[The maximum safe dosage of the low molecular weight hydroxyethyl starch, HESPANDAR (HES), estimated from HES induced...

The effects of hydroxyethyl starch on the coagulation system have received attention, and safe dosage of high molecular weight hydroxyethyl starch is generally found to be 20 ml.kg-1. Low molecular weight hydroxyethyl starch, HESPANDAR (HES), seems to induce weaker specific effects on blood coagulation than high molecular weight hydroxyethyl starch. The aims of this study are to estimate the maximum safe dosage of HES, and to investigate the etiology for coagulopathy induced by HES. Forty three patients (18 to 75 years old) who were free of bleeding disorders scheduled for abdominal operations received 20, 30, or 40 ml.kg-1 of HES. We measured coagulation parameters of them including platelet, hematocrit, total protein, activated partial thromboplastin time, prothrombin time and Factor 8, and observed the evidence of clinical microbleeding. As the HES was infused, the values of coagulation parameters except Factor 8 changed with blood dilution. Factor 8 decreased more than expected from the values calculated for hemodilution. The evidences of clinical microbleeding were observed when patients had received HES more than 30 ml.kg-1. The decrease of Factor 8 and the observed tendency of clinical microbleeding showed a significant positive relationship (P = 0.0002). We conclude from our results that the maximum safe dosage of HES is about 30 ml.kg-1, and HES may affect blood coagulation by lowering the plasma concentration of Factor 8.