PERIOPERATIVE VOLUME EFFECT OF HES 120 0.7 COMPARED WITH DEXTRAN 70 AND RINGER ACETATE/

Hydroxyethyl starch 120 (HES 120/0.7, Plasmafusin(R)) is the smallest medium molecular weight HES preparation used as a plasma substitute fo r all clinical purposes. We compared the volume and colloid osmotic ef fect of 6 % HES 120 with 6 % dextran 70 and Ringer's solution during a nd after surgery with minimal blood loss. Patients (n = 48) having gen eral anaesthesia were randomly divided into six groups. A thirty-minut e bolus infusion was started at the induction of anaesthesia, and ther eafter the infusions were continued at two different rates for five ho urs. The volume of the bolus was 10 % and 30 % of the calculated plasm a volume (CPV) in colloid and Ringer groups, respectively. The constan t infusion rates were 2 % and 6 % of the CPV for the colloids, and 10 % and 20 % for the two Ringer groups. Blood samples for the measuremen t of serum proteins and colloid osmotic pressure (COP) were obtained b efore induction, after the bolus, and thereafter hourly throughout the study. Albumin, prealbumin and total serum protein concentrations wer e used to calculate relative plasma volumes. After the bolus infusion, plasma volumes increased significantly in all six groups and the incr ements were sustained throughout the study. At the lower infusion rate s the volume changes of HES and Ringer groups were almost identical an d comparable to dextran group up to the third hour. At the higher infu sion rates, dextran 70 produced greater plasma volume expansions than HES 120, and the volume effect of Ringer's solution was clearly exceed ed by both colloids. The hourly estimated half-lives of dextran were c onstantly longer compared with HES. With both infusion rates the COPs of dextran and HES groups were higher compared with Ringer groups. The re were no differences in COP between the dextran and HES groups. It i s concluded, that in this clinical setting the volume effect of 6 % de xtran 70 exceeds that of HES 120/0.7, and that both colloids are super ior to Ringer's solution.