Influence of acute normovolaemic haemodilution on the dose–response relationship, time-course of action and pharmacokinetics of rocuronium bromide

Acute normovolaemic haemodilution (ANH) is an effective strategy for avoiding or reducing allogeneic blood transfusion. We aimed to study its effect on the pharmacological profile of rocuronium. In two study centres, 28 patients undergoing major surgery with ANH were matched with 28 control patients. In the dose–response groups, using the mechanomyograph, neuromuscular block of six consecutive incremental doses of rocuronium 50 μg kg−1, followed by 300 μg kg−1, was evaluated. In the pharmacokinetics groups, serial arterial blood samples were withdrawn for rocuronium assay after a single dose of rocuronium 600 μg kg−1. ANH resulted in a shift to the left of rocuronium dose–response curve. Rocuronium effective dose95 (ED95) was 26% lower (P