Clearance and rate of conjugated bilirubin removal during extracorporeal liver support therapy with FPSA Prometheus™

Abstract

The elimination of protein-bound solutes during extracorporeal liver support (ELS) therapy involves a sequence of steps and processes such as diffusion, convection, filtration, and adsorption. It was the purpose of this study to analyze the time course and the relative contribution of these processes to overall solute removal. Eighteen treatments done in 8 acute-on-chronic liver failure patients for a duration of 8 h using fractionated plasma separation and adsorption (FPSA) were studied. Conjugated bilirubin was measured in the extracorporeal circulation at 6 different sampling points in regular intervals. Clearance and removal rates were calculated for the whole system and for selected system components. Conjugated bilirubin concentrations decreased in the primary circuit directly connected to the patient and remained stable or increased in the secondary circuit which contained the adsorbers. Bilirubin clearance declined notably during the first 2 h of therapy for the whole system as well as for the adsorbers. The clearance for bilirubin in the primary circuit provided by the FX50 dialyzer was relatively small but constant. In the secondary circuit clearance was larger for the anion exchanger (Prometh02™) than for the neutral resin (Prometh01™) and decreased throughout the ELS treatment. Thus, approximately 90% of overall removal rate for conjugated bilirubin occurred in the adsorbers and about 10% in the dialyzer. The information obtained on the relative contribution of different ELS components to overall bilirubin removal could be helpful to improve the performance of selected components of FPSA and thereby of ELS as a whole. © 2009 Springer-Verlag.