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Acid base balance by suresh aadi8888

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Acid base balance by suresh aadi8888

  1. 1. ACID BASEBALANCEPresented by:- Mr. Suresh Kumar Sharma RN, ACCN,MSN(PSYCHIATRY )
  2. 2. 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
  3. 3. 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
  4. 4. 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
  5. 5. ACIDS 6
  6. 6. ACIDS Acids can be defined as a proton (H + ) donor Hydrogen containing substances which dissociate in solution to release H +Click Here 7
  7. 7. ACIDS Acids can be defined as a proton (H + ) donor Hydrogen containing substances which dissociate in solution to release H +Click Here 8
  8. 8. 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
  9. 9. 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
  10. 10. 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
  11. 11. BASES 12
  12. 12. BASES Bases can be defined as: A proton (H + ) acceptor Molecules capable of accepting a hydrogen ion (OH - )Click Here 13
  13. 13. BASES Bases can be defined as: A proton (H + ) acceptor Molecules capable of accepting a hydrogen ion (OH - )Click Here 14
  14. 14. 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
  15. 15. BASESPhysiologically important bases include: Bicarbonate (HCO 3 - )  Biphosphate (HPO 4 -2 ) Biphosphat e 16
  16. 16. pH SCALE 17
  17. 17. 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
  18. 18. pH SCALE♥ H + ion is an acid 19
  19. 19. pH SCALE♥ OH - ion is a base 20
  20. 20. pH SCALEH + ion is an acid OH - ion is a base 21
  21. 21. 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
  22. 22. 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
  23. 23. 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
  24. 24. 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 ALKALOSISDEATH DEATH 6.8 7.3 7.4 7.5 8.0 Venou Arteria s l Blood Blood 25
  25. 25. pH SCALE 26
  26. 26. pH SCALE 27
  27. 27. 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
  28. 28. 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
  29. 29. ACID-BASE BALANCEAci BASEd 30
  30. 30. ACID-BASE BALANCE♥Acid - Base balance is primarily concerned with two ions: ♠Hydrogen (H + ) ♠ Bicarbonate (HCO 3 - )H + HCO 3 31
  31. 31. ACID-BASE BALANCE♥Derangements of hydrogen and bicarbonate concentrations in body fluids are common in disease processes 32
  32. 32. pH 6.8 7.35 7.45 8.0 Death Acidosis Normal Alkalosis Death 1 part 20 partsCarbonic 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
  33. 33. 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
  34. 34. ACID-BASE BALANCE♥Primarily controlled by regulation of H + ions in the No body fluids rm al ♠Especially extracellular fluids 35
  35. 35. ACID-BASEREGULATION 36
  36. 36. 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
  37. 37. 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
  38. 38. 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
  39. 39. 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
  40. 40. 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
  41. 41. 1) Buffer Systems 2) Respiratory Responses 3) Renal Responses 42
  42. 42. ACID-BASE HOMEOSTASIS Buffers Acids = Acids < Bases > Bases Acids Bases Acids 43
  43. 43. 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
  44. 44. BUFFERS♥Buffering systems provide an immediate response to fluctuations in pH ♠1) Phosphate ♠2) Protein ♠3) Bicarbonate Buffer System 45
  45. 45. 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
  46. 46. 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
  47. 47. PHOSPHATE BUFFER SYSTEM♥1) Phosphate buffer systemNa 2 HPO 4 + H + NaH 2 PO 4 + Na + ♠Most important in the intracellular system +Na 2 HPO H + 4Click to NaH 2 PO+Na +animate 4 48
  48. 48. PHOSPHATE BUFFER SYSTEMNa 2 HPO 4 + H + NaH 2 PO 4 + Na +♥Alternately switches Na + with H + Disodium hydrogen phosphate +Na 2 HPO H + 4Click to NaH 2 PO+Na +animate 4 49
  49. 49. PHOSPHATE BUFFER SYSTEMNa 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
