1. ACID BASE
BALANCE
Presented by:-
Mr. Suresh Kumar
Sharma
RN, ACCN,
MSN(PSYCHIATRY )

3. ACID BASE HOMEOSTASIS
♥Acid-Base homeostasis
involves chemical and
physiologic processes
responsible for the
maintenance of the
acidity of body fluids at
levels that allow optimal
function of the whole
individual
3

4. ACID BASE HOMEOSTASIS
♥The chemical processes represent
the first line of defense to an acid or
base load and include the extracellular
and intracellular buffers
♥The physiologic processes modulate
acid-base composition by changes in
cellular metabolism and by adaptive
responses in the excretion of volatile
acids by the lungs and fixed acids by
the kidneys
4

5. ACID BASE HOMEOSTASIS
need for Acid-Base regulation
critical importance of the hydrogen
ion (H + ) concentration on the operation
of many cellular enzymes and function
of vital organs, most prominently the
brain and the heart
5

6. ACIDS
6

7. ACIDS
Acids can be defined as a proton (H + )
donor
Hydrogen containing substances which
dissociate in solution to release H +
Click Here
7

8. ACIDS
Acids can be defined as a proton (H + )
donor
Hydrogen containing substances which
dissociate in solution to release H +
Click Here
8

9. ACIDS
Acids can be defined as a proton (H + )
donor
Hydrogen containing substances which
dissociate in solution to release H +
H+
OH
H+
-
OH-
H+
O
H- -
OH
H+
9

10. ACIDS
Many other substance (carbohydrates)
also contain hydrogen but they are not
classified as acids because the
hydrogen is tightly bound within their
molecular structure and it is never
liberated as free H +
H+
OH
H+
-
OH-
H+
O
H- -
OH
H+
10

11. ACIDS
Physiologically important acids include:
Carbonic acid (H 2 CO 3 )
Phosphoric acid (H 3 PO 4 )
Pyruvic acid (C 3 H 4 O 3 )
Lactic acid (C 3 H 6 O 3 )
These acids are dissolved in body fluids
Phosphoric
Lactic
acid
acid
Pyruvic
acid
11

12. BASES
12

13. BASES
Bases can be defined as:
A proton (H + ) acceptor
Molecules capable of accepting a
hydrogen ion (OH - )
Click Here
13

14. BASES
Bases can be defined as:
A proton (H + ) acceptor
Molecules capable of accepting a
hydrogen ion (OH - )
Click Here
14

15. BASES
Bases can be defined as:
A proton (H + ) acceptor
Molecules capable of accepting a
hydrogen ion (OH - )
H+
OH
H+
-
OH-
H+
O
H- -
OH
H+
15

16. BASES
Physiologically important bases include:
Bicarbonate (HCO 3 - )
 Biphosphate (HPO 4 -2 )
Biphosphat
e
16

17. pH SCALE
17

18. pH SCALE
♥pH refers to P otential H ydrogen
♥Expresses hydrogen ion concentration in
water solutions
♥Water ionizes to a limited extent to form equal
amounts of H + ions and OH - ions
♠H 2 O H + + OH -
♦H + ion is an acid
♦OH - ion is a base 18

19. pH SCALE
♥ H + ion is an acid
19

20. pH SCALE
♥ OH - ion is a base
20

21. pH SCALE
H + ion is an acid OH - ion is a base
21

22. pH SCALE
♥Pure water is Neutral
♠ ( H + = OH - ) ACIDS, BASES OR NEUTRAL???
♦ pH = 7 H +
♥Acid OH H
+
-
H OH +
-
H OH H
- +
+
OH H -
♠( H > OH )
H H +
+
+
+ - OH OH - H +
OH H
-
OH H-
+ - +
♦pH < 7
H +
OH H OH OH
+ -
- -
1 H OH 3 +
♥Base
-
H OH +
-
OH
♠( H + < OH - )
-
2
♦ pH > 7
♥Normal blood pH is 7.35 - 7.45
♥pH range compatible with life is 6.8 - 8.0
22

23. pH SCALE
♥pH equals the logarithm (log) to the base
10 of the reciprocal of the hydrogen ion
(H + ) concentration
pH = log 1 / H + concentration
♥ H + concentration in extracellular fluid
(ECF)
4 X 10 -8 (0.00000004)
23

24. pH SCALE
♥Low pH values = high H + concentrations
♠H + concentration in denominator of
formula
pH = log 1 / H + concentration
♥Unit changes in pH represent a tenfold
change in H + concentrations
♠Nature of 10 -8 (0.00000004)
4X
logarithms
24

25. pH SCALE
♥pH = 4 is more acidic than pH = 6
♥pH = 4 has 10 times more free H +
concentration than pH = 5 and 100 times
more free H + concentration than pH = 6
ACIDOSIS NORMAL ALKALOSIS
DEATH DEATH
6.8 7.3 7.4 7.5 8.0
Venou Arteria
s l Blood
Blood 25

26. pH SCALE
26

27. pH SCALE
27

28. ACID BASE HOMEOSTASIS
♥The task imposed on
the mechanisms that
maintain Acid-Base
homeostasis is large
♠Metabolic pathways
are continuously
consuming or
producing H +
♠The daily load of
waste products for
excretion in the form
of volatile and fixed
acids is substantial
28

29. EFFECTS OF pH
♥The most general effect of pH changes
are on enzyme function
♠Also affect excitability of nerve and
muscle cells
p Excitabilit
H y
p Excitabili
29

30. ACID-BASE BALANCE
Aci BASE
d
30

31. ACID-BASE BALANCE
♥Acid - Base balance is primarily
concerned with two ions:
♠Hydrogen (H + )
♠ Bicarbonate (HCO 3 - )
H +
HCO 3 31

32. ACID-BASE BALANCE
♥Derangements of
hydrogen and
bicarbonate
concentrations in
body fluids are
common in
disease
processes
32

33. pH
6.8 7.35 7.45
8.0
Death Acidosis Normal Alkalosis Death
1 part 20 parts
Carbonic acid bicarbonate
(H 2 COз) (HCOз¯)
The normal ration of bicarbonate to carbonic acid is 20:1. As long as
this ratio is maintained, the pH remains within the normal range of

34. ACID-BASE
BALANCE
♥H + ion has
special
significance
because of the
narrow ranges
that it must be
maintained in
order to be
compatible with
living systems
34

35. ACID-BASE BALANCE
♥Primarily
controlled by
regulation of
H + ions in the
No
body fluids
rm
al
♠Especially
extracellular
fluids
35

36. ACID-BASE
REGULATION
36

37. ACID-BASE REGULATION
♥Maintenance of an acceptable pH range
in the extracellular fluids is accomplished
by three mechanisms:
♠1) Chemical Buffers
♦React very rapidly
(less than a second)
♠2) Respiratory Regulation
♦Reacts rapidly (seconds to minutes)
♠3) Renal Regulation
♦Reacts slowly (minutes to hours) 37

38. ACID-BASE REGULATION
♥Respiratory Regulation
♠Carbon dioxide is an important by-product
of metabolism and is constantly produced by
cells
♠The blood carries carbon dioxide to the
lungs where it is exhaled
Cell
CO CO CO
CO CO
Metabolis
2 CO
2
2
2
2
m
2
38

39. ACID-BASE REGULATION
Respiratory Regulation
♠When breathing ,
blood CO2 level
blood becomes more Base
♠ When breathing ,
blood CO2 level
blood becomes more Acidic
♠By adjusting the speed and depth of
breathing, the respiratory control centers
and lungs are able to regulate the blood pH
minute by minute
39

40. ACID-BASE REGULATION
♥Kidney Regulation
♠Excess acid is excreted
by the kidneys, largely in
the form of ammonia
♠The kidneys have some
ability to alter the amount
of acid or base that is
excreted, but this
generally takes several
days
40

41. RESPONSES TO:
ACIDOSIS AND ALKALOSIS
♥Mechanisms protect the body against
life-threatening changes in hydrogen
ion concentration
♠1) Buffering Systems in Body
Fluids
♠2) Respiratory Responses
♠3) Renal Responses
41

42. 1) Buffer Systems
2) Respiratory Responses
3) Renal Responses
42

43. ACID-BASE HOMEOSTASIS
Buffers
Acids =
Acids <
Bases >
Bases
Acids
Bases
Acids
43

44. ACID-BASE REGULATION
♥Chemical Buffers
♠The body uses pH buffers in the blood to
guard against sudden changes in acidity
♠A pH buffer works chemically to minimize
changes in the pH of a solution
Buffe
44

45. BUFFERS
♥Buffering systems provide an immediate
response to fluctuations in pH
♠1) Phosphate
♠2) Protein
♠3) Bicarbonate Buffer System
45

46. BUFFERS
♥A buffer is a combination of chemicals in
solution that resists any significant
change in pH
♥Able to bind or release free H + ions
46

47. BUFFERS
♥Chemical buffers are able to react
immediately (within milliseconds)
♥Chemical buffers are the first line of
defense for the body for fluctuations in pH
47

