Life is a struggle,not against sin,not againstMoney Power . .But againsthydrogen ions.Dr. MamtaKhandelwal                 ...
 Why acid base homeostasis is essential? hoW it is achieved ?                                            2
 The  need for the existence of multiple mechanisms, involved in Acid-Base homeostasis is important for the hydrogen ion ...
 Acid-Base  homeostasis involves chemical and physiologic processes responsible for the maintenance of the acidity of bod...
 The chemical processes represent the  first line of defense to an acid or base load  and include the extracellular and  ...
 The task imposed on the mechanisms that maintain Acid-Base homeostasis is large. ◦ Metabolic pathways are continuously  ...
 Acid- Base balance is primarily concerned with two ions: ◦ Hydrogen (H + ) ◦ Bicarbonate (HCO 3 - )H   +                ...
 H+ ion has special significance because of the narrow ranges that it must be maintained in order to be compatible with l...
9
 Maintenance   of an acceptable pH range in the extracellular fluids is accomplished by three mechanisms: ◦ 1) Chemical B...
 What is acid ? What are physiologically  important acids? What is base? What are physiologically  important bases?   ...
 Acids can be defined as a proton (H + ) donor Many other substance (carbohydrates) also  contain hydrogen but they are ...
 Bases can be defined as: ◦ A proton (H + ) acceptor ◦ Give up OH- in solution. ◦ Physiologically important bases include...
14
 What is ph? What is normal blood ph ? What is the ph range  compatible With life?                              15
   pH refers to P otential H ydrogen   Expresses hydrogen ion concentration in water    solutions.   Water ionizes to f...
 ThepH of the solution is defined as the negative logarithm ( base 10 )of the hydrogen ion (H + ) concentration        pH...
 Low  pH values = high H + concentrations ◦ H + concentration in denominator of formula        pH = log 1 / H + concentra...
 pH = 4 is more acidic than pH = 6   pH = 4 has 10 times more free H +    concentration than pH = 5 and 100 times    mor...
What is normal ratio o f HCO 3 -to H 2 CO 3 ?What is acidosis ?What is alkalosis?What is compensation ?What are the effect...
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   Deviati...
 An  increase in the normal 20:1 base to  acid ratio so there is  ◦ A decrease in the number of hydrogen    ions(ex: rati...
 Acidosis  is a decrease in pH below 7.35 ◦ Which means a relative increase of H +   ions. ◦ A relative decrease in HCO 3...
 The   body response to acid-base  imbalance is called compensation May be complete if brought back  within normal limit...
 If underlying problem is metabolic,  hyperventilation or hypoventilation  can help by respiratory  compensation. If pro...
 pH changes have dramatic effects on normal cell function ◦ 1) Changes in excitability of nerve and   muscle cells ◦ 2) I...
 pH  decrease (more acidic) depresses the  central nervous system  ◦ Can lead to loss of consciousness pH increase (more...
 pH  increases or decreases can alter the  shape of the enzyme rendering it non-  functional Changes in enzyme structure...
 When   reabsorbing Na + from the filtrate of  the renal tubules K + or H + is secreted  (exchanged) Normally K + is  se...
 IfH + concentrations are high (acidosis) than  H + is secreted in greater amounts This leaves less K + than usual excre...
 What are the different types of acidosis & alkalosis?                                 31
 Deviations from normal Acid-Base status are divided into four general categories, depending on the source and direction ...
◦ Respiratory Acidosis and Respiratory  Alkalosis◦ caused primarily by lung or breathing  disorders.◦ Metabolic Acidosis a...
34
What isrespiratoryacidosis?What are thedifferent causesof rac ?What is thetreatment of rac?                    35
 Caused by hypercapnia( CO2) due to Hypoventilation Or Increased CO2 production Characterized by a decrease pH and an ...
   Decreased CO 2 removal can be the result    of:    1) Obstruction of air passages    2) Decreased respiration (depress...
