The LPN procedure is performed under general anesthesia. The transperitoneal access to peripancreatic space is via the gastro-colic ligament and greater omentum, effusion and pus is removed by laparoscopic forceps and suction. Laparoscopic cholecystectomy (LC) is performed during the LPN procedure on patients with indication.

The NPN procedure is followed by the standard retroperitoneal approach. After the catheter is exchanged over a guide wire and serially dilated up from 6F to 24F followed by Seldinger technique, the access track to the necrotic cavity is established. A nephroscope is inserted into the cavity through the track for debridement. Using forceps and suction, the peripancreatic solid necrotic tissue and pus is grasped and removed. A large-bore irrigating drain is left in the cavity, with continuous irrigation by warm normal saline solution at a rate of 100-125 ml/h after surgery.

Inclusion Criteria:

• All patients ages 18 or above admitted to UPMC with a diagnosis of AP based on at least 2 of the following criteria:(i) abdominal pain characteristic of AP (ii) serum amylase and/or lipase ≥ 3 times the upper limit of normal (iii) characteristic findings of AP on abdominal CT scan will be screened for study enrollment.

Exclusion Criteria:

• Less than 18 years of age
• Pregnant women
• Presence of renal dysfunction (Cr>1.5mg/dL)
• Pre existing heart dysfunction or NYHA classification score above III
• Coagulation disorder