 This study will assess the influence of the High Cut-Off HCO CVVHD treatment on the disease progression in septic patients. The primary aim of the study is to evaluate whether HCO CVVHD leads to a significant improvement of the hemodynamic status mean arterial pressure, vasopressor requirements in septic patients in comparison to CVVHD treatment with conventional high-flux filters. For the HCO-group the investigators expect a 50 lower dosage of vasopressors needed to maintain an adequate organ perfusion. 