Periop. Cases on Endocrine Disorders

Thomas ManiatisDec. 16, 2010

Conflicts of Interest

• None

Case

• 65 female• DM2 on glyburide 10 bid, pioglitazone 30 qd,

metformin 1g bid• Cataract OR• Cholecystecomy• Colectomy for colon CA

Issues to consider

• Patient Factors– Type of diabetes– Treatments: Diet, oral agents, insulin– Adequacy of control: loose, optimal, tight

• Surgical Factors– Minor, major– Timing– NPO starting when and lasting how long

Preop control and periop complications

• No high-quality data suggesting preop control impacts on periop complications

• Small study suggested that HbA1c >7% associated with increased wound infections

• Case-control study showed increased risk for wound infections if sugars > 11 (CABG)

Effects of surgery on glucose control

• Stress response causing increased glucose levels– glucagon, epi, GH, IL-6 and TNF-alpha

Goals of therapy

• Prevent ketoacidosis• Avoid marked hyper / hypo glycemias• Balanced fluids/electrolytes• “Tight” vs. “loose” control– Varying evidence for “tight” control• Improved outcomes in certain populations at cost of

increased hypo’s– In general, “loose” control is acceptable

Case

• 65 female• DM2 on metformin 1 g bid, N 10-0-0-10• Cataract OR• Cholecystectomy• Colectomy for CA• Radical Neck Dissection for neck mass

Case

• 55 male• DM1 on rapid 12-14-18-0, glargine 0-0-0-20• Cataract OR• Neck Biopsy under GA (day surgery)• Cholecystectomy• CABG for CAD

IV Insulin

• How to write a protocol preop in stable patients

• When to transition from IV to SC postop

• How to transition from IV to SC postop

IV Insulin

• Protocols vary– Separate insulin/dextrose vs. combined GIK– Targets: tight vs. traditional– See Protocol

• Calculation of starting dose– Baseline total daily dose/24 – “safety margin” of 30-50%– Dextrose depends on fluid sensitivity

• D5 vs. D10– Monitoring, NPO, adjustments– Start early to stabilize dose by OR

IV insulin

• Intraop– Managed by anaesthesia

• Postop– Continue drips until no longer NPO– Plan transition to SC ahead of time

IV–SC insulin transition post-op

• Look at baseline dose pre-op• Compare with current “needs” and take into

account stressors (infection, etc.) and PO intake• Hourly dose x 24 = total daily needs if control

stable and eating well (and no infection…)• Preferred transition to 3 injections of short-

acting with meals and 1 intermediate-long acting before bed while in hospital

IV–SC insulin transition post-op

• Sliding scale– Traditional vs. adaptive sliding scale

• Monitor transition closely• Modify baseline doses daily• Closer to discharge, collapse regimen down to

patient-appropriate protocol

Case

• 35 male• Pituitary surgery for tumour• Panhypopit. subsequently• Cort. 25/12.5, thyroxin, testosterone• Hernia repair• Cholecystecomy• Colectomy for mass

Case

• 65 female• PMR on pred. 15/d• Cataract• Inguinal Hernia• Esophageal resection for tumour

Case

• 50 male• Mod-severe COPD on intermittent prednisone

4 x per year, inhaled steroids• Exczema on topical steroids• Cholecystectomy• Pneumonectomy for tumour

Effects of surgery on steroid secretion

• Basal secretion– 8-10 mg/d of cortisol

• Minor surgery– 50 mg/d

• Major surgery– 75-100 mg/d (up to 200 mg/d in severe stress)

• Timing– Biggest surge is immediately post-op (reversal of

anaesthesia, extubation)

Surgery and steroids

• Assess reason for steroid exposure– Primary adrenal or pituitary disease vs. other

• Assess magnitude of exposure– Dose and duration

• Consider further testing of axis– ACTH stimulation using the 250 microg dose– Uncertain meaning– Need adequate time

• Assess surgical “stress”

Effects of steroids on adrenal axis

• Likely not suppressed– Chronic use of < 5 mg of prednisone– Any patient on any dose of steroid for < 3 weeks

• Likely suppressed– Any patient on > 20 mg of prednisone for > 3 weeks– Any patient with clinical Cushing’s

• Intermediate– Everyone else!!

Surgery and steroids

• Supplement limited to immediate periop period– Hydrocortisone 50-100 mg IV pre-induction of

anaesthesia, then 25-50 mg IV Q8h x 3 doses, then halve dose QD to baseline dose (or d/c)

• Be aware of risks of steroids periop– Infections– Impaired wound healing

Thyroid disorders and surgery• Poor evidence base supporting recommendations• Hypothyroidism

– associated with intraop. hypotension in retrospective studies– Mild-mod: may choose to postpone elective surgery to

optimize– Severe: only emergency surgery, give T4 and T3 urgently – Risk for myxedema coma

• Hyperthyroidism– Beta blockers to control HR– Thionamides– Risk for thyroid storm

Pheochromocytoma and surgery

• Medical preparation focuses on avoiding hypertensive crises

• Alpha blockade starting 7-10 days preop– phenoxybenzamine

• Followed by beta blockade 2-3 days preop• Alternatives: Ca-channel blockers, metyrosine