[Comparative effects of low and medium molecular hydroxyethyl starch (HES) solutions on hemorrhagic shock in rats].

Hydroxyethyl starch (HES) solutions are frequently used plasma expanders. We examined the effects of medium-HES (mean molecular weight of 130,000 dalton) and low-HES (mean molecular weight of 70,000 dalton) on the survival rates (Exp. I), colloid osmotic pressure (COP) (Exp. II) and coagulation (Exp. III) with rats in hemorrhagic shock.Hemorrhagic shock was induced by removing 55% (Exp. I) and 20% (Exp. II and III) of the circulating blood volume. Saline, low-HES or medium-HES of the same volume with the removed blood was intravenously infused immediately after bleeding.Exp. I: In survival rate, effect of medium-HES was significantly superior to that of saline. Exp. II: The COP of medium-HES group was significantly higher than that of saline group 3 hrs after hemorrhagic shock. Exp. III: There were no changes in von Willerbrand factor and factor VIII 3 hrs after hemorrhagic shock among saline, low-HES and medium-HES.Medium-HES and low-HES are efficacious plasma volume substitutes; however, the ability of medium-HES to prolong maintenance of COP better than low-HES is a finding that would be significant in a clinical setting involving preoperative blood management and extreme blood loss.