1. 7
Caring for Clients With Altered Fluid, Electrolyte, or Acid-Base Balance

2. Learning Outcomes
Identify the functions and regulatory mechanisms that maintain water and electrolyte balance in the body.
Compare and contrast the causes and effects of fluid volume deficit and excess.
Identify tests used to diagnose and monitor treatment of fluid and electrolyte imbalances.

3. Learning Outcomes
Recognize normal and abnormal values of electrolytes in the blood.
Use arterial blood gas results to identify the type of acid–base imbalance present in a client.
Provide appropriate nursing care and teaching for clients with fluid, electrolyte, or acid–base disorders.

4. Water Primary component of body fluids
Transports nutrients and oxygen to cells and waste products from cells
Provides medium for metabolic reactions within cells
Insulates and helps regulate and maintain body temperature

5. Water
Provides for body structure and acts as shock absorber and a lubricant
To maintain fluid balance, intake should equal output 2500 mL/day

6. Electrolytes Substances that dissociate in solution to form ions
Cations are positively charged; anions are negatively charged
Help regulate water and acid–base balance
Contribute to enzyme reactions
Essential to neuromuscular activity

8. Body Fluid Distribution
Intracellular fluid (ICF)
Fluid within cells—40% total body weight
Contains electrolytes, glucose, oxygen
Extracellular fluid (ECF)
Interstitial fluid—15% total body weight
Intravascular fluid—5% total body weight
Transcellular fluid—<1% total body weight
Transports oxygen, electrolytes, and nutrients to cells
Transports waste products away from cells

9. Body Fluid Movement Osmosis Osmolality—concentration of solutes
Osmotic pressure—power of a solution
Tonicity—effect of osmotic pressure of a solution on cell within a solution

10. Body Fluid Movement
Diffusion

11. Body Fluid Movement
Filtration

12. Body Fluid Movement
Active transport

13. Body Fluid Regulation Thirst Kidneys
Regulator of water intake
Kidneys
Regulator of fluid volume and electrolyte balance
Renin–angiotensin–aldosterone system
Maintains intravascular fluid balance and blood pressure

14. Body Fluid Regulation Antidiuretic hormone (ADH)
Regulates water excretion from the kidneys
Diabetes insipidus
ADH is not produced
Syndrome of inappropriate ADH secretion
Excess ADH is produced

15. Body Fluid Regulation Atrial natriuretic factor (ANF)
Hormone released by cells in atria of heart in response to fluid overload
Inhibits renin secretion and blocks secretion and effects of aldosterone
Promotes sodium and water loss and causes blood vessels to dilate

16. Fluid Volume Deficit Excessive fluid losses Insufficient fluid intake
Results in hypovolemia

19. Fluid Volume Deficit Decrease in extracellular fluids
Loss of water and electrolytes
Interstitial fluid shifts into vascular space to maintain blood volume
Third spacing
Shift of fluid from vascular space into soft tissue or potential space, such as intra-abdominal

20. Fluid Volume Deficit
Priority of care is restoring blood and fluid volume
Teach ways to prevent fluid volume deficit: recommended fluid intake, avoid overexposure to heat and exercise, and monitor weight
Replace fluid and electrolytes enterally or intravenously

22. Fluid Volume Excess Fluid Volume Excess
Characterized by excess sodium that leads to water retention
Results in hypervolemia and interstitial edema

24. Fluid Volume Excess
Restricted fluid intake

25. Fluid Volume Excess
Medications
Diuretics

26. Fluid Volume Excess
Sodium-restricted diet

27. Fluid Volume Excess – Nursing Care
Priorities of care:
Decrease excess fluid volume and hypervolemia
Teach fluid and sodium restrictions and medication administration

28. Laboratory Tests (Fluid Balance, Sodium, and Potassium)
Serum electrolytes
Serum osmolality
Hematocrit and hemoglobin
Urine specific gravity and osmolality
Liver and kidney function tests for fluid volume excess
24-hour urine specimen to evaluate sodium excretion
Arterial blood gases
Serum glucose

29. Laboratory Tests (Calcium, Phosphorus, and Magnesium)
Total serum calcium
Serum magnesium
Serum phosphate
Serum parathyroid hormone

30. Diagnostic Studies and Invasive Monitoring
Central venous pressure (CVP)
Electrocardiogram

31. Laboratory/Diagnostic Studies Acid-Base Imbalances
Arterial blood gas studies
Serum electrolytes
Serum creatinine and BUN
Electrocardiogram

32. Sodium ( mEq/L)
Most plentiful electrolyte in extracellular fluid -regulates extracellular volume and distribution
Contributes to neuromuscular activity and acid–base balance
Affects osmolality of extracellular fluid
Kidneys work with the renin–angiotensin–aldosterone system and ANP to retain or excrete sodium

