Hemorheological effects of different solutions of dextran,albumin,gelatine and hydroxyethyl starch

Abstract

The influence of different molecular weight dextrans (MW: 6000, 10 000, 40 000, 70 000), hydroxyethyl starch, gelatine and albumin on plasma viscosity, apparent whole blood viscosity and erythrocyte flexibility was studied in vitro. Compared to blood samples two hours incubated with Ringers solution alone, dextrans of 40 000 and 70 000 molecular weight caused the most pronounced increase in plasma viscosity, erythrocyte aggregation and decrease in erythrocyte flexibility. For albumin, hydroxyethyl starch and gelatine these effects were less, but still significant in comparison to the control measurements.

The commercially available dextran solutions for clinical use vary widely with respect to their molecular weight (MW distribution: > 90% of the total amount within the range of 10 000–80 000). It has also been demonstrated, that the high molecular weight components are excreted at a lower rate, which leads to an increase of plasma concentration during repeated infusions (ARTURSON 1954, (1)). The results of our in vitro study support the hypothesis that the increase in apparent whole blood viscosity after repeated infusions, as demonstrated in several clinical experiments is due to an increase of higher molecular weight components, which accumulate in plasma during prolonged infusions with LMWD.