- Monitor VS, LOC, I and O, weight - Monitor Na levels closely - Seizure precautions - Oral care - Initiate feedings slowly - Educate on fluid restriction - Identify and treat underlying cause Prevent rapid correction to avoid osmotic demyelination syndrome 58  Potassium - Most abundant intracellular cation - 3.5-5.0 mEq/L - Regulated by: - Dietary intake - Renal excretion - Shift between intra/extracellular space Functions: - Important in nerve impulse conduction - Muscle contraction - Acid-base balance - Glucose metabolism

1. Water, Electrolyte, and Acid-Base
Balance
1

2. • Help maintain body
temperature and
cell shape
• Help transport
nutrients, gasses
and wastes
2

3. Fluid
• Is used to indicate that other
substances are also found in these
compartments and that they
influence the water balance in and
between compartments.
3

4. Fluids
• 60% of an adult’s body weight
* 70 Kg adult male: 60% X 70= 42 Liters
• Infants = more water
• Elderly = less water
• More fat = ↓water
• More muscle = ↑water
• Infants and elderly - prone to fluid
imbalance
4

5. FLUID BALANCE
TOTAL BODY WATER (AS PERCENTAGE OF BODY WEIGHT) IN
RELATION TO AGE AND SEX
AGE MALE FEMALE
UNDER 18 65% 55%
18-40 60% 50%
40-60 50-60% 40-50%
OVER 60 50% 40%
5

6. 60 %
Intracellular Fluid 40% or 2/3 Extracellular Fluid 20% or 1/3
Arterial Fluid
2%
Intravascular Interstitial
5% or 1/4 15% or 3/4
Venous
Fluid 3% Transcellular fluid 1-2%
ie csf, pericardial, synovial,
intraocular, sweat 6

7. Function of Water:
Most of cellular activities are performed in
water solutions.
7

8. Intracellular Fluid Compartment
• Includes all the water and electrolytes inside
the cells of the body.
• Contains high concentrations of:
– potassium,
– phosphate,
– magnesium and
– sulfate ions,
– along with most of the proteins in the body.
8

9. 9

10. Extracellular Fluid Compartment
• Includes all the fluid outside the cells:
– interstitial fluid, plasma, lymph, secretions of glands, fluid within
subcompartments separated by epithelial membranes.
• Contains high concentrations of :
– sodium,
– chloride and
– bicarbonate.
• One-third of the ECF is in plasma.
10

11. Extracellular Fluid Osmolality
• Osmolality
– Adding or • Decreased
removing water
osmolality
from a solution
changes this – Inhibits thirst and
ADH secretion
• Increased
osmolality
– Triggers thirst and
ADH secretion
11

12. Transcellular Exchange Mechanisms:
• ACTIVE TRANSPORT
• PASSIVE TRANSPORT
– Diffusion
– Osmosis
– Filtration
– Facilitated diffusion
12

13. Movement of Water Between Body
Fluid Compartments:
• HYDROSTATIC PRESSURE- pressure in the blood
vessels resulting from the weight of the water and
cardiac contraction
• OSMOTIC PRESSURE- pressure exerted by proteins
in plasma which pulls water into the circulatory
system
13

14. 4% TBW 40% TBW
Body Fluid
- makes up
~60% of total
body weight
(TBW)
- distributed in
three fluid
compartments.
14
16% TBW

15. 4% TBW 40% TBW
Fluid is continually
exchanged between
the three
compartments.
15
16% TBW

16. 4% TBW 40% TBW
Exchange between
Blood & Tissue Fluid
- determined by
four factors:
capillary blood
pressure
plasma colloid
osmotic
pressure
interstitium
Hydrostatic
Pressure
Interstitium
colloid osmotic
pressure
16
16% TBW

17. 4% TBW 40% TBW
Exchange between
Blood & Tissue Fluid
- not affected by
electrolyte
concentrations
- Edema = water
accumulation in
tissue fluid
17
16% TBW

18. Exchange between 4% TBW 40% TBW
Tissue Fluid &
Intracellular Fluid
- determined by two:
1) intracellular osmotic
pressure
electrolytes
2) interstitial osmotic
pressure
electrolytes
18
16% TBW