   Etiology :1) Alveolar hypoventilation   Emphysema,   Chronic bronchitis,   Severe pneumonia   Pulmonary edema   A...
 2) Increased CO2 production Malignant hyperthermia Thyroid storm Intensive shivering Prolonged seijures             ...
 Breathlessness Restlessness Lethargy and disorientation Tremors, convulsions, coma Respiratory rate rapid, then grad...
 Treat the under lying cause The treatment of respiratory acidosis aims to  improve the function of the lungs. Drugs to...
-metabolic balance before onset     of acidosis     -pH = 7.4     -respiratory acidosis     -pH = 7.1     -breathing is su...
What isrespiratoryalkalosis?What are thedifferent causesof ral ?What is thetreatment of ral?                    43
 Cause  is Hyperventilation leads to elimination of excessive amounts of CO 2. ◦ Increased loss of CO 2 from the lungs at...
 Can be the result of: ◦ 1) pain,anxiety, emotional   disturbances ◦ 2) Respiratory center lesions ◦ 3) Fever ◦ 4) Salicy...
 Kidneys compensate by:  Retaining hydrogen ions   Increasing bicarbonate excretion Respiratory system   Decreased CO 2 ...
 Usually the only treatment needed is to slow  down the rate of breathing Breathing into a paper bag or holding the  bre...
-metabolic balance before  onset of alkalosis  -pH = 7.4-respiratory alkalosis-pH = 7.7  - hyperactive breathing “ blows  ...
What is metabolicacidosis (mac) ?What are the differentcauses of mac ?What is the treatment ofmac ?                       ...
 Decrease in blood pH and bicarbonate level      (below 22mEq/L)     Excessive H + or decreased HCO -                   ...
 The causes of metabolic acidosis can be grouped into five major categories ◦ 1) Ingesting an acid (acetylsalicylic acid)...
 Unregulated  diabetes mellitus causes ketoacidosis ◦ Body metabolizes fat   rather than glucose ◦ Accumulations of   met...
 This leads to excessive production of   ketones:   ◦ Acetone   ◦ Acetoacetic acid   ◦ B-hydroxybutyric acid  Contribute...
   As the blood pH drops,    breathing becomes    deeper and faster as the    body attempts to rid the    blood of excess...
 Eventually, the kidneys  also try to compensate by  excreting more acid in the  urine However, both  mechanisms can be ...
◦ If the acidosis is mild, intravenous fluids and    treatment for the underlying disorder may be all    thats needed.  ◦ ...
- metabolic balance before            onset of acidosis            - pH 7.4           - metabolic acidosis           - pH ...
 What is anion gap ? What is the normal value? What is the effect of albumin?                                   58
 To achieve electrochemical balance, the concentration  of negatively-charged anions must equal the  concentration of pos...
   Unmeasured Anions                  Unmeasured    Cations   Albumin (15 mEq/L)*         Calcium (5 mEq/L)   Organic A...
Increased anion gap                       Normal anion gap                                          (hyperchloremic)Renal ...
What is metabolicalkalosis (mal) ?What are the differentcauses of mal ?What is the treatment ofmal ?                      ...
 Elevation   of pH due to an increased 20:1 ratio ◦ May be caused by:    An increase of bicarbonate    A decrease in hy...
   Can be the result of:   1) Ingestion of Alkaline Substances (NaHCO 3 ) often used as a    remedy for gastric hyperaci...
 Reaction   of the body to alkalosis is to lower pH by: ◦ Retain CO 2 by decreasing breathing rate. ◦ Kidneys increase th...
 Treatment   of metabolic alkalosis is most  often accomplished by replacing water and  electrolytes (sodium and potassiu...
- metabolic balance before onset            of alkalosis            - pH = 7.4           - metabolic alkalosis           -...
http://umed.med.utah.edu/MS2/renal/AcidBaseTables/img001.JP
RESP           RESP           METAB              METAB            ACIDOSIS       ALKALOSI       ACIDOSIS           ALKALOS...
disturbance             response   Expected changesRespiratory acidosisacute                   HCO3       1mEq/L/10 mm of ...