48. PHOSPHATE BUFFER
SYSTEM
♥1) Phosphate buffer system
Na 2 HPO 4 + H + NaH 2 PO 4 + Na +
♠Most important in the intracellular
system
+Na 2 HPO
H +
4
Click to NaH 2 PO+Na +
animate
4 48

49. PHOSPHATE BUFFER
SYSTEM
Na 2 HPO 4 + H + NaH 2 PO 4 + Na +
♥Alternately switches Na + with H +
Disodium hydrogen
phosphate
+Na 2 HPO
H +
4
Click to NaH 2 PO+Na +
animate
4 49

50. PHOSPHATE BUFFER
SYSTEM
Na 2 HPO 4 + H + NaH 2 PO 4 + Na +
♥Phosphates are more abundant within
the cell and are rivaled as a buffer in the
ICF by even more abundant protein
Na 2 HPO
4 Na 2 HPO
Na 4 HPO
2
50

51. PHOSPHATE BUFFER
SYSTEM
♥Regulates pH within the cells and the
urine
♠Phosphate concentrations are higher
intracellularly and within the kidney
tubules
♠Too low of a
concentration in
extracellular fluid
to have much HPO 4 -
importance as an 2
ECF buffer system
51

52. PROTEIN BUFFER SYSTEM
♥2) Protein Buffer System
♠Behaves as a buffer in both plasma
and cells
♠Hemoglobin is by far the most
important protein buffer
52

53. PROTEIN BUFFER SYSTEM
♥Most important
intracellular buffer
(ICF)
ICF
♥The most plentiful
buffer of the body
53

54. PROTEIN BUFFER SYSTEM
♥Proteins are excellent buffers because
they contain both acid and base groups
that can give up or take up H +
♥Proteins are extremely abundant in the
cell
♥The more limited number of proteins in
the plasma reinforce the bicarbonate
system in the ECF
54

55. PROTEIN BUFFER SYSTEM
♥Hemoglobin buffers H + from
metabolically produced CO 2 in the
plasma only
♥As hemoglobin releases O 2 it gains a
great affinity for H +
O2 O2
H
O2 O2
b
55

56. PROTEIN BUFFER SYSTEM
♥H + generated at the tissue level from the
dissociation of H 2 CO 3 produced by the
addition of CO 2
♥Bound H + to Hb (Hemoglobin) does not
contribute to the acidity of blood
O2 O2
H
O2 O2
b
56

57. PROTEIN BUFFER SYSTEM
♥As H + Hb picks up O 2 from the lungs the
Hb which has a higher affinity for O 2
releases H + and picks up O 2
♥Liberated H + from H 2 O combines with
HCO 3 -
HCO 3 -
O 2
HH 3
2 CO
+ CO 2 (exhaled)
H
O2 O2
b 57

58. PROTEIN BUFFER SYSTEM
♥Venous blood is only slightly more acidic
than arterial blood because of the
tremendous buffering capacity of Hb
♥Even in spite of the large volume of H +
generating CO 2 carried in venous blood
58

59. PROTEIN BUFFER SYSTEM
♥Proteins can act as a buffer for both
acids and bases
♥Protein buffer system works
instantaneously making it the most
powerful in the body
♥75% of the body’s buffer capacity is
controlled by protein
♠Bicarbonate and phosphate buffer
systems require several hours to be
effective
Pr -
added H + + Pr -
59

60. PROTEIN BUFFER SYSTEM
♥Proteins are very large, complex
molecules in comparison to the size and
complexities of acids or bases
♥Proteins are surrounded by a multitude
of negative charges on the outside and
numerous positive charges in the
crevices of the molecule
- - -+ + - + - - - -
- ++ + + -
- - - - ++ + + + -
-- + + +
-
- +
-
- + +++
- + + -
- + + + - -
- - - - - - - 60

61. PROTEIN BUFFER SYSTEM
♥H + ions are attracted to and held from
chemical interaction by the negative
charges
H+ H+ H+ H+ H+ H+ H+
H+
- - -+ - - - -- H+
- + ++
++ + -
- - - - ++ + + + - H+
H+ -- + + +
-
- + - H+
- + +++
- + + -
H+ - + + + - - H+
- - - - - - -
H+ H+
H+ H +
H + H+
H+ 61

62. PROTEIN BUFFER SYSTEM
♥OH - ions which are the basis of alkalosis
are attracted by the positive charges in
the crevices of the protein
OH - OH -
OH -
OH -
OH - - - -+ - - - --
- + ++
++ + -
- - - - ++ + + + - OH -
OH - -- + + +
-
- + -
- + +++
- + + - OH -
- + + + - -
OH - - - - - - - -
OH - OH -
OH - 62

63. PROTEIN BUFFER SYSTEM
H+ H+ H+ H+ H + OH - H + OH -
H+
OH -
H+ OH -
OH - - - -+ - - - -- H+
- + ++
++ + -
- - - - ++ + + + - OH - H +
H
OH+- -- + + +
-
- + - H+
- + +++
- + + - OH -
H+ - + + + - - H+
OH - - - - - - - -
OH - OH - H+
OH - H + H +
H+ H+
H+ H+
63

64. BICARBONATE BUFFER
SYSTEM
♥3) Bicarbonate Buffer System
♠Predominates in extracellular fluid (ECF)
ECF
HCO 3 - + added H +
H 2 CO 3 H 2 CO 3
HCO 3
-
64

65. BICARBONATE BUFFER
SYSTEM
♥This system is most important because
the concentration of both components can
be regulated:
♠Carbonic acid by the respiratory
system
♠Bicarbonate by the renal system
65

66. BICARBONATE BUFFER
SYSTEM
♥H 2 CO 3 H + + HCO 3 -
♠Hydrogen ions generated by metabolism
or by ingestion react with bicarbonate
base to form more carbonic acid
H 2 CO 3HCO
3
-
66

67. BICARBONATE BUFFER
♥ SYSTEM
Equilibrium shifts toward the formation of
acid
♠Hydrogen ions that are lost (vomiting)
causes carbonic acid to dissociate
yielding replacement H + and bicarbonate
H 2 CO 3
H + HCO 3
-
67

68. BICARBONATE BUFFER
SYSTEM
CO + H 2 H 2 CO 3 H + + HCO 3
2 O Addition of lactic
-
acid Exercis
e
Loss of HCl
Vomitin
g
68

69. 1) Buffer Systems
2) Respiratory
Responses
3) Renal Responses
69

70. RESPIRATORY RESPONSE
♥Neurons in the medulla oblongata and
pons constitute the Respiratory
Center
♥Stimulation and limitation of respiratory
rates are controlled by the respiratory
center
♥Control is
accomplished by
responding to CO 2
and H +
concentrations in
the blood 70

71. RESPIRATORY
CENTER
Pons
Respiratory centers
Medulla oblongata
71

72. CHEMOSENSITIVE AREAS
♥Chemosensitive areas of the respiratory
center are able to detect blood
concentration levels of CO 2 and H +
♥Increases in CO 2 and H + stimulate the
respiratory center
♠The effect is to raise
respiration rates
♦But the effect
diminishes in
1 - 2 minutes
CO 2
CO 2 2
Click to increase CO
CO 2
CO 2 2
CO 2 COCO 72
CO 2

73. CHEMOSENSITIVE AREAS
♥The effect of
stimulating the
respiratory centers
by increased CO 2
and H + is weakened
in environmentally
increased CO 2 levels
♥Symptoms may
persist for several
days
73

74. CHEMORECEPTORS
♥Chemoreceptors are also present in
the carotid and aortic arteries which
respond to changes in partial pressures
of O 2 and CO 2 or pH
♥Increased levels of
CO 2 (low pH) or
pH
decreased levels of
O 2 stimulate
respiration rates
to increase
74

75. CHEMORECEPTORS
♥Overall compensatory response is:
♠Hyperventilation in response to
increased CO 2 or H + (low pH)
pH
♠Hypoventilation in response to
decreased CO 2 or H + (high pH)
pH
75

76. RESPIRATORY CONTROL OF pH
cell production of CO 2 increases
CO 2 + H 2 O H 2 CO 3
H 2 CO 3 H + + HCO 3 -
H+ acidosis; pH drops
H + stimulates respiratory center in medulla oblongata
rate and depth of breathing increase
CO 2 eliminated in lungs
pH rises toward normal
76

77. 1) Buffer Systems
2) Respiratory Responses
3) Renal
Responses
77

78. RENAL RESPONSE
♥The kidney compensates for Acid -
Base imbalance within 24 hours and is
responsible for long term control
♥The kidney in response:
♠To Acidosis
♦Retains bicarbonate ions and
eliminates hydrogen ions
♠To Alkalosis
♦Eliminates bicarbonate ions and
retains hydrogen ions
78

