The acute peripancreatic fluid collections (AFPCs) is the most common complication in severe acute pancreatitis (SAP). There are controversies on optimal timing for drainage of APFCs in SAP. The early-stage percutaneous catheter drainage (PCD) of sterile peripancreatic fluid collections is questioned as a result of the major cause of secondary infection. The aim of the present randomized controlled trial is to compare the outcomes in terms of mortality, secondary infection of peripancreatic collections, organ failure, length of hospital/ICU stay and inflammatory biomarkers between the early-stage PCD of sterile AFPCs and conservative therapy.

The AFPCs is the most common complication in SAP and debate continues regarding the appropriate timing for drainage of sterile APFCs in SAP patients. Some researchers have reported that the massive amounts of inflammatory mediators in the peripancreatic fluid may aggravate the inflammatory reaction and contribute to organ failure (OF) when liberated into the bloodstream by peritoneal absorption. Additionally, bacterial colonization of APFCs may lead to peritoneal abscess formation and sepsis. In a recent study, Wang et al. revealed that early-stage PCD effectively attenuated the peritoneal pressure and decreased the incidence of infection and OF. Finally, APFCs and secondary infection are considered major causes of alimentary tract hemorrhage. Based on these factors, prompt drainage of APFCs seems reasonable for patients in early SAP. In addition, unlike the original 1992 Atlanta classification guidelines (1992-AC), the revision of the 1992-AC by international consensus in 2012 (2012-RAC) highlighted the significance of persistent OF in the classification of SAP. To be exact, those patients diagnosed with SAP according to the 1992-AC without OF or with transient OF were reclassified as having mild AP (MAP) or moderate severity AP (MSAP) by the 2012-RAC. Therefore, many studies have reported changes in the treatment of SAP in the early stages since the 2012-RAC were published. We have retrospectively analyzed 361 patients with AP and found that the early-stage PCD of sterile APFCs in SAP-2012RAC patients can significantly reduce the mortality rate. However, on the contrary, the mainstream viewpoint holds that drainage is not necessary in the absence of infection of the peripancreatic fluid as the fluid can be absorbed completely and sterile PCD may increase the risk of iatrogenic infection. However, these mainstream views aimed at 1992-AC's SAP patients, which actually contain 2012-RAC's SAP and MSAP. Therefore, we hypothesized that the introduction of new AP severity classification methods may alter the indications for early aseptic drainage of AFPCs.

Does early PCD of sterile APFCs benefits patients or increases the secondary infection rate? In view of these problems, we plan to design a randomized controlled trial to compare the outcomes in terms of mortality, secondary infection of peripancreatic collections, organ failure, length of hospital/ICU stay and inflammatory biomarkers between the early-stage PCD of sterile AFPCs and conservative therapy. The aim of this prospective study is to investigate whether early PCD of sterile AFPCs can be used to SAP patients with AFPCs at early stage.

Inclusion Criteria:

1. Age of 18 years to 70 years; and
2. Pain characteristic of pancreatitis; and
3. Elevated serum lipase or amylase (≥3-fold upper normal range); and
4. Persistent organ failure >48 hours; and
5. Organ dysfunction occurred within 7 days after onset of pain; and
6. Presentation with a width of ≥2cm of APFCs in the peripheral tissues of the pancreas, the cyst of lesser omentum , or the paracolic sulci on CT image.

Exclusion Criteria:

1. History diseases of chronic organ dysfunction; or
2. Traumatic pancreatitis; or
3. Post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis; or
4. Severe coagulopathy (INR>2); or
5. Severe thrombocytopenia (PLT≤50×109/L); or
6. No suitable route for puncturing; or
7. Pregnancy; or
8. Absent of informed consent from patient or representative.