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ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP
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ENDOCRINE SYSTEM PART II DENNIS STEVENS CRNA, MSN, ARNP

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  • 1. ENDOCRINE SYSTEM PART II
    • DENNIS STEVENS CRNA, MSN, ARNP
    • NOVEMBER 2007
    • FLORIDA INTERNATIONAL UNIVERSITY
    • ADVANCED BIOSCIENCE IN ANESTHESIOLOGY II
    • NGR 6145
  • 2. ENDOCRINE SYSTEM PART II
    • OBJECTIVES
    • Discuss the importance and physiologic effects of calcium on metabolic functions.
    • Explain the primary purposes of parathyroid hormone in relation to calcium regulation and phosphate metabolism.
    • State clinical manifestations and treatment modalities associated with hypercalcemia and hypocalcemia.
    • Describe significant metabolic effects related to insulin production and secretion.
    • Explain the pathologic processes and anesthetic considerations associated with insulin deficiency.
    • Discuss anesthetic management of the diabetic patient.
  • 3. ENDOCRINE SYSTEM PART II
    • CALCIUM REGULATION
    • Three principal hormones operate to regulate the plasma concentration of calcium:
      • Vitamin D
      • Parathyroid hormone (PTH)
      • Calcitonin
    • Only the free, ionized form of calcium exerts physiologic effects
    • Vitamin D and PTH raise serum calcium and calcitonin lowers it
    • Normal plasma calcium concentration: 8.5-10.5 mg/dL
  • 4. ENDOCRINE SYSTEM PART II
    • CALCIUM REGULATION
    • PTH is the most important regulator of plasma calcium:
      • Decreases in plasma calcium stimulate PTH secretion and increases in plasma calcium inhibit PTH secretion
    • Vitamin D augments intestinal absorption of calcium, facilitates action of PTH on bone, and augments renal absorption of calcium in distal tubules
    • Calcitonin secreted by parafollicular cells in the thyroid gland; secretion stimulated by hypercalcemia and inhibited by hypocalcemia
  • 5. ENDOCRINE SYSTEM PART II
    • PARATHYROID GLANDS
    • Small oval bodies located on the posterior surface of the thyroid gland
    • Most individuals have four parathyroid glands
    • Blood supply: inferior thyroid arteries
    • Parathyroid hormone (PTH) is secreted from chief cells of the parathyroid gland in response to a low serum ionized calcium concentration
  • 6. ENDOCRINE SYSTEM PART II
    • PARATHYROID GLANDS
    • PTH is the body’s major hormonal regulator of calcium and phosphate metabolism
    • Hypertrophy of the parathyroid glands may be produced by a sustained deficit in serum calcium levels
    • Elevation in serum calcium ion concentration produces an abrupt decline in PTH synthesis and output
    • Parathyroid gland function and PTH secretion are inhibited by severe and chronic hypomagnesemia
    • Increase in serum calcium level and decline in serum phosphate level in response to PTH are the result of the hormone’s effect on bone, the kidney, and the intestinal tract
  • 7. ENDOCRINE SYSTEM PART II
    • PARATHYROID GLANDS
    • Effect on bone:
      • When ionized calcium levels decline, PTH is released and acts directly on bone to mobilize skeletal calcium stores
    • Effect on the intestinal tract:
      • When plasma calcium level is low, PTH acts to stimulate the formation of active vitamin D, which in turn increases the intestinal absorption of calcium
    • Effect on the kidney:
      • PTH has two major effects on the kidney; increases calcium reabsorption and increases phosphate excretion
  • 8. ENDOCRINE SYSTEM PART II
    • HYPERCALCEMIA
    • Can occur as a result of a variety of disorders:
      • Primary hyperparathyroidism
      • Secondary hyperparathyroidism
    • Clinical manifestations:
      • Anorexia, nausea, vomiting, weakness, and polyuria
      • Ataxia, irritability, lethargy, or confusion can rapidly progress to coma
      • Hypertension presents initially
      • ECG signs
      • Pathological processes can complicate hypercalcemia
  • 9. ENDOCRINE SYSTEM PART II
    • HYPERCALCEMIA
    • Treatment:
      • Most effective initial treatment is rehydration followed by brisk diuresis
      • Additional therapy; administration of bisphosphonate or calcitonin
      • Treat underlying cause
    • Anesthetic considerations:
      • Monitor ionized calcium levels with serial measurements of K + and Mg + . Avoid hypovolemia and acidosis. Invasive monitoring may be necessary. Responses to anesthetic agents are not predictable
  • 10. ENDOCRINE SYSTEM PART II
    • HYPOCALCEMIA
    • Should be diagnosed only on the basis of plasma ionized calcium concentration
    • Hypocalcemia due to hypoparathyroidism is a relatively common cause of symptomatic hypocalcemia
    • Clinical manifestations of hypocalcemia:
      • Paresthesias, confusion, laryngeal stridor, carpopedal spasm, masseter spasm, and seizures
      • Cardiac irritability and decreased cardiac contractility may present
      • ECG findings…!
