CRRT patients are generally critical ill patients with unstable conditions, such as low blood pressure,severe SIRS,et al. Acute kidney injury(AKI)is especially prevalent,with even two or more organ failure. CRRT serves as an important supportive therapy.Continuous anticoagulation is needed to prevent treatment interruptions due to clotting of the extracorporeal circuit. Unfractionated heparin or low molecular weight heparin both increase the risk of bleeding and heparin induced thrombocytopenia in such cases.However, the problem of CRRT without anticoagulation is the early filter clotting. An alternative method is the use of heparin coated hemofilter. The AN69 ST hemofilter, a surface-treated polyacrylonitrile membrane hemofilter, allows irreversible fixing of heparin to filter membrane, is able to reduce thrombogenic properties of the membrane. In this study, we observe the efficacy and safety of heparin-coated AN69 ST hemofilter in CRRT patients, and compare to the original AN69 membrane hemofilter.

Inclusion Criteria:

• Critical ill patients who need continuous renal replacement therapy
• Continuous anticoagulation therapy is not necessarily during CRRT process

Exclusion Criteria:

• Patients needing continuous anticoagulation during each CRRT process
• Expectant survival time less than 72 hours
• Extremely unstable vital signs such as low blood pressure
• Any reasons that resulting in blood flow rate less than 150ml/min
• Pregnant women
• Patients allergic to heparin