  50. 50. 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
  51. 51. 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
  52. 52. PROTEIN BUFFER SYSTEM♥Most important intracellular buffer (ICF) ICF♥The most plentiful buffer of the body 53
  53. 53. 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
  54. 54. 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
  55. 55. 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
  56. 56. 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
  57. 57. 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
  58. 58. 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
  59. 59. 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
  60. 60. 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
  61. 61. 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
  62. 62. PROTEIN BUFFER SYSTEM H+ H+ H+ H+ H + OH - H + OH - H+ OH - H+ OH -OH - - - -+ - - - -- H+ - + ++ ++ + - - - - - ++ + + + - OH - H + HOH+- -- + + + - - + - H+ - + +++ - + + - OH - H+ - + + + - - H+ OH - - - - - - - - OH - OH - H+ OH - H + H + H+ H+ H+ H+ 63
  63. 63. 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
  64. 64. 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
  65. 65. 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
  66. 66. 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
  67. 67. BICARBONATE BUFFER SYSTEMCO + H 2 H 2 CO 3 H + + HCO 32 O Addition of lactic - acid Exercis e Loss of HClVomiting 68
  68. 68. 1) Buffer Systems2) Respiratory Responses3) Renal Responses 69
  69. 69. 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
  70. 70. RESPIRATORY CENTER PonsRespiratory centersMedulla oblongata 71
  71. 71. 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 2Click to increase CO CO 2 CO 2 2 CO 2 COCO 72 CO 2
  72. 72. 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
  73. 73. 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
  74. 74. 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
  75. 75. 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 dropsH + stimulates respiratory center in medulla oblongata rate and depth of breathing increase CO 2 eliminated in lungs pH rises toward normal 76
  76. 76. 1) Buffer Systems2) Respiratory Responses 3) Renal Responses 77
  77. 77. 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
  78. 78. 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+ ion2. Reabsorption of bicarbonate(HCO3-) 79
  79. 79. RENAL RESPONSEKidneys 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
  80. 80. 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
  81. 81. 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
  82. 82. RENAL RESPONSEExcretion 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
  83. 83. RENAL RESPONSEExcretion 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
  84. 84. ACIDIFICATIO N OF URINEBY EXCRETION OF AMMONIA 85
  85. 85. ACIDIFICATION OF URINE BY EXCRETION OF AMMONIA Capillar Distal Tubule y CellsNH 2 NH 3 3 NH H + WHAT HAPPENS NEXT? Tubular urine to be excreted 86
  86. 86. ACIDIFICATION OF URINE BY EXCRETION OF AMMONIACapillar Distal Tubule Notice they 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
  87. 87. ACIDIFICATION OF URINE BY EXCRETION OF AMMONIACapillar Distal Tubule Notice they 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
  88. 88. RESPIRATORY / EXCRETORY RESPONSECO 2 + H 2 O H 2 CO 3 H + + HCO 3yperventilation removes Kidneys eliminate or retai H + ion concentrations H + or bicarbonate ionsypoventilation increases H + ion concentrations 89
  89. 89. Factoraffecting acid- base balance 90
  90. 90. 1) Buffer Systems2) Respiratory Responses 3) Renal Responses 91
  91. 91. 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
  92. 92. 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
  93. 93. 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
  94. 94. ELECTROLYTE SHIFTS AcidosisCompensatory Response Result H+ - H + buffered intracellularly K+ - Hyperkalemia cell AlkalosisCompensatory Response Result H+ - Tendency to correct alkalos K+ - Hypokalemia cell 95
  95. 95. ACID-BASE REGULATION♥Enzymes, hormones and ion distribution are all affected by Hydrogen ion concentrations 96
