What are the preoperative medical management guidelines for a patient with comorbidities such as diabetes, hypertension, and cardiovascular disease undergoing pancreatectomy?

Preoperative Medical Management for Pancreatectomy

All patients undergoing pancreatectomy require comprehensive preoperative assessment focusing on diabetes management, cardiovascular risk stratification, symptom control for functional tumors, and optimization of comorbidities, with specific attention to preventing perioperative complications through evidence-based protocols. 1, 2

Diabetes Management

Preoperative Assessment

• Screen for gastroparesis by asking specifically about abdominal bloating, early satiety, postprandial fullness, nausea, or vomiting, as this occurs in 30-50% of Type 2 diabetes patients and necessitates rapid sequence intubation planning. 1, 2, 3
• Evaluate for cardiac autonomic neuropathy by asking about orthostatic symptoms, postprandial hypotension, or exercise intolerance, as this increases cardiovascular events and sudden death risk perioperatively. 1, 2, 3
• Document capillary blood glucose patterns from the past week, as recent disequilibrium affects perioperative management even with known HbA1c. 1, 2, 3
• Check for recent ketosis with urinary or blood ketones, as this mandates surgery postponement except for life-threatening emergencies. 1, 2, 3
• Identify any hypoglycemic episodes requiring assistance, as hypoglycemia unawareness occurs in 10% of insulin-treated Type 2 diabetes patients. 1, 2, 3

Medication Management Evening Before Surgery

• Administer all insulin at the usual dose the evening before surgery, including both basal insulin (NPH, glargine, detemir, degludec) and any prandial insulin with the evening meal. 2
• Maintain insulin pumps at usual settings until arrival at the surgical unit the next morning. 2
• Stop metformin from the evening before surgery to reduce lactic acidosis risk, particularly important given potential perioperative renal stress. 2, 3
• Continue all other oral agents (sulfonylureas, DPP-4 inhibitors, GLP-1 agonists) with the evening meal. 2
• Discontinue SGLT2 inhibitors 3-4 days prior to surgery due to euglycemic ketoacidosis risk. 2
• Allow patients to eat their normal evening meal without restriction. 2

Morning of Surgery

• Give 50% of usual morning dose of NPH insulin. 2
• Give 75-80% of usual dose of long-acting analogs (glargine, detemir, degludec). 2
• Hold all rapid-acting/prandial insulin on the morning of surgery. 2
• Hold all remaining oral hypoglycemic agents on the morning of surgery. 2

Critical Pitfall: Never allow insulin deficiency in insulin-treated patients, as this leads to ketoacidosis within hours, particularly critical in Type 1 diabetes. 2

Cardiovascular Risk Assessment

Risk Stratification

• Check for silent myocardial ischemia through history of other arterial disease or proteinuria, as 30-50% of Type 2 diabetes patients have asymptomatic coronary disease. 1, 3
• Approximately 75% of diabetic patients die from complications of atherosclerosis, making cardiovascular assessment critical. 1
• Measure coronary calcium score by CT scan (without iodinated contrast); a score >400 Agatston units is associated with worse prognosis and high prevalence of silent myocardial ischemia and should lead to investigations for ischemia. 1
• Perform ECG at rest in all diabetic patients. 1
• Assess for orthostatic hypotension by measuring arterial pressure lying down and standing. 1

Important Note: Systematic coronary revascularization before non-cardiac surgery is not useful to reduce postoperative myocardial ischemic episodes; however, repeated perioperative measurement of troponin associated with ECG allows detection of perioperative myocardial damage and helps initiate cardiovascular treatment. 1

Renal Function Assessment

• Confirm creatinine and GFR measurement is available, as diabetic nephropathy aggravates perioperative acute renal failure risk. 1, 2, 3
• Perform urinary test strip to check for proteinuria. 1
• Microalbuminuria is associated with increased cardiovascular risk in both Type 1 and Type 2 diabetes, and the risk is even greater with macroproteinuria or renal failure. 1

Clinical Context: Diabetes is an independent risk factor for pancreatic fistula formation after pancreatectomy (odds ratio 4.3,95% CI 1.18-15.8), and acute kidney injury is more frequent in diabetic patients (23.3% vs 12.6%). 4

