Inclusion Criteria:  Critically ill patients with severe septic shock Intraabdominal infection, proved or highly suspected gram-negative bacteria infection Change of sequential organ failure assessment (SOFA) score is above or equal to 2 Require norepinephrine infusion to maintain mean arterial pressure above 65 mm Hg Lactate level above 4 mmol/L SOFA score >= 9 or norepinephrine dose > 0.1 mcg/kg/min  Exclusion Criteria:  Aged < 20 SOFA score >=16 Lactate level >=16 High dose norepinephrine infusion (> 0.3 mcg/kg/min) more than 24 h after SOFA score was >=9 High dose norepinephrine infusion (> 0.3 mcg/kg/min) more than 24 h after Lactate level was >=4 White blood cell counts < 1000 cells/μL Platelet counts < 30 K/μL Allergy to heparin Receive continuous renal replacement therapy >8 hour before enrollment Receive other endotoxin removal filter Receive cardiopulmonary resuscitation within 4 weeks before enrollment Admitted to ICU for severe septic shock within 4 weeks before enrollment APACHE II score > 35 at enrollment