Acid Base Balance

  1. Acids are
    substances that release hydrogen when disolved in water
  2. Acid base balances can alter
    • respiration
    • metabolism
    • function of the CNS
  3. Acidosis
    excess of hydrogen ions
  4. acidosis ph
    arterial pH less than 7.35
  5. bases are
    substances that nind hydrogen ions when in water
  6. alkalosis
    excess of base (bicarbonate)
  7. alkalosis pH
    greater than 7.45
  8. acidosis seen in pts with
    • pneumonia
    • dehydration
    • infection
    • renal disease
  9. alkalosis seen in pts with
    • overhydration
    • heart failure
    • thazide and loop diuretics
    • digoxin insulin
    • chemotherapy
  10. respiratory rate increase will cause a drop in
    CO2 and pH
  11. decrease in respiration rate will cause a decrease in
    CO2 and pH
  12. Kidney's movement of HCO2
    • when pH is high, HCO2 is excreted in urine
    • when pH is low, HCO2 is reabsorbed
  13. When HCO2 is reabsorbed it binds with
    phosphate in the urine to make acid (H2PO4)
  14. Ammonium is formed by
    the kidneys when amino acids bind with H to form ammonium and is excreted in urine
  15. alkalosis is a excess of
  16. Acidic means
    • more acid than base
    • more hydrogen ions
    • lower pH
    • (kicking Down the pH) AciDosis
  17. Alkaline means
    • more acid than base
    • fewer hydrogen ions
    • higher pH
    • (Kicking Up the pH) Alkalosis
  18. normal pH range
    • 7.4
    • 0,5 up and 0.5 down
  19. pCO2 normal range
    • 40
    • 5 up and 5 down
  20. HCO3 normal range
    • 24
    • 2up and 2down
  21. pO2 normal range
    • 90
    • 10up and 10 down
  22. pH less than 6.8
  23. pH greater than 7.8
  24. ph lowers if
    • hydrogen level concentration increases
    • bicarbonate level decreases
  25. 3 physiologic systems act interdependently to maintain a normal serum pH
    • buffering of excess acid or base by blood buffer systems
    • excretion of acid by the lungs
    • excretion of acid or regeneration of base by the kidneys
  26. chemical buffers
    • act immediately to protect tissues and cells
    • combinds with acids or bases immediately to neutralize
    • located in ICF and ECF
    • control H ions by either absorbing them to make an acid or releasing them to make a base
  27. compensations
    • only works for respiratory acidiosis
    • resp system changes hydrogen ions concentration by changing respiratory rate and depth
    • more carbonic acid is formed with decrease respiration
  28. respirations will increase if
    more CO2 needs to be breathed off
  29. Buffers are found in
    • blood
    • ICF
    • interstitial fluid
  30. main buffers
    • bicarbonate
    • phosphate
    • protien
  31. bicarbonate buffers use a week
    acid or week base as carbonic acid or bicarb with a strong base or strong acid as HCL to make less strong base or acid
  32. protien buffers
    • most abundant in the body
    • hemoglobin and other protiens
    • neutralizes acid and base
  33. in RBCs hemoglobin will bind with what to act as a buffer
  34. PaCO2 is
    • measures dissolved carbon dioxide
    • regulate to amount produce in cells
    • regulate by lungs
    • related to alvolar ventilation
  35. an increase in ventilation will cause what in PaCO2
  36. a decrease in ventilation will cause a what in PaCO2
  37. CO2 combinds with what to make carbonic acid
  38. increased levels of carbonic acid will cause a what in pH
  39. what area of the brain has chemoreceptors that regulate rate and depth of breathing to control CO2
  40. the more CO2 that is lost the more
    carbonic acid is made
  41. alveoli hypoventilation occurs
    either from decreaseed respiration of inadequate gas exchange
  42. respiratory acidosis
    • caused by the under elimination of hyddrogen ions causing retention of carbon dioxide in the body
    • resulting in increased production of carbonic acid
  43. four causes of respiratiory acidosis
    • airway onbstruction
    • interference with capillary diffusion
    • poor chest expansion
    • respiratory depression
  44. In cronic respiratory acidosis as with COPD the kidneys have had time to compensate so the pH may be
    within normal range
  45. Respiratory depression
    • anesthesis
    • narcotic
    • head trauma
    • cardiac arrest
    • injury to chest, airway, lungs
  46. As brain cells become acidotic mental stauts
    • changes are noticed
    • disorientation
    • depression
    • weakness
    • stupor
    • warm and moist mucus membranes
  47. Respirtory acidosis oxygen and ECG changes
    • dyspnea
    • tachycardia
    • dysrhythmia
  48. Respiratory acidosis cases chemical changes
    • decrease in pH
    • increase in PaCO2
    • increase in HCO2
  49. Respiratory acidiosis casues
    • headache
    • mental status change
    • decreased level of conciousness
    • muscle twitching
    • electrolyte change
    • K and Ca
  50. interventions of respiratory acidosis
    • safety measures
    • assist with positioning
    • monitor IandO
    • admisister fluids as orderd
    • administer oxygen and medication as orderd
    • monitor ABGs
  51. Respiratory alkalidosis
    PaCO2 goes down and pH up
  52. respiratory alkalidosis causes hyperventilation resulting in
    • retain oxygen blow off CO2
    • fever
    • sailcylate intoxication (early ASA OD)
