ENDO - Perioperative diabetes

Question 1

Describe surgical stress response

Answer 1

• Elevation of catecholamines, growth hormone, glucagon and cortisol, ACTH
• Depression of insulin levels and insulin resistance
• Leads to glycogenolysis and gluconeogenesis with raised blood glucose levels, protein catabolism, lipolysis, free fatty acid production, ketone bodies

Question 2

Why would you want a good glycaemic control?

Answer 2

• Hyperglycaemia increases wound infection and impairs wound healing and worsens the outcome after neurologic damage and myocardial ischaemia
• Hyperglycaemia induces an osmotic diuresis that may lead to dehydration and electrolyte disturbance
• Type 1 diabetics may develop Diabetic Ketoacidosis
• Hypoglycaemia less than 2.2mmol/L may induce coma, arrhythmias and cognitive deficit

Question 3

Discuss the level of HbA1C and the eligibility of having an elective surgery

Answer 3

If over 9%, defer elective surgery and refer to an endocrinologist

Question 4

What are the (5) complications of diabetes that need to be considered when preparing the patient for surgery?

Answer 4

•Atherosclerosis
–Increased risk of MI (silent, higher mortality)
–Revascularize if indicated on medical grounds

•Autonomic neuropathy
–Increased risk of haemodynamic instability, gastroparesis – regurgitation and aspiration, and silent myocardial infarction

•Peripheral neuropathy
–Pre-existing neurologic symptoms (important to document if considering regional anaesthesia)
–Intra-operative nerve injury
–May have chronic pain and be on opioids or other analgesics

•Stiff joints
–Increases chances of difficult intubation

•Retinopathy may indicate nephropathy
–Drug doses and metabolism, risk of worsening renal failure (Acute Kidney Injury)

Question 5

What is the management of perioperative blood glucose?

Answer 5

•Outcome is better with tight glucose control 5-10 mmol/L
•Cornerstones of management are to:
–Define whether pre-operative control has been adequate,
–Monitor BSL regularly in the perioperative period and
–Administer insulin and glucose until the patient can tolerate a diet and have his normal medication

Question 6

Periop Mx of type 2 diabetes on diet management alone

Answer 6

• Early morning case if practical (not essential)
• No therapy required
• Check BSL pre-, intra and post operatively
• Supplemental short acting insulin if BSL over 10 mmol/L

Question 7

Periop Mx of type 2 diabetes on insulin

Answer 7

•Early morning case
•Oral medications previously
–CEASE 12 hours pre-operatively
–Monitor BSL 4 hourly and treat if less than 4 or greater than 10 mmol/L
–May need insulin supplementation for hyperglycaemia
–Resume oral agents when back to normal diet
•Insulin requiring
–As for type one diabetic

Question 8

Periop Mx of type 1 diabetes

• morning surgery
• afternoon surgery

Answer 8

•Morning surgery
–Measure blood glucose every 2 hours from 0800
–Give usual dose of long acting insulin
–Intravenous 5% dextrose infusion (100 ml/hr)

•Afternoon surgery
–Light breakfast with usual dose of long acting insulin and HALF of short/intermediate acting insulin
–Monitor blood glucose every 2 hours from admission
–Intravenous 5% dextrose
–Monitor BSL 2 hourly and urinary ketones for 48 hours