19. Water Gain
Water is gained from
three sources.
1) food (~700 ml/day)
2) drink – voluntarily
controlled
3) metabolic water (200
ml/day) --- produced as a
byproduct of aerobic
respiration
19

20. Routes of water loss
1) Urine – obligatory (unavoidable) and
physiologically regulated, minimum 400
ml/day
2) Feces -- obligatory water loss, ~200 ml/day
3) Breath – obligatory water loss, ~300
ml/day
4) Cutaneous evaporation -- obligatory
water loss, ~400 ml/day
5) Sweat – for releasing heat, varies
significantly
20

21. Regulation of Water Intake
- governed by thirst.
↓blood volume and
↑osmolarity
⇓
peripheral volume sensors
central osmoreceptors
⇓
hypothalamus
⇓
thirst felt
21

22. Regulation of Urine Concentration
and Volume
• Volume and composition depends on the
condition of the body.
• blood concentration = kidney produce urine.
– To eliminate solutes and conserve water – help to lower
blood concentration
• Blood concentration = kidney produce urine
– Water is lost, solutes are conserved, blood
concentration increases.
22

23. Regulation of Water Output
- The only physiological
control is through variations in
urine volume.
- urine volume regulated by
hormones
23

24. Water Content Regulation
• Content regulated so • Sources of water
total volume of water in – Ingestion
body remains constant – Cellular metabolism
• Kidneys primary • Routes of water loss
regulator of water – Urine
excretion
– Evaporation
• Perspiration
• Regulation processes • Respiratory passages
– Osmosis – Feces
– Osmolality
– Baroreceptors 24
– Learned behavior

25. HORMONAL MECHANISMS
Helps to regulate blood
composition and blood volume.
25

26. 1. ANTIDIURETIC HORMONE
(ADH)
• Secreted by posterior pituitary gland into
circulation to the kidney
• Function:
– to regulate the amount of water reabsorbed
BLOOD
– RETAINS WATER VOL
BLOOD
PRESSURE
CONC.
URINE
26

27. 1. ANTIDIURETIC HORMONE
(ADH)
• ADH
– permeability to water of the kidney
= more water is reabsorbed
= CONCENTRATED URINE
• ADH
– Kidney is less permeable to water
= DILUTED URINE
27

28. 1) ADH dehydration
⇓
↓blood volume and/or ↑osmolality
⇓
hypothalamic receptors / peripheral
volume sensors
⇓
posterior pituitary to release ADH
⇓
↑ H2O reabsorption
⇓
Water retention
28

29. 2. ATRIAL NATRIURETIC
FACTOR
• Secreted by the cells in the RIGHT ATRIUM
when the BP in the RA is
• Function:
– Reduces the ability of the kidney to concentrate urine
PRODUCTION OF LARGE VOLUME OF URINE
BLOOD VOLUME
CAUSES BP
29

30. 2) Atrial Natriuretic Factor
↑ blood volume =↑ BP
⇓
atrial volume sensors
⇓
atria to release ANF
⇓
inhibits Na+ and H2O reabsorption
⇓
↑ water output = ↓ BP
30

31. 3. ALDOSTERONE
• Secreted by ADRENAL GLAND
• Function:
– regulates the rate of active transport in the
kidney
– REABSORPTION OF NaCl
31

32. 3. ALDOSTERONE
• ABSENCE of aldosterone = Na+ and Cl-
remain in nephron = part of the urine
32

33. 4. RENIN AND ANGIOTENSIN
• FUNCTION: regulate aldosterone
secretion
• RENIN secreted by the cells in the
juxtaglomerular apparatus in the kidney.
– An enzyme that acts on proteins produce by
liver
33

34. RENIN AND ANGIOTENSIN
– Liver: In the protein, certain amino acids are
removed leaving ANGIOTENSIN I.
– ANGIOTENSIN I is rapidly converted into
smaller peptide called ANGIOTENSIN II.
– ANGIOTENSIN II acts on the adrenal gland
causing it to secrete
ALDOSTERONE!!!
34

