What is the perioperative management plan for a patient with poorly controlled type 2 diabetes mellitus (T2DM) on aspart (Novolog), Tresiba (insulin degludec), and metformin (MF) undergoing hysterectomy?

Perioperative Management for Poorly Controlled T2DM Patient Undergoing Hysterectomy

This patient requires immediate preoperative optimization with insulin dose adjustments, withholding metformin from the evening before surgery, continuation of basal insulin (Tresiba) at usual dose the night before, and transition to intravenous insulin infusion during surgery with hourly glucose monitoring targeting 100-180 mg/dL (5.6-10.0 mmol/L). 1, 2

Critical Questions to Ask Before Surgery

Assess Diabetes-Related Complications

• Screen for gastroparesis by asking about abdominal bloating, early satiety, postprandial fullness, nausea, or vomiting, as this occurs in 30-50% of T2DM patients and creates aspiration risk requiring rapid sequence intubation 1

• Evaluate for cardiac autonomic neuropathy (CAN) by asking about orthostatic symptoms, postprandial hypotension, or exercise intolerance, as CAN increases cardiovascular events and sudden death risk perioperatively 1

• Check for silent myocardial ischemia through history of other arterial disease or proteinuria, as 30-50% of T2DM patients have asymptomatic coronary disease 1

• Assess renal function by measuring creatinine and GFR preoperatively, as diabetic nephropathy aggravates perioperative acute renal failure risk 1

Review Recent Glycemic Control

• Document recent capillary blood glucose patterns from the past week, as recent disequilibrium affects perioperative management even with known HbA1c 1

• Identify hypoglycemic episodes in the last week, particularly any requiring assistance, as hypoglycemia unawareness occurs in 10% of insulin-treated T2DM patients 1

• Check for recent ketosis with urinary ketones or blood ketones, as this would mandate surgery postponement except for life-threatening emergencies 1

Preoperative Medication Management

Metformin

• Stop metformin from the evening before surgery (not just the morning of), as this reduces lactic acidosis risk 1, 2

Insulin Management Night Before Surgery

• Administer Tresiba 30 units at usual time the evening before surgery 1

• Give aspart doses at usual times with evening meal the night before 1

Morning of Surgery

• Hold all aspart (rapid-acting) insulin doses on the morning of surgery 1

• Do NOT give additional Tresiba on the morning of surgery, as the dose from the previous evening provides 24-hour coverage 1

Intraoperative Management

Insulin Infusion Protocol

• Initiate intravenous insulin infusion at 1-2 units/hour when patient arrives to surgical unit, as subcutaneous insulin has unreliable absorption perioperatively 2, 3, 4

• Monitor capillary blood glucose hourly during surgery 2, 3

• Target blood glucose 100-180 mg/dL (5.6-10.0 mmol/L) throughout the procedure 2, 3, 5

• Postpone surgery if blood glucose >297 mg/dL (16.5 mmol/L) and treat with corrective ultra-rapid insulin first 2

Dextrose and Electrolyte Management

• Administer separate dextrose infusion to prevent hypoglycemia while on insulin infusion 4

• Add potassium 10-20 mEq/L to dextrose infusion if preoperative potassium and renal function are normal, as insulin therapy lowers potassium 2, 4

• Monitor potassium every 4 hours during insulin infusion to prevent life-threatening hypokalemia 2

Postoperative Management

Transition from IV to Subcutaneous Insulin

• Calculate basal insulin dose as half of total 24-hour IV insulin requirement when transitioning back to subcutaneous insulin 1, 3

• Divide the other half of 24-hour IV insulin by 3 to determine mealtime aspart doses 1

• Administer basal insulin (Tresiba) at 20:00 hours when stopping IV insulin infusion 1

• Give first aspart dose with first meal, adjusting for carbohydrate intake 1

Glucose Monitoring

• Continue capillary blood glucose monitoring every 1-2 hours while NPO postoperatively 3

• Check glucose with any unexplained symptoms, as hypoglycemia unawareness is common 1

• Treat hypoglycemia <60 mg/dL (3.3 mmol/L) immediately with IV glucose if unable to take oral, or oral glucose if conscious 1

Hyperglycemia Management

• If glucose >297 mg/dL (16.5 mmol/L), check for ketosis with urine ketones or blood ketones 1

• Give 6 units ultra-rapid insulin subcutaneously if ketonuria is 0 or 1+, and recheck in 3 hours 1

• Transfer to ICU for IV insulin if ketonuria is 2+ or blood ketones >1.5 mmol/L, as this suggests impending ketoacidosis 1

Discharge Planning

Given HbA1c 8.4%

• Resume home insulin regimen at hospital doses (not preoperative doses), as these reflect actual insulin requirements 1

• Continue metformin 750mg twice daily once oral intake established and renal function confirmed normal 1

• Schedule consultation with diabetologist within 1-2 weeks for HbA1c 8-9%, as this requires treatment intensification 1

Critical Pitfalls to Avoid

• Never use sliding scale insulin alone without basal insulin coverage, as this leads to erratic glucose control 6, 4

• Never allow insulin deficiency in insulin-treated T2DM patients, as this can precipitate ketoacidosis within hours 1

• Never resume metformin until confirming adequate renal function postoperatively and patient tolerating oral intake 1, 2

• Never discharge without clear written instructions on modified insulin doses and when to resume metformin 1