33. Hyponatremia
Loss of sodium or water gain that dilutes extracellular fluid
Serum sodium < 135 mEq/L
Affects functioning of voluntary and involuntary muscles
Brain cells swell
Leading to neurologic manifestations and possible brain damage

34. Hyponatremia Intake of foods high in sodium Restrict oral fluids
Administer sodium-containing intravenous fluids
Medications
Administer loop diuretic and sodium replacement to remove excess water
Priority of care is to increase sodium intake or decrease excess water

35. Hyponatremia
Teach importance of drinking liquids containing sodium and other electrolytes:
When perspiring heavily
In hot environment
When experiencing prolonged watery diarrhea

36. Hypernatremia
Gain of sodium in excess of water or loss of water in excess of sodium
Serum sodium > 145 mEq/L
Dehydration of brain cells
Leads to neurologic manifestations and dry, sticky mucous membranes

37. Hypernatremia Correct water deficit Medications
Administer diuretics to increase sodium excretion
Prescribe low-sodium diet
Priorities of care are to decrease sodium intake and increase water intake
Teach low-sodium diet and sufficient water intake

39. Potassium ( mEq/L)
Regulates the transmission of nerve impulses and the normal contractility of smooth, skeletal, and cardiac muscle
Imbalance can result in fatal dysrhythmias

40. Hypokalemia Excess potassium loss or insufficient intake
Serum potassium level < 3.5 mEq/L
Loss through the kidneys
Loss through the gastrointestinal tract

41. Hypokalemia Shift into the intracellular space as result of: Alkalosis
Rapid tissue repair
High insulin levels

42. Hypokalemia (continued)
Affects transmission of nerve impulses
Affects normal contractility of smooth, skeletal, and cardiac muscle
Results in cardiac dysrhythmias

43. Hypokalemia Potassium replacement orally or intravenously
Increased intake of foods high in potassium

44. Hypokalemia
Priorities of care are early identification and monitoring of cardiac status
Teach high-potassium diet, administering potassium supplements, and regular follow-up assessment

45. Hyperkalemia Abnormally high serum potassium
Serum potassium > 5.3 mEq/L
Inadequate potassium excretion
Excessive potassium intake
Shift of potassium from intracellular to extracellular fluid

46. Hyperkalemia Alters neuromuscular function
Results in decreased cardiac contractility
Weakness of skeletal muscles
Gastrointestinal symptoms

47. Hyperkalemia Medications
Administer loop diuretics, sodium polystyrene sulfonate (Kayexalate)
Administer intravenous insulin, glucose, sodium bicarbonate, and calcium gluconate
Administer hemodialysis or peritoneal dialysis

48. Hyperkalemia
Priorities of care are early detection and monitoring of cardiac status
Teach administration of medications, low-potassium diet, obtaining regular laboratory tests, and follow-up care

50. Calcium (9-11 mg/dL)
One of most abundant ions in body, mostly in bones and teeth with small amount in extracellular fluid

51. Calcium Regulation Parathyroid hormone Calcitriol
Mobilizes calcium from bones
Increases calcium absorption in intestines
Promotes calcium reabsorption by the kidneys
Calcitriol
Assists parathyroid hormone processes

52. Calcium Regulation Calcitonin Inhibits movement of calcium out of bone
Reduces intestinal absorption of calcium
Promotes urinary calcium excretion

53. Hypocalcemia Serum calcium < 9 mg/dL At risk:
Removal of parathyroid glands
Older adults (especially women)
Alcoholics

54. Hypocalcemia
Insufficient ionized calcium in the extracellular fluid causes neuromuscular excitability or tetany
Critically low levels can cause respiratory or cardiac arrest or convulsions

55. Hypocalcemia Medications
Administer oral calcium replacements and vitamin D
Administer intravenous calcium chloride, calcium gluconate, or calcium gluceptate via slow IV push or infusion

56. Hypocalcemia Increase dietary intake of calcium
Priority of care is to replace deficient calcium to prevent dysrhythmias and seizures.
Teach dietary intake of calcium foods and vitamin D, administration of medications, and follow-up care

57. Hypercalcemia Serum calcium > 11 mg/dL High calcium levels due to:
Increased calcium release (resorption) from bones
Increased calcium intake
Decreased renal excretion of calcium

58. Hypercalcemia
Increased resorption of calcium from bones may result from:
Hyperparathyroidism and excess hormone secretion
Prolonged immobilization
Malignancies (lung, breast, multiple myeloma)
Impaired renal excretion of calcium

59. Hypercalcemia Sedative effect on neuromuscular transmission
Behavior is disturbed with excess calcium in cerebrospinal fluid
Kidney stones occur from excess calcium in urine
Critically high levels cause heart block and cardiac arrest