35. – BP
– Na+
RENIN production
– K+
– BP = RENIN IS RELEASED
Na+ reabsorbed by nephron
H2O is reabsorbed
CONSERVE WATER = PREVENT IN BP
35

36. Dehydration
- decrease in body fluid
- Causes
2) the lack of drinking water
2) excessive loss of body fluid due to:
overheat
diabetes
overuse of diuretics
diarrhea
36

37. Edema
- the accumulation of fluid in the
interstitial spaces
caused by:
1) increased capillary filtration,
or
2) reduced capillary reabsorption,
or
3) obstructed lymphatic drainage
37

38. ELECTROLYTE BALANCE
HORMONE REGULATION:
Insulin and Epinephrine = cause K+ and phosphate to move from
extracellular fluid into cells
Parathyroid hormone = cause Ca++ and phosphate to move from bone to
extracellular fluid
Calcitonin = moves calcium to bones
38

39. Electrolytes = small ions that carry charges
39

40. 40

41. Distribution of Electrolytes
Na+
Ca ++ K+ Cell
PO4---
Cl-
Extracellular
space
41

42. Ions
• Factors which influence the concentration of water
and solutes inside the cells:
– Transport mechanisms
– Permeability of the cell membrane
– Concentration of water and solutes in the extracellular fluid
42

43. Ions
NORMAL VALUES AND MASS CONVERSION FACTORS
Normal Plasma Values Mass Conversion
Sodium (Na+) 135 – 145 meq/L 23 mg = 1 meq
Potassium (K+) 3.5 – 5.0 meq/L 39 mg = 1 meq
Chloride (Cl-) 98 – 107 meq/L 35 mg = 1 meq
Bicarbonate (HCO3-) 22 – 26 meq/L 61 mg = 1 meq
Calcium (Ca2+) 8.5 – 10.5 mg/dL 40 mg = 1 mmol
Phosphorus 2.5 – 4.5 mg/dL 31 mg = 1 mmol
Magnesium (Mg2+) 1.8 – 3.0 mg/dL 24 mg = 1 mmol
Osmolality 285 – 295 mosm/kg -
43

44. Sodium
• Dominant extracellular ion.
• About 90 to 95% of the osmotic pressure of the
extracellular fluid results from sodium ions and the
negative ions associated with them.
• Recommended dietary intake is less than 2.5 grams
per day.
• Kidneys provide the major route by which the excess
sodium ions are excreted. 44

45. SODIUM (Na)
• MOST ABUNDANT cation in the ECF
• 135-145 mEq/L
• Aldosterone increases sodium reabsorption
• ANP increases sodium excretion
• Cl accompanies Na
FUNCTIONS:
1. assists in nerve transmission and muscle contraction
2. Major determinant of ECF osmolality
3. Primary regulator of ECF volume
45

46. Sodium
• Primary mechanisms that regulate the sodium ion
concentration in the extracellular fluid:
– Changes in the blood pressure
– Changes in the osmolality of the extracellular fluid
46

47. Regulation of plasma Na+
4) Aldosterone
↓plasma Na+
Na+
⇓
↑ aldosterone
⇓
↓renal Na + excretion
plasma
⇓
↑ plasma Na +
47

48. 1) Renin-angiotensin-II
renin
⇓
angiotensin-II
⇓ Na+
↑ aldosterone
⇓
↓ renal Na+ excretion
⇓ plasma
↑ plasma Na+
48

49. 3) ADH
increases water
reabsorption in
kidneys
⇓
H2O
water retention
⇓
dilute plasma Na+ Na+
plasma
49

50. 1) Atrial Natriuretic
Factor
inhibits renal reabsorption
of Na+ and H2O and
the excretion of renin Na+
and ADH
⇓
eliminate more sodium
and water plasma
⇓ Na+
↓ plasma Na +
50

51. Sodium imbalance
hypernatremia
plasma sodium > 145 mEq/L,
hyponatremia
plasma sodium < 130 mEq/L
51

52. 52

53. HYPERNATREMIA
• Na > 145 mEq/L
• Assoc w/ water loss or sodium gain
• Etiology:
– inadequate water intake,
– excessive salt ingestion /hypertonic feedings w/o water
supplements,
– near drowning in sea water,
– diuretics
53

