Coagulation effects of a recently developed hydroxyethyl starch (HES 130/0.4) compared to hydroxyethyl starches with higher molecular weight

Background: Hydroxyethyl starches (HES) are known to interfere with blood coagulation according to molecular weight, the degree of substitution and the C2/C6 ratio. A recently developed low molecular hydroxyethyl starch (HES 130/0.4) was designed to reduce the blood compromising potency. Methods: In this study, effects of a 30% in vitro haemodilution with the new HES preparation (HES 130/0.4) in comparison to HES 200/0.5, HES 450/0.7 and sodium chloride solution were investigated using intrinsic and extrinsic activated thrombelastography (TEG) and plasmatic coagulation tests. Results: Whereas plasmatic tests revealed no prolongation of coagulation by HES in comparison to sodium chloride, the TEG variables clotting time, clot formation time and maximal clot firmness showed a significant (P<0.05) inhibition by all the HES preparations. The inhibition was most pronounced in HES 450 (P<0.05 vs HES 130) while HES 130 did not show a statistically significant difference in extrinsic activated maximal clot firmness when compared to sodium chloride. Conclusion: These in vitro results demonstrate that hydroxythyl starches especially compromise clot polymerisation. The new preparation HES 130/0.4 seems to inhibit platelet function to a lesser extent than hydroxyethyl starch preparations with a higher molecular weight and degree of substitution. (C) Acta Anaesthesiologica Scandinavica 44 (2000).