79. Contd.
♥Urine ph < blood ph (6 < 7.4)
♥Means H+ ion generated in the
body in normal circumstances &
excreted by acidified urine.
♥PH is regulated by four
mechanism:-
1. Excretion of H+ ion
2. Reabsorption of
bicarbonate(HCO3-)
79

80. RENAL RESPONSE
Kidneys regulate acid-base balance
by excreting either acidic or
alkaline urine H + excretion ,
HCO 3
-
reabsorption and
formation of new
HCO 3 - are closely
linked
Slow response
Infinite
capacity

81. RENAL RESPONSE
♥Excretion of H+ ion:-
BLOOD RENAL TUBULAR CELL TUBULAR
LUMEN
Na+ Na+ Na+
HCO3- HCO3- + H+ H+ + B-
H2C03 HB
CA
CO2 + H20 EXCRETED
81

82. RENAL RESPONSE
♥Reabsorption of bicarbonate:-
BLOOD RENAL TUBULAR CELL TUBULAR
LUMEN
Na+ Na+ Na+
HCO3- HCO3- + H+ H+ + HCO3
H2C03 H2CO3
CA
CA
CO2 + H20 CO2 +
H20 82

83. RENAL RESPONSE
Excretion of titratable acid
BLOOD RENAL TUBULAR CELL TUBULAR
LUMEN
Na+ Na+ Na+
HCO3- HCO3- + H+ H+ + NAHPO4-
PH
7.4
H2C03 NAH2PO4-
CA
PH
CO2 + H20 EXCRETED 4.5
83

84. RENAL RESPONSE
Excretion of ammonium ion(NH4+):-
BLOOD RENAL TUBULAR CELL TUBULAR
GLUTAMINE LUMEN
NH3+
GLUTAMATE NH3+
Na+ Na+ Na+
HCO3- HCO3- + H+ H+ + NH3+
H2C03 NH4
CA
CO2 + H20 EXCRETED
84

85. ACIDIFICATIO
N OF URINE
BY EXCRETION
OF AMMONIA
85

86. ACIDIFICATION OF URINE BY EXCRETION OF
AMMONIA
Capillar Distal Tubule
y Cells
NH 2
NH 3 3
NH H
+
WHAT
HAPPENS
NEXT?
Tubular
urine to be
excreted
86

87. ACIDIFICATION OF URINE BY EXCRETION OF
AMMONIA
Capillar Distal Tubule Notice the
y Cells H + - Na +
NH 3 exchange to
maintain
electrical
neutrality
Dissociation
of carbonic
acid Na + Cl -
NaCl
HCOCO H
H2 3 + +
- +
NaHCO 3
3
NH 3 Cl -
NH 4 Cl
Click Mouse to
Click Mouse to
Start Animation
See Animation Tubular
Again Urine 87

88. ACIDIFICATION OF URINE BY EXCRETION OF
AMMONIA
Capillar Distal Tubule Notice the
y Cells H + - Na +
NH 3 exchange to
maintain
electrical
neutrality
Na + Cl -
NaCl
HCOCO H
H2 3 + +
- +
NaHCO 3
3
NH 3 Cl -
NH 4 Cl
Click Mouse to
Click Mouse to
Start Animation
See Animation Tubular
Again Urine 88

89. RESPIRATORY / EXCRETORY
RESPONSE
CO 2 + H 2 O H 2 CO 3 H + + HCO 3
yperventilation removes Kidneys eliminate or retai
H + ion concentrations H + or bicarbonate ions
ypoventilation increases
H + ion concentrations
89

90. Factor
affecting acid-
base balance
90

91. 1) Buffer Systems
2) Respiratory Responses
3) Renal Responses
91

92. HYPERKALEMIA
♥Hyperkalemia is generally associated
with acidosis
♠Accompanied by a shift of H + ions into
cells and K + ions out of the cell to
maintain electrical neutrality
H +
K +
92

93. HYPERKALEMIA
♥Hyperkalemia is an elevated serum K +
♠H + ions are buffered in cell by proteins
♥Acidosis may cause Hyperkalemia
and Hyperkalemia may cause
Acidosis
H +
K +
93

94. HYPOKALEMIA
♥Hypokalemia is generally associated
with reciprocal exchanges of H + and K + in
the opposite direction
♠Associated with alkalosis
♥ Hypokalemia is a depressed serum K +
H +
K +
94

95. ELECTROLYTE SHIFTS
Acidosis
Compensatory Response Result
H+ - H + buffered intracellularly
K+ - Hyperkalemia
cell
Alkalosis
Compensatory Response Result
H+ - Tendency to correct alkalos
K+ - Hypokalemia
cell
95

96. ACID-BASE REGULATION
♥Enzymes, hormones and ion
distribution are all affected by
Hydrogen ion concentrations
96

97. Acid-Base
Imbalance
Acid Base
97

98. ACIDOSIS /
ALKALOSIS
98

99. ACIDOSIS / ALKALOSIS
♥An abnormality in one or more of the pH
control mechanisms can cause one of
two major disturbances in Acid-Base
balance
♠Acidosis
♠Alkalosis
99

100. ACIDOSIS / ALKALOSIS
♥Acidosis
♠A condition in which the blood has too
much acid (or too little base),
frequently resulting in a decrease in
blood pH
♥Alkalosis
♠A condition in which the blood has too
much base (or too little acid),
occasionally resulting in an increase in
blood pH 100

101. ACIDOSIS / ALKALOSIS
♥Acidosis and alkalosis are not diseases
but rather are the results of a wide
variety of disorders
♥The presence of
acidosis or
alkalosis provides
an important clue
to physicians that
a serious
metabolic
problem exists
101

102. ACIDOSIS / ALKALOSIS
♥pH changes have dramatic effects on
normal cell function
♠1) Changes in excitability of nerve
and muscle cells
♠2) Influences enzyme activity
♠3) Influences K + levels
102

103. CHANGES IN CELL
EXCITABILITY
♥pH decrease (more acidic) depresses
the central nervous system
♠Can lead to loss of consciousness
♥pH increase (more basic) can cause
over-excitability
♠Tingling sensations, nervousness,
muscle twitches
103

104. INFLUENCES ON ENZYME
ACTIVITY
♥pH increases or decreases can alter the
shape of the enzyme rendering it non-
functional
♥Changes in enzyme structure can result
in accelerated or depressed metabolic
actions within the cell
104

105. INFLUENCES ON K + LEVELS
♥When reabsorbing Na + from the filtrate
of the renal tubules K + or H + is secreted
(exchanged)
♥ Normally K + is
secreted in much
greater amounts
than H +
K+ Na +
H+
K+
105

106. INFLUENCES ON K + LEVELS
♥If H + concentrations are high (acidosis)
than H + is secreted in greater amounts
♥This leaves less K + than usual excreted
♥ The resultant K + retention can affect
cardiac function and other systems
K+ Na +
H+
106

107. ACIDOSIS
♥A relative increase in hydrogen ions
results in acidosis
H +
OH -
107

108. ALKALOSIS
♥A relative increase in bicarbonate
results in alkalosis
H +
OH -
108

109. ACIDOSIS / ALKALOSIS
♥Acidosis
H +
OH -
♥Alkalosis
H +
OH -
109

110. ACIDOSIS / ALKALOSIS
BASE ACID
♥Normal ratio of HCO 3 - to H 2 CO 3 is 20:1
♠ H 2 CO 3 is source of H + ions in the body
♥Deviations from this ratio are used to identify
Acid-Base imbalances
H +
H 2 CO
HCO 3 110

111. ACIDOSIS / ALKALOSIS
♥Acidosis and Alkalosis can arise in two
fundamentally different ways:
♠1) Excess or deficit of CO 2
( Volatile Acid )
♦Volatile Acid can be eliminated by
the respiratory system
♠2) Excess or deficit of Fixed Acid
♦Fixed Acids cannot be
eliminated by the
respiratory system
111

112. ACIDOSIS / ALKALOSIS
♥Normal values of bicarbonate
(arterial)
♠pH = 7.4
♠PCO 2 = 40 mm Hg
♠ HCO 3 - = 24 meq/L
112

113. ACIDOSIS
♥A decrease in a normal 20:1 base to
acid ratio
♠An increase in the number of
hydrogen ions
(ex: ratio of 20:2 translated to 10:1)
♠A decrease in the number of
bicarbonate ions (ex: ratio of 10:1)
♥Caused by too much acid or too little base
ACI BAS
113

114. ALKALOSIS
♥An increase in the normal 20:1 base to
acid ratio
♠A decrease in the number of
hydrogen ions
(ex: ratio of 20:0.5 translated to 40:1)
♠An increase in the number of
bicarbonate ions (ex: ratio of 40:1)
♥Caused by base excess or acid deficit
ACI BAS
114

115. SOURCES OF
HYDROGEN IONS
H H H H H H
C C C C C C
H H H H H H
115

116. SOURCES OF HYDROGEN
IONS (CO )
♥1) Cell Metabolism 2
♥2) Food Products
♥3) Medications
♥4) Metabolic Intermediate by-
products
♥5) Some Disease processes
116