54. HYPERNATREMIA
S/SX:
• Polyuria Dx:
• Anorexia • inc serum sodium and Cl
• Nausea/vomiting,
level,
• Thirst
• Dry and swollen tongue • inc serum osmolality,
• Fever • inc urine sp.gravity,
• Dry and flushed skin • inc urine osmolality
• Altered LOC
• Seizure
• Muscle weakness
• Crackles
• Dyspnea
• Cardiac manifestations
dependent on type of
hypernatremia 54

55. • Mgt:
– sodium restriction,
– water restriction,
– diuretics,
– isotonic non saline soln. (D5W) or hypotonic soln,
– Desmopressin Acetate for Diabetes Insipidus
Nsg considerations
• History – diet, medication
• Monitor VS, LOC, I and O, weight, lung sounds
• Monitor Na levels
• Oral care
• Initiate gastric feedings slowly
• Seizure precaution
55

56. HYPONATREMIA
• Na < 135 mEq/L
• Etiology:
– diuretics,
– excessive sweating,
– vomiting,
– diarrhea,
– SIADH,
– aldosterone deficiency,
– cardiac, renal, liver disease
56

57. HYPONATREMIA
s/sx: • Dx:
• headache,
• apprehension, – dec serum and urine
• restlessness, sodium and osmolality,
• altered LOC, – dec Cl
• seizures(<115meq/l),
• coma,
• poor skin turgor,
• dry mucosa,
• orthostatic
• hypotension,
• crackles,
• nausea/vomiting,
• abdominal cramping 57

58. • Mgt:
– sodium replacement,
– water restriction,
– isotonic soln for moderate hyponatremia,
– hypertonic saline soln for neurologic manifestations,
– diuretic for SIADH
Nsg. Consideration
Monitor I and O, LOC, VS, serum Na
Seizure precaution
diet
58

59. Hyponatremia
Hypernatremia
59

60. Potassium (K)
• MOST ABUNDANT cation in the ICF
• 3.5-5.5 mEq/L
• Major electrolyte maintaining ICF balance
• maintains ICF Osmolality
• Aldosterone promotes renal excretion of K+
• Mg accompanies K
FUNCTIONS:
1. nerve conduction and muscle contraction
2. metabolism of carbohydrates, fats and proteins
3. Fosters acid-base balance
60

61. 61

62. Potassium
• Electrically excitable tissue such as muscle and
nerves are highly sensitive to slight changes in
extracellular potassium concentration.
• concentration of potassium must be maintained
within a narrow range for tissues to function
normally.
62

63. Potassium
CONDITIONS THAT MAKE K+ BECOME MORE
CONC
– Circulatory system shock resulting from plasma loss
– dehydration
– tissue damage
• In response, aldosterone secretion increases and
causes potassium secretion to increase.
63

64. Regulation of Potassium
- by aldosterone
Aldosterone
K+
⇓
stimulates K+
secretion by the kidneys
⇓
↓ Plasma K+ plasma K+
64

65. Potassium Imbalance
hyperkalemia (> 5.5 mEq/L)
hypokalemia (< 3.5 mEq/L)
65

66. Abnormal Concentration of Potassium
Ions
66

67. HYPERKALEMIA
67

68. a. HYPERKALEMIA
• K+ > 5.0 mEq/L
• Dx:
• Etiology: – inc serum K level
– IVF with K+,
– acidosis, – ECG: peaked T waves and
– hyper-alimentation wide QRS
– excess K+ replacement, – ABGs – metabolic acidosis
– decreased renal excretion,
– Diuretics
• s/sx:
– nerve and muscle irritability
– Tachycardia
– Diarrhea
– ECG changes
– ventricular dysrythmia and
– cardiac arrest
– skeletal muscle weakness, 68
paralysis

69. Mgmt:
K restriction (coffee, cocoa, tea, dried fruits, beans, whole grain breads,
milk, eggs)
diuretics
Polystyrene Sulfonate (Kayexalate)
IV insulin
Beta 2 agonist
IV Calcium gluconate
IV NaHCo3 – alkalinize plasma
Dialysis
Nsg consideration:
Monitor VS, urine output, lung sounds, Crea, BUN
monitor K levels and ECG
observe for muscle weakness and dysrythmia, paresthesia and GI
symptoms
69