  • 11. ENDOCRINE SYSTEM PART II
    • HYPOCALCEMIA
    • Treatment:
      • IV administration; calcium chloride or calcium gluconate
      • Serial ionized calcium measurements. Assess plasma magnesium concentration
      • Chronic hypocalcemia…!
    • Anesthetic considerations:
      • Hypocalcemia should be corrected preoperatively
      • Monitor ionized calcium levels intraoperatively, avoid alkalosis, and concern with citrated blood products
      • Negative inotropic effects of anesthetic agents and responses to neuromuscular blocking agents…!
  • 12. ENDOCRINE SYSTEM PART II
    • PANCREAS
    • Contains both exocrine and endocrine functions
    • Acinar cells synthesize and secrete digestive enzymes and bicarbonate into the pancreatic ducts
    • Adults normally secrete ~50 units of insulin each day from β -cells of the islets of Langerhans and α -cells secrete glucagon
  • 13. ENDOCRINE SYSTEM PART II
    • INSULIN
    • Insulin and glucagon are crucial in regulating carbohydrate, fat, and protein metabolism
    • Rate of insulin secretion is primarily determined by the plasma glucose level and is essential for the maintenance of proper plasma glucose levels
    • Insulin stimulates anabolism while its lack is associated with catabolism and a negative nitrogen balance
    • Insulin is synthesized within the β -cells of the pancreas, and is packaged and stored in membrane lined vesicles within the β -cell cytoplasm
  • 14. ENDOCRINE SYSTEM PART II
    • INSULIN
    • Metabolic effects:
      • Important to many cellular activities related to growth
      • Intimately involved in the regulation of carbohydrate, fat, and protein metabolism
      • Most cells have insulin receptors, but the major targets of insulin action are the liver, muscle, and adipose tissue
      • Key hormone in controlling glucose removal from the plasma
      • Facilitates the disposition of glucose by stimulating its uptake into liver, muscle, and adipose tissue
  • 15. ENDOCRINE SYSTEM PART II
    • INSULIN
    • Control of insulin secretion:
      • Ingestion of a meal increases rate of insulin secretion
      • Plasma insulin levels rise reaching peak levels 30 -60 minutes after eating is initiated
      • Between meals, insulin levels drift downward
      • Elevated plasma glucose levels directly activate β -cells of the pancreas, stimulating insulin synthesis and secretion. Low plasma glucose concentrations inhibit this response
      • Maximal insulin response…!
      • Amino acids also are potent stimulators of insulin release
  • 16. ENDOCRINE SYSTEM PART II
    • GLUCAGON
    • Linear polypeptide hormone produced by the α -cells of the pancreatic islets
    • Most important role is to enhance hepatic glucose output and increase plasma glucose
    • Insulin and glucagon have opposing biologic actions
    • Glucagon in concert with other hormones are strong defenders against hypoglycemia and are critical in restoring normal glucose levels during periods of hypoglycemic stress
    • Secreted in response to…!
  • 17. ENDOCRINE SYSTEM PART II
    • INSULIN DEFICIENCY
    • Diabetes mellitus (DM) is a complex metabolic derangement
    • Glucose is present in abundance but, due to lack of insulin, is unable to reach cells for energy provision
    • Recommended guidelines for diagnosing diabetes include a fasting plasma glucose (FPG) of 126 mg/dL or greater
    • Incidence of diabetes is increasing and can be attributed to a combination of three factors:
      • Overweight population
      • More sedentary lifestyles
      • Rise in the number of elderly
  • 18. ENDOCRINE SYSTEM PART II
    • INSULIN DEFICIENCY
    • Insulin-dependent diabetes mellitus (IDDM):
      • ~ 10% of diabetics have type 1 or IDDM
      • These patients have an absolute deficiency of insulin
      • Disease course may be complicated by periods of ketosis and acidosis
      • Type 1 DM is believed to be caused by autoimmune destruction of the β -cells of the pancreatic islets
      • Usually develops before the age of 40 years
      • Classic symptoms of type 1 DM appear when at least 90% of the β -cells are destroyed
  • 19. ENDOCRINE SYSTEM PART II
    • INSULIN DEFICIENCY
    • Non-insulin dependent diabetes mellitus (NIDDM):
      • ~ 90% of patients with DM have type II or NIDDM
      • NIDDM characterized by:
        • Impaired insulin secretion, or
        • Peripheral insulin resistance, or both
      • Type 2 DM occurs in patients who have some degree of endogenous insulin production
      • Typically, type 2 DM occurs in patients who are older than 40 years, obese (80%), and with a family history
      • Insidious onset
      • Treatment modalities…!
