Rapidly degradable hydroxyethyl starch solutions impair blood coagulation after cardiac surgery: a prospective randomized trial.

Background: There is continuing concern about the effect of hydroxyethyl starch (HES) solutions on blood coagulation. Rapidly degradable HES solutions with more favorable effects on clot strength have therefore been developed. Because the risk of bleeding is increased after cardiopulmonary bypass, we examined whether these types of HES solutions could be administered after cardiac surgery without an alteration of coagulation.

Methods: Two new rapidly degradable HES solutions were compared with human albumin in 45 patients scheduled for elective primary cardiac surgery. After admission to the cardiac surgical intensive care unit, the patients were allocated in random order to receive either 15 mL/kg of HES solution with low molecular weight and low molar substitution (either 6% HES200/0.5 or 6% HES130/0.4) or 4% human albumin solution as a short-time (70-240 min) infusion.

Results: Clot formation time was prolonged and maximum clot firmness was decreased in thromboelastometry tracings after infusion of both HES solutions. This impairment in thromboelastometry tracings partly recovered (using InTEM and ExTEM coagulation activators) at 2 h after the completion of the study infusion. Platelet contribution to maximum clot firmness remained unaffected in all of the study groups. HES did not induce fibrinolysis. No changes in thromboelastometry tracings were observed after human albumin infusion. Chest tube drainage was comparable in the study groups.

Conclusions: We conclude that a short-time infusion of rapidly degradable HES solutions after cardiac surgery produces impairment in fibrin formation and clot strength in thromboelastometry tracings. In this clinical setting, human albumin does not impair hemostasis.