What are the perioperative management guidelines for patients taking Oral Hypoglycemic Agents (OHAs)?

Perioperative Management of Oral Hypoglycemic Agents (OHAs)

Hold all oral hypoglycemic agents on the morning of surgery except SGLT2 inhibitors, which must be discontinued 3-4 days preoperatively to prevent life-threatening euglycemic diabetic ketoacidosis. 1, 2

Preoperative Medication Management

SGLT2 Inhibitors (Highest Priority)

• Discontinue 3-4 days before surgery for canagliflozin, dapagliflozin, empagliflozin, and other SGLT2 inhibitors 1, 2
• This extended discontinuation period is critical because SGLT2 inhibitors cause euglycemic diabetic ketoacidosis (DKA) that can occur even with normal glucose levels 2
• The risk of perioperative DKA is significantly elevated (1.02 vs 0.69 per 1000 patients) 2
• Postoperative ketoacidosis can occur even when withheld for >72 hours, requiring vigilant monitoring 2
• Caveat: Cessation may worsen heart failure in patients with existing heart failure—perform careful risk-benefit assessment 2

Metformin

• Hold only on the day of surgery 1, 3
• Current guidelines support this less restrictive approach compared to historical practice of holding 48 hours preoperatively 2
• The FDA label indicates temporary discontinuation may be required for surgical procedures due to lactic acidosis risk 4

All Other Oral Hypoglycemic Agents

• Hold on the morning of surgery for sulfonylureas, DPP-4 inhibitors, thiazolidinediones, and meglitinides 1, 2
• This includes any oral glucose-lowering agents not specifically mentioned above 1

Perioperative Glucose Targets and Monitoring

Target Ranges

• Maintain blood glucose 100-180 mg/dL in the perioperative period within 4 hours of surgery 1, 3
• Do not pursue stricter targets (<80-180 mg/dL or <100 mg/dL) as they do not improve outcomes and significantly increase hypoglycemia risk 1, 5
• For elective surgeries, target A1C <8% whenever possible 1, 5

Monitoring Protocol

• Monitor blood glucose at least every 2-4 hours while the patient is NPO (nothing by mouth) 1, 3
• Dose with short- or rapid-acting insulin as needed to maintain target range 1, 3
• Continue monitoring postoperatively every 2-4 hours while NPO 5

Insulin Management During OHA Discontinuation

Basal Insulin Adjustments

• Reduce basal insulin by 25% the evening before surgery compared to usual dosing—this achieves better perioperative glucose control with lower hypoglycemia risk 1, 5
• For NPH insulin: give half (50%) of the usual dose on the morning of surgery 1, 3
• For long-acting insulin analogs: give 75-80% of the usual dose on the morning of surgery 1, 3

Postoperative Insulin Strategy

• Use basal-bolus insulin regimens (basal insulin plus premeal short/rapid-acting insulin) rather than correction-only insulin in noncardiac general surgery patients 1, 5
• This approach improves glycemic outcomes and reduces perioperative complications compared to reactive sliding-scale insulin alone 1, 5
• Never use correction-only insulin without basal insulin in general surgery patients—this is associated with worse outcomes 5

Resumption of Oral Hypoglycemic Agents

SGLT2 Inhibitors

• Do not restart until the patient is clinically stable and has resumed a normal diet, typically 24-48 hours after surgery 2
• Ensure capillary ketones are <0.6 mmol/L before restarting 2
• Maintain adequate hydration and avoid prolonged fasting periods during the discontinuation period 2

Other OHAs

• Resume metformin and other oral agents when the patient has stable oral intake and normal renal function 1
• Restart gradually in line with postoperative return to solid food 6

Special Considerations and Prevention Strategies

During SGLT2 Inhibitor Discontinuation

• Maintain adequate hydration 2
• Avoid prolonged fasting periods 2
• Consider glucose-containing IV fluids if prolonged fasting is unavoidable 2

Glucocorticoid Therapy

• If glucocorticoids are administered perioperatively, expect hyperglycemia in 56-86% of patients 1, 5
• Require substantial increases in prandial and correction insulin (40-60% or more) in addition to basal insulin 5
• Daily adjustments based on glycemia levels and anticipated changes in glucocorticoid dosing are critical 1

GLP-1 Receptor Agonists

• There are limited data on safe use and influence on glycemia and delayed gastric emptying in the perioperative period 1
• Exercise caution and clinical judgment when managing these agents perioperatively 1

Critical Pitfalls to Avoid

• Never continue SGLT2 inhibitors within 3-4 days of surgery—this poses risk of euglycemic DKA that can be fatal 2, 5
• Never pursue glucose targets <100 mg/dL perioperatively—this increases hypoglycemia without benefit 5
• Never fail to reduce insulin doses appropriately—this leads to perioperative hypoglycemia 3
• Never use correction-only insulin without basal insulin in general surgery patients 5
• Perioperative fasting with continued oral antidiabetic medication leads to severe hypoglycemia, increased morbidity and mortality, and extended ICU and hospital stays 6