Managing Hypoglycemia in Preoperative Patients Before General Anesthesia

Assessment and Management of Hypoglycemic Patients

The American Society of Anesthesiologists recommends that hypoglycemia (blood glucose <0.7 g/L or <3.9 mmol/L) in preoperative patients be addressed before proceeding with anesthesia, as it represents a serious risk 1
Any unexplained malaise in a diabetic patient should be considered a hypoglycemic episode until proven otherwise, even if subsequent blood glucose measurements appear normal, according to the American Diabetes Association 1

The American College of Anesthesiologists recommends setting up a glucose infusion (G 10% at 40 mL/h) for patients with hypoglycemia, especially those on insulin or insulin secretagogues, with a target blood glucose range of 5-10 mmol/L (0.9-1.8 g/L) before proceeding with anesthesia 2, 3, 4
The American Society of Anesthesiologists suggests monitoring capillary blood glucose levels until normalization before proceeding with anesthesia, with a strength of evidence level of high 1

Once blood glucose is normalized (5-10 mmol/L or 0.9-1.8 g/L), general anesthesia can safely proceed, according to the American College of Anesthesiologists, with no evidence that any specific anesthetic agent is associated with better outcomes in diabetic patients 4, 5
The American Heart Association states that either volatile-based anesthesia or total intravenous anesthesia is reasonable with no apparent difference in associated cardiovascular events, with a strength of evidence level of moderate 6

The American Diabetes Association recommends continuing hourly blood glucose monitoring during the procedure, especially if surgery is lengthy, with corrective insulin therapy administered if blood glucose exceeds 16.5 mmol/L (3 g/L) during the procedure 4
The American Society of Anesthesiologists suggests maintaining glucose infusion for insulin-dependent patients to prevent recurrent hypoglycemia during prolonged procedures, with a strength of evidence level of low 2

The American College of Anesthesiologists notes that hypoglycemia unawareness is common in patients with long-standing diabetes (affects ~40% of type 1 diabetes patients and ~10% of insulin-treated type 2 diabetes patients), requiring more vigilant monitoring 1
Patients with autonomic neuropathy may not exhibit typical symptoms of hypoglycemia, requiring more vigilant monitoring, according to the American Autonomic Society 1