Equivalence of hydroxyethyl starch HES 130/0.4 and HES 200/0.5 for perioperative volume replacement in major gynaecological surgery

Background: Hydroxyethyl starch solutions (HES) are increasingly used for the compensation of surgical blood loss. The objective of this clinical trial was to compare a novel 6% HES 130/0.4 solution with a favourable pharmacological profile and a standard 6% HES 200/0.5 solution for maintenance of haemodynamic stability in major gynaecological surgery. Methods: Sixty female patients aged 18 - 80 years undergoing major gynaecological surgery with indication for perioperative colloidal volume replacement were enrolled in this prospective, randomized double-blinded clinical study. The administration of study medication was dependent on individual requirements to maintain haemodynamic stability. The amount of study medication required from induction of anaesthesia until 6 h postoperatively served as the primary investigative parameter. Results: The two one-sided test procedure by Westlake demonstrated equivalence of mean infused volumes between HES 130/0.4 and HES 200/0.5 during the study period ( 1224 +/- 544 ml and 1389 +/- 610 ml, respectively, P< 0.05). Perioperatively, haemodynamics did not differ significantly between treatment groups. While none of the mean values of coagulation parameters shifted outside the normal range, the degree of haemodilution revealed reduced haematocrit values in HES 200/0.5 treated patients at 6 h postoperatively ( P< 0.05). Moreover, prothrombin time ( PT) was higher and consequently international normalized ratio (INR) was lower at the same time point for patients who received HES 130/0.4 ( P< 0.05). Conclusion: This clinical trial demonstrated therapeutic equivalence of this novel low-substituted HES 130/0.4 solution and a standard HES 200/0.5 solution for perioperative volume replacement. Moreover, both HES preparations were equally well-tolerated and safe.