70. Abnormal Concentration of Potassium
Ions
70

71. HYPOKALEMIA
71

72. b. HYPOKALEMIA
• s/sx:
• K+ < 3.5 mEq/L – anorexia,
– Nausea/vomiting,
• Etiology: – decreased bowel motility,
– use of diuretic, – fatigue,
– corticosteroids and penicillin, – muscle weakness,
– vomiting and diarrhea, – leg cramps,
– ileostomy, – paresthesias,
– villous adenoma, – shallow respiration,
– alkalosis, – SOB
– hyperinsulinism, – dysrhythmias and increased sensitivity
– to digitalis,
hyperaldosteronism
– hypotension,
– weak pulse,
– dilute urine,
– glucose intolerance
72

73. • Dx:
– dec serum K level
– ECG - flattened , depressed T waves, presence of
“U” waves
– ABGs - metabolic alkalosis
• Medical Mgmt:
– diet ( fruits, fruit juices, vegetables, fish, whole
grains, nuts, milk, meats)
– oral or IV replacement
• Nsg mgmt:
– monitor cardiac function, pulses, renal function
– monitor serum potassium concentration
– IV K diluted in saline
– monitor IV sites for phlebitis
73

74. Normal ECG
Hypokalemia
Hyperkalemia
74

75. CALCIUM (Ca)
 Majority of calcium - bones and teeth
 Normal serum range 8.5-10.5 mg/dL
 Ca++ has an inverse relationship with PO4
FUNCTIONS
1. formation and mineralization of bones/teeth
2. muscular contraction and relaxation
3. cardiac function
4. blood coagulation
5. Promotes absorption and utilization of Vit B12 75

76. Functions of Ca++
- lends strength to the skeleton
- activates muscle contraction
++
Excitation [ Ca ]i Contraction
(Action Potentials) (shortening)
76

77. Functions of Ca++
- lends strength to the skeleton
- activates muscle contraction
- serves as a second messenger for some
hormones and neurotransmitters
77

78. Functions of Ca++
- lends strength to the
skeleton
- activates muscle
contraction
- serves as a second
messenger for some
hormones and
neurotransmitters
- activates exocytosis
of neurotransmitters and
other cellular secretions
78

79. Muscle Contraction
79

80. Functions of Ca++
- lends strength to the skeleton
- activates muscle contraction
- serves as a second messenger for some Ca++
hormones and neurotransmitters
- activates exocytosis of neurotransmitters
and other cellular secretions
- essential factor
in blood clotting.
80

81. Functions of Ca++
- lends strength to the skeleton
- activates muscle contraction
- serves as a second messenger for some
hormones and neurotransmitters
- activates exocytosis of neurotransmitters
and other cellular secretions
- essential factor in blood clotting.
- activates many cellular
enzymes
81

82. Dynamics of Calcium
Ca++
Ca++
Ca++
plasma
Ca++
82

83. Regulation of calcium
1) parathyroid hormone (PTH):
-dissolving Ca++ in bones
-Respond ↓blood Ca++ →↑ PTH production
= ↑ blood Ca++
-- reducing renal excretion of Ca++
PTH increases Vit.
D synthesis in the
kidney which Ca++
increases Ca2+
absorption in the
small intestine.
PTH decreases
urinary Ca2+
excretion and
increases urinary Ca++
phosphate
excretion.
plasma 83

84. 2) calcitonin (secreted by C cells in thyroid
gland):
84

85. 2) calcitonin (secreted by C cells in thyroid gland):
depositing Ca++ in bones
Respond when high Ca++ in the blood
Ca++
Ca++
plasma
85

86. 3) calcitrol (derivative of vitamin D):
- enhancing intestinal absorption of Ca++ from food
Ca++
Ca++
plasma
Ca++
86

