Perioperative management - Necrosectomy and continuous closed irrigation in infected hemorrhagic-necrotizing pancreatitis

The prognosis of severe acute pancreatitis is significantly determined by the bacterial infection of pancreatic necroses. 40-70 percent of all patients with necrotizing pancreatitis develop infected necroses. The incidence increases with the extent of necroses and the duration of the course.

The necroses occurring in the initial phase of severe acute pancreatitis are primarily sterile. Bacterial superinfection occurs later in the course of the disease, usually in the second to fourth week after the onset of the disease.

If acute abdominal complications occur, immediate surgical or interventional action is required.

• Hollow organ perforation
• Hemorrhage: primarily radiologically interventional
• Abdominal compartment
• Infected necroses

Proven infected necroses (positive FNA / air in the necrosis area) in conjunction with septic complications are generally accepted indications for surgical or interventional therapy. The mortality of patients with septic complications is 30–80%. Mortality rates of up to 100% are reported if intervention is omitted in patients with infected necroses and organ complications.

• Persistent multi-organ dysfunction syndrome

Even with sterile necroses and organ dysfunctions, surgical therapy may be indicated if there is a deterioration of the clinical situation in the sense of progressive SIRS under conservative therapy. In these patients with sterile necroses and progressive organ complications despite maximum intensive therapy (non-responders), the indication for surgical therapy is established. It remains unclear at what point a patient is defined as a non-responder. Generally, at least 6 weeks of conservative therapy in an intensive care unit is required here.

• Fulminant acute pancreatitis -> Surgery as a last resort!

Patients with fulminant acute pancreatitis represent a rare course. Here, despite intensive therapy, rapid progressive organ failure occurs within the first days of the disease. In these cases, early surgical therapy is considered a treatment option. Unfortunately, neither surgical nor conservative therapy can significantly improve the poor prognosis in this disease course.

Surgical Technique:

The goal of the surgical approach is to clear the infection focus. The procedure should be performed later rather than early, preferably 3-6 weeks after the onset of symptoms! Whether minimally invasive or conventionally open depends on the extent of the necroses.

• Open approach with necrosectomy and postoperative lavage
• Video-assisted retroperitoneal debridement (VARD)
• Endoscopic transgastric necrosectomy for limited necroses

Conventional Open Surgical Necrosectomy

The surgical necrosectomy is performed after laparotomy and opening of the omental bursa through the gastrocolic ligament using blunt dissection without sharp instruments.

Since recurrent intra-abdominal sepsis after one-time necrosectomy is a potential problem, different concepts have been developed for the removal of postoperatively remaining necrotic tissue and exudate.

Four methods are known:

• Open Packing
• Planned repeated relaparotomies (staged lavage)
• Closed Packing
• Closed continuous lavage

Open Packing and Planned Relaparotomy

In cases of massive fluid retention or development of an abdominal compartment syndrome in early disease stages. The open abdomen can best be managed with a vacuum dressing.

In principle, a primary abdominal wall closure is sought.

Open Packing and planned relaparotomy share the need for multiple repetitions of necrosectomy and lavage until treatment completion, thus causing high subsequent morbidity. Repeated necrosectomies, typically required 5 to 10 times, correlate with more frequent intra-abdominal complications including pancreatic fistulas (about 25–50%) and bleeding (about 20–45%), as well as increased systemic complications. Both surgical methods are therefore only used when surgical intervention is necessary in an early phase of acute pancreatitis, i.e., at a time when the necrosis areas are not yet fully demarcated and further operations are necessary anyway.

Closed Packing and Closed Continuous Lavage

In closed packing, Penrose drains are introduced into the abscess cavity and left for at least 7 days.

In continuous lavage, closed drains are placed in the pancreatic bed. Postoperative lavage begins with a flushing volume of about 10–20 liters per day, which is slowly reduced under control of infection values.

Postoperative continuous lavage and closed packing are two surgical methods that allow the postoperative removal of necrotic parts and exudate without reoperation. This can avoid relaparotomy in most cases and complete the surgical treatment with a single intervention in about 70–80%. Although this does not reduce mortality, it reduces postoperative morbidity, particularly regarding fistulas (about 15–30%) and bleeding (about 5–15%) and scar hernias.

In our clinic, we prefer closed continuous lavage. This prevents relaparotomy in the majority of cases. This approach is now the most commonly used worldwide among all surgical procedures.

Minimally Invasive Techniques

Today, in addition to open surgical techniques, various minimally invasive techniques including surgery, endoscopy, and interventional radiology are available.

The retroperitoneoscopic procedure in different variants is the minimally invasive surgical procedure of choice.

