Action of hydroxyethyl starch (HES) on the activity of plasmatic clotting factors

Article type: Research Article

Authors: Langer, R. | Jordan, U. | Wölfle, A. | Henrich, H.A.

Affiliations: Chirurgische Universitätsklinik, Experimentelle Chirurgie, 97080 Würzburg, Germany

Abstract: Studies were carried out on the effects of different doses of hydroxyethyl starch 200/0.5 (HES) on plasma clotting factors in dogs, as an animal model for the human clotting system. In 8 German shepherd dogs 15% of the total blood was isovolemically substituted either by Ringer’s solution with lactate alone (controls) or with 0.6, 1.3, 1.9, 2.5 g HES/kg b.w. Immediately after the infusion, the HES concentration in the recipients’ plasma amounted to 8 mg/ml up to 38 mg/ml. In the following 6 h, the HES decreased to 25% in each case. It was found that the higher the plasma HES content was, the lower the haematocrit. Neither the thrombin‐ nor the batroxobin‐time showed any significant change, irrespective of the plasma HES concentration. The prothrombin‐time was decreased directly after the infusion in parallel to the haematocrit. The single clotting factors FI, FII, FV, FVII, FVIII, FX, and FXII behaved approximately in the same way: their activities directly after infusion, but also 6 h later, were lowered in proportion to the amount of HES infused. The loss of factor activity correlated with the volume‐expanding effect of HES shortly after the infusion, but not 6 h later. It is concluded that there are two different modes of HES action on clotting factors: the dilution by plasma volume expansion and a non‐dilutional action. Cautious handling might be required in patients with clotting disturbances as well as in long‐term treatment.

Journal: Clinical Hemorheology and Microcirculation, vol. 18, no. 2-3, pp. 103-116, 1998