117. SOURCES OF HYDROGEN
IONS
♥1) Cellular Metabolism of
carbohydrates release CO 2 as a waste
product
♠Aerobic respiration
C 6 H 12 O 6  CO 2 + H 2 O + Energy
117

118. SOURCES OF HYDROGEN
IONS
♥ CO diffuses into the bloodstream where
2
the reaction:
CO 2 + H 2 O H 2 CO 3
H + + HCO 3 -
♥This process occurs in red blood cells
♠H 2 CO 3 (carbonic acid)
♠Acids produced as a result of the
presence of CO 2 is
referred to as a
Volatile acid
118

119. SOURCES OF HYDROGEN
IONS
♥Dissociation of H 2 CO 3 results in the
production of free H + and HCO 3 -
♥The respiratory system removes CO 2
thus freeing HCO 3 - to recombine with H +
♥Accumulation or deficit of CO 2 in blood
leads to respective H + accumulations or
deficits CO 2 H+ p
H
CO 2 H+ p
H 119

120. CARBON DIOXIDE DIFFUSION
Systemic
Red Blood Cell
Plasma Circulation
Cl -
carbonic (Chloride
anhydrase
Shift)
CO 2 + H 2 O H + +HCO 3-
HCO 3 -
CO 2 diffuses into plasma and into RBC
CO 2 Within RBC, the hydration of CO 2 is
catalyzed by carbonic anhydrase
Bicarbonate thus formed diffuses into
plasma Tissues
CO 2
120

121. CARBON DIOXIDE DIFFUSION
Systemic Circulation
Red Blood Cell
Plasma
carbonic
anhydrase
Cl -
+ H + + HCO 3 -
H + is buffered by
Hemoglobin Hb
H 2O
Click for
Carbon
Dioxide
diffusion
CO 2 CO 2 CO 2 CO TissuesCO 2 CO 2 CO 2 CO 2
2 121

122. SOURCES OF HYDROGEN
IONS
♥2) Food products
♠Sauerkraut
♠Yogurt
♠Citric acid in fruits
122

123. SOURCES OF HYDROGEN
IONS
♥3) Medications
♠May stimulate
HCl production
by parietal cells
of the stomach
123

124. SOURCES OF HYDROGEN
IONS
♥4) Metabolic
Intermediate
by-products
♠Lactic acid
♠Pyruvic acid
♠Acetoacetic acid
♠Fatty acids
C 6 H 12 O 6 2 124

125. SOURCES OF HYDROGEN
IONS
♥Inorganic acids can also be produced
during breakdown of nutrients
♠Proteins (meat products)
♦Breakdown leads to
productions of sulfuric
acid and phosphoric acid
♠Fruits and Vegetables
♦Breakdown produces
bases which can help
to equalize acid
production
125

126. SOURCES OF HYDROGEN
IONS
♥5) Some disease processes
♠Ex: diabetes causes improper
metabolism of fats which results
in the generation of a waste
product called a Keto Acid
126

127. SOURCES OF
BICARBONATE IONS
127

128. SOURCES OF BICARBONATE
IONS
♥1) CO 2 diffusion into red blood
cells
♥2) Parietal cell
secretion of the
gastric mucosa
128

129. 1) CO 2 DIFFUSION
♥ Hemoglobin buffers H +
♥Chloride shift insures electrical
neutrality
Red Blood Cl - Cl -
H+ Cell
Cl -
H+ + Hb
+H
H H+ Cl -
H+ Cl -
H+ + Cl -
H Cl -
Cl - 129

130. CARBON DIOXIDE DIFFUSION
Red Blood Cell Systemic Circulation
Plasma
Cl -
carbonic (Chloride
anhydrase Shift)
CO 2 + H 2 O H + + HCO 3 -
HCO 3 -
CO 2 diffuses into the plasma and into
the RBC
CO 2 Within the RBC, the hydration of CO 2 is
catalyzed by carbonic anhydrase
CO 2
Tissues 130

131. BICARBONATE DIFFUSION
Red Blood Cell Pulmonary Circulation
Plasma
Cl -
HCO 3 -
CO 2 + H 2 O H + + HCO 3 -
CO 2 Bicarbonate diffuses back into RBC in
pulmonary capillaries and reacts with
hydrogen ions to form carbonic acid
The acid breaks down to CO 2 and water
Alveolus
131

132. BICARBONATE DIFFUSION
Red Blood Cell Pulmonary Circulation
Plasma
Cl -
CO 2+ H 2 O + HCO 3 -
CO 2 H+
Alveolus
132

133. 2) PARIETAL CELL
SECRETION
♥Secrete hydrogen ions into the lumen of
the stomach
Bloo Parieta Lumen
♥Bicarbonate d l Cells
CO 2 +
of
Stomac
ions diffuse into h
the bloodstream H 2O
Cl
HCl-
to maintain H+
electrical
neutrality in the HCO 3
parietal cell -
Click to see
ion movement
133

134. PANCREATIC CELL
SECRETION
♥In pancreatic cells the direction of ion
movement is reversed
Bloo Pancreatic Pancreati
♥H + ions are d Cells c
duct
secreted into
the blood and
bicarbonate
ions diffuse into H+
pancreatic juice HCO 3
HCO 3 -
-
Click to see
ion movement
134

135. PARIETAL CELL SECRETION
♥If the two processes are balanced, there
is no net change in the amount of
bicarbonate in blood
♠Loss of gastric or pancreatic juice
can change that balance
HCO 3 HCO 3
- -
HCO 3 HCO 3
- -
HCO 3 HCO 3
135

136. BICARBONATE SECRETION
Parietal cells of
gastric mucosa
♥Cells of the gastric
mucosa secrete H +
H+ ions into the lumen
lumen of of the stomach in
stomach exchange for the
HCO 3 - diffusion of
blood
bicarbonate ions
into blood
Pancreatic
epithelial cells
♥The direction of the
HCO 3 - diffusion of these
pancreatic ions is reversed in
juice pancreatic epithelial
H+
blood cells
136

137. ACIDOSIS /
ALKALOSIS
137

138. ACIDOSIS / ALKALOSIS
♥Deviations from normal Acid-Base
status are divided into four general
categories, depending on the source
and direction of the abnormal change in
H + concentrations
♠Respiratory Acidosis
♠Respiratory Alkalosis
♠Metabolic Acidosis
♠Metabolic Alkalosis
138

139. ACIDOSIS / ALKALOSIS
♥Acidosis and Alkalosis are categorized
as Metabolic or Respiratory
depending on their primary cause
♠Metabolic Acidosis and Metabolic
Alkalosis
♦caused by an imbalance in the
production and excretion of acids or
bases by the kidneys
♠Respiratory Acidosis and
Respiratory Alkalosis
♦caused primarily by lung or
breathing disorders 139

140. ACIDOSIS
♥A pH of 7.4 corresponds to a 20:1 ratio of
HCO 3 - and H 2 CO 3
♠ Concentration of HCO 3 - is 24 meq/liter
and H 2 CO 3 is 1.2 meq/liter
Bicarbonat Bicarbonat Bicarbonat
7.
e Bicarbonat eBicarbonat Bicarbonat
e
e e
Bicarbonat Bicarbonat e
eBicarbonat Bicarbonat Carbonic
e
e
Bicarbonat e Bicarbonat Acid Bicarbonat
e
e Bicarbonat Bicarbonat e
Bicarbonat
e Bicarbonat e Bicarbonat e Bicarbonat
e
Bicarbonat e 140

141. ACIDOSIS
♥Acidosis is a decrease in pH below
7.35
♠Which means a relative increase of
H + ions
♠pH may fall as low as 7.0 without
irreversible damage but any fall less
than 7.0 is usually fatal
H +
= p
141

142. ACIDOSIS
♥May be caused by:
♠An increase in H 2 CO 3
♠A decrease in HCO 3 -
♥Both lead to a decrease in the ratio of
20:1
H 2 CO HCO 3 -
142

143. ACIDOSIS
H+
♥1) Respiratory Acidosis
H+
♥2) Metabolic Acidosis H + H+
H+
+
H
H + H H +
+ + H+
H H+
H+ H
+ H+ H+
+ H
+
H+ H H
+
H + H+
H + H+
H+ H+ H+
H+ H+ H+ H+
143

144. ALKALOSIS
♥1) Respiratory alkalosis H +
♥2) Metabolic alkalosis+
H
H+ H+
H+
H+ H+
H+ H+ H+
H+ H+
H + H+
H+ H+ 144

145. RESPIRATORY
ACIDOSIS
145

146. RESPIRATORY ACIDOSIS
♥Caused by hyperkapnia due to
hypoventilation
♠Characterized by a pH decrease
and an increase in CO 2
p
CO 2 H CO 2
CO 2 CO 2
CO CO 2
2 CO 2
COCO 2
2 CO 2 CO 2
p CO 2
CO 2
H
146

