Acid Base Balance

Uploaded on


  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
No Downloads


Total Views
On Slideshare
From Embeds
Number of Embeds



Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide
  • Metabolic alkalosis
  • Decreased chest excursion
  • 40 mm Hg
  • Resp acidosis
  • #4
  • Uncompensated because the pH is below normal levels. Interventions maintain airway, enhance gas exchange including drug therapy to open airways and to treat pna, ox therapy, pulmonary hygiene-positioning and breathing techniques, ventilatory support, prevention of complications
  • Keeping in mind that the only respiratory trigger for clients with COPD to breathe is a decreased arterial oxygen level, you should immediately reduce the o2 to the ordered amount, assess LOC, pulse ox, breath sounds and other resp assessments. Instruct the client to notify you if he has difficulty breathing and explain the rationale for leaving the oxygen at low levels of delivery
  • Metabolic acidosis
  • Overelimination of HCO3 (metabolic alkalosis)
  • Administer fluids
  • Serum potassium levels are often elevated as a result of the body’s attempt to maintain electronneutrality during buffering. As hydrogen ions move into the cells potassium ions move out to balance the intracellular charge. As a result the extracellular potassium levels increase, causing hyperkalemia. Blood glucose should be monitored to ensure that diabetic ketoacidosis is not contributing to the client’s acidotic condition. Continue to monitor ABGs and PaCO2 level