87. Calcium imbalances
hypocalcemia (< 4.5 mEq/L)
hypercalcemia (> 5.8 mEq/L).
87

88. Regulation:
• GIT absorbs Ca+ in the intestine with the help of
Vitamin D
• Kidney Ca+ is filtered in the glomerulus and
reabsorbed in the tubules
• PTH increases Ca+ by bone resorption, increase
intestinal and renal Ca+ reabsorption and activation
of Vitamin D
• Calcitonin reduces bone resorption, increase Ca
and Phosphorus deposition in bones and secretion in
urine
88

89. a. HYPERCALCEMIA
• Serum calcium > 10.5 • s/sx:
– anorexia,
mg/dL – Nausea/vomiting,
– polyuria,
• Etiology: – muscle weakness,
– Overuse of calcium – fatigue,
– lethargy
supplements and antacids,
– excessive Vitamin A and D,
• Dx:
– malignancy, – inc serum Ca
– hyperparathyroidism, – ECG:
– prolonged immobilization, • Shortened QT interval, ST
segments
– thiazide diuretic – inc PTH levels
– xrays - osteoporosis
89

90. • Mgmt:
0.9% NaCl
IV Phosphate
Diuretics – Furosemide
IM Calcitonin
corticosteroids
dietary restriction (cheese, ice cream, milk, yogurt, oatmeal,
tofu)
Nsg Mgmt:
Assess VS, apical pulses and ECG, bowel sounds, renal
function, hydration status
safety precautions in unconscious patients
inc mobility
inc fluid intake
90
monitor cardiac rate and rhythm

91. b. HYPOCALCEMIA
• Calcium < 8.5 mg/dL
• s/sx:
• Etiology: – Tetany,
– removal of parathyroid gland – (+) Chovstek’s
during thyroid surgery, – (+) Trousseaus’s,
– Vit. D and Mg deficiency,
– Furosemide, – seizures,
– infusion of citrated blood, – depression,
– inflammation of pancreas, – impaired memory,
– renal failure, – confusion,
– thyroid CA,
– low albumin,
– delirium,
– alkalosis, – hallucinations,
– alcohol abuse, – hypotension,
– osteoporosis (total body Ca – dysrythmia
deficit)
91

92. (+) Chovstek’s Trousseaus Sign
92

93. • Dx:
dec Ca level
ECG: prolonged QT interval
• Mgmt:
Calcium salts
Vit D
diet (milk, cheese, yogurt, green leafy vegetables)
• Nsg mgmt
monitor cardiac status, bleeding
monitor IV sites for phlebitis
seizure precautions
reduce smoking
93

94. Magnesium Mg
• Second to K+ in the ICF
• Normal range is 1.3-2.1 mEq/L
FUNCTIONS
1. intracellular production and utilization of ATP
2. protein and DNA synthesis
3. neuromuscular irritability
4, produce vasodilation of peripheral arteries
94

95. a. HYPERMAGNESEMIA
• M > 2.1 mEq/L
• Etiology: use of Mg antacids, K sparing diuretics,
Renal failure, Mg medications, DKA, adrenocortical
insufficiency
• s/sx: hypotension, nausea, vomiting, flushing,
lethargy, difficulty speaking, drowsiness, dec LOC,
coma, muscle weakness, paralysis, depressed tendon
reflexes, oliguria, ↓RR
95

96. • Mgmt: discontinue Mg supplements
Loop diuretics
IV Ca gluconate
Hemodialysis
Nsg mgmt:
monitor VS
observe DTR’s and changes in LOC
seizure precautions
96

97. b. HYPOMAGNESEMIA
• Mg < 1.5 mEq/l
• Etiology: alcohol w/drawal, tube feedings, diarrhea,
fistula, GIT suctioning, drugs ie antacid, aminoglycosides,
insulin therapy, sepsis, burns, hypothermia
• s/sx: hyperexcitability w/ muscle weakness, tremors,
tetany, seizures, stridor, Chvostek and Trousseau’s signs,
ECG changes, mood changes
97

98. • Dx: serum Mg level
ECG – prolonged PR and QT interval, ST depression,
Widened QRS, flat T waves
low albumin level
• Mgmt:
diet (green leafy vegetables, nuts, legumes, whole
grains, seafood, peanut butter, chocolate)
IV Mg Sulfate via infusion pump
• Nsg Mgmt:
seizure precautions
Test ability to swallow, DTR’s
Monitor I and O, VS during Mg administration 98

