What is the best approach for controlling hyperglycemia in a patient with type 2 diabetes who missed a dose of Lantus (insulin glargine) and is NPO for a right heart catheterization?

Immediate Management of Missed Lantus Dose with Hyperglycemia Before NPO Procedure

Give a Reduced Dose of Lantus Tonight

For this 47-year-old male with type 2 diabetes who missed his 60-unit Lantus dose and now has blood glucose of 400 mg/dL before being NPO at midnight for a right heart catheterization, administer 60-80% of his usual dose (36-48 units) this evening, along with correction insulin to address the current hyperglycemia. 1

Rationale for Reduced Basal Insulin Dosing

• Basal insulin must be continued even when NPO to prevent severe hyperglycemia and metabolic decompensation in type 2 diabetes patients, though the risk of ketoacidosis is lower than in type 1 diabetes 1

• The American Diabetes Association recommends administering 60-80% of the usual glargine dose the evening before surgery to balance preventing hyperglycemia while minimizing hypoglycemia risk during the NPO period 1

• Complete cessation of basal insulin can lead to severe hyperglycemia and metabolic decompensation 1

Address the Current Hyperglycemia (400 mg/dL)

• Administer correction insulin immediately using rapid-acting insulin analogue (4-8 units depending on his usual correction factor) to bring blood glucose down before the procedure 2

• In the presence of hyperglycemia >16.5 mmol/L (297 mg/dL) in a type 2 diabetes patient treated with insulin, check for ketosis systematically 2

• If ketosis is present, suspect early ketoacidosis, call a duty physician, and consider transfer to ICU 2

• If no ketosis, initiate ultra-rapid analogue insulin and ensure good hydration 2

Perioperative Monitoring Protocol

• Check blood glucose every 4-6 hours while NPO to detect both hyperglycemia and hypoglycemia 1

• Target blood glucose range of 140-180 mg/dL (7.8-10 mmol/L) during the perioperative period 2

• If blood glucose falls below 100 mg/dL, decrease the glargine dose by 10-20% 1

• For blood glucose <70 mg/dL (3.8 mmol/L), administer glucose immediately even without symptoms 1

Intraoperative Management

• During the procedure, if insulin is required, use continuous IV insulin infusion with IV glucose and electrolytes 1

• Maintain blood glucose between 90-180 mg/dL (5-10 mmol/L) during surgery 1

• Check blood glucose every 1-2 hours during the procedure 1

• Monitor potassium levels every 4 hours in patients receiving insulin 1

Post-Procedure Management

• Resume his usual 60-unit Lantus dose once he can eat, along with rapid-acting insulin at meals adapted to carbohydrate intake 1

• If he remains NPO temporarily after the procedure, continue basal insulin at the reduced dose (60-80% of usual) 1

• When transitioning from IV insulin (if used during procedure) to subcutaneous glargine, give half the total 24-hour IV insulin dose as once-daily glargine in the evening 1

Critical Pitfalls to Avoid

• Never completely stop basal insulin in a patient on chronic insulin therapy, even when NPO—this is the most dangerous error and can precipitate severe hyperglycemia or ketoacidosis 1

• Do not rely solely on sliding-scale correction insulin without basal coverage—this approach is discouraged and leads to poor glycemic control 2

• Avoid targeting strict normoglycemia (80-120 mg/dL) perioperatively as this increases severe hypoglycemia risk and possibly mortality 1

• Do not ignore the current hyperglycemia of 400 mg/dL—this requires immediate correction insulin in addition to restarting basal insulin 2