    • CNS trauma
    • excess mechanical ventilation with O2>CO2
  53. Respiratory alkalosis skin, oxygen, ecg problems
    • warm flush mucous membranes
    • sweating and diaphoresis
    • RAPID, SHALLOW BREATHING (compensating)
    • palpitations
  54. Respiratory alkaladosis biochemical effects
    • increase in pH
    • decrease in PaCO2
  55. Respiratory Alkalidosis causes these problems
    • anorexia (to rid acid) N/V
    • abd pain
    • weakness
    • altered mental staus
    • decreased LOC
    • dysthrythmia
    • bradycardia
    • tetany convulsions
  56. Respiratory alkalosis cognitive and sensory
    • hyperactive reflexes
    • tetany
    • positive chvostek's sign
    • positve trousseau sign
    • vertigo
    • unconciousness
  57. causes of respiratory alkalosis
    • hyperventlation
    • early PE
    • fever
    • anxitey (blows of CO2)
  58. Metabolic alkalosis causes
    • loss of gastric juice
    • potassium wasting diuretic (loss of H)
    • misuse of antacids
    • too much bicard or loose acid
    • high carb diet
    • hyperkalemia hypercalcemia
  59. metabolic alkalosis
    hypokalemia occurs as K is exchanged for H ions in the cell
  60. Lungs will begin to retain CO2 to lower pH when
    • metabolic alkalosis
    • clinical manifestation
    • hypotension
    • tachycardia
    • confusion
    • decreased LOC
    • hyperreflexia
    • tetany
    • dysthrhymia
    • seizures
    • respiratory failure
    • as pH increases , respiratry failure dysthrhythmia, seizure coma occur
  61. Acidosis caused by
    • respiratory hypoventilation
    • pulmonary edema
    • drug overdose
    • airway obstruction
    • chest trauma
    • COPD
  62. Metabolic acidosis causes
    • asprin overdose
    • sepsis
    • diarrhea
    • Renal Failure (K increase)
    • fasting, DKA, Salicylates poisoning, diarrhea, interstiatl suction, Pancreatic damage, renal impairment, saline infusions, bicarb is lost
  63. hyperventilation is a cardinal sign of
    metabolic acidosis
  64. fluid is lost>
    acidity increases>lowering pH
  65. to correct metabolic acidosis the lungs blow off
    CO2 to increase pH (promoting alkaline HCO3)
  66. metabolic acidosis regulaters do what
    • meausres bicarbonate ion
    • regulated by kidneys
    • acts as buffer in acid base system
    • kidneys have slower response to adjust pH than lungs
  67. if blood has more base and less acid then
    kidneys hold hydrogen and excrete bicarb
  68. respiratory helps to regulate metabolic imbalances; lack of bicarb causes acidosis
    lungs will increase rate of breathing and blow off CO2, thus raising pH
  69. An excess of bicarb causes alkalosis; lungs will decrease rate of breathing and retain CO2
    thus lowering the pH
  70. acid base balance exists when
    • the body produces acids or bases equal to the rate they are excreted
    • metabolic processes maintain a steady balance between acids and bases for optimal functioning of cells
  71. ratio of acids to base
    20 base to 1part acid
  72. if acids increase or base decreases then
    scale tips toward acidic side lowering pH
  73. if acid decreases or base increases then
    tips to base side and pH increases
  74. Volatile acid is in what system
    respiratory, can be excreted as a gas
  75. Nonvolatile acid
    renal, must be metabolized or excreted from the body in a water form
  76. drawing sites for ABGs
    • radial
    • brachial
    • femoral
  77. things that will alter the result of ABGs
    • air bubble in syrnge may alter level
    • venous blood will alter results
    • cup of ice immediately
    • hold pressure for 5 min
  78. increase or decrease in PaCO2 levels shows that what has occured
    • decrease, hyperventilation (blows off)
    • increase, hypoventilation (retained)
  79. ROME
    • Respiratory (PaCO2 and pH)
    • Oposite
    • Metabolic (HCO3 and pH)
    • Equal
  80. is there a normal decline in older adults
    yes of PaCO2
  81. hypoxemia may cause
    hyperventilation resulting in resiratory alkalosis
  82. oxygen saturation
    the point at which hemoglobin is saturated by oxygen
  83. oxygen saturation can be effected by
    • changes in temperature
    • changes in pH
    • changes in PaCO2
    • when PaCO2 falls below 60 there is a large drop in saturation
  84. serum bicarbonate HCO3
    the major renal componet of acid base balance is excreted and reproduced by the kidneys to maintain a normal acid base environment
  85. bicarbonate reflects the renal systems ability to
    • compensate for changes in the pH
    • pH is high (basic) HCO3 is excreted by the kidney
    • pH is low (acid) HCO2 is reabsorbed by kidneys, H, ammonia, and protien excreted by diney
  86. How to read ABGs
    • evaluate PaO2 and SaO2
    • evaluate pH
    • evaluate PaCO2
    • evaluate HCO3
    • evaluate in respiratory or metabolic
    • evaluate compensation
    • pull it all together
  87. high PaCO2
    • hypercapnia
    • breathing slowly/shallow/poor expiratory effort and not blowing off CO2
  88. Compensation
    • body's attempt to maintain normal pH
    • respiratory system controls PaCO2
    • renal system controls HCO3

    if one system changes: other system changes to compensate
  89. if compensation is metabolic then all go
    • up or down
    • pH, HCO3, PCO2
Card Set
Acid Base Balance
nursing 105