Retroperitoneoscopic necrosectomy is part of a step-up approach in the sense of an escalation therapy scheme. In this scheme, when an infected necrosis is detected in a septic patient, an interventional drain is placed in the infection focus, and only if clinical stabilization is not achieved in the following days is a minimally invasive necrosectomy performed. The inserted drain serves as a guide for the necrosectomy.

Depending on the technique variant, the marked access is then dilated/incised and the necrosectomy is performed video-assisted using a cystoscope, nephroscope, mediastinoscope ("minimal access retroperitoneal pancreatic necrosectomy", MARPN; "video-assisted retroperitoneal debridement", VARD) or with the help of an endoscope.

If two accesses are created, postoperative continuous lavage with high flushing volume can be performed. The endoscope offers the advantage of flexible direction change, allowing removal of necrosis parts located far retrocolically without additional accesses.

Comparison of Open and Minimally Invasive Surgical Techniques

It is assumed that selection occurs as to which procedure the respective patient is subjected.

In contrast to conventional surgical procedures, several minimally invasive interventions are usually necessary to control sepsis, and patients generally remain longer in intensive care and in the hospital.

Unlike minimally invasive retroperitoneoscopic techniques, the open conventional surgical technique can also be used in emergencies, e.g., in suspected bowel ischemia or bleeding, as well as when a stoma or cholecystectomy is necessary.

Endoscopic Transgastric Necrosectomy

Endoscopic necrosectomy is an alternative to the methods already mentioned. Since the endoscopic technique makes areas in the pancreatic head easier to reach than percutaneously, while left-sided areas are better accessible percutaneously, a combination of techniques is certainly sensible in the future. Potential advantages of the transgastric approach are

• painlessness and
• avoidance of cutaneous fistulas.

Disadvantages may include

• the obligatory secondary contamination of the necrosis with intestinal flora,
• the lack of possibility for continuous postoperative lavage, and
• the rapid closure of the access (keeping the access open by inserting plastic stents or a special metal stent (hot-Axios-stent, beware of erosion bleeding after 2 weeks!).

Cholecystectomy

In biliary pancreatitis, the gallbladder should be removed as the source of the triggering stones.

In the case of a mild course with conservative therapy and healing, this procedure can then be performed electively, usually also laparoscopically. The cholecystectomy should be performed during the first hospital stay – directly following the resolved pancreatitis – as this is possible without increased morbidity and reduces the risk of a recurrent pancreatitis episode in the interval.

In the case of severe pancreatitis requiring laparotomy, preoperative ERCP with papillotomy and possibly stent placement should have been performed in biliary genesis of the acute pancreatitis.

• Not in sterile necroses!
• Avoid procedure within the first 2 weeks after symptom onset
• Timing: better late than early: preferably 3-6 weeks after symptom onset

The diagnosis is made clinically through abdominal pain accompanied by an increase in amylase or lipase to at least three times the normal level.

Imaging procedures are initially secondary!

Symptoms: often unilateral or bilateral radiating flank pain as well as a still compressible but diffusely tender abdominal finding ("rubber belly"), accompanied by nausea and vomiting.

The assessment of the disease course in patients with acute pancreatitis is often difficult. Upon hospital admission, the severity of the disease course can only be assessed very unreliably through clinical examination.

There are various scoring systems for assessing and predicting the severity of the disease course, including:

• Ranson score
• Glasgow score
• APACHE-II score.

However, scoring systems are also only conditionally suitable for assessing a patient's risk for a severe disease course. Moreover, due to their complexity, they are rarely used in clinical practice.

Many different laboratory markers have been investigated as specific and reliable predictors of severe disease courses. However, CRP remains the best-evaluated parameter and is considered a reliable predictor of pancreatic necrosis from the third day of illness. The cut-off value for a severe disease course is a CRP over 150 mg/dl.

Since the majority of fatal courses are caused by the infection of pancreatic necroses, detecting the infection is particularly important. However, there is still no laboratory parameter that reliably predicts the infection of pancreatic necrosis. Procalcitonin is a marker that can already provide indications of a severe disease course in the first 2 days, but it loses sensitivity and specificity in the further course.

Clinical signs of severe acute pancreatitis: Grey-Turner sign or the Cullen sign:

• In this case, bluish-greenish spots appear in the flank or navel area. They are caused by edema of the subcutis with local bleeding from small vessels, also referred to as ecchymoses, which are caused by autodigestion of blood vessels by pancreatic enzymes or by bleeding in the retroperitoneum.
• Ecchymoses below the inguinal ligament (so-called Fox sign) are very rare.