  96. 96. Acid-BaseImbalanceAcid Base 97
  97. 97. ACIDOSIS /ALKALOSIS 98
  98. 98. 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
  99. 99. 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
  100. 100. 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
  101. 101. 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
  102. 102. 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
  103. 103. 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
  104. 104. 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
  105. 105. 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 systemsK+ Na +H+ 106
  106. 106. ACIDOSIS♥A relative increase in hydrogen ions results in acidosis H + OH - 107
  107. 107. ALKALOSIS♥A relative increase in bicarbonate results in alkalosis H + OH - 108
  108. 108. ACIDOSIS / ALKALOSIS♥Acidosis H + OH -♥Alkalosis H + OH - 109
  109. 109. 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
  110. 110. 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
  111. 111. ACIDOSIS / ALKALOSIS♥Normal values of bicarbonate (arterial) ♠pH = 7.4 ♠PCO 2 = 40 mm Hg ♠ HCO 3 - = 24 meq/L 112
  112. 112. 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
  113. 113. 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
  114. 114. SOURCES OF HYDROGEN IONSH H H H H H C C C C C CH H H H H H 115
  115. 115. SOURCES OF HYDROGEN IONS (CO )♥1) Cell Metabolism 2♥2) Food Products♥3) Medications♥4) Metabolic Intermediate by- products♥5) Some Disease processes 116
  116. 116. 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
  117. 117. 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
  118. 118. 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
  119. 119. CARBON DIOXIDE DIFFUSION Systemic Red Blood CellPlasma 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
  120. 120. 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 diffusionCO 2 CO 2 CO 2 CO TissuesCO 2 CO 2 CO 2 CO 2 2 121
  121. 121. SOURCES OF HYDROGEN IONS♥2) Food products ♠Sauerkraut ♠Yogurt ♠Citric acid in fruits 122
  122. 122. SOURCES OF HYDROGEN IONS♥3) Medications ♠May stimulate HCl production by parietal cells of the stomach 123
  123. 123. SOURCES OF HYDROGEN IONS♥4) Metabolic Intermediate by-products ♠Lactic acid ♠Pyruvic acid ♠Acetoacetic acid ♠Fatty acidsC 6 H 12 O 6 2 124
  124. 124. 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
  125. 125. 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
  126. 126. SOURCES OFBICARBONATE IONS 127
  127. 127. SOURCES OF BICARBONATE IONS♥1) CO 2 diffusion into red blood cells♥2) Parietal cell secretion of the gastric mucosa 128
  128. 128. 1) CO 2 DIFFUSION ♥ Hemoglobin buffers H + ♥Chloride shift insures electrical neutrality Red Blood Cl - Cl - H+ Cell Cl -H+ + Hb +HH H+ Cl -H+ Cl -H+ + Cl - H Cl - Cl - 129
  129. 129. CARBON DIOXIDE DIFFUSION Red Blood Cell Systemic CirculationPlasma Cl - carbonic (Chloride anhydrase Shift) CO 2 + H 2 O H + + HCO 3 - HCO 3 - CO 2 diffuses into the plasma and into the RBCCO 2 Within the RBC, the hydration of CO 2 is catalyzed by carbonic anhydrase CO 2 Tissues 130
  130. 130. BICARBONATE DIFFUSION Red Blood Cell Pulmonary CirculationPlasma 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
  131. 131. BICARBONATE DIFFUSION Red Blood Cell Pulmonary CirculationPlasma Cl - CO 2+ H 2 O + HCO 3 -CO 2 H+ Alveolus 132
  132. 132. 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
  133. 133. 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
  134. 134. 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
  135. 135. 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 ofblood 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
  136. 136. ACIDOSIS /ALKALOSIS 137
  137. 137. 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
  138. 138. 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
  139. 139. 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 eBicarbonat e Bicarbonat Acid Bicarbonat ee Bicarbonat Bicarbonat e Bicarbonat e Bicarbonat e Bicarbonat e Bicarbonat e Bicarbonat e 140
  140. 140. 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
