Anaesthetic Management of Type 2 Diabetes Mellitus

Preoperative Assessment and Optimization

The American Diabetes Association recommends measuring HbA1c and recent capillary blood glucose levels to assess baseline control and adjust treatments before surgery 2, 3
If HbA1c indicates poor control, consider therapeutic intensification before elective procedures, validated by an expert prescriber 3, 4
Screen for recent hypoglycemic episodes (blood glucose <0.7 g/L or <3.9 mmol/L), particularly in the last week, as these predict perioperative risk 5, 4
Assess for gastroparesis through questioning about abdominal pain, bloating, and vomiting, as this creates aspiration risk requiring rapid sequence induction 2, 3
Evaluate for silent myocardial ischemia, present in 30-50% of T2D patients, through ECG and consider stress testing if major surgery with Lee score ≥2 2, 4
Measure glomerular filtration rate preoperatively as diabetic nephropathy increases acute renal failure risk 2
Screen for cardiac autonomic neuropathy through orthostatic blood pressure changes and heart rate variability, as this increases sudden death risk 3, 4

Target blood glucose 0.90-1.80 g/L (5-10 mmol/L) intraoperatively to balance infection risk against hypoglycemia 1, 8
Perioperative hyperglycemia >1.80 g/L (10 mmol/L) increases morbidity and mortality, particularly from infection 1, 8
Hyperglycemia >2.5 g/L (13.5 mmol/L) carries 10-fold higher complication risk 1
Use continuous IV insulin infusion via electronic syringe for T2D patients requiring insulin or experiencing stress hyperglycemia 1, 8
Prioritize regional anaesthesia when possible for superior postoperative pain control and reduced insulin resistance 1, 8

Continue hourly capillary blood glucose monitoring until patient is fully conscious and capable of self-management 7, 9
Maintain glucose infusion (G 10% at 40 mL/h) for insulin-dependent patients to prevent recurrent hypoglycemia 7, 9
Resume insulin pump basal infusion once patient can manage their device and is eating 7, 9
Start bolus insulin dosing with first postoperative carbohydrate ingestion 7, 9

Do not aim for strict normoglycemia as this increases hypoglycemia frequency without improving outcomes 1, 8
Avoid stopping insulin pumps without immediate IV insulin replacement in T1D patients, as ketoacidosis develops within hours 2
Do not use CGM readings for intraoperative glucose management due to lag time and perfusion-dependent inaccuracy 7, 9
Recognize that 40% of T1D and 10% of insulin-treated T2D patients have hypoglycemia unawareness, requiring more vigilant monitoring 6