147. HYPOVENTILATION
♥Hypo = “Under”
Elimination of
CO 2
H +
pH 147

148. RESPIRATORY ACIDOSIS
♥Hyperkapnia is defined as an
accumulation of carbon dioxide in
extracellular fluids
p
CO 2 H CO 2
CO 2 CO 2
CO CO 2
2 CO 2
COCO 2
2 CO 2 CO 2
p CO 2
CO 2
H
148

149. RESPIRATORY ACIDOSIS
♥Hyperkapnia is the underlying cause of
Respiratory Acidosis
♠Usually the result of decreased CO 2
removal from the lungs
p
CO 2 H CO 2
CO 2 CO 2
CO CO 2
2 CO 2
COCO 2
2 CO 2 CO 2
p CO 2
CO 2
H
149

150. RESPIRATORY ACIDOSIS
♥The speed and depth of breathing control the
amount of CO 2 in the blood
♥Normally when CO 2 builds up, the pH of the
blood falls and the blood becomes acidic
♥High levels of CO 2 in the blood stimulate the
parts of the brain that regulate breathing,
which in turn stimulate faster and deeper
breathing
150

151. CAUSES
♥Respiratory acidosis
develops when the
lungs don't expel CO 2
adequately
♥This can happen in
diseases that severely
affect the lungs, such
as emphysema, chronic
bronchitis, severe
pneumonia, pulmonary
edema, and asthma
151

152. CAUSES
♥Respiratory acidosis can also develop when
diseases of the nerves or muscles of the chest
impair the mechanics of breathing
♥In addition, a person can develop respiratory
acidosis if overly sedated from narcotics and
strong sleeping medications that slow
respiration
152

153. RESPIRATORY ACIDOSIS
♥ Decreased CO 2 removal
can be the result of:
1) Obstruction of air
passages
2) Decreased
respiration
(depression of
respiratory
centers)
3) Decreased gas
exchange between
pulmonary
153

154. RESPIRATORY ACIDOSIS
♥1) Obstruction of air passages
♠Vomit, anaphylaxis, tracheal cancer
154

155. RESPIRATORY ACIDOSIS
♥2) Decreased Respiration
♠Shallow, slow breathing
♠Depression of the respiratory centers in the
brain which control breathing rates
♦Drug overdose
155

156. RESPIRATORY ACIDOSIS
♥3) Decreased
gas exchange
between
pulmonary
capillaries and
air sacs of
lungs
♠Emphysema
♠Bronchitis
♠Pulmonary
edema
156

157. RESPIRATORY ACIDOSIS
♥4) Collapse of lung
♠Compression injury, open thoracic
wound
Left lung
collapsed
157

158. Respiratory Acidosis
pH
6.8 7.35 7.45
8.0
Death Acidosis Normal Alkalosis Death
2 part
Carbonic acid
(H 2 COз)
20 parts
bicarbonate
(HCOз¯)

159. MANISFESTATIONS OF
RESPIRATORY ACIDOSIS
♥ Acute Respiratory Acidosis
♠ Headache, feeling of fullness in the head
♠ Warm flushed skin, diaphoresis
♠ Blurred vision
♠ Irritability, altered mental status--cloudiness,confusion,
disoriented
♠ Decreasing level of consciousness, lethargy, restless,
apprehensive
♠ Cardiac arrest, dysrhythmias, tachycardia, hypotension
♥ Chronic Respiratory Acidosis
♠ Weakness
♠ Dull headache
♠ Sleep disturbances with daytime sleepiness
♠ Impaired memory, Personality changes
♠ Bounding pulse with rapid shallow breathing
♥ Cyanosis--late sign

160. MANAGEMENT OF
RESPIRATORY ACIDOSIS
♥Goal focuses on improving ventilation and ↓
PaCO2
♥Pulmonary Hygiene – CPT, coughing, deep
breathing, repositioning—semi-fowler’s,
suctioning, hyperventilating pt. before and
after treatments
♥Pursed-lip breathing (for chronic resp.
acidosis)
♥Monitor resp. rate; may use mechanical
ventilation
♥IVF for hydration & PO fluids--up to 3000ml/24
hours
♥Medications

161. RESPIRATORY ACIDOSIS
♥The treatment of respiratory acidosis
aims to improve the function of the lungs
♥Drugs to improve breathing may help
people who have lung diseases such as
asthma and emphysema
161

162. RESPIRATORY ACIDOSIS
-metabolic balance before onset
of acidosis
-pH = 7.4
-respiratory acidosis
-pH = 7.1
-breathing is suppressed holding
CO 2 in body
-body’s compensation
-kidneys conserve HCO 3 - ions to
restore the normal 40:2 ratio
-kidneys eliminate H + ion in acidic
urine
- therapy required to restore
metabolic balance
40
- lactate solution used in therapy
is converted to bicarbonate ions in
the liver 162

163. RESPIRATORY ACIDOSIS
H2CO3 : Carbonic Acid
HCO3- : Bicarbonate Ion
H 2 CO HCO 3
3
-
(Na+) HCO3-
(K+) HCO3-
1 : 20 (Mg++) HCO3-
(Ca++) HCO3-
- metabolic balance before onset of acidosis
- pH = 7.4
163

164. RESPIRATORY ACIDOSIS
CO CO
2
HCO 3
2
CO
CO
- 2
CO
2
H2
3
2 : 20
-breathing is suppressed holding CO2 in body
-pH = 7.1
164

165. RESPIRATORY ACIDOSIS
H 2 CO
3
HCO 3
HCO 3 - HCO
H 2C O - -
3 +
3
H+
2 : 30
acidic
BODY’S COMPENSATION urine
-kidneys conserve HCO3- ions to restore the
normal 40:2 ratio (20:1)
-kidneys eliminate H+ ion in acidic urine 165

166. RESPIRATORY ACIDOSIS
Lactate
H 2 CO HCO 3 LIVE
-
R
Lactat
3
e
HCO 3
-
2 : 40
- therapy required to restore metabolic balance
- lactate solution used in therapy is converted to
bicarbonate ions in the liver 166

167. RESPIRATORY
ALKALOSIS
167

168. RESPIRATORY ALKALOSIS
♥Normal 20:1 ratio is increased
♠pH of blood is above 7.4
H2 C
H 2 CO O HCO 3
HCO
= 7.4
=
3 -
3 - 3
0. 1 : 20
5
168

169. RESPIRATORY ALKALOSIS
♥Cause is Hyperventilation
♠Leads to eliminating excessive
amounts of CO 2
♠Increased loss of CO 2 from the lungs
at a rate faster than it is produced
♠Decrease in H +
CO CO
CO CO CO CO CO
CO CO 2 CO
2
2 CO 2
2
CO
2 2
2 2
2
2 2
169

170. HYPERVENTILATION
♥Hyper = “Over”
Elimination of
CO 2
H +
pH 170

171. Respiratory Alkalosis
pH
6.8 7.35 7.45
8.0
Death Acidosis Normal Alkalosis Death
20 parts
bicarbonate
(HCOз¯)
0.6 part
Carbonic acid
(H 2 COз)

172. CAUSES
♥Can be the result of:
♠1) Anxiety, emotional
disturbances
♠2) Respiratory center
lesions
♠3) Fever
♠4) Salicylate poisoning
(overdose)
♠5) Assisted respiration
♠6) High altitude (low
P O 2)
172

173. CAUSES
♥Anxiety is an emotional
disturbance
♥The most common
cause of
hyperventilation, and
thus respiratory
alkalosis, is anxiety
173

174. CAUSES
♥Respiratory center
lesions
♠Damage to brain
centers responsible
for monitoring
breathing rates
♦Tumors
♦Strokes
174

175. CAUSES
♥Fever
♠Rapid shallow
breathing blows off
too much CO 2
175

176. CAUSES
♥Salicylate poisoning
(Aspirin overdose)
♠Ventilation is
stimulated without
regard to the status of
O 2 , CO 2 or H + in the
body fluids
176

177. CAUSES
♥Assisted Respiration
♠Administration of CO 2 in the exhaled
air of the care - giver Your insurance won’t
cover a ventilator any
longer, so Bob here
will be giving you
mouth to mouth for the
next several days
177

178. CAUSES
♥High Altitude
♠Low concentrations of O 2 in the arterial
blood reflexly stimulates ventilation in an
attempt to obtain more O 2
♠Too much CO 2 is “blown off” in the
process
178

179. RESPIRATORY ALKALOSIS
♥Kidneys compensate by:
♠Retaining hydrogen ions
♠Increasing bicarbonate
excretion
HCO 3 -
HCO 3 -
H +
H+
HCO 3 HCO -
-
H+ 3
H H+
+
HCO 3 -
HCO 3 - H
+
H + HCO 3
-
HCO 3 - H+
HCO 3 -
H +
HCO - H
+
3
H+
179

180. RESPIRATORY ALKALOSIS
♥Decreased CO 2 in the lungs will
eventually slow the rate of breathing
♠Will permit a normal amount of
CO 2 to be retained in the lung
180

