1. Fluid and Electrolytes: Balance and Distribution

2. Homeostasis State of equilibrium in body
Naturally maintained by adaptive responses
Body fluids and electrolytes are maintained within narrow limits

3. Water Content of the Body
60% of body weight in adult
45% to 55% in older adults
70% to 80% in infants
Varies with gender, body mass, and age

4. Changes in Water Content with Age
Fig. 17-1

5. Compartments Intracellular fluid (ICF) Extracellular fluid (ECF)
Intravascular (plasma)
Interstitial
Transcellular

6. Fluid Compartments of the Body
Fig. 17-2

7. Intracellular Fluid (ICF)
Located within cells
42% of body weight

8. Extracellular Fluid (ECF)
One third of body weight
Between cells (interstitial fluid), lymph, plasma, and transcellular fluid

9. Transcellular Fluid
Part of ECF
Small but important
Approximately 1 L

10. Transcellular Fluid Includes fluid in Cerebrospinal fluid
Gastrointestinal tract
Pleural spaces
Synovial spaces
Peritoneal fluid spaces

11. Electrolytes
Substances whose molecules dissociate into ions (charged particles) when placed into water
Cations: positively charged
Anions: negatively charged

12. Measurement of Electrolytes
International standard is millimoles per liter (mmol/L)
U.S. uses milliequivalent (mEq)
Ions combine mEq for mEq

13. Electrolyte Composition
ICF
Prevalent cation is K+
Prevalent anion is PO43-
ECF
Prevalent cation is Na+
Prevalent anion is Cl-

14. Mechanisms Controlling Fluid and Electrolyte Movement
Diffusion
Facilitated diffusion
Active transport
Osmosis
Hydrostatic pressure
Oncotic pressure

15. Diffusion Movement of molecules from high to low concentration
Occurs in liquids, solids, and gases
Membrane separating two areas must be permeable to diffusing substance
Requires no energy

16. Diffusion
Fig. 17-4
Copyright © 2007, 2004, 2000, Mosby, Inc., an affiliate of Elsevier Inc. All Rights Reserved.

17. Facilitated Diffusion
Movement of molecules from high to low concentration without energy
Uses specific carrier molecules to accelerate diffusion

18. Active Transport
Process in which molecules move against concentration gradient
Example: sodium–potassium pump
External energy required

19. Sodium–Potassium Pump
Fig. 17-5
Copyright © 2007, 2004, 2000, Mosby, Inc., an affiliate of Elsevier Inc. All Rights Reserved.

20. Osmosis
Movement of water between two compartments by a membrane permeable to water but not to solute
Moves from low solute to high solute concentration
Requires no energy

21. Osmosis
Fig. 17-6

22. Osmotic Pressure
Amount of pressure required to stop osmotic flow of water
Determined by concentration of solutes in solution

23. Hydrostatic Pressure Force within a fluid compartment
Major force that pushes water out of vascular system at capillary level

24. Oncotic Pressure
Osmotic pressure exerted by colloids in solution (colloidal osmotic pressure)
Protein is major colloid

25. Fluid Movement in Capillaries
Amount and direction of movement determined by
Capillary hydrostatic pressure
Plasma oncotic pressure
Interstitial hydrostatic pressure
Interstitial oncotic pressure

26. Fluid Shifts Plasma to interstitial fluid shift results in edema
Elevation of hydrostatic pressure
Decrease in plasma oncotic pressure
Elevation of interstitial oncotic pressure

27. Fluid Shifts Interstitial fluid to plasma
Fluid drawn into plasma space with increase in plasma osmotic or oncotic pressure
Compression stockings decrease peripheral edema

28. Fluid Movement between ECF and ICF
Water deficit (increased ECF)
Associated with symptoms that result from cell shrinkage as water is pulled into vascular system

29. Fluid Movement between ECF and ICF
Water excess (decreased ECF)
Develops from gain or retention of excess water

30. Fluid Spacing First spacing Second spacing
Normal distribution of fluid in ICF and ECF
Second spacing
Abnormal accumulation of interstitial fluid (edema)

31. Fluid Spacing Third spacing
Fluid accumulation in part of body where it is not easily exchanged with ECF

32. Regulation of Water Balance
Hypothalamic regulation
Pituitary regulation
Adrenal cortical regulation
Renal regulation

33. Regulation of Water Balance
Cardiac regulation
Gastrointestinal regulation
Insensible water loss

34. Hypothalamic Regulation
Osmoreceptors in hypothalamus sense fluid deficit or increase
Stimulates thirst and antidiuretic hormone (ADH) release
Result in increased free water and decreased plasma osmolarity

