Volume therapy or infusion therapy is used worldwide for the treatment of hypovolemia caused by surgical blood and plasma losses, trauma, burns, or infections. Interestingly, significant differences exist between countries regarding the use of plasma substitutes. In the United States, crystalloids and albumin are more popular, whereas in Europe artificial colloids such as hydroxyethyl starch are preferred. From an international perspective, it is notable that volume therapy using hydroxyethyl starch is an established therapy for the treatment of cerebral, retinal, otogenic, and peripheral circulation disorders in Germany. In other countries, crys talloids are mostly used to treat dehydration or hypovolemia, for example in brain stroke. In recent years, new data made it possible to overcome national differences and agree on an evidence-based, international con sensus. The efficacy of different plasma substitutes for a volume therapy last ing several days has not been sufficiently studied in the past. Long-term volume therapy of patients with cerebral perfusion disorders is an excel lent model for studying the effects of artificial colloids in detail, because of the high doses of colloids that are administered. Through a compari son of commonly used plasma substitutes, we were able to show that sig nificant differences exist between different colloids, for example in their effect on coagulation. After repeated infusion, hydroxyethyl starches that are difficult to degrade lead to an accumulation of large molecules that are difficult to eliminate. These large molecules impair factor VIII/von Willebrand factor."

H. KIESEWETTER, J. KosciELNY, and F. JuNG Tbe byperoncotic colloid-osmotic pressure of tbe 10% Haes solution causes an increased intravascular volume because free tissue water flows into the vascular system [206]. Witb a volume expansion effect of about 50% an increase in intravascular volume of 750 ml (500 mi Haes and 250 mi tissue water) is expected immediately after hypervolemic hemodilution, after isovolemic bemodilution only an in crease of 250 mi ( only tissue water due to a pblebotomy of 500 mi). The blood is diluted by overloading the vascular system [245]. After isovolemic bemodilution tbe dilution effect is more marked due to the pblebotomy. Estimated by means of the total protcin concentration (Fig. 67) the dilution of plasma was 22% 1 h after isovolemic hemodilution but only 14% after bypervolemic bemodilution. Tbe plasma dilutions were almost confirmed by the concentration changes of albumin (Fig. 68). Therefore, the mixing ratio is 4. 1 to 1 (plasma to bydroxyetbyl starcb) for bypervolemic infusion of 500 ml Haes-sterillO% (200/0. 5) and 3. 7 to 1 for isovolemic dilution. Consequently, the hydroxyethyl starch concentration after isovolemic hemodilution was signifi- cantly bigher at all measuring times tban after hypervolemic hemodilution (Fig. 61). If tbe infusion was performed quickly so that no renal output of the Haes solution could ensue, a mean bydroxyetbyl starch concentration of 10. 3 g per liter plasma would be expected immediately after isovolemic hemodilution for tbe above mixing ratio, and one of 9. 0 g after hypervolemic bemodilution.

Das Buch Hamodilution stellt die konservative Therapie bei Durchblutungsstorungen und den Volumenersatz mit Hydroxyathylstarke vor. Die Informationen basieren auf langjahrigen klinischen Erfahrungen. Insbesondere die Themen Kontraindikationen, mogliche Nebenwirkungen und Vorsichtsmassnahmen werden behandelt und diskutiert. Desweiteren werden die Pharmakokinetik und die biologischen Wirkungen vorgestellt. Die eingesetzten Messmethoden sowie Schwankungsbreite und Referenzbereiche der einzelnen Messmethoden sind im Anhang genannt. Das Ziel ist, dem Kliniker und Praktiker bei der Anwendung der Hamodilution, unter besonderer Berucksichtigung der Therapiesicherheit, kompakte Information bereitzustellen, die in kurzester Zeit nachgeschlagen werden kann.