Chapter 13

1. Chapter 13 Assessment and Care of Patients with Fluid and Electrolyte Imbalances

2. Homeostasis • Extracellular fluid • Intracellular fluid • Interstitial fluid • Transcellular fluids

3. Clinical Significance: Blood Pressure • Blood pressure is an example of hydrostatic filtering forces. It moves whole blood from the heart to capillaries where filtration can occur to exchange water, nutrients, and waste products between the blood and the tissues.

4. Blood Pressure

5. Clinical Significance: Edema • Edema develops with changes in normal hydrostatic pressure differences.

6. Fluid Balance

7. Clinical Significance: Diffusion • Diffusion is important in the transport of most electrolytes and particles through cell membranes. • Sodium pumps. • Glucose cannot enter most cell membranes without the help of insulin.

8. Clinical Significance: Osmosis and Filtration • The thirst mechanism is an example of how osmosis helps maintain homeostasis. • The feeling of thirst is caused by the activation of cells in the brain that respond to changes in ECG osmolarity.

9. Fluid Balance • Fluid intake • Fluid loss: • Minimum amount of urine needed to excrete toxic waste products is 400 to 600 mL • Insensible water loss

10. Hormonal Regulation of Fluid Balance • Aldosterone • Antidiuretic hormone • Natriuretic peptides

11. Dehydration • Fluid intake is less than what is needed to meet the body’s fluid needs, resulting in a fluid volume deficit. • Consideration for older adults.

12. Collaborative Care—Dehydration • Assessment • History • Physical assessment/clinical manifestations: • Cardiovascular changes • Respiratory changes • Skin changes • Neurologic changes • Renal changes

13. Dehydration: Laboratory Assessment • Elevated hemoglobin • Elevated hematocrit • Elevated serum osmolarity • Elevated glucose • Elevated protein • Elevated BUN • Elevated electrolytes • Hemoconcentration

14. Dehydration: Interventions • Patient safety • Fluid replacement • Drug therapy

15. Fluid Overload • Excess of body fluid. • Most problems caused by overhydration are related to fluid volume excess in the vascular space or to dilution of specific electrolytes and blood components.

16. Collaborative Care—Fluid Overload • Assessment • Patient safety • Pulmonary edema • Drug therapy • Nutrition therapy • Monitoring of I&O

17. Sodium (135 to 145 mmol/L) • Sodium level is vital for skeletal muscle contraction, cardiac contraction, nerve impulse transmission, and normal osmolarity and volume of the ECF.

18. Hyponatremia • Sodium level below 136 mEq/L • Cerebral changes • Neuromuscular changes • Intestinal changes • Cardiovascular changes

19. Hyponatremia Interventions • The priority for nursing care of the patient with hyponatremia is monitoring the patient’s response to therapy and preventing hypernatremia and fluid overload. • Drug therapy. • Nutrition therapy.

20. Hypernatremia • Serum sodium level over 145 mEq/L • Nervous system changes • Skeletal muscle changes • Cardiovascular changes

21. Hypernatremia Interventions • Priorities for nursing care of the patient with hypernatremia include monitoring the patient's response to therapy and preventing hyponatremia and dehydration. • Drug therapy. • Nutrition therapy.

22. Potassium (3.5 to 5.0 mEq/L) • Depolarization and generation of action potentials, as well as regulating protein synthesis and glucose use and storage

23. Hypokalemia • Serum potassium level below 3.5 mEq/L • Can be life threatening because every body system is affected • Respiratory changes • Musculoskeletal changes • Cardiovascular changes • Neurologic changes • Intestinal changes

24. Hypokalemia Interventions • The priorities for nursing care of the patient with hypokalemia are ensuring adequate oxygenation and patient safety for falls prevention, preventing injury from potassium administration, and monitoring the patent's response to therapy. • Drug therapy. • Nutrition therapy. • Safety measures. • Respiratory monitoring.

25. Hyperkalemia • Serum potassium greater than 5.0 mEq/L. • Cardiovascular changes are the most severe problems from hyperkalemia and are the most common cause of death in patients with hyperkalemia. • Neuromuscular changes. • Intestinal changes.

