyethyl starch (HES) solutions may have detrimental effects on haemostatic mechanisms.
  
  
  METHODS
  In a crossover study blood was withdrawn from ten volunteers. Ringer's acetate, 6% low molecular weight HES (MW 120,000/molar substitution ratio 0.7), 10% low molecular weight HES MW 200,000/0.5) and 6% high molecular weight HES (MW 400,000/0.7) or 4% albumin was added to venous blood samples to make either 20 vol.% or 50 vol.% concentrations of each of the solutions. Samples were analyzed by thrombelastography (TEG).
  
  
  RESULTS
  All HES solutions at 20 vol.% concentration impaired haemostasis as demonstrated by decreased clot formation rate (alpha-angle and maximum amplitude (MA)). In contrast, Ringer's acetate and albumin improved coagulability at 20 vol.% concentrations. Coagulation time (r + K) was prolonged at 50 vol.% dilutions of all solutions. The median r + K was greater with HES 400 (P < 0.05) and HES 200 (N.S.) than with HES 120.
  
  
  CONCLUSIONS
  We conclude that HES at 20 and 50 vol.% concentrations has an adverse effect on in vitro measures of coagulation. A 50% dilution with high molecular weight HES seems to impair coagulation more than low molecular weight HES. Ringer's acetate and albumin caused a hypercoagulable state at a concentration of 20 vol.%, but the higher concentration decreased coagulability.
authors.affiliation: Department of Anaesthesiology, Helsinki University Central Hospital, Finland.
authors.forename: T T
authors.initials: TT
authors.lastname: Niemi
authors.forename: A H
authors.initials: AH
authors.lastname: Kuitunen
mesh_terms: D000328:Adult; D001777:Blood Coagulation / Q000187:drug effects*; D018592:Cross-Over Studies; D006438:Hemodilution; D006487:Hemostasis / Q000187:drug effects; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000009:adverse effects*; D008297:Male; D010952:Plasma Substitutes / Q000009:adverse effects*
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes