Perioperative Diabetes Management

Dr. Ken Locke

March 2007

Objectives

At the end of the seminar, you will be able to:

• Describe the problems created by inadequate perioperative glycemic control

• Develop a series of goals in the perioperative management of diabetes, and prioritize them

• Explain strategies for managing diabetes, and apply them to clinical cases

Outline

• Clinical cases

• Background on perioperative hyperglycemia

• Principles of perioperative diabetes management

• Recommendations

• Cases revisited

Clinical Cases

• A 25 year old type 1 diabetic woman is scheduled for hysteroscopy for infertility

– What are the important considerations in her periop management?

– What strategies could be used?

Clinical cases cont.

• A 72 year old man with type 2 diabetes on 150 units of insulin/day is scheduled for cataract extraction

– What are the important considerations in his periop management?

– What strategies could be used?

Clinical cases cont.

• A 58 year old type 2 diabetic woman on glyburide and metformin is scheduled for AAA resection

– What are the important considerations in her periop management?

– What strategies could be used?

Why is perioperative glycemic control important?

• Improvement in wound healing parameters (tissue level data)

• Improvement in infection parameters (tissue level and case series)

• Improved mortality seen in critical illness, post CV surgery, and post AMI with STRICT glycemic control (RCT level data)

Why is perioperative glycemic control difficult?

• Altered glucose inputs– NPO, changes in motility, enteral feeds, TPN

• Altered hypoglycemic therapy– Cannot use OHAs– SC insulin may have different absorption profile

• Altered glucose homeostasis– Increased counter-regulation in perioperative

environment– Decreased ambulation– Increased tissue consumption after larger surgeries

Principles of Perioperative DM Management

• 1st Goal: Avoid intra-operative hypoglycemia

• 2nd Goal: Avoid acute complications of hyperglycemia

• 3rd Goal: Maintain optimum glycemic control

Avoid Intraoperative Hypoglycemia

• Hypoglycemia is potentially damaging at any time

• Intraoperative hypoglycemia is impossible to detect clinically– Sympathetic responses are ablated by anaesthesia

• Hypoglycemia is more likely intraoperatively– Increased glucose consumption in response to

surgery

Avoid Intraoperative Hypoglycemia

• Solution: Support patients with IV D5W who take any pharmacologic DM therapy

– Remember, yesterday’s evening doses are peaking during this morning’s OR!

• Minimum is 5g of glucose/hour = 100 cc/hour

– Also prevents catabolism

Avoid Acute Complications of DM

• Type 1 patients are prone to ketoacidosis– But Type 2 patients can develop it with great

stress

• Type 2 patients are at risk of hyperosmolarity

• Risk of both of these increases with duration and complexity of surgery– Direct effects of counter-regulation and fluid

balance

Avoid Acute Complications of DM

• Solution: – Ensure adequate insulin is present during

surgery and afterward– Remember that insulin resistance in Type 2

patients may require dose increases– Monitor glucose before, during and after OR– Ensure appropriate fluids are being given to

assist in glucose clearance

Maintain Optimum Glucose Levels

• Range of 8-11 typically used– Avoids hypoglycemia but not beyond range of

control

• Choose the strategy that fits:– type of surgery (metabolic stress)– duration of surgery– availability of resources

Options

• Rely exclusively on residual insulin from previous day’s therapy (oral or SC insulin)– Best for short procedures where risk of acute

hyperglycemia is very low

• SC long acting insulin (adjusted dose)– May not be adequate for longer procedures

• IV insulin infusion with frequent monitoring of glucose level– Requires time/personnel to monitor and adjust

Best Practices

• All patients hold their usual doses on day of surgery while NPO

• No agreement on anything beyond this!• IV insulin preferred to achieve optimum glucose

control– Use for Type 1&2 DM, longer procedures, especially

with significant insulin resistance

• SC insulin when IV insulin not necessary– Can be more liberal with Type 2 than Type 1

• “Yesterday’s insulin” – never for Type 1

Postoperative Management

• When patients resume eating, can usually resume usual therapy

• Alterations (NPO, reduced diet, enteral feeds etc.) require altered management

• Oral agents should wait until reliable diet

• IV insulin easiest to titrate/achieve control– Remember to anticipate rather than react to

abnormal glucose

Back to the Cases

• Develop a plan for each case:

• A 25 year old type 1 diabetic woman is scheduled for hysteroscopy for infertility

• A 72 year old man with type 2 diabetes on 150 units of insulin/day is scheduled for cataract extraction

• A 58 year old type 2 diabetic woman on glyburide and metformin is scheduled for AAA resection