[Second increase in plasma volume after single infusion of hydroxyethyl starch (author's transl)]

6 patients without evidence for renal, hepatic or pancreatic disease were treated with intravenous infusions of 500 ml hydroxyethyl starch (6%) over a period of 60 min. In the course of the infusion we observed an increase in plasma volume from 2.72 +/- 0.101 to 3.36 +/- 0.141. After 2 h plasma volume decreased to 3.02 +/- 0.101 but showed a second peak of 3.23 +/- 0.121 after 4 h (p less than 0.01). 24 h following infusion an increase in plasma volume of 4,8% was found as compared to preinfusion values. The second increase in plasma volume cannot be explained by the total concentration of hydroxyethyl starch since the latter decreased continuously. The increase in plasma volume was accompanied by a decrease in average molecular weight (-Mw and -Mn). It is suggested that serum amylase produces small osmotic active molecules by degradation of hydroxyethyl starch, thus leading to an increase in plasma volume. 12--24 h after the infusion of hydroxyethyl starch serum amylase was more than twice as high basal values. This is caused by the formation of a high molecular hydroxyethyl starch-amylase-complex which cannot be eliminated easily. When hydroxyethyl starch is given repeatedly to normovolemic patients, the second increase in plasma volume should be considered as a possible cause for acute hypervolemia. This is especially true for patients with myocardial insufficiency.