1. Diabetes and the Surgical Patient
Dr. Cathy Code
October 14, 2008

2. Objectives Review the various agents used to treat diabetes
Discuss the impact of surgery on diabetes
Provide a framework for the preoperative assessment of a diabetic patient
Provide a practical approach to the perioperative management of diabetes

3. Diabetes Common chronic disorder
Associated with both macrovascular and microvascular complications
More surgical interventions
A diabetic has a 50% chance of requiring a surgery in their lifetime
20% of surgical patients have diabetes

4. Diabetes
Complex interaction b/w operative procedure, type of anesthesia, and postoperative factors
Diabetic patient requires careful assessment prior to surgery
Increased length of hospital stay and cost
Increased risk of periop infection and postop CVS morbidity and mortality

5. Type 1 DM Primarily a result of pancreatic beta cell destruction
Absolute insulin deficiency
Prone to ketoacidosis
Autoimmune process vs idiopathic
Requires ongoing insulin treatment

6. Type 2 DM Predominant abnormality is insulin resistance
May be treated with diet, OHG and or insulin
Others:
Diseases of pancreas
Endocrinopathies
Drugs

7. Oral Hypoglycemics Acarbose Sulfonylureas Meglitinides
Alpha-glucosidase inhibitor
Sulfonylureas
Insulin secretagogues
ex. Glyburide (Diabeta), Gliclazide (Diamicron)
Rapid BG lowering potential
Meglitinides
ex. Repaglinide (GlucoNorm)

8. Oral Hypoglycemics Metformin TZDs Negligible hypoglycemic risk
CI in renal failure (GFR < 30ml/min) and hepatic failure
TZDs
ex. Pioglitazone (Actos), Rosiglitizone (Avandia)
Avoid in CHF
? Association with increased cardiovascular events

9. Insulin Type
Onset
Peak
Duration
Prandial Insulins
Rapid–acting
Aspart (Novorapid)
Lispro (Humalog)
10-15 mins
1-1.5 hrs
1-2 hrs
3-5 hrs
hrs
Short-acting
Humulin R
Novolin Toronto
30 mins
2-3 hrs
6.5 hrs
Basal Insulins
Intermediate-acting
Humulin N
Novolin NPH
1-3 hrs
5-8 hrs
Up to 18 hrs
Long-acting
Detemir (Levemir)
Glargin (Lantus)
90 mins
n/a
Up to 24 hrs

10. Preoperative Assessment:
Focus on cardiopulmonary risk assessment and modification
CHD more common in diabetics
Associated conditions:
HTN
Obesity
CKD
Cerebrovascular disease
Autonomic neuropathy

11. Preoperative Assessment:
Key elements:
Type of DM
Longterm complications
Baseline glycemic control
Assessment of hypoglycemia
Diabetic meds
Other meds
Characteristics of surgery
Type of anesthetic

12. Preoperative Testing:
Baseline ECG
Renal Function
Hgb A1C
Determination of chronic glycemic control
Elevated levels may predict a higher rate of postop infections
Noninvasive cardiac testing if indicated

13. Impact of Surgery
Surgery and anesthesia lead to a neuroendocrine stress response
Counterregulatory hormones:
Epinephrine
Glucagon
Cortisol
Growth Hormone
Inflammatory cytokines

14. Impact of Surgery Leads to: Hyperglycemia and possibly ketosis
Insulin resistance
Decreased peripheral glucose utilization
Impaired Insulin secretion
Increased lipolysis
Protein catabolism
Hyperglycemia and possibly ketosis

15. Impact of Surgery Varies per individual
Influenced by type of anesthesia
GA > spinal anesthesia
Extent of surgery
Major vs minor
Postoperative factors
Sepsis, hyperalimentation, steroid use

16. Goals Maintenance of fluid and electrolyte balance
uncontrolled DM leads to volume depletion from osmotic diuresis
Prevention of ketoacidosis
Type 1 diabetics are insulin deficient and require continuous insulin administration

17. Goals Avoidance of marked hyperglycemia Avoidance of hypoglycemia
DKA in Type 1 diabetics
Nonketotic hyperosmolar state in Type 2 diabetics
Avoidance of hypoglycemia
Potentially a life threatening complication
Cardiac arrhythmias
Cognitive deficits and neurologic sequelae

18. Glycemic Targets Exact target unclear
Limited evidence and lack of controlled trials except….
Coronary bypass surgery, IV insulin to maintain BS , associated with less sternal wound infection and mortality
Surgical ICU patients with hyperglycemia, IV insulin to maintain BS 4.5 – 6.0, reduced mortality and morbidity

19. Glycemic Targets Meta-analysis of RCTs in JAMA 2008
29 RCTs of tight glycemic control in critically ill patients in an ICU setting
No evidence of improved patient oriented outcomes
Found increased frequency in potentially harmful hypoglycemia in patients treated with glucose control

20. Glycemic Targets Otherwise……
Published guidelines collectively propose attempting to achieve reasonable normoglycemia
2008 CDA guidelines:
Perioperative glycemic levels should be maintained between 5.0 – 11.0
avoid hypoglycemia
Grade D, consensus

21. Diabetes Management: Early perioperative phase
Several various strategies
No consensus on optimal therapy
Aim to have surgery early in am to minimize disruption of their management while NPO

