Hematocrit as a risk factor for vascular disease.

Besides the classical risk factors for vascular diseases, markedly elevated or reduced hematocrit values may also affect the course of circulatory disturbances. To find out an appropriate hematocrit for sufficient oxygen perfusion of the tissues, several studies have been conducted. Most of the surveys indicate that a hematocrit between 35% and 40% is the best solution. To achieve this aim by iso- and hypervolumetric hemodilution, a clinical double-blind trial with three substances, dextran 40, middle-molecular hydroxyethyl starch and isotonic saline solution was carried out. With regard to clinical results and the possible side effects of dextran middle molecular hydroxyethyl starch seems to be the best choice for hemodilution.