181. RESPIRATORY ALKALOSIS
♥Usually the only treatment needed is to
slow down the rate of breathing
♥Breathing into a paper bag or holding
the breath as long as possible may help
raise the blood CO 2 content as the
person breathes carbon dioxide
back in after breathing it out
181

182. MANIFESTATIONS OF
RESPIRATORY
ALKALOSIS
♥Dizziness, lightheadedness
♥Numbness and tingling (mouth, hands &
feet)
♥Palpitations, tachycardia
♥Deep rapid breathing with dyspnea
♥*Cardiac dysrhythmias, chest tightness
♥Anxious, panic, restlessness
♥Tremors, muscle weakness
♥Seizures, loss of consciousness
♥Diaphoresis
♥Inability to concentrate

183. MANAGEMENT OF
RESPIRATORY
ALKALOSIS
♥Identify cause, then treat
♠If Anxiety, teach slow deep breathing or
breathing into paper bag, sedative may be
needed
♠If Pain, administer pain meds.
♠If needs emotionally upset, provide support
♥Safety measures
♥Seizure precautions
♥Administer oxygen if cause is acute

184. RESPIRATORY ALKALOSIS
-metabolic balance before
onset of alkalosis
-pH = 7.4
-respiratory alkalosis
-pH = 7.7
- hyperactive breathing “ blows
off ” CO 2
- body’s compensation
- kidneys conserve H + ions and
eliminate HCO 3 - in alkaline urine
- therapy required to restore
metabolic balance
- HCO 3 - ions replaced by Cl - ions
184

185. RESPIRATORY ALKALOSIS
H2CO3 : Carbonic Acid
HCO3- : Bicarbonate Ion
H 2 CO HCO 3
3
-
(Na+) HCO3-
(K+) HCO3-
1 : 20 (Mg++) HCO3-
(Ca++) HCO3-
-metabolic balance before onset of alkalosis
-pH = 7.4
185

186. RESPIRATORY ALKALOSIS
CO 2
CO 2 + H 2 O H2 C
O
3 HCO
- 3
0.5 : 20
-respiratory alkalosis
-pH = 7.7
-hyperactive breathing “ blows off ” CO 2
186

187. RESPIRATORY ALKALOSIS
HCO 3 -
H2 C O
HCO
3
3 -
0.5 : 15
Alkaline
BODY’S COMPENSATION Urine
- kidneys conserve H+ ions and eliminate HCO3- in
alkaline urine 187

188. RESPIRATORY ALKALOSIS
H 2 CO
3
HCO 3
-
Cl
-
Chloride
containin
0.5 : 10 g solution
- therapy required to restore metabolic balance
- HCO3- ions replaced by Cl- ions 188

189. RESPIRATORY
ACIDOSIS / ALKALOSIS
CO 2 + H 2 O H 2 CO 3 H+ +
HCO 3 -
Respiratory
Acidosis
Respiratory
Alkalosis
189

190. METABOLIC
ACIDOSIS
190

191. METABOLIC ACIDOSIS
♥Occurs when there is a decrease in the
normal 20:1 ratio
♠Decrease in blood pH and
bicarbonate level
♥Excessive H + or decreased HCO 3 -
H 2 CO CO 3
HHCO 3
O
H32C
= 7.4
= 7.4
--
3
1 : 10
20 191

192. METABOLIC ACIDOSIS
♥Any acid-base
imbalance not
attributable to CO 2 is
classified as
metabolic
♠Metabolic
production of
Acids
♠Or loss of Bases
192

193. METABOLIC ACIDOSIS
♥If an increase in acid overwhelms the
body's pH buffering system, the blood can
become acidic
♥As the blood pH drops,
breathing becomes
deeper and faster as the
body attempts to rid the
blood of excess acid by
decreasing the amount
of carbon dioxide
193

194. METABOLIC ACIDOSIS
♥Eventually, the kidneys
also try to compensate
by excreting more acid
in the urine
♥However, both
mechanisms can be
overwhelmed if the
body continues to
produce too much acid,
leading to severe
acidosis and eventually
a coma
194

195. METABOLIC ACIDOSIS
♥Metabolic acidosis is always
characterized by a reduction in plasma
HCO 3 - while CO 2 remains normal
Plasma
Levels
HCO 3
-
CO 2
195

196. METABOLIC ACIDOSIS
♥Acidosis results from excessive loss of
HCO 3 - rich fluids from the body or from an
accumulation of acids
♠Accumulation of non-carbonic plasma
acids uses HCO 3 - as a buffer for the
additional H + thus reducing HCO 3 - levels
Muscle
Cell
tic
d
196

197. METABOLIC ACIDOSIS-
causes
♥The of metabolic acidosis can be
grouped into five major categories
♠1) Ingesting an acid or a substance
that is metabolized to acid
♠2) Abnormal Metabolism
♠3) Kidney Insufficiencies
♠4) Strenuous Exercise
♠5) Severe Diarrhea
197

198. METABOLIC ACIDOSIS
♥1) Ingesting An Acid
♠Most substances that cause acidosis
when ingested are considered poisonous
♠Examples include
wood alcohol
(methanol) and
antifreeze
(ethylene glycol)
♠However, even an overdose
of aspirin (acetylsalicylic acid)
can cause metabolic acidosis
198

199. METABOLIC ACIDOSIS
♥2) Abnormal Metabolism
♠The body can produce excess acid as
a result of several diseases
♦One of the most significant is Type I
Diabetes Mellitus
199

200. METABOLIC ACIDOSIS
♥Unregulated
diabetes mellitus
causes
ketoacidosis
♠Body metabolizes
fat rather than
glucose
♠Accumulations of
metabolic acids
(Keto Acids)
cause an increase
in plasma H +
200

201. METABOLIC ACIDOSIS
♥This leads to excessive production of
ketones:
♠Acetone
♠Acetoacetic acid
♠B-hydroxybutyric acid
♥Contribute excessive numbers of
hydrogen ions to body fluids
Acetone
H + H+
Acetoacetic
H+ H+ H+
acid
Hydroxybutyric
H
acid+ + 201

202. METABOLIC ACIDOSIS
♥2) Abnormal Metabolism
♠The body also produces excess acid
in the advanced stages of shock, when
lactic acid is formed through the
metabolism of sugar
202

203. METABOLIC ACIDOSIS
♥3) Kidney
Insufficiencies
♠Even the production
of normal amounts of
acid may lead to
acidosis when the
kidneys aren't
functioning normally
203

204. METABOLIC ACIDOSIS
♥3) Kidney
Insufficiencies
♠Kidneys may be unable
to rid the plasma of even
the normal amounts of H +
generated from
metabolic acids
♠Kidneys may be also
unable to conserve an
adequate amount of
HCO 3 - to buffer the
normal acid load 204

205. METABOLIC ACIDOSIS
♥3) Kidney Insufficiencies
♠This type of kidney malfunction is
called renal tubular acidosis or
uremic acidosis and may occur in
people with kidney failure or with
abnormalities that affect the kidneys'
ability to excrete acid
205

206. METABOLIC ACIDOSIS
♥4) Strenuous Exercise
♠Muscles resort to anaerobic
glycolysis during strenuous exercise
♠Anaerobic respiration leads to the
production of large amounts of lactic
acid
Enzymes
C 6 H 12 O 6 2C 3 H 6 O 3 + ATP
(energy) Lactic
Acid
206

207. METABOLIC ACIDOSIS
♥5) Severe Diarrhea
♠ Fluids rich in HCO 3 - are released and
reabsorbed during the digestive process
♠ During diarrhea this HCO 3 - is lost from
the body rather than reabsorbed
207

208. METABOLIC ACIDOSIS
♥5) Severe Diarrhea
♠ The loss of HCO 3 - without a
corresponding loss of H+ lowers the pH
♠ Less HCO 3 - is available for buffering H +
♠Prolonged deep (from duodenum)
vomiting can result in the same situation
208

209. MANIFESTATIONS OF
METABOLIC ACIDOSIS
♥ Anorexia
♥ Nausea and vomiting
♥ Abdominal pain
♥ Weakness, fatigue, general malaise
♥ ↓ levels of consciousness, confusion, drowsiness &
lethargy
♥ Dysrhythmias with hyperkalemia
♥ Bradycardia, decreased BP and cardiac output
♥ Warm, flushed skin, peripheral vasodilation
♥ ↑ RR and depth (Kussmaul) (FIRST CLUE)
♥ Dull Headache
♥ Hyperreflexia and ↓ muscle tone
♥ Shock

210. MANAGEMENT OF
METABOLIC ACIDOSIS
♥Identify cause and treat (as with DKA)
♥Administer HCO3¯
♥Dialysis (hemodialysis or peritoneal)
♥Monitor I&O and electrolyte balance
♥Daily weights
♥Assess skin color and temperature; VS
♥Assess for dysrhythmias
♥Fluid replacement
♥Safety measures

