Dexamethasonesuppressiontest

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Unformatted text preview: l cortisol Induction: ketamine Maintenance: nitrous oxide plus short acting opioids, benzo’s or ketamine Low dose muscle relaxants Controlled ventilation of the lungs (vulnerable to excessive decrease in PaCO2) Treat hypotension with ephedrine Watch for CHF, consider arterial line and PA catheter ADRENAL GLAND ADRENAL GLAND DYSFUNCTION Hypercortisolism= Cushing’s Syndrome 2. Hypocortisolism= Addison’s Disease 3. Pheochromocytoma 1. CUSHING’S SYNDROME CUSHING’S SYNDROME Caused by excessive secretion of corticotropin by anterior pituitary corticotroph tumors (microadenomas) Increased aldosterone, cortisol and testosterone in the adrenal cortex Signs and symptoms: hypertension, hypokalemic alkalosis, hyperglycemia, hypernatremia, osteoporosis, easy bruising, polyuria, buffalo hump, moon facies, excessive body hair, menstrual abnormalities, weight gain, skeletal muscle wasting/weakness, depression and insomnia Diagnosis with 24 hour urinary secretion of cortisol Dexamethasone suppression test distinguishes Cushing’s disease from the ectopic corticotropin syndrome Treatment of choice is transsphenoidal microadenomectomy or 85­90% resection of the anterior pituitary gland ANESTHETIC MANAGEMENT ANESTHETIC MANAGEMENT Preop evaluation of systemic blood pressure, electrolyte balance and the blood glucose No single anesthetic the best Replacement therapy hydrocortisone 10 mg/ hr for 24 hours Treat hypertension and hypervolemia with a potassium sparing diuretic Treat hyperglycemia with insulin Care when positioning patient due to osteoporosis CORTISOL CORTISOL THE ONLY ESSENTIAL HORMONE FOR LIFE Maintains blood pressure by facilitating the conversion of norepi to epi Converts amino acids to glucose Suppresses inflammation ADDISON’S DISEASE ADDISON’S DISEASE Absense of cortisol and aldosterone due to destruction of the adrenal cortex Causes: hemorrhage in anticoagulated patients, sepsis, surgical or accidental trauma Diagnosis by measurement of plasma cortisol before and 1 hour after administration of corticotropin Signs and symptoms: weight loss, skeletal muscle weakness, hypotension, fluid depletion, hyperkalemia, hyponatremia, hypoglycemia, abdominal/back pain MANAGEMENT OF A PATIENT MANAGEMENT OF A PATIENT WITH ADDISON’S DISEASE You must give exogenous corticosteriods! Intraveneous infusion of sodium containing fluids Invasive monitoring with arterial line and CVP or PA catheter Frequent measurements of glucose and electrolytes Decrease initial dose of muscle relaxants PHEOCHROMOCYTOMA PHEOCHROMOCYTOMA Catecholamine­secreting tumor that originates in the adrenal medulla or in the chromaffin tissues along the paravertebral sympathetic chain, extending from the pelvis to the base of the skull Age: 30­50 years 50% deaths occur during unrelated surgery or pregnancy Diagnosis by 24 hour urine for norepinepherine and CT scan Associated with Multiple endocrine neoplasia (MEN) Signs and symptoms: tachycardia, diaphoresis, headache, hypertension, hyperglycemia, hypovolemia, tremulous, palpitations, weight loss Treatment is surgical excision of the tumor(s) ANESTHETIC MANAGEMENT OF ANESTHETIC MANAGEMENT OF PHEOCHROMOCYTOMA Correct hypovolemia (serial hematocrits) Alpha blockade before beta blockade Alpha blockage: phenoxybenzamine 10­20 mg PO bid for 14 days pre­op Beta blockade: propranolol 40 mg PO bid pre­ op Pre­op: benzo with scopalamine Avoid histamine releasing drugs Arterial line pre­induction Induction: etomidate, thiopental or propofol Lidocaine 1­2 mg/kg prior to intubation Consider PA catheter Maintenance: sevoflurane due to rapid changes in concentration and fentanyl or remifentanyl Treat hypertension with phentolamine 1­5 mg IV or nitroprusside Treat reflex tachycardia with an esmolol infusion...
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This note was uploaded on 12/16/2011 for the course BIOLOGY 101 taught by Professor Mr.wallace during the Fall '11 term at Montgomery College.

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