 Mechanisms  protect the body against life- threatening changes in hydrogen ion concentration ◦ 1) Buffering Systems in B...
 Buffering  systems provide an immediate  response to fluctuations in pH  ◦ 1) Phosphate  ◦ 2) Protein  ◦ 3) Bicarbonate ...
 1)   Phosphate buffer systemNa 2 HPO 4 + H +          NaH 2 PO 4 + Na + Most  important in the intracellular system. P...
 2) Protein Buffer System ◦ Behaves as a buffer in both plasma and   cells. ◦ Hemoglobin is by far the most important   p...
 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 Libera...
 Protein        buffer system works instantaneously making it the most powerful in the body. 75% of the body’s buffer ca...
   3) Bicarbonate Buffer System    ◦ Predominates in extracellular fluid (ECF)                                           ...
 Neurons   in the medulla oblongata and pons  constitute the Respiratory Center Increases in CO and H +                 ...
 Chemoreceptors    are also present in the  carotid and aortic arteries which respond to  changes in partial pressures of...
 Overallcompensatory response is: ◦ Hyperventilation in response to   increased CO 2 or H + (low pH)                     ...
cell production of CO 2 increases             CO 2 + H 2 O      H 2 CO 3           H 2 CO 3       H + + HCO 3 -           ...
 The   kidney compensates for Acid - Base  imbalance within 24 hours and is  responsible for long term control The kidne...
CO 2 + H 2 O           H 2 CO 3          H + + HCO 3yperventilation removes    Kidneys eliminate or retai H + ion concentr...
 Hyperkalemia    is generally associated with acidosis ◦ Accompanied by a shift of H + ions into cells   and K + ions out...
 Hypokalemia     is generally associated with reciprocal exchanges of H + and K + in the opposite direction ◦ Associated ...
THANKS     86
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Acid base balance

  1. 1. Life is a struggle,not against sin,not againstMoney Power . .But againsthydrogen ions.Dr. MamtaKhandelwal 1
  2. 2.  Why acid base homeostasis is essential? hoW it is achieved ? 2
  3. 3.  The need for the existence of multiple mechanisms, involved in Acid-Base homeostasis is important for the hydrogen ion (H + ) concentration which is essential for the operation of many cellular enzymes and function of vital organs, most prominently the brain and the heart 3
  4. 4.  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 4
  5. 5.  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 3
  6. 6.  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. 6
  7. 7.  Acid- Base balance is primarily concerned with two ions: ◦ Hydrogen (H + ) ◦ Bicarbonate (HCO 3 - )H + HCO 3 7
  8. 8.  H+ ion has special significance because of the narrow ranges that it must be maintained in order to be compatible with living systems 8
  9. 9. 9
  10. 10.  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) 10
  11. 11.  What is acid ? What are physiologically important acids? What is base? What are physiologically important bases? 11
  12. 12.  Acids can be defined as a proton (H + ) donor Many other substance (carbohydrates) also contain hydrogen but they are not acids because the hydrogen is tightly bound and it is never liberated as free H + 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 ) 12
  13. 13.  Bases can be defined as: ◦ A proton (H + ) acceptor ◦ Give up OH- in solution. ◦ Physiologically important bases include: ◦ Bicarbonate (HCO 3 - ) ◦ Biphosphate (HPO 4 -2 ) 13
  14. 14. 14
  15. 15.  What is ph? What is normal blood ph ? What is the ph range compatible With life? 15
  16. 16.  pH refers to P otential H ydrogen Expresses hydrogen ion concentration in water solutions. Water ionizes to form equal amounts of H + ions and OH - ions ◦ H 2O H + + OH - Pure water is Neutral ( H + = OH - )  pH = 7 Acid ( H + > OH - )  pH < 7 Base ( H + < OH - )  pH > 7 Normal blood pH is 7.35 - 7.45 pH range compatible with life is 6.8 - 8.0 ◦ 16
