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  • Image not available.Diabetic autonomic neuropathy may limit the heart’s ability to compensate for intravascular volume changes and may predispose patients to cardiovascular instability (eg, postinduction hypotension) and even sudden cardiac death.
  • Image not available.Diabetic patients should be routinely evaluated preoperatively for adequate temporomandibular joint and cervical spine mobility to help anticipate difficult intubations, which occur in approximately 30% of persons with type I diabetes.
  • Image not available.Sulfonylureas and metformin should not be used for 24–48 h before surgery because of their long half-lives. They can be started postoperatively when the patient is taking drugs per os. Metformin is restarted if renal and hepatic function remain adequate.
  • Image not available.Hyperthyroid patients can be chronically hypovolemic and vasodilated and are prone to an exaggerated hypotensive response during induction of anesthesia.
  • Image not available.Hypothyroid patients are more susceptible to the hypotensive effect of anesthetic agents because of their diminished cardiac output, blunted baroreceptor reflexes, and decreased intravascular volume.
  • Image not available.Patients with Cushing’s syndrome tend to be volume overloaded and have hypokalemic metabolic alkalosis resulting from the mineralo-corticoid activity of glucocorticoids.
  • Image not available.The key to the anesthetic management of patients with glucocorticoid deficiency is to ensure adequate steroid replacement therapy during the perioperative period.
  • Image not available.In patients with a pheochromocytoma anesthetic drugs or techniques that stimulate the sympathetic nervous system (eg, ephedrine, ketamine, hypoventilation), potentiate the arrhythmic effects of catecholamines (eg, halothane), inhibit the parasympathetic nervous system (eg, pancuronium), or release histamine (eg, atracurium, morphine sulfate) may precipitate hypertension and are best avoided.
  • Image not available.Particular attention should be paid to the airway in obese patients because they are often difficult to intubate as a result of limited mobility of the temporomandibular and atlantooccipital joints, a narrowed upper airway, and a shortened distance between the mandible and sternal fat pads.
  • Image not available.The key to anesthetic management of patients with carcinoid syndrome is to avoid anesthetic techniques or agents that could cause the tumor to release vasoactive substances.

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The underproduction or overproduction of hormones can have dramatic physiological and pharmacological consequences. Therefore, it is not surprising that endocrinopathies affect anesthetic management. This chapter briefly reviews the normal physiology and discusses the dysfunction of four endocrine organs: the pancreas, the thyroid, the parathyroids, and the adrenal gland. It also considers obesity and carcinoid syndrome.

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Physiology

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Adults normally secrete approximately 50 U of insulin each day from the β cells of the islets of Langerhans in the pancreas. The rate of insulin secretion is primarily determined by the plasma glucose level. Insulin, the most important anabolic hormone, has multiple metabolic effects, including increased glucose and potassium entry into adipose and muscle cells; increased glycogen, protein, and fatty acid synthesis; and decreased glycogenolysis, gluconeogenesis, ketogenesis, lipolysis, and protein catabolism.

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In general, insulin stimulates anabolism, whereas lack of insulin is associated with catabolism and a negative nitrogen balance (Table 36–1).

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Table Graphic Jump Location
Table 36–1. Endocrinologic Effects of Insulin.1

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