61. Hypercalcemia Medications
Administer intravenous normal saline solution
Administer diuretics
Administer biphosphonates, calcitonin, intravenous plicamycin, glucocorticoids

62. Hypercalcemia
Decrease dietary intake of calcium

63. Hypercalcemia Priorities of care Monitor mental status
Monitor respiratory and cardiac status
Protect against injury due to falls from muscular weakness and fatigue
Decrease incidence of kidney stones

64. Hypercalcemia
Teach administration of medications, decreased dietary intake of calcium, increased dietary intake of fiber, and encourage weight-bearing activities

65. Magnesium ( mEq/L)
Found mostly in bones with some in the intracellular and extracellular fluid
Serum magnesium range —1.5 to 2.5 mEq/L or 1.8 to 3.0 mg/dL
Extracellular magnesium affects neuromuscular irritability and contractility
The kidneys control conservation or excretion of magnesium

66. Hypomagnesemia Serum magnesium < 1.5 mEq/L or 1.8 mg/dL
Total body deficit of magnesium
Increases neuromuscular excitability
Affects electrical conduction of the heart and the central nervous system
Affects potassium and calcium metabolism
Common in chronic alcoholism

67. Hypomagnesemia Medications
Administer oral magnesium supplements, such as antacids
Administer magnesium via IV or deep intramuscular injection

68. Hypomagnesemia
Increase dietary intake of foods high in magnesium

69. Hypomagnesemia Priorities of care
Monitor deep tendon reflexes and serum magnesium levels
Teach administration of magnesium supplements, dietary intake of magnesium foods, and referrals for alcohol problems

70. Hypermagnesemia Serum magnesium > 2.5 mEq/L or 3.0 mg/dL
Renal insufficiency or failure
Excessive intake of magnesium-containing antacids or laxatives
Magnesium treatments in complications of pregnancy

71. Hypermagnesemia
Elevated levels interfere with neuromuscular transmission and depress the central nervous system
Affects cardiovascular and respiratory functioning

73. Hypermagnesemia Medications
Withhold all medications and solutions containing magnesium
Administer IV calcium to counteract cardiac effects
Perform hemodialysis or peritoneal dialysis if renal failure
Mechanical ventilation to support respirations

74. Hypermagnesemia Priorities of care
Monitor cardiac and respiratory status
Monitor changes in neuromuscular excitability
Monitor gastrointestinal function
Teach to avoid magnesium-containing medications and to decrease dietary intake of magnesium foods

75. Phosphorus (2.5-4.5 mg/dL) Found in all body tissues
Primary anion in intracellular fluid with very small amount in extracellular fluid
Important for energy (ATP) production, metabolism, and red blood cell function
Phosphate, ionized form of phosphorus, is responsible for its effects

76. Phosphorus Imbalances
An inverse relationship exists between phosphorus and calcium
When one increases, the other decreases

77. Hypophosphatemia Serum phosphate < 2.5 mg/dL
Decreased absorption of phosphate from gastrointestinal tract
Increased excretion by the kidneys
Depletion of cellular energy resources

78. Hypophosphatemia
Tissue hypoxia due to decreased ability of red blood cells to transport oxygen
Alcoholism can cause severe hypophosphatemia

79. Hypophosphatemia
Increase phosphorus in the diet, especially milk and milk products
Medications
Administer oral phosphorus supplements
Administer intravenous phosphate solutions
Priorities of care
Monitor for signs of phosphate imbalance and serum phosphate levels
Protect from infection

80. Hypophosphatemia
Teach administration of medications, dietary intake of phosphorus, effects of phosphorus-binding antacids, referrals for alcohol use

81. Hyperphosphatemia Serum phosphate > 4.5 mg/dL
Acute or chronic renal failure
Impaired renal excretion
Increased phosphate intake or absorption
Phosphate is released into extracellular fluid when cells are damaged or destroyed, resulting in excess serum levels

82. Hyperphosphatemia Decrease phosphorus in the diet Medications
Administer aluminum hydroxide (Amphogel)
Administer IV normal saline
Administer glucose and insulin to drive phosphate into cells
Perform dialysis

83. Hyperphosphatemia Priorities of care
Monitor and report signs of phosphate imbalance
Monitor phosphate levels
Teach to recognize signs of imbalance, avoid phosphate-containing laxatives and enemas, avoid dietary intake of phosphorus, and to take medications as ordered

85. Acid-Base Regulation
Acids are produced by metabolic processes in the body
Volatile acids (carbonic acid) can be eliminated as gas
Nonvolatile acids (i.e., lactic acid, hydrochloric acid) must be metabolized or excreted from the body in fluid