  141. 141. 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 20:1H 2 CO HCO 3 - 142
  142. 142. ACIDOSIS H+♥1) Respiratory Acidosis H+♥2) Metabolic Acidosis H + H+ H+ + HH + 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
  143. 143. ALKALOSIS♥1) Respiratory alkalosis H +♥2) Metabolic alkalosis+ H H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ H + H+ H+ H+ 144
  144. 144. RESPIRATORY ACIDOSIS 145
  145. 145. 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
  146. 146. HYPOVENTILATION♥Hypo = “Under” Elimination of CO 2 H + pH 147
  147. 147. 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
  148. 148. 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
  149. 149. 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
  150. 150. CAUSES♥Respiratory acidosis develops when the lungs dont 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
  151. 151. 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
  152. 152. 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
  153. 153. RESPIRATORY ACIDOSIS♥1) Obstruction of air passages ♠Vomit, anaphylaxis, tracheal cancer 154
  154. 154. RESPIRATORY ACIDOSIS♥2) Decreased Respiration ♠Shallow, slow breathing ♠Depression of the respiratory centers in the brain which control breathing rates ♦Drug overdose 155
  155. 155. RESPIRATORY ACIDOSIS♥3) Decreased gas exchange between pulmonary capillaries and air sacs of lungs ♠Emphysema ♠Bronchitis ♠Pulmonary edema 156
  156. 156. RESPIRATORY ACIDOSIS♥4) Collapse of lung ♠Compression injury, open thoracic wound Left lung collapsed 157
  157. 157. Respiratory Acidosis pH 6.8 7.35 7.45 8.0Death Acidosis Normal Alkalosis Death 2 partCarbonic acid (H 2 COз) 20 parts bicarbonate (HCOз¯)
  158. 158. 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
  159. 159. 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
  160. 160. 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
  161. 161. 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
  162. 162. 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
  163. 163. RESPIRATORY ACIDOSIS CO CO 2 HCO 3 2 CO CO - 2 CO 2H2 3 2 : 20-breathing is suppressed holding CO2 in body-pH = 7.1 164
  164. 164. RESPIRATORY ACIDOSIS H 2 CO 3 HCO 3 HCO 3 - HCO H 2C O - - 3 + 3 H+ 2 : 30 acidicBODY’S COMPENSATION urine-kidneys conserve HCO3- ions to restore thenormal 40:2 ratio (20:1)-kidneys eliminate H+ ion in acidic urine 165
  165. 165. 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 tobicarbonate ions in the liver 166
  166. 166. RESPIRATORY ALKALOSIS 167
  167. 167. RESPIRATORY ALKALOSIS♥Normal 20:1 ratio is increased ♠pH of blood is above 7.4 H2 CH 2 CO O HCO 3 HCO = 7.4 = 3 -3 - 30. 1 : 205 168
  168. 168. 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
  169. 169. HYPERVENTILATION♥Hyper = “Over” Elimination of CO 2 H + pH 170
  170. 170. Respiratory Alkalosis pH 6.8 7.35 7.45 8.0Death Acidosis Normal Alkalosis Death 20 parts bicarbonate (HCOз¯) 0.6 partCarbonic acid (H 2 COз)
  171. 171. 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
  172. 172. CAUSES♥Anxiety is an emotional disturbance♥The most common cause of hyperventilation, and thus respiratory alkalosis, is anxiety 173
  173. 173. CAUSES♥Respiratory center lesions ♠Damage to brain centers responsible for monitoring breathing rates ♦Tumors ♦Strokes 174
  174. 174. CAUSES♥Fever ♠Rapid shallow breathing blows off too much CO 2 175
  175. 175. 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
  176. 176. 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
  177. 177. 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
  178. 178. 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
  179. 179. 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
  180. 180. 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
  181. 181. 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
  182. 182. 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
  183. 183. 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
  184. 184. 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
  185. 185. 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