35. Pituitary Regulation
Under control of hypothalamus, posterior pituitary releases ADH
Stress, nausea, nicotine, and morphine also stimulate ADH release

36. Adrenal Cortical Regulation
Releases hormones to regulate water and electrolytes
Glucocorticoids
Cortisol
Mineralocorticoids
Aldosterone

37. Factors Affecting Aldosterone Secretion
Fig. 17-9

38. Renal Regulation
Primary organs for regulating fluid and electrolyte balance
Adjusting urine volume
Selective reabsorption of water and electrolytes
Renal tubules are sites of action of ADH and aldosterone

39. Effects of Stress on F&E Balance
Fig

40. Cardiac Regulation Natriuretic peptides are antagonists to the RAAS
Produced by cardiomyocytes in response to increased atrial pressure
Suppress secretion of aldosterone, renin, and ADH to decrease blood volume and pressure

41. Gastrointestinal Regulation
Oral intake accounts for most water
Small amounts of water are eliminated by gastrointestinal tract in feces
Diarrhea and vomiting can lead to significant fluid and electrolyte loss

42. Insensible Water Loss
Invisible vaporization from lungs and skin to regulate body temperature
Approximately 600 to 900 ml/day is lost
No electrolytes are lost

43. Gerontologic Considerations
Structural changes in kidneys decrease ability to conserve water
Hormonal changes lead to decrease in ADH and ANP
Loss of subcutaneous tissue leads to increased loss of moisture

44. Gerontologic Considerations
Reduced thirst mechanism results in decreased fluid intake
Nurse must assess for these changes and implement treatment accordingly

45. Fluid and Electrolyte Imbalances
Common in most patients with illness
Directly caused by illness or disease (burns or heart failure)
Result of therapeutic measures (IV fluid replacement or diuretics)

46. Extracellular Fluid Volume Imbalances
ECF volume deficit (hypovolemia)
Abnormal loss of normal body fluids (diarrhea, fistula drainage, hemorrhage), inadequate intake, or plasma-to-interstitial fluid shift
Treatment: replace water and electrolytes with balanced IV solutions

47. Extracellular Fluid Volume Imbalances
Fluid volume excess (hypervolemia)
Excessive intake of fluids, abnormal retention of fluids (CHF), or interstitial-to-plasma fluid shift
Treatment: remove fluid without changing electrolyte composition or osmolality of ECF

48. Nursing Management Nursing Diagnoses
Hypovolemia
Deficient fluid volume
Decreased cardiac output
Potential complication: hypovolemic shock

49. Nursing Management Nursing Diagnoses
Hypervolemia
Excess fluid volume
Ineffective airway clearance
Risk for impaired skin integrity
Disturbed body image
Potential complications: pulmonary edema, ascites

50. Nursing Management Nursing Implementation
Monitor cardiovascular changes
Assess respiratory status and monitor changes
Daily weights
Skin assessment

51. Nursing Management Nursing Implementation
Neurologic function
LOC
PERLA
Voluntary movement of extremities
Muscle strength
Reflexes

52. Electrolyte Disorders Signs and Symptoms
Excess
Deficit
Sodium (Na)
Hypernatremia
Thirst
CNS deterioration
Increased interstitial fluid
Hyponatremia
Potassium (K)
Hyperkalemia
Ventricular fibrillation
ECG changes
CNS changes
Hypokalemia
Bradycardia

53. Electrolyte Disorders Signs and Symptoms
Excess
Deficit
Calcium (Ca)
Hypercalcemia
Thirst
CNS deterioration
Increased interstitial fluid
Hypocalcemia
Tetany
Chvostek’s, Trousseau’s signs
Muscle twitching
CNS changes
ECG changes
Magnesium (Mg)
Hypermagnesemia
Loss of deep tendon reflexes (DTRs)
Depression of CNS
Depression of neuromuscular function
Hypomagnesemia
Hyperactive DTRs

54. Sodium
Imbalances typically associated with parallel changes in osmolality
Plays a major role in
ECF volume and concentration
Generation and transmission of nerve impulses
Acid–base balance
NV: mEq/L

55. Hypernatremia
Elevated serum sodium occurring with water loss or sodium gain
Causes hyperosmolality leading to cellular dehydration
Primary protection is thirst from hypothalamus

