INFLUENCE OF 6°/o HYDROXYETHYLSTARCH (HES) ON HAEMOSTASIS IN PATIENTS UNDERGOING MAJOR SURGERY

Abstract

Hydroxyethyl starch (HES) is a synthetic plasma volume expander manufactured from amylopectin which is a starch of plant origin and derived from miaze. The material used in this study was a low molecular weight HES 6o/o in isotonic saline (HES 200/0.05) under the registered name of HAES- steril. It has an average MW of 200.000 dalton and a molar substitution 0.5. Hydroxyethyation of the starch prevents its rapid enzymatic hydrolysis by plasma a-amylase and thus prolongs its intravascular volume effectiveness.

The physicohemical properties of HES preparation are defined by their molecular weight and molar substitution ratio. Original HES preparations were characterized by high molecular weight and high molar substitution ratio (HES 450/0. 7). Side effects on haemostasis and prolonged accumulation in the body have promoted the development of a new HES with lower molecular weight and lower molar substitution ratio such as HAES-steril (200/0.5). These HES preparations are less accumulated and do not interfere with haemostasis.