211. METABOLIC ACIDOSIS
♥Treating the underlying cause of metabolic
acidosis is the usual course of action
♠For example, they may control diabetes
with insulin or treat poisoning by
removing the toxic substance
from the blood
♠Occasionally
dialysis is needed
to treat severe
overdoses and
poisonings
211

212. METABOLIC ACIDOSIS
♥Metabolic acidosis may
also be treated directly
♠If the acidosis is mild,
intravenous fluids and
treatment for the
underlying disorder may
be all that's needed
212

213. METABOLIC ACIDOSIS
♥When acidosis is severe,
bicarbonate may be given
intravenously
♠Bicarbonate provides
only temporary relief
and may cause harm
213

214. METABOLIC ACIDOSIS
- metabolic balance before
onset of acidosis
- pH 7.4
- metabolic acidosis
- pH 7.1
- HCO 3 - decreases because of
excess presence of ketones,
chloride or organic ions
- body’s compensation
- hyperactive breathing to “
blow off ” CO 2
- kidneys conserve HCO 3 - and
eliminate H + ions in acidic urine
- therapy required to restore
metabolic balance
- lactate solution used in therapy
0.5 10 is
converted to bicarbonate ions 214

215. METABOLIC ACIDOSIS
H2CO3 : Carbonic Acid
HCO3- : Bicarbonate Ion
H 2 CO HCO 3
3
-
(Na+) HCO3-
(K+) HCO3-
1 : 20 (Mg++) HCO3-
(Ca++) HCO3-
-metabolic balance before onset of
acidosis
-pH 7.4 215

216. METABOLIC ACIDOSIS
HCO 3
O
H 2C
= 7.4
-
3
1 : 10
-HCO 3 - decreases because of excess
presence of ketones, chloride or organic
ions
216

217. METABOLIC ACIDOSIS
CO 2 HCO 3 - +
H+
HCO 3 -
HCO 3
O +
H 2C -
CO 2 + H+
H 2O 3
0.75 : 10
Acidic
BODY’S urine
COMPENSATION
- hyperactive breathing to “ blow off ”
CO 2
- kidneys conserve HCO 3 - and eliminate
H + ions in acidic urine 217

218. METABOLIC ACIDOSIS
H 2 CO HCO 3 Lactat
3
- e
Lactate
containin
g solution
0.5 : 10
- therapy required to restore metabolic
balance
- lactate solution used in therapy is
converted to bicarbonate ions in the 218

219. METABOLIC
ALKALOSIS
219

220. METABOLIC ALKALOSIS
♥Elevation of pH due to an increased
20:1 ratio
♠May be caused by:
♦An increase of
bicarbonate(HCO3-)
♦A decrease in hydrogen ions(H+)
♠Imbalance again cannot be due to
CO 2
respiratory origin 7.4
♠Increase in pH which has a non-
220

221. Metabolic Alkalosis
pH
6.8 7.35 7.45
8.0
Death Acidosis Normal Alkalosis Death
26 parts
bicarbonate
(HCOз¯)
1 part
Carbonic acid
(H 2 COз)

222. METABOLIC ALKALOSIS
♥A reduction in H + in the case of
metabolic alkalosis can be caused by a
deficiency of non-carbonic acids
♥This is associated with an increase in
HCO 3 -
222

223. METABOLIC ALKALOSIS
♥Can be the result of:
♠1) Ingestion of Alkaline
Substances
♠2) Vomiting ( loss of HCl )
223

224. METABOLIC ALKALOSIS
♥1) Ingestion of Alkaline
Substances
♠Influx of NaHCO 3
224

225. METABOLIC ALKALOSIS
♥Baking soda (NaHCO 3 ) often used as a
remedy for gastric hyperacidity
♠NaHCO 3 dissociates to Na + and
HCO 3 -
225

226. METABOLIC ALKALOSIS
♥Bicarbonate neutralizes high
acidity in stomach (heart burn)
♥The extra bicarbonate is
absorbed into the plasma
increasing pH of plasma as
bicarbonate binds with free H +
226

227. METABOLIC ALKALOSIS
♥Commercially prepared alkaline
products for gastric hyperacidity are not
absorbed from the digestive tract and do
not alter the pH status of the plasma
227

228. METABOLIC ALKALOSIS
♥2) Vomiting (abnormal loss of
HCl)
♠Excessive loss of H +
228

229. METABOLIC ALKALOSIS
♥Gastric juices contain large amounts of
HCl
♥During HCl secretion, bicarbonate is
added to the plasma
K+ H+
HC
l HCO 3
-
Cl - Click to
View Animation
229

230. METABOLIC ALKALOSIS
♥The bicarbonate is neutralized as HCl is
reabsorbed by the plasma from the
digestive tract
K+
HC
H Cl+ -
l
H 2 CO
HCO 3 - Click to
View Animation
3
230

231. METABOLIC ALKALOSIS
♥During vomiting H + is lost as HCl and the
bicarbonate is not neutralized in the plasma
♠Loss of HCl increases the plasma
bicarbonate and thus results in an increase
in pH of the blood
K+
HC
l Bicarbonate not
neutralized
HCO 3 - Click to
View Animation
231

232. METABOLIC ALKALOSIS
♥Reaction of the body to alkalosis is to
lower pH by:
♠Retain CO 2 by decreasing breathing
rate
♠Kidneys increase the retention of H +
H+
H+
CO H+
CO 2 H+
2
232

233. MANIFESTATIONS OF
METABOLIC ALKALOSIS
♥Confusion and apathy, ↓ levels of
consciousness
♥Hyperreflexia
♥Dysrythmias
♥Hypotension/dizziness and hypoxemia
♥Seizures
♥Respiratory failure, slow shallow respirations
♥Tingling of fingers and toes
♥Cyanosis
♥Anorexia, nausea and vomiting
♥Weakness
♥Muscle twitching

234. MANAGEMENT OF
METABOLIC ALKALOSIS
♥Restoring normal fluid volume
♥Potassium supplement if hypokalemic
♥Monitor VS, esp. RR
♥Monitor I&O and electrolyte imbalances
♥Assess for S&S hypokalemia (muscle
weakness, dec. peristalsis, dysrhythmias,
dizziness)
♥Safety measures
♥Irrigate NG tubes with NS instead of tap
water
♥Stop NG suction, if possible
♥Seizure precautions
♥Patient teaching regarding use of

235. METABOLIC ALKALOSIS
♥Treatment of metabolic alkalosis is most
often accomplished by replacing water
and electrolytes (sodium and
potassium) while treating the
potassium
underlying cause
♥Occasionally when metabolic alkalosis
is very severe, dilute acid in the form of
ammonium chloride is given by IV
235

236. METABOLIC ALKALOSIS
- metabolic balance before onset
of alkalosis
- pH = 7.4
- metabolic alkalosis
- pH = 7.7
- HCO 3 - increases because of
loss of chloride ions or excess
ingestion of NaHCO 3
- body’s compensation
- breathing suppressed to hold
CO 2
- kidneys conserve H + ions and
eliminate HCO 3 - in alkaline urine
- therapy required to restore
metabolic balance
1.2 25 - HCO 3 - ions replaced by Cl - ions
5
236

237. METABOLIC ALKALOSIS
H2CO3 : Carbonic Acid
HCO3- : Bicarbonate Ion
H 2 CO HCO 3
3
-
(Na+) HCO3-
(K+) HCO3-
1 : 20 (Mg++) HCO3-
(Ca++) HCO3-
- metabolic balance before onset of
alkalosis
- pH = 7.4 237

238. METABOLIC ALKALOSIS
H2 C HCO
O 3
-
3
1 : 40
- pH = 7.7
- HCO 3 - increases because of loss of
chloride ions or excess ingestion of 238

239. METABOLIC ALKALOSIS
HCO 3 - +
H+
H+
H2 C O H C O3
- +
CO 2 + 3
HCO 3 -
H 2O
1.25 : 30
BODY’S Alkaline
COMPENSATION urine
- breathing suppressed to hold CO 2
- kidneys conserve H + ions and
eliminate HCO 3 - in alkaline urine 239

240. METABOLIC ALKALOSIS
H 2 CO HCO 3
-
Cl -
3
Chloride
containin
g solution
1.25 : 25
- Therapy required to restore metabolic
balanceions replaced by Cl - ions
- HCO 3 - 240

241. ACIDOSIS
decreased failure of metabolic production absorption of prolonged
removal of kidneys to acid of keto acids metabolic acids diarrhea
CO 2 from excrete from GI tract
lungs acids
accumulation accumulation excessive loss
of CO 2 in blood of acid in blood of NaHCO 3
from blood
deep
vomiting
from
respiratory metabolic GI tract
increase in
acidosis plasma H + acidosis
concentrati kidney
on disease
(uremia)
depression of
nervous system
241