26. Hyperkalemia Interventions • Drug therapy—Kayexalate, insulin • Cardiac monitoring • Health teaching

27. Calcium (9.0 to 10.5 mg/dL) • Calcium is a mineral with functions closely related to those of phosphorus and magnesium. • Absorption of dietary calcium requires the active form of vitamin D. • Calcium is stored in the bones. • Parathyroid hormone. • Thyrocalcitonin.

28. Hypocalcemia • Total serum calcium level below 9.0 mg/dL • Cultural considerations • Women’s health considerations • Neuromuscular changes

29. Hypocalcemia (Cont’d)

30. Hypocalcemia (Cont’d) • Cardiovascular changes • Intestinal changes • Skeletal changes

31. Hypocalcemia Interventions • Drug therapy • Nutritional therapy • Environmental management—seizure precautions • Injury prevention strategies

32. Hypercalcemia • Total serum calcium level above 10.5 mg/dL. • Effects of hypercalcemia occur first in excitable tissues. • All systems are affected.

33. Hypercalcemia (Cont’d) • Cardiovascular changes are the most serious and life-threatening problems of hypercalcemia. • Neuromuscular changes. • Intestinal changes.

34. Hypercalcemia Interventions • Drug therapy—IV 0.9% sodium chloride, furosemide, calcium chelators, phosphorus, calcitonin, bisphosphonates, and prostaglandin synthesis inhibitors • Dialysis • Cardiac monitoring

35. Phosphorus (3.0 to 4.5 mg/dL) • Most phosphorus can be found in the bones. • Phosphorus is needed for activating vitamins and enzymes, forming adenosine triphosphate, and assisting in cell growth and metabolism. • Food sources include meats, fish, dairy products, and nuts. • Plasma levels of calcium and phosphorus exist in a balanced reciprocal relationship.

36. Hypophosphatemia • Serum phosphorus level below 3.0 mEq/L. • Most of the effects of hypophosphatemia are related to decreased energy metabolism and imbalances of other electrolytes and body fluids.

37. Hypophosphatemia (Cont’d) • Manifestations are most apparent in the cardiac, musculoskeletal, and hematologic systems and the CNS. • Cardiac changes. • Musculoskeletal changes—rhabdomyolysis. • CNS changes.

38. Hypophosphatemia Interventions • Oral replacement of phosphorus • Vitamin D supplements • IV phosphorus • Nutrition therapy—increasing the intake of phosphorus-rich foods while decreasing the intake of calcium-rich foods

39. Hyperphosphatemia • Serum phosphorus level above 4.5 mEq/L. • Problems caused by hyperphosphatemia center on the hypocalcemia that results when serum phosphorus levels increase. • Does not cause many direct problems with body function. • Causes include renal insufficiency, certain cancer treatments, increased phosphorus intake, and hypoparathyroidism.

40. Hyperphosphatemia Interventions • Because calcium and phosphorus ions exist in the blood in a balanced reciprocal relationship, management of hyperphosphatemia entails the management of hypocalcemia.

41. Magnesium (1.3 to 2.1 mg/dL) • Magnesium is critical for skeletal muscle contraction, carbohydrate metabolism, ATP formation, vitamin activation, and cell growth.

42. Hypomagnesemia • Serum magnesium level below 1.2 mEq/L. • Effects of hypomagnesemia are caused by increased membrane excitability and the accompanying serum calcium and potassium imbalances.

43. Hypomagnesemia (Cont’d) • Neuromuscular changes. • CNS changes. • Intestinal changes. • Interventions for hypomagnesemia: • Drugs—IV magnesium sulfate

44. Hypermagnesemia • Serum magnesium level above 2.1 mEq/L. • When magnesium excess occurs, excitable membranes are less excitable and need a stronger-than-normal stimulus to respond. • Cardiac changes. • CNS changes. • Neuromuscular changes. • Respiratory changes.

45. Hypermagnesemia Interventions • Magnesium-free IV fluids • Furosemide • Calcium

46. Chloride (98 to 106 mEq/L) • Imbalances of chloride usually occur as a result of other electrolyte imbalances. • Usually corrected by interventions for correcting other electrolyte or acid-base problems.