Ultrasound Diagnostics

Basic diagnostics include abdominal sonography to assess the following situations:

• free fluid
• Status of the bile ducts and gallbladder
  • Stones?
  • Bile duct dilation?
  • Inflammation?
• Pancreas, if visible
  • Edema?
  • Calcifications?
  • Free fluid?

X-ray Diagnostics

• Plain abdominal X-ray for differential diagnostic exclusion of perforation (free air) and to assess any accompanying intestinal paralysis (mirror formation).
• Depending on the patient's clinical condition, a chest X-ray should be taken to assess the pulmonary status, particularly for accompanying pleural effusions.

Contrast-enhanced CT

• Contrast-enhanced CT is now the gold standard for diagnosing pancreatic necrosis and thus for identifying locally complicated pancreatitis.
• Contrast-enhanced CT as extended basic diagnostics is often performed upon patient admission, also depending on the quality of the sonography.
• Since necrosis is only fully developed after 4–5 days, follow-up should be conducted to properly assess the extent of the necroses.
• The detection of superinfection of pancreatic necroses is hardly possible with CT alone, as gas inclusions as an indication of bacterial infection rarely occur. Here, a fine-needle aspiration of necrotic material for microbiological processing must be performed.

Endoscopic Retrograde Cholangiopancreatography (ERCP)

• In mild pancreatitis: not necessary
• In severe pancreatitis: controversial
• If persistent obstruction of the bile ducts: Yes, as soon as possible!

IMC (Intermediate Care)

The goal of basic therapy is to avoid secondary complications of acute pancreatitis such as pulmonary, cardio-circulatory, renal, and metabolic decompensations. Therapeutic intervention is only possible through early detection and treatment of complicated courses.

The basis for reducing the high mortality in the early phase of acute pancreatitis is the immediate initiation of symptomatic intensive care standard therapy.

Risk factors for a severe course:

• High BMI
• Cardiopulmonary pre-existing conditions

Primary and early IMC due to volume needs and monitoring:

• Pulse oximetry,
• Hematocrit
• Renal retention parameters
• Urine output

Volume substitution

In the early phase of acute pancreatitis, several factors lead to the development of cardio-circulatory decompensation:

• particularly the shift of several liters of fluid from intravascular to the "third space,"
• electrolyte shift,
• the influx of toxic and vasoactive substances.

To compensate for intravascular volume, central venous pressure, and systemic blood pressure, generous volume substitution (often 300–500 ml/h) is necessary.

Antibiotic therapy

The infection of pancreatic necrosis in the second phase of the disease is the main risk factor for sepsis and multi-organ failure and is associated with high mortality. Prophylactic antibiotic therapy in severe necrotizing pancreatitis aims to reduce the occurrence of infections and septic disease courses, the rate of necessary surgeries, and also mortality.

However, the study situation is controversial:

In the guidelines for the treatment of acute pancreatitis in the United Kingdom, the general recommendation for antibiotic prophylaxis was omitted based on a published multicenter double-blind study. The study could not demonstrate the effectiveness of antibiotic prophylaxis.

Considering all available data, prophylactic antibiotic administration is still recommended for patients with necrotizing forms, especially if more than 50% of the organ is affected or in early organ failure.

Carbapenems are currently considered the antibiotics of choice due to their spectrum of activity and penetration into pancreatic tissue.

Anti-fungal prophylaxis is not recommended.

Intra-arterial application or selective bowel decontamination is being tested in studies.

Analgesia

Adequate analgesia is an important pillar of therapy and has a positive effect on patient outcomes.

Potent opioid analgesics are used, such as buprenorphine, which can be administered sublingually (e.g., 4 × 200–400 µg/d) or intravenously (e.g., 4 × 300 µg/d as a short infusion). Pethidine and piritramide are also suitable as highly potent analgesics, possibly in combination with a peripherally acting painkiller such as metamizole.

In rare cases of failure of intravenous medication pain therapy, a thoracic epidural catheter is an alternative.

The side effect of increased tone of the Sphincter of Oddi with consequent worsening of the course of pancreatitis does not seem to be significant with modern opioid analgesics.

Ventilation therapy

If oxygen saturation drops, oxygen should be administered, and if necessary, intubation and controlled ventilation should be performed. Under no circumstances should adequate fluid substitution be interrupted due to impending respiratory insufficiency.

Oliguria in the first 48 hours after the onset of the disease is associated with a high complication rate of acute pancreatitis in most cases. Nephrotoxic medications should be avoided.