Hypertension Management

• Assess for orthostatic hypotension as part of cardiovascular autonomic neuropathy screening. 1
• Continue antihypertensive medications through the morning of surgery with small sips of water, except for ACE inhibitors and ARBs which should be held on the morning of surgery to prevent intraoperative hypotension. 1
• Document blood pressure control patterns, as arterial hypertension is a key co-existing risk factor that increases cardiovascular risk heterogeneity in diabetic patients. 1

Management of Functional Pancreatic Neuroendocrine Tumors

Preoperative Symptom Control

• For most pancreatic NET subtypes, octreotide or lanreotide can be considered for symptom control before excision. 1, 5
• For insulinomas, stabilize glucose levels with diet and/or diazoxide; everolimus can also be considered. 1
• Use octreotide or lanreotide with extreme caution in patients with insulinoma because they can suppress counterregulatory hormones (growth hormone, glucagon, catecholamines) and precipitously worsen hypoglycemia, resulting in fatal complications. 1, 5
• Somatostatin analogues should generally not be used in patients with insulinoma who have negative somatostatin scintigraphy. 1
• For gastrinomas, treat gastrin hypersecretion with proton pump inhibitors. 1
• For glucagonomas, take appropriate measures to treat hyperglycemia and diabetes, including intravenous fluids. 1

Vaccination for Splenectomy Risk

• All patients who might require splenectomy should receive preoperative trivalent vaccine (pneumococcus, haemophilus influenzae b, meningococcus group c). 1

Prophylactic Measures NOT Recommended

Somatostatin Analogues for Fistula Prevention

• Somatostatin and its analogues have no beneficial effects on outcome after pancreaticoduodenectomy; in general, their use is not warranted for fistula prevention. 1, 5
• While somatostatin analogues reduce crude rates of pancreatic fistulas, the rate of clinically significant fistulas as well as overall major morbidity and mortality remain unchanged. 1, 5
• Subgroup analyses of pancreaticoduodenectomy patients showed no significant effect of somatostatin/octreotide on any reported outcomes. 1, 5
• The commonly believed beneficial effect in cases with acknowledged risk factors (soft pancreas, small pancreatic duct) is not substantiated by available evidence. 1, 5

Critical Distinction: The role of octreotide differs completely between symptom control for functional NETs (where it is indicated) versus fistula prevention in standard pancreatectomy (where it is not indicated). 1, 5

Preoperative Biliary Drainage

• Preoperative biliary drainage is recommended only in patients with severe jaundice, as it can lead to infectious cholangitis, pancreatitis, and delay in resection, which can lead to tumor progression. 6

Nutritional Assessment

• Assess preoperative serum albumin, as levels <3.5 mg/dl are among the strongest predictors for reoperation after pancreatic resection. 7
• Check total bilirubin levels, as higher levels are associated with increased reoperation risk. 7

Comorbidity Assessment

• Document respiratory comorbidities, as these are associated with increased reoperation risk. 7
• Assess American Society of Anesthesiologists (ASA) class, as class 3 or 4 is a strong predictor for reoperation after pancreatic resection. 7
• Male sex is independently associated with higher reoperation rates and should factor into risk counseling. 7

Supportive Care Assessment

• Patients with potentially curable pancreatic cancer should have a full assessment of symptom burden, psychological status, and social supports as early as possible, preferably at the first visit, as this may indicate need for formal palliative care consult and services. 1

Perioperative Fluid Management Strategy

• Plan for near-zero fluid balance intraoperatively, as avoiding overload of salt and water results in improved outcomes. 1
• Use balanced crystalloids rather than 0.9% saline, as excessive saline leads to hyperchloremic acidosis, renal edema, reduced cortical tissue perfusion, and increased postoperative complications. 1
• Plan for perioperative monitoring of stroke volume with trans-esophageal Doppler to optimize cardiac output with fluid boluses. 1
• Consider vasopressors for intra- and postoperative management of epidural-induced hypotension rather than excessive fluid administration. 1

Urinary Drainage Planning

• Plan for transurethral catheter removal on postoperative day 1 or 2 unless otherwise indicated, as this is superior in terms of infection rates and does not lead to increased re-catheterization rates. 1
• Suprapubic catheterization is superior to transurethral catheterization if drainage is needed for >4 days. 1