99. The Anions
• CHLORIDE
• PHOSPHATES
• BICARBONATES
99

100. Chloride (Cl)
• The MAJOR Anion in the ECF
• Normal range is 95-108 mEq/L
• Inc Na reabsorption causes increased Cl
reabsorption
FUNCTIONS
1. major component of gastric juice aside from H+
2. together with Na+, regulates plasma osmolality
3. participates in the chloride shift – inverse
relationship with Bicarbonate
4. acts as chemical buffer 100

101. Regulation of Cl–
- No direct regulation
- indirectly regulated as an effect of Na+
homeostasis. As sodium is retained or
excreted, Cl– passively follows.
Chloride Imbalance
hyperchloremia (> 105 mEq/L)
hypochloremia (< 95 mEq/L).
101

102. a. HYPERCHLOREMIA
• Serum Cl > 108 mEq/L
• Etiology: sodium excess, loss of bicarbonate ions
• s/sx: tachypnea, weakness, lethargy, deep rapid
respirations, diminished cognitive ability and
hypertension, dysrhytmia, coma
102

103. • Dx: inc serum Cl
dec serum bicarbonate
Mgmt:
Lactated Ringers soln
IV Na Bicarbonate
Diuretics
Nsg mgmt:
monitor VS, ABGs, I and O, neurologic, cardiac and
respiratory changes 103

104. b. HYPOCHLOREMIA
• Cl < 96 mEq/l
• Etiology: Cl deficient formula, salt restricted diets,
severe vomiting and diarrhea
• s/sx: hyperexcitability of muscles, tetany, hyperactive
DTR’s, weakness, twitching, muscle cramps,
dysrhytmias, seizures, coma
104

105. • Dx: dec serum Cl level
ABG’s – metabolic alkalosis
Mgmt:
Normal saline/half strength saline
diet ( tomato juice, salty broth, canned vegetables,
processed meats and fruits
avoid free/bottled water)
Nsg mgmt:
monitor I and O, ABG’s, VS, LOC, muscle strength
and movement 105

106. Phosphates (PO4)
• The MAJOR Anion in the ICF
• Normal range is 2.5-4.5 mg/L
• Reciprocal relationship w/ Ca
• PTH inc bone resorption, inc PO4 absorption from
GIT, inhibit PO4 excretion from kidney
• Calcitonin increases renal excretion of PO4
FUNCTIONS
1. component of bones
2. needed to generate ATP
3. components of DNA and RNA 106

107. Phosphates
- needed for the synthesis of:
ATP, GTP
DNA, RNA
phospholipids
107

108. Regulation of
Phosphate
- by parathyroid hormone
PTH
⇓
PO4---
increases renal excretion
of phosphate
⇓
decrease plasma
phosphate
plasma PO4---
- no real phosphate
imbalances
108

109. a. HYPERPHOSPHATEMIA
• Serum PO4 > 4.5 mg/dL
• Etiology: excess vit D, renal failure, tissue trauma,
chemotherapy, PO4 containing medications,
hypoparathyroidism
• s/sx: tetany, tachycardia, palpitations, anorexia,
vomiting, muscle weakness, hyperreflexia,
tachycardia, soft tissue calcification
109

110. • Dx: inc serum phosphorus level
dec Ca level
xray – skeletal changes
Mgmt:
diet – limit milk, ice cream, cheese, meat, fish, carbonated
beverages, nuts, dried food, sardines
Dialysis
Nsg mgmt:
dietary restrictions
monitor signs of impending hypocalcemia and changes in
urine output
110

111. b. HYPOPHOSPHATEMIA
• Serum PO4 < 2.5 mg/dl
• Etiology: administration of calories in severe CHON-
Calorie malnutrition (iatrogenic), chronic alcoholism,
prolonged hyperventilation, poor dietary intake,
DKA, thermal burns, respiratory alkalosis, antacids
w/c bind with PO4, Vit D deficiency
• s/sx: irritability, fatigue, apprehension, weakness,
hyperglycemia, numbness, paresthesias, confusion,
seizure, coma
111

