title: Artificial colloids impair haemostasis. An in vitro study using thromboelastometry coagulation analysis.
abstract: BACKGROUND
  Hydroxyethyl starch (HES) solutions impair haemostatic mechanisms. The impact of the degree of substitution (DS) of a HES solution on thromboelastometry tracings is unclear. Therefore we tested the hypothesis of whether the DS has an effect on the haemostatic defect caused by HES, and assessed whole blood coagulation by thromboelastometry coagulation analysis (ROTEM, Pentapharm Co., Munich, Germany) in serial in vitro haemodilutions of colloids.
  
  
  METHODS
  Whole blood was withdrawn from 12 volunteers in a crossover study. Six per cent low-molecular weight HES with a high (HES MW 120 kDa/degree of substitution 0.7) and low (HES MW 130 kDa/0.4) degree of substitution, 4% succinylated gelatin (GEL) or 4% albumin (ALB) was added to citrated venous whole blood samples to make 20, 40, 60 vol.% end-concentrations of each of the solutions. Samples were analyzed by ROTEM.
  
  
  RESULTS
  There was a comparable decrease in maximum clot firmness (MCF) and shear elastic modulus [G = 5000 x MCF/(100-MCF)] by HES 120/0.7 and HES 130/0.4 at 20 and 40 vol.% dilutions. At 60 vol.% dilution HES 120/0.7 decreased less alpha-angle and MCF than HES 130/0.4 (P < 0.05). With moderate dilutions all colloids shortened coagulation time (CT). At 20, 40 and 60 vol.% dilutions MCF and G were more decreased in both HES groups than in the ALB and GEL groups (P < 0.05). Furthermore, at 40 and 60 vol.% dilutions G deteriorated more in the GEL than in the ALB group (P < 0.05).
  
  
  CONCLUSIONS
  In vitro the impact of the degree of substitution of HES solution on thromboelastometry coagulation analysis was modest. Haemodilution with gelatin and albumin induced fewer coagulation abnormalities than HES. In addition, the haemodilution with gelatin impaired coagulation more than albumin solution.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Central Hospital, Helsinki, Finland. tomi.niemi@hus.fi
authors.forename: T T
authors.initials: TT
authors.lastname: Niemi
authors.forename: A H
authors.initials: AH
authors.lastname: Kuitunen
mesh_terms: D000328:Adult; D000418:Albumins / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects*; D003102:Colloids / Q000009:adverse effects* / Q000494:pharmacology; D018592:Cross-Over Studies; D005260:Female; D005780:Gelatin / Q000009:adverse effects / Q000494:pharmacology; D006438:Hemodilution / Q000379:methods; D006487:Hemostasis / Q000187:drug effects*; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000009:adverse effects* / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010952:Plasma Substitutes / Q000009:adverse effects* / Q000494:pharmacology; D012016:Reference Values; D013386:Succinates / Q000494:pharmacology; D013916:Thrombelastography / Q000379:methods*; D013997:Time Factors; D014914:Whole Blood Coagulation Time / Q000379:methods
chemical_list: D000418:Albumins; D003102:Colloids; D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D013386:Succinates; C060085:succinylated gelatin; D005780:Gelatin