  17. 17.  ThepH of the solution is defined as the negative logarithm ( base 10 )of the hydrogen ion (H + ) concentration pH = log 1 / H + concentration H+ concentration in extracellular fluid (ECF) 4 X 10 -8 (0.00000004) 17
  18. 18.  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 18
  19. 19.  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 19
  20. 20. What is normal ratio o f HCO 3 -to H 2 CO 3 ?What is acidosis ?What is alkalosis?What is compensation ?What are the effects of phchange on cell functions? 20
  21. 21. 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 21
  22. 22.  An increase in the normal 20:1 base to acid ratio so there is ◦ A decrease in the number of hydrogen ions(ex: ratio of 20:0.5) An increase in the number of bicarbonate ions (ex: ratio of 40:1) Caused by base excess or acid deficit ACI BAS 22
  23. 23.  Acidosis is a decrease in pH below 7.35 ◦ Which means a relative increase of H + ions. ◦ A relative decrease in HCO 3 - ◦ Both lead to a decrease in the ratio of 20:1H + = p 23
  24. 24.  The body response to acid-base imbalance is called compensation May be complete if brought back within normal limits Partial compensation if range is still outside norms. 24
  25. 25.  If underlying problem is metabolic, hyperventilation or hypoventilation can help by respiratory compensation. If problem is respiratory, renal mechanisms can bring about normal pH--- metabolic compensation . 25
  26. 26.  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 26
  27. 27.  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 27
  28. 28.  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 28
  29. 29.  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+ 29
  30. 30.  IfH + 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+ 30
  31. 31.  What are the different types of acidosis & alkalosis? 31
  32. 32.  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 32
  33. 33. ◦ Respiratory Acidosis and Respiratory Alkalosis◦ caused primarily by lung or breathing disorders.◦ Metabolic Acidosis and Metabolic Alkalosis  caused by an imbalance in the production and excretion of acids or bases by the kidneys. 33
  34. 34. 34
  35. 35. What isrespiratoryacidosis?What are thedifferent causesof rac ?What is thetreatment of rac? 35
  36. 36.  Caused by hypercapnia( CO2) due to Hypoventilation Or Increased CO2 production Characterized by a decrease pH and an increase in CO2 High levels of CO in the blood stimulate the 2 parts of the brain that regulate breathing, which leads to faster and deeper breathing. 36
  37. 37.  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 capillaries and air sacs of lungs (emphycema,bronchitis) 4) Collapse of lung 37
  38. 38.  Etiology :1) Alveolar hypoventilation Emphysema, Chronic bronchitis, Severe pneumonia Pulmonary edema Asthma Flail chest Diseases of the nerves or muscles of the chest . Over sedation from narcotics and strong sleeping medications . 38
  39. 39.  2) Increased CO2 production Malignant hyperthermia Thyroid storm Intensive shivering Prolonged seijures 39
  40. 40.  Breathlessness Restlessness Lethargy and disorientation Tremors, convulsions, coma Respiratory rate rapid, then gradually depressed Skin warm and flushed due to vasodilation caused by excess CO2 40
  41. 41.  Treat the under lying cause 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. Ventilatory support. 41
  42. 42. -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 balance40 - lactate solution used in therapy is converted to bicarbonate ions in the liver 42
  43. 43. What isrespiratoryalkalosis?What are thedifferent causesof ral ?What is thetreatment of ral? 43
  44. 44.  Cause is Hyperventilation leads to elimination of excessive amounts of CO 2. ◦ Increased loss of CO 2 from the lungs at a rate faster than it is produced. ◦ There is increase in pH and decrease in H+ 44
