Pancreatoduodenal resection – Procedures

What the Anesthesiologist Should Know before the Operative Procedure

A pancreatoduodenal resection, Whipple’s procedure, is performed primarily to remove an adenocarcinoma in the head of the pancreas. There are two major phases of the procedure: the dissection of the pancreas and tumor from the remaining structures (most notably the portal vein, superior mesenteric vein and the superior mesenteric artery), and the re-anastomosis of those structures — i.e. a choledochojejunostomy, a gastrojejunostomy and a pancreaticojejunostomy. The former phase is the most critical for the anesthesiologist as an accidental perforation of the portal vein may cause an abrupt loss of blood.

Other indications for a Whipple include other tumors in the head of the pancreas, such as cystadenomas, functioning and non-functioning islet cell tumors, cancer of the duodenum, cholangiocarcinoma, cancer of the ampulla of Vater, and certain cases of chronic pancreatitis.

Despite the fact that a large fraction of the pancreas is removed, non-diabetic patients do not appear to become diabetic following the procedure. Diabetic patients, however, may find that their glucose control worsens following the surgery.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Although this procedure is not considered emergent, or even urgent, it should be remembered that without surgery the median survival following the diagnosis of adenocarcinoma of the pancreas is approximately six months. Therefore, the likelihood of a surgical cure decreases rapidly with each day the surgery is delayed. Consequently, surgery should not be delayed unnecessarily.

2. Preoperative evaluation

The incidence of pancreatic cancer increases with age. The medical conditions affecting the anesthetic care of the patient presenting for a Whipple are generally the same as those encountered in any elderly patient.

Medically unstable conditions warranting further evaluation include: acute coronary syndromes, unstable dysrhythmias, and acute heart failure.

Delaying surgery may be indicated if the delay will improve the chances of a successful perioperative outcome in terms of survival or quality of remaining life. Consequently, delays for medical conditions which can be stabilized in a relatively short period of time (e.g. valvuloplasty for critical aortic stenosis) might be appropriate.

3. What are the implications of co-existing disease on perioperative care?

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b. Cardiovascular system

Acute/unstable conditions: Evaluate by history, physical exam and labs. Look for signs and symptoms of ischemia, dysrhythmias, heart failure and valve dysfunction.

Baseline coronary artery disease or cardiac dysfunction – Continue most of the cardiac medications the patient is on: beta-blockers, diuretics, nitrates. Consider withholding ACE-Inhibitors on the day of surgery since following an induction with propofol patients on ACE-Inhibitors frequently become hypotensive; this hypotension is often resistant to treatment with sympathomimetics, but responsive to vasopressin.

c. Pulmonary

COPD: Evaluate by history, physical exam and labs. Especially note baseline home oxygen requirement. Baseline labs, including arterial blood gases and pulmonary function tests, are not usually necessary to start surgery. Maintain the current medication regimen, keep the peak airway pressures low, and avoid stacking breaths by allowing enough time to exhale. Note that PEEP may make shunting worse in some patients.

Reactive airway disease (Asthma): Evaluate by history, physical exam and labs. Assess triggers, severity, and successful treatments. Ask about recent steroid use, and a history of emergency room visits, hospitalizations and intubations. Continue the patient’s medication regimen, and consider having the patient use an inhaler or nebulizer before induction. High dose opiates help in blunting the response to intubation. If the patient becomes bronchospastic after induction, deepening the anesthetic, inhalational agents, or low-dose epinephrine (10 microgram boluses or an infusion at 0.25 mcg/min) may help.

d. Renal-GI:

Assess by history, physical exam and labs. Patients presenting for pancreatoduodenectomy for adenocarcinoma typically have a normally functioning GI tract, but occasionally have some obstruction at the level of the duodenum. Assess whether the patient needs to be treated as having a full stomach.

e. Neurologic:

Acute issues: Acute stroke should be treated before going to surgery.

Chronic disease: Patients with carotid stenoses may need to have their blood pressure maintained on the higher side to allow adequate cerebral perfusion.

f. Endocrine:

Although adenocarcinoma of the pancreas is the most common cancer in the pancreas, functioning islet cell tumors may also occur there. Named after the hormones they secrete, these are insulinomas, gastrinomas, glucagonomas, VIPomas and somatostatinomas. Insulinomas may result in hypoglycemia by secreting too much insulin; gastrinomas often produce stomach ulcers; glucagonomas may produce mild diabetes; VIPomas produce a watery diarrhea; and somatostatinomas (only 100 reported worldwide) produce a mild diabetes and steatorrhea.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

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4. What are the patient's medications and how should they be managed in the perioperative period?

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h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

This may include medications specific to diseases associated with surgery- Cancer is a risk factor for the development of deep-vein thromboses and pulmonary emboli. Consequently, these patients should receive an anticoagulant such as subcutaneous heparin, or mechanical compression boots, as prophylaxis.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac: Patients on beta-blockers should be continued on them. Patients on statins should have them continued as well. Consider having patients on ACE-Inhibitors hold them on the morning of surgery.

Pulmonary: Pulmonary medications should be continued perioperatively.

GI: Continue proton-pump inhibitors and H2 blockers in patients with reflux symptoms.

Endocrine: Hold oral antiglycemic agents on the day of surgery. Give 1/2 the patient’s total insulin (regular and NPH) dose as NPH on the day of surgery. Arrange to have a glucose level measured when the patient arrives to the hospital — the patient may need an infusion of D5W if the surgery is later in the day.

Neurologic: Anti-Parkinson’s and anti-seizure medications should be continued intraoperatively.

