- 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.
- 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.
- 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
- Hyperthyroid patients can be chronically hypovolemic
and vasodilated and are prone to an exaggerated hypotensive response
during induction of anesthesia.
- Hypothyroid patients are more susceptible to
the hypotensive effect of anesthetic agents because of their diminished
cardiac output, blunted baroreceptor reflexes, and decreased intravascular
- Patients with Cushing’s syndrome tend
to be volume overloaded and have hypokalemic metabolic alkalosis
resulting from the mineralo-corticoid activity of glucocorticoids.
- The key to the anesthetic management of patients
with glucocorticoid deficiency is to ensure adequate steroid replacement
therapy during the perioperative period.
- 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.
- 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.
- 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.
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.
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.
In general, insulin stimulates anabolism, whereas lack of insulin
is associated with catabolism and a negative nitrogen balance (Table 36–1).
Table 36–1. Endocrinologic
Effects of Insulin.1
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