  45. 45.  Can be the result of: ◦ 1) pain,anxiety, emotional disturbances ◦ 2) Respiratory center lesions ◦ 3) Fever ◦ 4) Salicylate poisoning (overdose) ◦ 5) Assisted respiration ◦ 6) High altitude (low P O 2 ) 45
  46. 46.  Kidneys compensate by: Retaining hydrogen ions Increasing bicarbonate excretion Respiratory system 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 theHHCO H lung + + - 3 HCO 3 - H + H + HCO 3 - HCO 3 - H+ HCO 3 - H + HCO - H + 3 H+ 46
  47. 47.  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 47
  48. 48. -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 48
  49. 49. What is metabolicacidosis (mac) ?What are the differentcauses of mac ?What is the treatment ofmac ? 49
  50. 50.  Decrease in blood pH and bicarbonate level (below 22mEq/L)  Excessive H + or decreased HCO - 3 H 2 CO CO 3 HHCO 3 OH32C = 7.4 = 7.4 --3 1 : 10 20 50
  51. 51.  The causes of metabolic acidosis can be grouped into five major categories ◦ 1) Ingesting an acid (acetylsalicylic acid) ◦ 2) Abnormal Metabolism (type I DM,shock) ◦ 3) Kidney Insufficiencies(renal tubular acidosis or uremic acidosis ) ◦ 4) Strenuous Exercise ◦ 5) Severe Diarrhea 51
  52. 52.  Unregulated diabetes mellitus causes ketoacidosis ◦ Body metabolizes fat rather than glucose ◦ Accumulations of metabolic acids (Keto Acids) cause an increase in plasma H+ 52
  53. 53.  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+ + 53
  54. 54.  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 54
  55. 55.  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 55
  56. 56. ◦ If the acidosis is mild, intravenous fluids and treatment for the underlying disorder may be all thats needed. ◦ control diabetes with insulin or treat poisoning by removing the toxic substance. When acidosis is severe, bicarbonate may be given (NaHCO3=BD X 30% X BODY WEIGHT ◦ Bicarbonate provides only temporary relief and may cause harm. 56
  57. 57. - 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 57
  58. 58.  What is anion gap ? What is the normal value? What is the effect of albumin? 58
  59. 59.  To achieve electrochemical balance, the concentration of negatively-charged anions must equal the concentration of positively-charged cations. Na+UC=(Cl+HCO3)+UA Rearranging: Na-(Cl+HCO3)=UA-UC The difference (UA - UC) is a measure of the relative abundance of unmeasured anions and is called the anion gap (AG).The normal value of the AG was originally set at 12 ± 4 mEq/L (range = 8 to 16 mEq/L) 59
  60. 60.  Unmeasured Anions Unmeasured Cations Albumin (15 mEq/L)* Calcium (5 mEq/L) Organic Acids (5 mEq/L) Potassium (4.5 mEq/L) Phosphate (2 mEq/L) Magnesium (1.5 mEq/L) Sulfate (1 mEq/L) Total UA: (23 mEq/L) Total UC: (11 mEq/L) Anion Gap = UA - UC = 12 mEq/L *If albumin is reduced by 50%, anion gap = 4 mEq/L 60
  61. 61. Increased anion gap Normal anion gap (hyperchloremic)Renal failure Increased HCO3 loss by GITKetoacdosis (DM,starvation) Diarrhea, fistula, ureterosigmoidostomyLactic acidosis Increased loss of HCO3 by kidneysIngestion of toxin-salicylate methanol, Renal tubularethylene glycol acidosis,hypoaldosteronismrabdomyolysis Dilutional –large amt of HCO3 free fluids 61
  62. 62. What is metabolicalkalosis (mal) ?What are the differentcauses of mal ?What is the treatment ofmal ? 62
  63. 63.  Elevation of pH due to an increased 20:1 ratio ◦ May be caused by:  An increase of bicarbonate  A decrease in hydrogen ions ◦ Imbalance again cannot be due to CO 2 ◦ Increase in pH which has a non-respiratory origin 63
  64. 64.  Can be the result of: 1) Ingestion of Alkaline Substances (NaHCO 3 ) often used as a remedy for gastric hyperacidity. ◦ 2)Vomiting ,gastric drainage( loss of HCl ) ◦ 3)certain diuretics ◦ 4)endocrine disorders: ◦ prim. hyperaldosteronism, cushing synd. ◦ 5)massive blood transfusion ◦ 6)severe dehydration 64
