Effects on Plasma Exchange on Functional Capacity of Serum Albumin, Circulatory Dysfunction, Renal and Cerebral Function in Cirrhotic Patients With "Acute-on-chronic Liver Failure"

Inclusion Criteria: * Age between 18 and 80 years old * Hepatic cirrhosis diagnosed by biopsy or clinical, analytic and ultra sound data. * acute on chronic liver failure: defined by an acute deterioration in hepatic function produced in 2-4 weeks with jaundice (total serum bilirubin ≥ 5 mg/dl ) and hepatic encephalopathy (≥ grade 2) and/or renal insufficiency (serum creatinine ≥ 2 mg/dl) Exclusion Criteria: * Neoplasm disease including hepatocarcinoma which exceed Milan criteria (1 tumour \> 5cm, up to 3 tumours \<3 cm) * Active bacterial or fungal infection with hemodynamic instability which require the utilization of vasoactive drugs at moderate dose (\>0,5 μg/Kg/min of noradrenaline) * Structural moderate to severe cardiopathy (Cardiac Index \<2l/min/m2) * Chronic renal insufficiency in treatment with haemodialysis * Chronic moderate o severe pulmonary disease (maximum expiratory volume in a second \<50%) * Active transplant * human immunodeficiency virus infection * Pregnancy or lactation * Acute respiratory distress syndrome (P02/Fi02\< 200mm Hg) or acute lung injury (P02/Fi02\< 300mm Hg) * Hemodynamic instability (\>0,5 μg/Kg/min of noradrenaline) * Bleeding in the digestive tract in the previous 72h to the treatment * Severe coagulopathy: INR ≥ 3.0 (Quick ≤ 20%) and/or platelets \< 30000//mm3 * Extrahepatic cholestasis * Hepatobiliary surgery in the last 6 months (except laparoscopic Cholecystectomy) * Concentrations bilirubin ≥ 5mg/dl during the period above 4 weeks previous to inclusion * Concomitant participation in an other clinical trial * Drug addiction * Mental status which does not allow the patient to understand the trial, with the exception of hepatic encephalopathy.