56. Hypernatremia Manifestations Impaired LOC Produced by clinical states
Thirst, lethargy, agitation, seizures, and coma
Impaired LOC
Produced by clinical states
Central or nephrogenic diabetes insipidus

57. Hypernatremia
Serum sodium levels must be reduced gradually to avoid cerebral edema

58. Nursing Management Nursing Diagnoses
Risk for injury
Potential complication: seizures and coma leading to irreversible brain damage

59. Nursing Management Nursing Implementation
Treat underlying cause
If oral fluids cannot be ingested, IV solution of 5% dextrose in water or hypotonic saline
Diuretics

60. Hyponatremia
Results from loss of sodium-containing fluids or from water excess
Manifestations
Confusion, nausea, vomiting, seizures, and coma

61. Nursing Management Nursing Diagnoses
Risk for injury
Potential complication: severe neurologic changes

62. Nursing Management Nursing Implementation
Caused by water excess
Fluid restriction is needed
Severe symptoms (seizures)
Give small amount of IV hypertonic saline solution (3% NaCl)

63. Nursing Management Nursing Implementation
Abnormal fluid loss
Fluid replacement with sodium-containing solution

64. Potassium Major ICF cation Necessary for
Transmission and conduction of nerve and muscle impulses
Maintenance of cardiac rhythms
Acid–base balance

65. Potassium Sources Fruits and vegetables (bananas and oranges)
Salt substitutes
Potassium medications (PO, IV)
Stored blood
NV: mEq/L

66. Hyperkalemia High serum potassium caused by
Massive intake
Impaired renal excretion
Shift from ICF to ECF
Common in massive cell destruction
Burn, crush injury, or tumor lysis

67. Hyperkalemia Manifestations Weak or paralyzed skeletal muscles
Ventricular fibrillation or cardiac standstill
Abdominal cramping or diarrhea

69. Nursing Management Nursing Diagnoses
Risk for injury
Potential complication: dysrhythmias

70. Nursing Management Nursing Implementation
Eliminate oral and parenteral K intake
Increase elimination of K (diuretics, dialysis, Kayexalate)

71. Nursing Management Nursing Implementation
Force K from ECF to ICF by IV insulin or sodium bicarbonate
Reverse membrane effects of elevated ECF potassium by administering calcium gluconate IV

72. Hypokalemia Low serum potassium caused by
Abnormal losses of K+ via the kidneys or gastrointestinal tract
Magnesium deficiency
Metabolic alkalosis

73. Hypokalemia Manifestations Most serious are cardiac
Skeletal muscle weakness
Weakness of respiratory muscles
Decreased gastrointestinal motility

75. Nursing Management Nursing Diagnoses
Risk for injury
Potential complication: dysrhythmias

76. Nursing Management Nursing Implementation
KCl supplements orally or IV
Should not exceed 10 to 20 mEq/hr
To prevent hyperkalemia and cardiac arrest

77. Calcium Obtained from ingested foods
More than 99% combined with phosphorus and concentrated in skeletal system
Inverse relationship with phosphorus

78. Calcium Bones are readily available store
Blocks sodium transport and stabilizes cell membrane
Ionized form is biologically active
NV: mg/dl
NV: (total) 9-11 mg/dl

79. Calcium Functions Transmission of nerve impulses
Myocardial contractions
Blood clotting
Formation of teeth and bone
Muscle contractions

80. Calcium
Balance controlled by
Parathyroid hormone
Calcitonin
Vitamin D

81. Hypercalcemia High serum calcium levels caused by
Hyperparathyroidism (two thirds of cases)
Malignancy
Vitamin D overdose
Prolonged immobilization

82. Hypercalcemia Manifestations Decreased memory Confusion Disorientation
Fatigue
Constipation

83. Nursing Management Nursing Diagnoses
Risk for injury
Potential complication: dysrhythmias

84. Nursing Management Nursing Implementation
Excretion of Ca with loop diuretic
Hydration with isotonic saline infusion
Synthetic calcitonin
Mobilization

85. Hypocalcemia Manifestations Positive Trousseau’s or Chvostek’s sign
Laryngeal stridor
Dysphagia
Tingling around the mouth or in the extremities

86. Hypocalcemia Low serum Ca levels caused by Decreased production of PTH
Acute pancreatitis
Multiple blood transfusions
Alkalosis
Decreased intake

87. Tests for Hypocalcemia
Chvostek’s – contraction of facial muscles in response to a light tap over the facial nerve in front of the ear
Trousseau’s sign - carpal spasm induced by inflating a blood pressure cuff above the systolic pressure for a few minutes
Fig