Stress ulcer prophylaxis

In severe pancreatitis, acid blockade is indicated for stress ulcer prophylaxis. Controlled studies on the benefit of stress ulcer prophylaxis are lacking, but prophylaxis is generally recommended. Here, too, intravenous administration of proton pump inhibitors (PPI, e.g., 40–80 mg/d pantoprazole) is preferred.

Enteral nutrition

In recent years, several studies have indicated that enteral nutrition via a jejunal tube in severe courses of acute pancreatitis may have a positive effect on the course of pancreatitis. Early enteral nutrition seems to maintain mucosal integrity and thus prevent bacterial translocation and is superior to parenteral nutrition. However, enteral nutrition depends on the extent of subileus and is not feasible in every case. The recommendation for exclusively parenteral nutrition in the early phase of acute pancreatitis is no longer tenable.

A primary nasojejunal tube is favored, especially due to the almost invariably present gastric paralysis in severe acute pancreatitis. This also results in the exclusion of duodenal passage and thus a negative stimulus on the pancreas.

Since patients are already threatened by general complications such as thromboembolism, pneumonia, and bleeding due to the preoperative septic condition and usually have undergone long-term intensive medical treatment, one should focus on the urgency of the surgical procedure in addition to general complications such as

• Injury to adjacent structures (intestine, vessels, nerves, other organs)
• Extension of the surgery at the discretion of the surgeon
• Subsequent interventions

and inform about specific complications:

• Induction of bleeding with possible transfusions of donor blood
• Resection of functional tissue with subsequent exocrine and endocrine pancreatic insufficiency
• Pancreatic fistula
• Persistent sepsis
• Late abscesses
• Gastrointestinal fistulas
• Incisional hernia
• Gastric outlet obstruction
• Bile duct strictures
• Pseudocysts

• Intubation anesthesia
• Central venous catheter (CVC)
• Arterial pressure measurement
• Triple-lumen catheter
• Indwelling urinary catheter
• Evaluate intra- and postoperative analgesia with epidural catheter (EDC)

• Supine position
• Arms can be positioned outwards

The surgeon stands on the right, the first assistant opposite. The scrub nurse stands at the foot of the table on the surgeon's side.

• Basic abdominal surgical instruments
• Cable retraction system
• Gallbladder sieve
• Large-bore drains
• Possibly VAC system

Postoperative Analgesia:

Pain management depends on the underlying severity of the primary disease, possibly using an epidural catheter. Follow the link to PROSPECT (Procedures Specific Postoperative Pain Management). Follow the link to the current guideline Treatment of acute perioperative and post-traumatic pain.

Medical Follow-up:

• Postoperative lavage through the three large-bore drains located in the pancreatic bed. It starts with a flushing volume of about 10–20 liters per day, which is slowly reduced under control of infection values.
• Two drains serve as outflow, one drain is used for inflow. The inflow drain is rotated every 8 hours, while the other two serve as outflow.
• Nutrition via nasojejunal tube, at least villous nutrition.
• Antibiotic treatment according to antibiogram, carbapenems are favored due to their penetration into pancreatic tissue.
• If an abdominal vacuum dressing is applied, at least one more surgery (for closure) is required.

In the later course

• Blood sugar daily profiles to assess endocrine insufficiency
• Pancreatic enzyme substitution and nutritional counseling
• PPI prophylaxis: initially i.v., then orally beyond discharge.

Thrombosis Prophylaxis:

In the absence of contraindications, due to the high risk of thromboembolism, low molecular weight heparin should be administered prophylactically, possibly in weight- or disposition risk-adapted dosage until full mobilization is achieved. It is recommended to continue pharmacological thromboembolism prophylaxis beyond discharge. Note: Renal function, HIT II (history, platelet control) Follow the link to the current guideline Prophylaxis of venous thromboembolism (VTE).

Mobilization:

• As soon as possible,

Physiotherapy:

• Pneumonia prophylaxis (physiotherapy, breathing exercises)

Dietary Advancement

• depends on the course of the underlying severe primary disease.
• Due to the usually present gastric and intestinal paralysis, initial nutrition via nasojejunal tube
• Due to the almost always present intestinal paralysis, peristalsis-stimulating medications such as acetylcholinesterase inhibitors e.g. neostigmine and laxatives (diphenylmethane derivatives) are indicated.
• Once oral dietary advancement is possible, substitution of pancreatic enzymes

Incapacity for Work

• very individual
• The quality of life for most patients is good after discharge from the hospital, and almost 90% of patients can return to work. Only with persistent alcohol consumption is a mortality rate of about 10% in the following years to be expected, even after initially good recovery.