86. Buffer System
Prevents changes in pH by attaching to or releasing hydrogen ions
Major buffer systems are:
Bicarbonate-carbonic acid buffer system
Phosphate buffer system
Protein buffers
Hemoglobin acts as a buffer in red blood cells

87. Buffer System Normal serum bicarbonate level: 24 mEq/L
Normal carbonic acid serum level: 1.2 mEq/L
Bicarbonate-to-carbonic acid ratio of 20:1 maintains a pH of 7.35 to 7.45

88. Respiratory System
Regulates carbonic acid by eliminating or retaining carbon dioxide
Increase in carbon dioxide or hydrogen ions stimulates respiratory center in brain to increase rate and depth of respirations
Eliminates carbon dioxide, carbonic acid levels fall, and pH becomes normal

89. Respiratory System Alkalosis depresses the respiratory center
Causes rate and depth of respirations to decrease
Carbon dioxide is retained
Retained carbon dioxide combines with water
Carbonic acid levels and pH return to normal

90. Renal System
Regulates bicarbonate levels in extracellular fluid to excrete or retain hydrogen ions
Excessive hydrogen ions cause pH to fall
Kidneys excrete hydrogen ions and retain bicarbonate

91. Renal System
Excessive bicarbonate levels cause the kidneys to retain hydrogen ions and excrete bicarbonate to restore acid–base balance

93. Acid-Base Imbalances Acidosis Alkalosis
Hydrogen ion concentration increases above normal
pH falls below 7.35
Alkalosis
Hydrogen ion concentration decreases below normal
pH rises above 7.45

94. Acidosis Metabolic acidosis Respiratory acidosis
Bicarbonate is decreased
pH < 7.35, bicarbonate < 22 mEq/L, PaCO2 < 35 mm Hg
Respiratory acidosis
Carbon dioxide is retained
Increases carbonic acid

95. Alkalosis Metabolic alkalosis Respiratory alkalosis
Excessive bicarbonate
Respiratory alkalosis
Carbon dioxide decreases
Carbonic acid decreases

96. Acid-Base Disorders Primary or simple disorders
One cause respiratory or metabolic
Compensated by amount of change in pH
Kidneys alter bicarbonate and hydrogen
Lungs change rate and depth of respirations
Mixed disorders
Metabolic and respiratory imbalances are present

98. Metabolic Acidosis

99. Metabolic Acidosis

100. Metabolic Acidosis Insufficient oxygen leads to lactic acidosis
Affects the central nervous system, gastrointestinal tract, cardiovascular function
Kussmaul’s respirations (hyperventilation)
Priorities of care are to treat the underlying cause and monitor cardiac and neurologic functioning

101. Metabolic Acidosis - Treatment
Medications
Administer bicarbonate, lactate, acetate, or citrate solutions
Teach proper diabetes mellitus care to prevent ketoacidosis
Obtain treatment for alcoholism with proper diet and medications
Manage renal failure with diet and dialysis
Prevent or treat diarrhea

102. Metabolic Alkalosis

103. Metabolic Alkalosis

104. Metabolic Alkalosis Loss of acid or excess bicarbonate in the body
Respiratory system attempts to return pH to normal by slowing respiratory rate
Priorities of care
Treat underlying cause
Restore normal fluid volume
Monitor respirations

105. Metabolic Alkalosis - Treatment
Medications
Administer potassium chloride and sodium chloride solutions
Administer dilute hydrochloric acid or ammonium chloride for critically high pH
Teach how to prevent and manage acute gastroenteritis or vomiting, the advantages of a potassium-rich diet or potassium supplements, and to avoid use of antacids

106. Respiratory Acidosis

107. Respiratory Acidosis

108. Respiratory Acidosis
Excess of dissolved carbon dioxide or carbonic acid
Alveolar hypoventilation leads to carbon dioxide retention
Kidneys compensate by retaining bicarbonate

109. Respiratory Acidosis Priorities of care Administer oxygen
Clear the airways
Support ventilation
Provide adequate hydration

110. Respiratory Acidosis - Treatment
Medications
Administer bronchodilator medications
Administer antibiotics
Administer medications to reverse narcotic and anesthetic effects
Teach to avoid respiratory infections, to immunize against pneumococcal pneumonia and influenza, and to obtain treatment for narcotic or drug abuse

111. Respiratory Alkalosis

112. Respiratory Alkalosis

113. Respiratory Alkalosis
Hyperventilation leads to carbon dioxide deficit
Low carbon dioxide levels cause cerebral blood vessels to constrict
Causes decrease in calcium ionization
Priorities of care
Breathe slowly into a paper bag or rebreather mask to prevent excess loss of carbon dioxide

114. Respiratory Alkalosis - Treatment
Medications
Administer a sedative or antianxiety medication
Teach to decrease anxiety, to seek counseling, and to identify hyperventilation and how to treat it