 Local or systemic release of bacteria-derived compounds, leading to the production of proinflammatory cytokines, induce systemic inflammatory reactions in septic patients. Continuous renal replacement therapies CRRT such as hemodialysis CVVHD, hemofiltration CVVH or hemodiafiltration CVVHDF with conventional high-flux membranes allow to control fluid and electrolyte balance, and to improve the hemodynamic status of the patients. However, conventional high flux membranes have a limited permeability for sepsis-associated mediators with molecular weights in the range of 15.000 to 60.000 Da. 