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 1 st Goal: Avoid intra-operative hypoglycemia 2 nd Goal: Avoid acute complications of hyperglycemia 3 rd 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