88. Nursing Management Nursing Diagnoses
Risk for injury
Potential complication: fracture or respiratory arrest

89. Nursing Management Nursing Implementation
Treat cause
Oral or IV calcium supplements
Not IM to avoid local reactions
Treat pain and anxiety to prevent hyperventilation-induced respiratory alkalosis

90. Phosphate Primary anion in ICF
Essential to function of muscle, red blood cells, and nervous system
Deposited with calcium for bone and tooth structure
NV: mg/dl

92. Phosphate
Involved in acid–base buffering system, ATP production, and cellular uptake of glucose
Maintenance requires adequate renal functioning
Essential to muscle, RBCs, and nervous system function

93. Hyperphosphatemia High serum PO43- caused by
Acute or chronic renal failure
Chemotherapy
Excessive ingestion of phosphate or vitamin D

94. Hyperphosphatemia Manifestations
Calcified deposition in soft tissue such as joints, arteries, skin, kidneys, and corneas
Neuromuscular irritability and tetany

95. Hyperphosphatemia Management Identify and treat underlying cause
Restrict foods and fluids containing PO43-
Adequate hydration and correction of hypocalcemic conditions

96. Hypophosphatemia Low serum PO43- caused by
Malnourishment/malabsorption
Alcohol withdrawal
Use of phosphate-binding antacids
During parenteral nutrition with inadequate replacement

97. Hypophosphatemia Manifestations CNS depression Confusion
Muscle weakness and pain
Dysrhythmias
Cardiomyopathy

98. Hypophosphatemia Management Oral supplementation
Ingestion of foods high in PO43-
IV administration of sodium or potassium phosphate

99. Magnesium 50% to 60% contained in bone
Coenzyme in metabolism of protein and carbohydrates
Factors that regulate calcium balance appear to influence magnesium balance

100. Magnesium Acts directly on myoneural junction
Important for normal cardiac function
NV: mEq/L

101. Hypermagnesemia High serum Mg caused by
Increased intake or ingestion of products containing magnesium when renal insufficiency or failure is present

102. Hypermagnesemia Manifestations Lethargy or drowsiness Nausea/vomiting
Impaired reflexes
Respiratory and cardiac arrest

103. Hypermagnesemia Management Prevention Emergency treatment
IV CaCl or calcium gluconate
Fluids to promote urinary excretion

104. Hypomagnesemia Low serum Mg caused by Prolonged fasting or starvation
Chronic alcoholism
Fluid loss from gastrointestinal tract
Prolonged parenteral nutrition without supplementation
Diuretics

105. Hypomagnesemia Manifestations Confusion
Hyperactive deep tendon reflexes
Tremors
Seizures
Cardiac dysrhythmias

106. Hypomagnesemia Management Oral supplements Increase dietary intake
Parenteral IV or IM magnesium when severe

107. IV Fluids Purposes Maintenance Replacement
When oral intake is not adequate
Replacement
When losses have occurred

108. IV Fluids Hypotonic More water than electrolytes
Pure water lyses RBCs
Water moves from ECF to ICF by osmosis
Usually maintenance fluids

109. IV Fluids
Isotonic
Expands only ECF
No net loss or gain from ICF

110. IV Fluids
Hypertonic
Initially expands and raises the osmolality of ECF
Require frequent monitoring of
Blood pressure
Lung sounds
Serum sodium levels

111. D5W Isotonic Provides 170 cal/L Free water Moves into ICF
Increases renal solute excretion

112. D5W Used to replace water losses and treat hyponatremia
Does not provide electrolytes

113. Normal Saline (NS) Isotonic No calories More NaCl than ECF
30% stays in IV (most)
70% moves out of IV

114. Normal Saline (NS) Expands IV volume Does not change ICF volume
Preferred fluid for immediate response
Risk for fluid overload higher
Does not change ICF volume
Blood products
Compatible with most medications

115. Lactated Ringer’s Isotonic More similar to plasma than NS Expands ECF
Has less NaCl
Has K, Ca, PO43-, lactate (metabolized to HCO3-)
Expands ECF

116. D5 ½ NS Hypertonic Common maintenance fluid
KCl added for maintenance or replacement

117. D10W Hypertonic Provides 340 kcal/L Free water
Limit of dextrose concentration may be infused peripherally

118. Plasma Expanders Stay in vascular space and increase osmotic pressure
Colloids (protein solutions)
Packed RBCs
Albumin
Plasma