Chapter 60. Endocrine Surgery and Intraoperative Management of Endocrine Conditions

1. Endocrine diseases are common comorbid conditions in surgical patients.

2. The patient's type of diabetes mellitus must be known and the differing therapies of Types 1 and 2 appreciated.

3. Frequent monitoring of glucose levels is a mainstay in the management of the diabetic patient undergoing anesthesia and surgery.

4. Tight perioperative glucose control is no longer generally recommended. Consider keeping glucose levels less than 150 to 180 mg/dL.

5. Hypothyroid patients may exhibit sensitivity to sedative and hypnotic drugs used perioperatively. Hemodynamic instability should be anticipated.

6. Hyperthyroid patients may exhibit dehydration, hemodynamic instability and are at particular risk for tachydysrhythmias, metabolic or vascular decompensation, and thyroid storm.

7. The airway is a key consideration in patients undergoing thyroid surgery.

8. Pheochromocytoma patients require careful preoperative preparation, and plans must be made to manage hemodynamic extremes during surgery.

9. Glucocorticoid deficiency in patients at risk for adrenal suppression should be anticipated.

10. The implications of growth hormone excess (acromegaly) and adrenal steroid excess (Cushing disease) should be considered when preparing patients for pituitary surgery.

Endocrine diseases are common comorbid conditions in patients undergoing surgery. The consequences of a coexisting endocrine disorder may have an impact on anesthetic and immediate perioperative management. Diabetes mellitus (DM) is the most common comorbid endocrine condition, affecting as many as 20% of patients scheduled for surgery and requiring anesthesia.1,2 The prevalence of thyroid disease is approximately 20% in the general population, so large numbers of patients who present for nonendocrine surgery have concomitant diagnoses of a thyroid disorder.

The surgical condition may result in part or entirely from the endocrine disorder, for example, vasoocclusive disease in the patient with DM requiring peripheral vascular surgery. Alternatively, the surgery may directly target endocrine tissue, either for biopsy or for excision. The pathophysiologic implications of the endocrine lesion and of surgical manipulation of the diseased tissue must be understood in the context of anesthetic and perioperative management.3 The most common endocrine surgery involves the thyroid gland.

This chapter reviews the immediate perioperative implications of major endocrine disorders and addresses the specific issues encountered in surgery for common endocrine pathologies.

DM is a condition with an absolute (Type 1) or a relative (Type 2) deficiency of insulin. Chapter 13 discusses the complex physiology of DM. Recent comprehensive reviews discuss perioperative glucose management.2,4,5 A fundamental concept is that the Type 1 diabetic patient has an absolute requirement for continuous exogenous insulin.1 In the absence of insulin, despite a normal or low blood sugar concentration, the patient with Type 1 DM will develop ketoacidosis. The pharmacokinetic profiles of the various insulin preparations warrant careful consideration (Table 60-1).6 Without a source of glucose in the perioperative period, a patient may develop hypoglycemia from the residual effects of a long-acting insulin preparation.