242. ALKALOSIS
anxiety overdose high prolonged ingestion of excess
of certain altitudes vomiting excessive aldosterone
drugs alkaline drugs
hyperventilati loss of acid accumulation
on of base
loss of CO 2
and
H 2 CO 2 from
blood
respiratory metabolic
alkalosis alkalosis
decrease
in plasma
H+
concentrati
on
overexcitability
of nervous
system
242

243. ACID – BASE DISORDERS
Acid-Base
Clinical State
Disorder
Pulmonary Embolus Respiratory Alkalosis
Cirrhosis Respiratory Alkalosis
Pregnancy Respiratory Alkalosis
Diuretic Use Metabolic Alkalosis
Vomiting Metabolic Alkalosis
Chronic Obstructive Pulmonary Disease Respiratory Acidosis
Shock Metabolic Acidosis
Severe Diarrhea Metabolic Acidosis
Renal Failure Metabolic Acidosis
Respiratory Alkalosis,
Sepsis (Bloodstream Infection)
Metabolic Acidosis
243

244. APPLICATIO
N IN
NURSING
244

245. How to
determine
whether it is
acidosis or
alkalosis ?????
?????????????
??? 245

246. INTERPRETING ABGs
STEPS:
1. Check the pH to determine whether it is
acidosis or alkalosis.
2. Check the PaCO2 to determine if the problem
is respiratory.
3. Check the HCO3 ¯ . This provides information
about the metabolic aspect of acid base
disorders.
4. Check the PaO2 and the SaO2 . Normals for
PaO2 is 80-100 and SaO2 is 95 - 100%.
5. Determine whether compensated or
uncompensated

247. SUMMARY
♥When evaluating ABGs with a pH in the normal
range, use 7.40 as the cutoff:
♠< 7.40 is acidosis; > 7.40 is alkalosis
♥Use same idea with CO2:
♠< 40 is alkalosis; > 40 is acidosis

248. NORMAL VALUES OF
ABGs
♥pH 7.35 – 7.45
♥PaCO2 35 – 45
♥HCO3¯ 22 – 26
♥PaO2 80 – 100
♥SaO2 95 – 100%
♥BE/BD -2 – +2
Normal pH is slightly alkaline at 7.35 – 7.45

249. Partial Pressure of CO2
PaCO2
♥Reflects the concentration of CO2 in
arterial blood
♥Indicates effectiveness of
ventilation
♥normal range—35-45
♥PaCO2 < 35 = alkalosis
♥PaCO2 > 45 = acidosis

250. BICARBONATE (HCO 3 ¯ )
♥Normal range is 22 - 26
♥HCO3¯ < 22 = acidosis
♥HCO3¯ > 26 = alkalosis

251. CASE STUDY #1
♥Robert Miller is a 70-year-old diabetic who has
a long history of not taking his insulin. He has
just been admitted to your unit and you receive
the following ABG results; pH 7.26, PaCO2 42,
HCO3¯ 17. Plot these numbers on the grid.
Acid Normal Alkaline
pH PaCO2
HCO3¯
Disorder: Metabolic acidosis

252. CASE STUDY #2
♥A 50 year old female is brought to the EC
following an auto accident. She sustained no
injuries, but is extremely upset and anxious.
She has been breathing rapidly since the
accident and now feels faint. Her ABG results
are: pH 7.49, PaCO2 30, HCO3¯ 23. Plot on
the grid.
Acid Normal Alkaline
HCO3¯ pH
PaCO2
Disorder: Respiratory Alkalosis

253. Case Study #3
♥A 64-year-old patient who has a long history
of COPD. He presents today with a slight
fever and complains of dyspnea and
coughing up green-colored sputum. His
ABG results are: pH 7.26, PaCO2 52, and
HCO3¯ 34. Plot on the grid.
Acid Normal Alkalosis
pH HCO3¯
PaCO2
Disorder: Respiratory acidosis

254. Nursing responsibility in
maintaining acid-base
balance
Assessment
♥Identify the risk factor
♥ Identify client present health status-
1.Body weight:-
 sudden lost or gain?
2.Skin & mucus membrane:-
Tempt, turger, edema & moistness
3. Cv & respiratory system:-
♠RR, PULSE & BP
♠REGULAR
254

255. Contd…
4. GI system
♠N, V & D. IF YES how long?
♠Food & fluids?
5.Urinary system:-
♠Output & gravity?
6.Musculoskeletal system:-
♠Muscle tone & symmetry?
7.Neurological system:-
LOC & Alert?
255

256. Nursing management
Nsg diagnosis:-
1. Actual or high risk for fluid
volume deficit
2. fluid volume excess
3. high risk for impaired skin
integrity
4. Impaired oral mucus membrane
5. Altered peripheral tissue
perfusion
6. Decreased cardiac output
256

257. Actual or high risk for fluid
volume deficit R/T excessive
diarrhoea
Intervention:-
Iv line
Ant diarrhoeal medicine
Comfort measure- lip balm, mouth wash,
perineal hygiene
Keep skin & mucus membrane intact
Prevents irritation & skin breakdown
257

258. fluid volume excess
Intervention:-
♥NBM
♥Reduced Na intake
♥Diuretics
♥Administered supplements
♥Nurse initiates the such measure or
reducing anxiety, improving pulmonary
function, controlling the loss of GI
content
258

259. Anxiety R/T different type of
disease condition of acid-
base
♥intervention:-
♠For client with respiratory alkalosis
resulting from anxiety
♠Measure to reduce anxiety
♠Instruct the client to breath in
paperbag
♠Repeated counselling
259

260. Impaired gas exchange R/T
etiological factor
Intervention:-
♥Safety measure
♥Positioning to maintain patent airway
♥Monitor I/O
♥O2 & MEDICATION
♥Monitor vitals
♥Monitor ABG’S values
260

261. Health education
♥Inform about general risk factor
♥Prefer ORT when client experience diarrhoea
♥Teach client with chronic health alteration
♥Instruct about Recognition of acid base
imbalance
♥Teach clients & care giver fluid dietary &
medicine
♥Renal failure need to understand amount &
type of fluid
♥Safety measure for positioning to mobilize
oedema, skin care
♥Teach about complication of IV therapy 261

262. .
262

263. NOW TIME
FOR
ASSIGNMENT
263

264. Case 1
Young female admitted with overdose of
unknown tablets
pO2 90% on air
pH 7.24 H+ 58 nmol/l
PaCO2 41
HCO3 8 mmol/l
BE: -10mmol/l
Na+ 135 K+ 5, Cl - 103,
lactate 1.1
What differential diagnosis would you
consider?

265. Case 1
♥Metabolic acidosis with respiratory
compensation
♥Anion gap is high suggesting added
acid…TCA
♥DKA, lactic acidosis or other poisoning
could be considered

266. Case 2
Elderly male admitted from nursing home
with one week history of fever and
vomiting
PaO2 92%
pH 7.49
PaCO2 38
HCO3 35mmol/l
BE: 7mmol/l
Na+ 135 K+ 2.8 Cl - 88
lactate 2.1

267. Case 2
♥ The patient is dehydrated due to the vomiting
♥ This patient’s PaO2 should be greater than 12kPa
♥Metabolic alkalosis with respiratory
compensation has occurred due to loss of gastric
acid
♥ Note that the patient is profoundly hypokalaemic and
this must be corrected as rehydration occurs
♥ The patient had pyloric outlet obstruction secondary
to chronic duodenal ulcer… now increasingly rare
due to PPI prescription

268. Case 3
Middle aged man admitted with cough
sputum and haemoptysis. Life-long
smoker
paO2 85
pH 7.19 H+ 65
PaCO2 52
HCO3 26mmol/l
BE: -6mmol/l
Na+ 145 K+ 3.8 Cl - 108
lactate 3.1

269. Case 3
♥Acute respiratory acidosis with
dehydration
♥Treatment?
♥Acute respiratory acidosis due to
respiratory failure
♠no time for metabolic compensation
♥The patient should receive a higher FiO2
♥Consider NIV

270. Case 4
Middle aged man post cardiac arrest.
Breathing spontaneously on ET tube
pO2 70
pH 6.9
H+ 126 nmol/l
PaCO2 53
HCO3 23 mmol/l
BE: -11mmol/l
Na 135 K 5.0 Chloride 99, lactate 6

271. Case 4
♥Oxygenation: Not an issue
♥respiratory acidosis
♥Very sick… ICU ventilated
♥Mixed metabolic and respiratory acidosis
following cardiac arrest
♥Patient needs to remain ventilated
despite the good PaO2, to optimise acid-
base balance before extubation
♥Anion gap 28…..added acid…lactic
acidosis

272. Case 5
Young diabetic male admitted with chest
infection, vomiting and drowsiness
pO2 95
pH 7.31 H+ 49
PaCO2 40
HCO3 6.0mmol/l
BE: -7mmol/l
Na 132 K 4.2 chloride 101 lactate 5.2

273. Case 5
♥Acute metabolic acidosis
♥DKA most likely
♥Consider
♠overdose
♠lactic acidosis due to sepsis
♥Anion gap 29

274. END
ACID - BASE
BALANCE
274