Hydroxyethyl starch polymer (HES)

Hydroxyethyl starch polymers (HES) are synthetic derivatives of amylopectin (branched polysaccharides) chemically modified with hydroxyethyl groups primarily at positions C2, C3, and C6 of the glucose units, which increase molecular resistance to enzymatic degradation and enhance their ability to act as plasma volume expanders. In clinical practice, HES solutions are used intravenously to restore and maintain intravascular oncotic pressure, especially in the setting of hypovolemia due to acute blood loss or low plasma protein states. By sustaining colloid osmotic pressure, HES helps keep fluid within the vascular space. However, HES solutions can produce significant adverse effects including coagulopathy (by interfering with clotting factors and platelet function), renal dysfunction, tissue persistence over years, and increased mortality in critically ill populations. These effects are dose-dependent and influenced by the molecular weight, degree of hydroxyethylation, and solution concentration. HES is not a receptor, enzyme, nor an endogenous molecular target, but a drug formulation designed to manipulate a physiological parameter (oncotic pressure).

Other names

HetastarchTetrastarchPentastarchVoluvenElohesHaes-Steril

Hydroxyethyl starch polymers exert osmotic pressure in the intravascular compartment by increasing plasma colloid concentration, thereby promoting fluid retention within blood vessels, and sustaining blood volume following fluid loss; they also impact coagulation, partly by interfering with platelet function (e.g., fibrinogen receptor GPIIb/IIIa binding)