Continuous Blood Purification for Regulation of Early Inflammatory Response In Severe Acute Pancreatitis

Systemic Inflammatory response syndrome(SIRS) is common in patients with severe acute pancreatitis (SAP) in early stage. Continuous Blood Purification (CBP), especially Continuous Veno-Venous Hemofiltration(CVVH) is proved to have an important role in SAP patients to control SIRS. But the detail treatment for this is controversial. In this study, the investigators aim to evaluate the different effects of three kinds of treatment protocols which is CVVH 6h,continuous venovenous hemodiafiltration(CVVHDF) 6h,CVVH 10h for first three days in SAP patients. Compare the vital sign, SIRS parameters, and others between these three groups. This study will try to find a better way for CBP in patients with SAP