Severe acute pancreatitis (SAP), characterized by digestion of its own tissue by pancreatic enzymes, is followed by a strong local and systemic explosive inflammatory response, multi-organ damage, pancreatic vascular damage embolism, pancreatic necrosis, and secondary infection, with a mortality rate of 20%-30% to date.
From January 1997 to March 2009, 2085 cases of acute pancreatitis were admitted to our clinic, including 1033 cases of SAP, and 764 of 1033 SAP patients were transferred after treatment from outside hospitals. According to the course of the disease, the treatment focuses on early resuscitation, control of pancreatic necrosis and infection, maintenance of organ function, and treatment of complications.
Treatment model: emphasis on multidisciplinary cooperation
The traditional treatment model based on a single discipline is difficult to adapt to the treatment and technological development of severe pancreatitis. Since 1997, we have established a comprehensive treatment model centered on organ function maintenance, and based on this, we have developed treatment specifications and established a treatment team consisting of multidisciplinary physicians (intensive care, surgery, endoscopy, imaging and blood purification, etc.) based on the SICU, and multi-disciplinary collaboration on the platform of the SICU, so that the advantages of each specialty are organically combined to ensure that patients receive systematic and optimal treatment.
Emphasis is placed on ICU monitoring and treatment and organ function maintenance. All SAP patients are monitored, including vital signs, hemodynamics, respiratory function, metabolic and renal function, acid-base electrolytes and intra-abdominal pressure.
The treatment measures included: 1. fasting, gastrointestinal decompression. 2. fluid resuscitation, adequate fluid resuscitation under hemodynamic monitoring and close clinical observation to correct hypovolemia. 3. 179 patients were drained via nasopancreatic (or biliary) drainage within 5 days of onset. 4. all patients were given oxygen therapy, 365 cases of mechanical ventilation and 218 cases of tracheotomy. 5. various measures such as enema and magnesium sulfate via gastric tube were used to promote recovery of gastrointestinal function. The patients were treated with growth inhibitors and their analogues to inhibit pancreatic secretion. 7. Patients with combined peritoneal effusion were given timely percutaneous laparotomy for drainage and prophylactic antibiotics (including cephalosporins and carbapenems).
Early bedside: continuous high-flow hemofiltration
The Seldinger technique was used to establish vascular access by central venous cannulation, and the replacement fluid was fed in a predilution mode with a flow rate of 4000 ml/h, resulting in a continuous filtration volume of 96 liters for 24 hours. The blood flow was 250-300 ml/min for 72 hours without interruption. The filter was AN69 membrane with an area of 1.2m2 and was replaced every 24h. Anticoagulation with citrate or low molecular heparin was used.
Indications for early bedside continuous high-flow CVVH in SAP: in the acute response phase of SAP with systemic inflammatory response syndrome (SIRS); APACHEII score >10 and one of the following conditions: 1. with more than 2 organ dysfunction. 2. severe acid-base hydropower mediator disorder. 3. persistent hyperthermia, and 4. systemic edema, heart failure, and pulmonary edema.
To date, we have performed bedside continuous high-flow hemodialysis in 159 patients with SAP, which has played an important role in the control of inflammatory response, prevention of MODS and organ function support.
Surgical treatment: introduction of damage control concept
After 2001, we applied the concept of damage control to surgery for pancreatitis and improved the surgical drainage method: using limited necrotic tissue removal and excision, combined with continuous postoperative peripancreatic and retroperitoneal flushing to remove as much retroperitoneal necrotic tissue and exudate as possible. We designed and developed our own continuous negative pressure drainage plus flushing system (Lai’s “double set drainage tube”), and repeatedly explored the location and care of the drainage tube.
The surgical protocol included gallbladder/choledochostomy drainage, gastrostomy and jejunostomy. Peripancreatic necrotic tissue was removed, multiple were placed in the peripancreatic area, and continuous postoperative flushing and drainage was performed. The vast majority of patients avoided a repeat cesarean drainage procedure.
CT/B ultrasound-guided percutaneous peripancreatic puncture and drainage was explored and used to treat some selected patients with peripancreatic fluid, pseudocysts and abscesses with good results and improved the success rate of non-surgical treatment. In some cases (about 50%), surgical drainage was intermediate due to ineffective drainage, and the failure was mainly due to necrotic tissue blocking the drainage tube and multiple lumens.
Nutritional support: from parenteral to early enteral
The nutritional support paradigm for SAP has changed and has had a significant impact on treatment.
Phase I: 1970s~early 1990s, for parenteral nutrition (TPN) model. tPN provides nutrition for patients with prolonged fasting; does not increase the exocrine secretion of the pancreas; creates conditions for postponed surgery and effectively reduces morbidity and mortality.
Phase II: In the early 1990s~2000, the phased nutritional support model was implemented by combining the different characteristics of each phase of SAP.
Phase III: After 2000, early enteral nutrition model. During the acute period, after hemodynamic and endostasis stabilization, jejunal nutrition channels were established immediately and EN was started, and parenteral nutrition was considered only when EN could not be implemented.
After 2000, we have increased our research on series of related techniques: 1. endoscopically guided placement of feeding tube 20-30 cm below the Treitz ligament. 2. x-ray guided placement of feeding tube into the upper jejunum. 3. endoscopic percutaneous gastrostomy (PEG). 4. endoscopic percutaneous jejunostomy (PEJ). 5. improvement of enteral nutrition preparation and optimization of infusion technique. 6. Early promotion of intestinal peristalsis, application of hypertonic laxatives (e.g., mannitol), restoration of intestinal patency, etc. Changing the nutrition pattern and maintaining the intestinal mucosal barrier are among the important reasons for the improved success rate of SAP salvage.
By treating 1033 patients with SAP, 975 were discharged cured (94.4%), 38 patients died (3.7%), 12 were discharged well (1.2%), and 8 patients were discharged spontaneously (0.8%, mostly for financial reasons). Compared to the previous 9 years (1988-1996), the number of cases increased 30 times, the overall mortality rate decreased from 20.4% to 3.7%, the mortality rate of surgical patients decreased from 24% to 7.1%, and the length of stay and hospitalization costs decreased every year.