22. Diabetes Management: Early perioperative phase
T2DM, diet alone:
Usually do not require any therapy periop
Supplemental short acting insulin (regular, humalog, novorapid) may be given by sliding scale if levels above target
Check BS preop and postop
IV dextrose not required unless insulin is administered and patient NPO

23. Diabetes Management: Early perioperative phase
T2DM on OHG:
Hold OHG am of OR
Most patients with good control will not require insulin for short surgical procedures
Short-acting supplemental insulin by sliding scale can be used for hyperglycemia
Restart OHG when patients resume eating
Hold metformin is patient has developed renal impairment

24. Diabetes Management: Early perioperative phase
Type 1 DM or insulin treated Type 2 DM:
For short, non complex procedures patients can usually continue SC insulin
Continue long-acting insulin while NPO and on IV dextrose
For patients with tight control or prone to hypoglycemia, reduce evening/hs insulin night before surgery

25. Diabetes Management: Timing of Procedure
Minor, early morning procedures, breakfast only delayed
patients can take their insulin after surgery
Procedures where breakfast and lunch missed
Omit short-acting insulin and give 1/2 to 2/3 of long-acting insulin OR
Take 1/3 to 1/2 of total morning dose as long-acting only OR
SC insulin pump, continue basal rate OR
Start dextrose containing IV solution

26. Diabetes Management: Timing of Procedure
Long and complex procedures
IV insulin is required for Type 1 diabetics and Insulin requiring Type 2 diabetics
Safe
Easily titrated with a short ½ life (5 – 10 minutes)
Usually started morning prior to surgery
IV insulin infusion algorithms

27. Diabetes Management: Late postoperative phase
Preoperative diabetes treatment can be reinstated once the patient is eating well
Metformin should not restart in renal insuff
Sulfonylureas should only be started after patient eating well, consider stepwise approach
Avoid TZDs in CHF or problematic fluid retention

28. Diabetes Management: Late postoperative phase
Insulin infusions should be continued until solids well tolerated then switch to SC insulin
For patients on SC insulin, continue IV dextrose until patient eating well

29. Sliding Scales Often used to correct elevated levels
Problematic if used as the sole method of diabetic treatment
Reactive process, causes wide fluctuation in serum glucose
Should never be the sole method of treatment in T1DM due to risk of ketosis

30. Example - standard Regular, Humalog, Novorapid Insulin, TID, ac meals
BS reading
Insulin
0 – 4.0
No insulin, give sugar
4.1 – 8.0
No insulin
8.1 – 11.0
2 units
11.1 – 14.0
4 units
14.1 – 16.0
6 units
16.1 – 18.0
8 units
18.1 – 20.0
10 units
> or = 20.1
Call MD

31. Example – Insulin sensitive
Elderly, lean patients or individuals with renal or liver dysfunction
BS reading
Insulin
0 – 4.0
No insulin, give sugar
4.1 – 8.0
No insulin
8.1 – 11.0
11.1 – 14.0
2 units
14.1 – 16.0
3 units
16.1 – 18.0
4 units
18.1 – 20.0
5 units
> or = 20.1
Call MD

32. Example – Insulin resistant
Obesity, treatment with glucocorticoids
BS reading
Insulin
0 – 4.0
No insulin, give sugar
4.1 – 8.0
No insulin
8.1 – 11.0
4 units
11.1 – 14.0
8 units
14.1 – 16.0
12 units
16.1 – 18.0
16 units
18.1 – 20.0
20 units
> or = 20.1
Call MD

33. Special Considerations
Glucocorticoids
Used to treat many disorders, given in “stress” doses perioperatively
Can worsen existing DM and trigger hyperglycemia in others
Augment hepatic gluconeogenesis, inhibit glucose uptake, and alter receptor function
2 to 3 fold increase in total daily insulin can be required with stress doses

34. Special Considerations
Hyperalimentation
TPN
increase blood glucose
Increase basal insulin, add insulin to TPN
NG feeds
Either a IV insulin infusion or BID long-acting insulin + sliding scale
Make sure to change insulin if feeds changes to bolus

35. Case examples
Case #1
Mr S, 58 yr old man with newly dx’d colorectal Ca
Scheduled for Right Hemicolectomy
Hx of T2DM maintained on metformin and Novolin NPH 16u SC qam and 10u SC qpm
Hx of controlled HTN, stable angina
How should this patient be managed?

36. Case #1 cont…. Preop Postop Bowel prep and NPO at midnight
Hold Metformin morning of OR
Give 8u of NPH insulin am of OR
Provide IV dextrose during OR
Postop
Hold metformin until eating well
Give 16u of NPH qam and 10u of NPH qpm
Continue IV dextrose until eating well
Insulin sliding scale TID prn with meals

37. Case examples
Case #2
Ms P, 36 yr old female with perforated DU awaiting in ER for urgent OR
Type 1 DM for 15 yrs complicated by retinopathy, neuropathy, and gastroparesis
On Levemir 20u BID and Novorapid sliding scale with meals by carb counting, average 4-6u per meal
How should this patient be managed?

38. Case #2 cont.. Preop Postop NPO, frequent glucoscans
IV regular insulin starting at 2u/hr
IV dextrose
Postop
Continue IV insulin and dextrose until eating well and overlap with SC insulin
Watch for nausea and vomiting given hx of gastroparesis

39. Take Home Message Common chronic health problem
Needs to be managed closely perioperatively
Associated with increased perioperative risk
Not aiming for perfect glucose measurements but instead safe measurements