The effect of dextran infusion on antithrombin III concentrations and on platelet function during minor surgery.

The effects of dextran on the antithrombin (AT) III activity and blood coagulation, evaluated with thromboelastography, were investigated in 26 patients (anaesthesia risk class I or II) scheduled for minor surgery under general anaesthesia. In the Dextran group the patients were infused first with dextran 7 ml/kg, then with Ringer's acetate. In the Ringer group, the patients received only Ringer's acetate. In the recovery room fluid therapy was continued with 5% dextrose in water until the first postoperative day. Blood loss and fluid replacement were comparable in the groups. Haematocrit (Hcr) decreased significantly in the Dextran group, and the platelet count decreased in both groups during surgery. The median baseline AT III values were similar in the study groups. In the recovery room, the median AT III value was lower in the Dextran than in the Ringer group, 78% and 92%, respectively (P < 0.05). By the following day, the AT III values had returned near the initial level. After surgery, the maximal amplitude of thromboelastogram was 48 mm in the Dextran group, and 58 mm in the Ringer group (P < 0.05). In conclusion, fluid replacement with dextran resulted in modest and short-lived alterations in blood coagulation.