Anti-platelet: Patients on aspirin may continue on it, or, if stopped perioperatively, should restart it as soon as possible after surgery. Glycoprotein IIb/IIIa inhibitors – when prescribed following the insertion of a coronary stent, a discussion should be had with the cardiologist and the surgeon about the need to continue these. The cardiologist’s decision will be influenced by the type of stent and when placed; the surgeon’s with the risk of surgical bleeding.

j. How To modify care for patients with known allergies –

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k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

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l. Does the patient have any antibiotic allergies? (common antibiotic allergies and alternative antibiotics)

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m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia:

Avoid all trigger agents, such as succinylcholine and inhalational agents: Ensure MH cart is available: [- MH protocol].

5. What laboratory tests should be obtained and has everything been reviewed?

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Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

The procedure is performed under general anesthesia with or without an epidural.

a. Neuraxial

• Benefits: opiates have been suggested to blunt the immune response; the procedure is an upper abdominal incision and neuraxial analgesia may improve post-op breathing mechanics.

• Drawbacks; neuraxial analgesia is contraindicated in patients on many antiplatelet drugs and anticoagulants; the patient with an epidural may not tolerate sympatholysis and the consequent hypotension.

• Issues The surgical incision is typically from about the T6 to T10 dematomes. Consequently, the epidural catheter should be placed at about T8-9.

b. General Anesthesia

• Benefits: Because of the complexity of the case, this intraabdominal procedure is of relatively long duration. Regional anesthesia alone is not a sound anesthetic option.

• Drawbacks: Many inhalational agents are associated with post-operative cognitive dysfunction.

• Other issues: Because of the long duration, meticulous care should be taken to assure appropriate positioning and padding.

• The patient should be kept warm.

• A nasogastric tube should be placed.

• Airway concerns: routine

c. Monitored Anesthesia Care is not an option.

6. What is the author's preferred method of anesthesia technique and why?

My preferred method for anesthetic is a general anesthetic with a mid-thoracic epidural. At my institution, we typically monitor the patients with standard monitors unless their unique physiology requires additional measures.

What prophylactic antibiotics should be administered? A second-generation cephalosporin such as cefoxitin or cefotetan is our antibiotic of choice to cover bile flora as well as skin flora. For patients allergic to those drugs, we administer a fluoroquinolone.

What do I need to know about the surgical technique to optimize my anesthetic care?

• The long duration requires attention to proper positioning and padding

• Evidence of metastases will likely abort the pancreatoduodenectomy.

• Risk of rapid bleeding suggests that adequate IV access be obtained before the resection.

What can I do intraoperatively to assist the surgeon and optimize patient care? Pancreatoduodenectomies are some of the longer intra-abdominal surgeries given the possibility of a challenging resection and the multiple anastomoses that follow. That which makes the surgeon’s life easier makes your life easier. We avoid nitrous oxide to avoid making small gas pockets in the bowel into large gas pockets. We avoid giving large amounts of fluid intraop to avoid making the bowel edematous. After about a liter of crystaloid, I start an infusion of Hextend (with the goal of giving one liter over the course of the operation). Additional crystaloid is given as needed.

What are the most common intraoperative complications and how can they be avoided/treated? From an anesthetic perspective, the most worrisome event is rapid hemorrhage if the surgeon enters a vein while dissecting the portal and superior mesenteric veins from the head of the pancreas. Consequently, venous access is dictated by the proximity of the tumor to the veins and the surgeon’s experience in performing this operation [Note — even those surgeons whose practice is predominantly pancreatoduodenectomies may enter a quickly bleeding vessel on rare occasion].

a. Neurologic:

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b. If the patient is intubated, are there any special criteria for extubation?

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c. Postoperative management

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What's the Evidence?

Wijeysundera, DN, Beattie, WS, Austin, PC, Hux, JE, Laupacis, A. “Epidural anaesthesia and survival after intermediate-to-high risk non-cardiac surgery: a population-based cohort study”. Lancet. vol. 372. 2008. pp. 562-69. (This is a population-based administrative database to perform a retrospective cohort study of ~260,000 patients who underwent intermediate- to high-risk noncardiac procedures in Canada. They document that the 22% of patients who received epidural anesthesia and analgesia had a small reduction in mortality and the procedure improved pain relief and was very safe.)

Ahlers, O, Nachtigall, I, Lenze, J, Goldmann, A, Schulte, E, Hohne, C, Fritz, G, Keh, D. “Intraoperative thoracic epidural anesthesia attenuates stress-induced immunosuppression in patients undergoing major abdominal surgery”. Br J Anaesth. vol. 101. 2008. pp. 781-7. (An investigation of 54 patients undergoing major abdominal surgery who had a thoracic epidural catheters placed for anesthesia/analgesia. The study documented a reduced concentration of stress mediators in these patients.)

Koerner, P, Busemann, A, Traeger, T, Kessler, W, Cziupka, K, Diedrich, S, Kloecker, C, Jack, R, Heidecke, C-D, Maier, S. “Postoperative immune suppression in visceral surgery: characterisation of an intestinal mouse model”. Eur Surg Res. vol. 47. 2011. pp. 260-6. (There is a postoperative acquired immune dysfunction that was explored using anesthetized mice that underwent laparotomy and then had their small bowels manipulated. The mediator release and histology were documented and showed that surgical trauma is followed by immune dysfunction postoperatively.)

Kawaraguchi, Y, Horikawa, YT, Murphy, AN, Murray, F, Miyanohara, A, Ali, SS, Head, BP, Patel, PM, Roth, DM, Patel, HH. “Volatile anesthetics protect cancer cells against tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis via caveolins”. Anesthesiology. vol. 115. 2011. pp. 499-508. (This is an in vitro study of the effect of isoflurane on human colon cancer cells. The study documents that isoflurane protected the cancer cells from apoptosis, or from programmed cell-death.)

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