  186. 186. RESPIRATORY ALKALOSIS HCO 3 - H2 C O HCO 3 3 -0.5 : 15 AlkalineBODY’S COMPENSATION Urine- kidneys conserve H+ ions and eliminate HCO3- inalkaline urine 187
  187. 187. 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
  188. 188. RESPIRATORY ACIDOSIS / ALKALOSISCO 2 + H 2 O H 2 CO 3 H+ + HCO 3 - Respiratory Acidosis Respiratory Alkalosis 189
  189. 189. METABOLIC ACIDOSIS 190
  190. 190. 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 OH32C = 7.4 = 7.4 --3 1 : 10 20 191
  191. 191. METABOLIC ACIDOSIS♥Any acid-base imbalance not attributable to CO 2 is classified as metabolic ♠Metabolic production of Acids ♠Or loss of Bases 192
  192. 192. METABOLIC ACIDOSIS♥If an increase in acid overwhelms the bodys 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
  193. 193. 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
  194. 194. 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
  195. 195. 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 Cellticd 196
  196. 196. 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
  197. 197. 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
  198. 198. 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
  199. 199. 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
  200. 200. METABOLIC ACIDOSIS♥This leads to excessive production of ketones: ♠Acetone ♠Acetoacetic acid ♠B-hydroxybutyric acid♥Contribute excessive numbers of hydrogen ions to body fluidsAcetone H + H+ Acetoacetic H+ H+ H+ acidHydroxybutyric Hacid+ + 201
  201. 201. 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
  202. 202. METABOLIC ACIDOSIS♥3) Kidney Insufficiencies ♠Even the production of normal amounts of acid may lead to acidosis when the kidneys arent functioning normally 203
  203. 203. 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
  204. 204. 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
  205. 205. 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 EnzymesC 6 H 12 O 6 2C 3 H 6 O 3 + ATP(energy) Lactic Acid 206
  206. 206. 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
  207. 207. 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
  208. 208. 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
  209. 209. 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
  210. 210. 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
  211. 211. 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 thats needed 212
  212. 212. METABOLIC ACIDOSIS♥When acidosis is severe, bicarbonate may be given intravenously ♠Bicarbonate provides only temporary relief and may cause harm 213
  213. 213. 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 therapy0.5 10 is converted to bicarbonate ions 214
  214. 214. 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 ofacidosis-pH 7.4 215
  215. 215. METABOLIC ACIDOSIS HCO 3 OH 2C = 7.4 -3 1 : 10 -HCO 3 - decreases because of excess presence of ketones, chloride or organic ions 216
  216. 216. 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
  217. 217. METABOLIC ACIDOSIS H 2 CO HCO 3 Lactat 3 - e Lactate containin g solution 0.5 : 10- therapy required to restore metabolicbalance- lactate solution used in therapy isconverted to bicarbonate ions in the 218
  218. 218. METABOLICALKALOSIS 219
  219. 219. 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
  220. 220. Metabolic Alkalosis pH 6.8 7.35 7.45 8.0Death Acidosis Normal Alkalosis Death 26 parts bicarbonate (HCOз¯) 1 partCarbonic acid (H 2 COз)
  221. 221. 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
  222. 222. METABOLIC ALKALOSIS♥Can be the result of: ♠1) Ingestion of Alkaline Substances ♠2) Vomiting ( loss of HCl ) 223
  223. 223. METABOLIC ALKALOSIS♥1) Ingestion of Alkaline Substances ♠Influx of NaHCO 3 224
  224. 224. METABOLIC ALKALOSIS♥Baking soda (NaHCO 3 ) often used as a remedy for gastric hyperacidity ♠NaHCO 3 dissociates to Na + and HCO 3 - 225
  225. 225. 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
  226. 226. 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
  227. 227. METABOLIC ALKALOSIS♥2) Vomiting (abnormal loss of HCl) ♠Excessive loss of H + 228
