Molecular adsorbent recirculating system (MARS) and continuous veno-venous hemodiafiltration (CVVHDF) for diltiazem removal: An in vitro study

Abstract

The objective of the present study was to evaluate the efficacy of the molecular adsorbent recirculating system (MARS) vs continuous veno-venous hemodiafiltration (CVVHDF). Diltiazem poisoning was simulated in a central compartment consisting in a 5L dialysis solute spiked with diltiazem at two different toxic concentrations: 750 and 5000 µg/L. For CVVHDF, mean extraction coefficients (EC = (in concentration − out concentration)/in concentration) were concentration-dependent with a decrease all along the dialysis. At the end of the sessions the mean amounts remaining in the central compartment were 8% and 7% of the initial dose at 750 and 5000 µg/L, respectively. The mean cumulative amounts found in the effluent were 60% and 75% of the initial dose, respectively. The missing amounts accounted for 32% and 18% of the initial dose, respectively, corresponding to an adsorption to the dialysis membrane. In contrast, the different compartments of the MARS resulted in undetectable output concentration earlier that the end of the session. The mean concentrations of diltiazem remaining in the central compartment were <1 µg/L at the end of the sessions. Global ECs were around 50% all along the experiment at both concentrations, and the average charcoal cartridge ECs was 80% throughout the experiments. CVVHDF system in the developed model was efficient for diltiazem removal, mainly by diffusion, convection and to a lesser extent by adsorption to the dialysis membrane. In MARS system, resin cartridge and hemodialysis components are ineffective, charcoal cartridge is responsible for almost all drug removal.