112. • Dx: dec serum PO4 level
Mgmt:
oral or IV Phosphorus correction
diet (milk, organ meat, nuts, fish, poultry, whole
grains)
Nsg mgmt:
introduce TPN solution gradually
prevent infection
112

113. ACID-BASE BALANCE
113

114. Acid
An acid is any chemical that
releases H+ in solution.
Base
A base is any chemical that accepts H+.
114

115. pH
is the negative logarithm of H+
concentration, and an indicator of acidity.
pH = - log [H+ ]
Example: [H+ ] = 0.1 µM = 10 –7 M
115

116. Normal functions of proteins (especially
enzymes) heavily depend on an optimal pH.
pH7.35-pH7.45
116

117. Regulation of acid-base balance
1) Chemical Buffers
2) Respiratory Control of pH
3) Renal Control of pH
117

118. Buffer
•is any mechanism that resists changes in pH.
•substance that can accept or donate hydrogen
•prevent excessive changes in pH
118

119. Dynamics of Acid Base Balance
• Acids and bases are constantly produced
in the body
• They must be constantly regulated
• CO2 and HCO3 are crucial in the
balance
• Respiratory and renal system are active
in regulation
119

120. Kidney
- Regulate bicarbonate level in ECF
1. RESPIRATORY/METABOLIC ACIDOSIS
- kidney excrete H and reabsorbs/generates
Bicarbonate
2. RESPIRATORY/METABOLIC ALKALOSIS
- kidney retains H ion and excrete Bicarbonate
120

121. Lung
- Control CO2 and Carbonic acid content of ECF
1. METABOLIC ACIDOSIS
- increased RR to eliminate CO2
2. METABOLIC ALKALOSIS
- decreased RR to retain CO2
121

122. Chemical Buffers
There are three major buffers in body fluid.
1) The Bicarbonate (HCO3-) Buffer
2) The Phosphate Buffer
3) The Protein Buffer
122

123. Properties of Chemical Buffers
- respond to pH changes within a fraction
of a second.
- Bind to H+ but can not remove H+ out of
the body
- Limited ability to correct pH changes
123

124. ↓ pH
⇓
stimulate peripheral/central chemoreceptors
⇓
↑ pulmonary ventilation
⇓
removal of CO2 and ↑ pH
H+ + HCO3- H2CO3 H2O + CO2
124

125. Limit to respiratory control of pH
The respiratory regulatory mechanism
cannot remove H+ out of the body. Its
efficiency depends on the availability of
HCO3- .
H+ + HCO3- H2CO3 H2O + CO2
125

126. Renal Control of pH
3. The kidneys can neutralize more acid
or base than both the respiratory
system and chemical buffers.
a. Renal tubules secrete
hydrogen ions into the tubular fluid,
where most of it combines with
bicarbonate, ammonia, and
phosphate buffers.
b. Bound and free H+ are then
excreted in urine.
126

127. • The kidneys are the only organs
that actually expel H+ from the
body. Other buffering systems
only reduce its concentration by
binding it to another chemical.
3. Tubular secretion of H+ continues
as long as a sufficient
concentration gradient exists
between the tubule cells and the
tubular fluid.
127

128. Disorders of Acid-Base Balance
Acidosis: < pH 7.35 , Alkalosis: > pH 7.45
- Mild acidosis
depresses CNS, causing
confusion, disorientation, and coma.
- Mild alkalosis
CNS becomes hyperexcitable.
Nerves fire spontaneously and overstimulate
skeletal muscles.
- Severe acidosis or alkalosis is lethal.
128

129. Respiratory vs Metabolic Cause
Respiratory acidosis / alkalosis
- caused by hypoventilation or hyperventilation
Initial change
H+ + HCO- H2CO3 H2O + CO2
Emphysema
129

130. Respiratory acidosis / alkalosis
- caused by hypoventilation or hyperventilation
Metabolic acidosis or alkalosis
- result from any causes but respiratory problems
Diabetes Chronic vomiting
⇓ ⇓
↑ production of loss of stomach acid
organic acids ⇓
⇓ metabolic alkalosis
metabolic
acidosis
130