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Management of the diabetic patient prior to surgery.
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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