  65. 65.  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 65
  66. 66.  Treatment of metabolic alkalosis is most often accomplished by replacing water and electrolytes (sodium and potassium) potassium while treating the underlying cause Occasionally when metabolic alkalosis is very severe, dilute acid in the form of ammonium chloride is given by IV 66
  67. 67. - 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 67
  68. 68. http://umed.med.utah.edu/MS2/renal/AcidBaseTables/img001.JP
  69. 69. RESP RESP METAB METAB ACIDOSIS ALKALOSI ACIDOSIS ALKALOSIS SCOMPENSAT Kidneys Kidneys Increased AlkalosisION eliminate conserve ventilation commonly hydrogen ion hydrogen ion Renal occurs with and retain Excrete excretion of H renal bicarbonate bicarbonate ions. dysfunction, ion ion K+ exchanges so can’t count with excess H+ on kidneys. in ECF Respiratory ( H+ into cells, compensation K+ out of cells) difficult – hypoventilatio n limited by hypoxiaTREATMENT Restore Breathe into IV lactate Electrolytes to ventilation, a paper bag solution replace those IV lactate IV Chloride lost, solution containing IV chloride 69
  70. 70. disturbance response Expected changesRespiratory acidosisacute HCO3 1mEq/L/10 mm of Hg inc .in Paco2chronic HCO3 4mEq/L/10 mm of Hg inc .in Paco2Respiratory alkalosisacute HCO3 2mEq/L/10 mm of Hg dec .in Paco2chronic HCO3 4mEq/L/10 mm of Hg dec .in Paco2Metabolic acidosis PPaco2 1.2 x the decrease in HCO3Metabolic alkalosis Paco2 0.7 x the increase in HCO3 70
  71. 71.  Mechanisms protect the body against life- threatening changes in hydrogen ion concentration ◦ 1) Buffering Systems in Body Fluids ◦ 2) Respiratory Responses ◦ 3) Renal Responses ◦ 4) Intracellular Shifts of Ions 71
  72. 72.  Buffering systems provide an immediate response to fluctuations in pH ◦ 1) Phosphate ◦ 2) Protein ◦ 3) Bicarbonate Buffer System A buffer is a combination of chemicals in solution that resists any significant change in pH Able to bind or release free H + ions 72
  73. 73.  1) Phosphate buffer systemNa 2 HPO 4 + H + NaH 2 PO 4 + Na + Most important in the intracellular system. Phosphate concentrations are higher intracellularly and within the kidney tubules. 73
  74. 74.  2) Protein Buffer System ◦ Behaves as a buffer in both plasma and cells. ◦ Hemoglobin is by far the most important protein buffer. Proteinsare excellent buffers because they contain both acid and base groups that can give up or take up H + 74
  75. 75.  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 + combines with HCO - 3HCO 3 - H 2 CO 3 CO 2 (exhaled) O2 H+ H O2 O2 b 75
  76. 76.  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 76
  77. 77.  3) Bicarbonate Buffer System ◦ Predominates in extracellular fluid (ECF) ECF HCO 3 - + H + H 2 CO 3 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 77
  78. 78.  Neurons in the medulla oblongata and pons constitute the Respiratory Center Increases in CO and H + 2 stimulate the respiratory center. ◦ The effect is to raise respiration rates, but the effect diminishes in Respiratory 1 - 2 minutes. centers 78
  79. 79.  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 79
  80. 80.  Overallcompensatory 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 80
  81. 81. 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 81
  82. 82.  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 82
  83. 83. CO 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 83
  84. 84.  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. ◦ Acidosis may cause Hyperkalemia and Hyperkalemia may cause Acidosis H + K + 84
  85. 85.  Hypokalemia is generally associated with reciprocal exchanges of H + and K + in the opposite direction ◦ Associated with alkalosis H + K + 85
  86. 86. THANKS 86
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