  • 20. ENDOCRINE SYSTEM PART II
    • INSULIN DEFICIENCY
    • DM may be associated with other conditions
    • Long-term diabetic complications:
      • Extensive arterial diseases
      • Cataracts
      • Peripheral neuropathies
      • Autonomic nervous system dysfunctions
    • There is a strong relationship between the hyperglycemia of diabetes and end-organ diseases
  • 21. ENDOCRINE SYSTEM PART II
    • ANESTHETIC MANAGEMENT OF THE DIABETIC PATIENT
    • DM is the most common endocrine disorder encountered in surgical patients
    • Diabetic patients have higher morbidity and mortality in the perioperative period
    • Elective surgical procedures should be scheduled early in the day if possible
    • Preoperative considerations:
      • Detailed preanesthetic assessment is warranted
      • Examine patient’s history of glycemic control
      • Recommended target blood glucose range…!
      • Review of oral hypoglycemic and insulin regimens
  • 22. ENDOCRINE SYSTEM PART II
    • ANESTHETIC MANAGEMENT OF THE DIABETIC PATIENT
    • Intraoperative management:
      • No specific anesthetic technique is superior overall for diabetic patients
      • RA may produce less deleterious changes in glucose homeostasis
      • Patients under anesthesia are generally maintained with a mild transient hyperglycemia to avoid the potentially catastrophic effects of hypoglycemia
      • Frequent blood glucose determinations during surgery and in the immediate postoperative period are central to safe practice
      • Universal goal…!
  • 23. ENDOCRINE SYSTEM PART II
    • ACUTE DERANGEMENTS IN GLUCOSE HOMEOSTASIS
    • Hypoglycemia:
      • Medications and certain pathologic disorders are causes of hypoglycemia
      • Blood glucose levels in the range of 40-60 mg/dL commonly produce mild symptoms of hypoglycemia
      • Acute treatment for the hypoglycemic surgical patient…
        • IV administration of 25 mL of 50% glucose
      • Hypoglycemia is potentially catastrophic during surgery
      • Frequent blood glucose determinations, maintenance of mild hyperglycemia, and careful monitoring help to avoid this serious complication during anesthesia
  • 24. ENDOCRINE SYSTEM PART II
    • ACUTE DERANGEMENTS IN GLUCOSE HOMEOSTASIS
    • Diabetic ketoacidosis (DKA):
      • DKA is a medical emergency triggered by a hyperglycemic event
      • Major signs and symptoms of DKA include hyperglycemia (>250 mg/dL), volume depletion, tachycardia, metabolic acidosis (arterial pH <7.3) with ketonemia, electrolyte depletion, hyperosmolarity (>320 mOsm/L), N&V, abdominal pain, and lethargy
      • Preoperative management of the surgical patient with DKA…!
  • 25. ENDOCRINE SYSTEM PART II
    • ACUTE DERANGEMENTS IN GLUCOSE HOMEOSTASIS
    • Hyperglycemic hyperosmolar nonketotic syndrome (HHNS):
      • A hyperosmolar state triggered by a hyperglycemic event
      • Commonly occurs in type 2 diabetics
      • Hyperglycemic episode overwhelms the pancreas and produces severe hyperglycemia and glucosuria
      • Usually not associated with acidosis or significant ketogenesis
      • Spectrum of symptoms is associated with HHNS
      • Profound dehydration is always present
      • Mortality rate…!
      • Treatment goals…!
  • 26. ENDOCRINE SYSTEM PART II
    • REFERENCES
    • Morgan, G.E., Mikhail, M.S., and Murray, M.J. (2006).
    • Clinical Anesthesiology . (4 th Ed.) New York, NY:
    • McGraw-Hill.
    • Nagelhout, J.J. and Zaglaniczny, K.L. (2005). Nurse
    • Anesthesia . (3 rd Ed.) St. Louis, MO: Elsevier-
    • Saunders.

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