  228. 228. 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
  229. 229. 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
  230. 230. 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
  231. 231. 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
  232. 232. 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
  233. 233. 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
  234. 234. 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
  235. 235. 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 balance1.2 25 - HCO 3 - ions replaced by Cl - ions5 236
  236. 236. METABOLIC ALKALOSIS H2CO3 : Carbonic Acid HCO3- : Bicarbonate IonH 2 CO HCO 33 - (Na+) HCO3- (K+) HCO3- 1 : 20 (Mg++) HCO3- (Ca++) HCO3-- metabolic balance before onset ofalkalosis- pH = 7.4 237
  237. 237. METABOLIC ALKALOSIS H2 C HCO O 3 - 3 1 : 40- pH = 7.7- HCO 3 - increases because of loss ofchloride ions or excess ingestion of 238
  238. 238. 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
  239. 239. METABOLIC ALKALOSIS H 2 CO HCO 3 - Cl - 3 Chloride containin g solution 1.25 : 25- Therapy required to restore metabolicbalanceions replaced by Cl - ions- HCO 3 - 240
  240. 240. 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 fromrespiratory metabolic GI tract increase in acidosis plasma H + acidosis concentrati kidney on disease (uremia) depression of nervous system 241
  241. 241. ALKALOSISanxiety 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
  242. 242. ACID – BASE DISORDERS Acid-Base Clinical State DisorderPulmonary Embolus Respiratory AlkalosisCirrhosis Respiratory AlkalosisPregnancy Respiratory AlkalosisDiuretic Use Metabolic AlkalosisVomiting Metabolic AlkalosisChronic Obstructive Pulmonary Disease Respiratory AcidosisShock Metabolic AcidosisSevere Diarrhea Metabolic AcidosisRenal Failure Metabolic Acidosis Respiratory Alkalosis,Sepsis (Bloodstream Infection) Metabolic Acidosis 243
  243. 243. APPLICATIO N IN NURSING 244
  244. 244. How todeterminewhether it isacidosis oralkalosis ????????????????????? 245
  245. 245. INTERPRETING ABGsSTEPS: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
  246. 246. 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
  247. 247. NORMAL VALUES OF ABGs♥pH 7.35 – 7.45♥PaCO2 35 – 45♥HCO3¯ 22 – 26♥PaO2 80 – 100♥SaO2 95 – 100%♥BE/BD -2 – +2Normal pH is slightly alkaline at 7.35 – 7.45
  248. 248. 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
  249. 249. BICARBONATE (HCO 3 ¯ )♥Normal range is 22 - 26♥HCO3¯ < 22 = acidosis♥HCO3¯ > 26 = alkalosis
  250. 250. 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
  251. 251. 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 PaCO2Disorder: Respiratory Alkalosis
  252. 252. 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¯ PaCO2Disorder: Respiratory acidosis
  253. 253. Nursing responsibility in maintaining acid-base balanceAssessment♥Identify the risk factor♥ Identify client present health status-1.Body weight:-  sudden lost or gain?2.Skin & mucus membrane:- Tempt, turger, edema & moistness3. Cv & respiratory system:- ♠RR, PULSE & BP ♠REGULAR 254
  254. 254. 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
  255. 255. Nursing managementNsg 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
  256. 256. Actual or high risk for fluid volume deficit R/T excessive diarrhoeaIntervention:-Iv lineAnt diarrhoeal medicineComfort measure- lip balm, mouth wash, perineal hygieneKeep skin & mucus membrane intactPrevents irritation & skin breakdown 257
  257. 257. fluid volume excessIntervention:-♥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
  258. 258. 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
  259. 259. Impaired gas exchange R/T etiological factorIntervention:-♥Safety measure♥Positioning to maintain patent airway♥Monitor I/O♥O2 & MEDICATION♥Monitor vitals♥Monitor ABG’S values 260
  260. 260. 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
  261. 261. . 262
  262. 262. NOW TIME FORASSIGNMENT 263
  263. 263. Case 1Young 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 1.1What differential diagnosis would you consider?

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