  • 1. Acid-Base Balance
    C Washington RN, MSNEd
  • 2. Acid-Base Balance
    Homeostasis & optimal cellular function
    Hydrogen ion concentration of body fluids wnl
    Hydrogen ion concentration falls
    pH rises
    solution become more alkaline or basic
  • 3. 3 Systems that maintenance pH
    • Moves or release hydrogen ions
    Respiratory system
    • Regulate carbonic acid by eliminating or retaining CO2
    Renal system
    • Long term regulation of acid-base in body
  • ABG Interpretation: 1st Step
    Determine if the pH represents acidosis or alkalosis or is perfectly normal
  • 4. Acid-Base Disorders
    Hydrogen ions (H+) determines acidity of body fluids
    Acids release H+ ions in solution
    Bases accepts H+ ions in solution
  • 5. Acid-Base Disorders
    H+ ions concentration of a solution is measured by its pH
    Normal pH
    7.35-7.45 (pH of 7 is neutral)
  • 6. Relationship between H+ ions & pH
    • H+ ion concentration increases
    • 7. pH falls
    • 8. Solution becomes more acid
    • 9. H+ ions concentration falls
    • 10. pH rises
    • 11. Solution becomes more alkaline
  • 12. Acidic or Alkalotic
    pH 7.0
    pH 7.9
    pH 7.4
    pH 7.5
    pH 7.3
  • 13. Note:
    • pH alone is not sufficient to tell us whether an imbalance is due to a respiratory or metabolic problem
    • 14. Evaluate other values of ABGs to determine the primary problem
    • 15. Or whether the body is attempting to compensate for the imbalance
  • Regulation of Acid-Base Balance
    • Buffer Systems
    • 16. Protein molecules, phosphate
    • 17. Helps to maintain a stable pH
    • 18. Removes or release H+ ions
    • 19. Excess acid (acidosis) pH <7.35
    • 20. buffers bind with H+ ions
    • 21. To alkaline (alkaline) pH >7.45
    • 22. buffers release H+ ions
  • Most Important Buffer system
    Bicarbonate-carbonic acid buffer system
    Controlled by lungs & kidneys
    Aeorobic metabolism = to forms of acid
    respiratory acid (carbonic acid)
    metabolic acids
    In order to maintain proper pH balance, the
    body attempts to maintain a ratio of 20:1 (bicarb to carbonic acid)
  • 23. Regulation of Acid-Base Balance
    • Respiratory System
    • 24. Eliminates or retains carbon dioxide
    • 25. ↑ carbon dioxide (acid) stimulate respiration
    • 26. ↑rate & depth of resp↓ pH to normal range
    • 27. Alkalosis depresses respiration
    • 28. ↓ rate & depth of resp retains carbon dioxide
    Normal PaCO2 = 35- 45 mmHg
  • 29. ABG Interpretation: 2nd Step
    • Evaluate the pCO2
    • 30. Determine if it falls within the acceptable range
    • 31. If pCO2 falls below the lower limit (resp alkalosis)
    • 32. Id pCO2 falls above the upper limit (respiratory acidosis)
    • 33. High pCO2 represents acidosis (retention of CO2)
    • 34. Note: High value in pH represents alkalosis.
    • 35. High CO2 =CO2 retention or hypoventilation
    • 36. CO2 is acidotic in the blood=respiratory acidosis
  • Interpreting pCO2 values
    pCO2 of 22
    pCO2 of 32
    pCO2 of 35
    pCO2 of 40
    pCO2 of 45
    pCO2 of 50
    pCO2 of 60
  • 37. Regulation of Acid-Base Balance
    • Renal System
    • 38. Normal bicarbonate 22-26 mEq/L
    • 39. Acidosis
    • 40. Excess H+ ions
    • 41. pH falls
    • 42. kidneys excrete H+ and retain bicarbonate
    • 43. Alkalosis
    • 44. Kidneys retains H+ ions
    • 45. excrete bicarbonate
  • Metabolic Components
    • When there is a loss of acid in the body or
    • 46. An excess base
    • 47. HCO3 will be greater than 26
    • 48. Resulting in metabolic alkalosis
    • 49. When there is an excess of metabolic acid
    • 50. Or not enough base
    • 51. HCO3 will be less than 22
    • 52. Causing metabolic acidosis
  • ABG Interpretation: 3rd Step
    • Determine the direction of the the metabolic component HCO#
    • 53. Whether it is within normal limits
    • 54. High (metabolic alkalosis)
    • 55. Low (metabolic acidosis)
    Think of HCO3 as a base
    *too much causes metabolic alkalosis
    *too little causes metabolic acidosis
  • 56. Interpreting HCO3 Values
    HCO3 of 22
    HCO3 of 16
    HCO3 of 30
    HCO3 of 25
    HCO3 of 12
    HCO3 of 27
  • 57. Base Excess (BE)
    • Metabolic component
    • 58. Calculation of circulating buffer/base
    • 59. Normal range BE is -2 to +2
    BE of -8 represents a deficit of base=metabolic acidosis
    BE of +10 representsan excess of base=metabolic alkalosis
  • 60. Metabolic Acidosis
    Deficit HCO3
    Common in cases of kidney disease and diabetes
    Respiratory Acidosis
    Excess HCO3
    Caused by hypoventilation
    Metabolic Alkalosis
    Excess HCO3
    Caused by diarrhea, steroid or diuretic therapy.
    Respiratory Alkalosis
    Deficit HCO3
    Caused by hyperventilation
    Acid-Base Imbalances
  • 61.
  • 62. Acid-Base Imbalances
  • 68.
  • 69. Acid Base Imbalances
  • 75. Acid Base Imbalance
  • 76. Practice: Analyzing ABGs
  • 77. Compensation
    When there is an imbalance in one parameter of the buffer system (bicarbonate-kidneys) – carbonic acid (lungs) the other tries to compensate for it by causing the opposite imbalance
    Goal: Restore the 20:1 ratio & return the pH back to the acceptable range 7.35-7.45
  • 78. ABG Interpretation: Final Step
    Determine if compensation is present and to what extent
    When compensation is present, you will see two imbalances
    The question-Which is the primary problem & which imbalance is due to compensation
  • 79. Compensation
    The Clue: pH
    If the pH is leaning toward acidosis or alkalosis then the parameter with the matching imbalance is the primary problem & the other is due to compensation
  • 80. Compensation: Example
    Pt has chronic pulmonary problems & is in a chronic respiratory acidosis.
    His kidneys will compensate by retaining bicarbonate
    Creating a metabolic alkalosis to balance his chronic respiratory acidosis
  • 81. Compensation
    pH 7.30 acidosis
    PCO2 70 respiratory acidosis
    HCO3 30 mild metabolic alkalosis
    Respiratory acidosis with partial compensation by the kidneys.
    The kidneys have only begun to compensate, because the pH is not back to acceptable limits yet
  • 82. Supplementary Resources
    “Interpreting Arterial Blood Gases”
    Nursing Article
    ”Perfecting your acid-base balancing act: How to detect and correct acid-base disorders”
  • 83.
    • The nursing caring for a patient undergoing several days of gastric decompression recognizes that the patient is at risk for which of the following acid-base imbalances?
    • 84. Metabolic acidosis
    • 85. Metabolic alkalosis
    • 86. Respiratory acidosis
    • 87. Respiratory alkalosis
    • A patient is admitted with suspected heroin overdose & a resp rate of 5 to 6 per minute. Which of the following assessment data would the nurse anticipate? (select all that apply)
    • 88. pH 7.29
    • 89. Alert & oriented
    • 90. PaCO2- 54 mmHg
    • 91. HCO3- 32 mEq/L
    • 92. Skin warm & flushed
  • Client diagnosis: bacterial pneumoniaABGs: pH 7.24, PCO2 65 mmHg & HCO3- 24 mEq/L Antibiotics and O2 started. What is a priority nursing intervention?
  • 93. Mrs. Mendoza
    Which assessment data indicate that this client has impaired gas exchange?
    H/O emphysema
    Adm with Pneumonia
    Decreased urine output
    Decreased chest excursion
  • 94. Mrs. Mendoza
    Which of the following
    ABG values indicates that
    this client is a CO2
    PaCO2 = 40 mm Hg
    PaCO2 = 60 mm Hg
    Bicarbonate = 42
    PaO2 = 60 mm Hg
  • 95. Mrs. Mendoza
    Which of the following ABGs most likely indicate that she is having a negative response to the administration of oxygen. (next slide)
    Baseline ABG’s
    pH 7.36
    PaCO2 60 mm Hg
    Pa02 52 mmHg
    Bicarbonate 42 mEq/L
  • 96. Mrs. Mendoza
  • Mrs Mendoza
    Based on your answer from the last slide, is the client’s respiratory acidosis compensated or uncompensated? Explain your answer.
    Which immediate interventions are needed for this client.
  • 112. Mrs Mendoza
    Later in the shift, you note that his oxygen is set at 5 L/minute.
    The client says that he asked the nursing assistant to turn up his oxygen because he was havng trouble breathing.
    What actions, if any, should you take at this time
  • 113. Mr. Henderson: H/O Cellulites
    What is the patients acid
    base imbalance?
    T 101 F 90/60
    Diarrhea 2 days
    pH 7.30
    pCO2 28
    Pa02 88
    HCO3 17
  • 114. Mr Williams HCO3 level of 17 mEq/L is a result
    • Respiratory hypoventilation
    • 115. Overelimination of bicarbonate
    • 116. Respiratory compromise
    • 117. Underelimination of hydrogen ions
  • Mr. Williams
    Which of the following symptoms would
    indicate a worsening of the acidotic condition?
    Increased blood pressure
    Rising PaCO2
    Increased urinary output
  • 118. Mr. Williams
    • Which of the following interventions would be critical in reversing the client’s condition?
    • 119. Explain whether or not bicarbonate would be given to this client to correct her condition
  • 120. Mr. Williams
    What other lab values would be important to monitor at this time? Explain
  • 121. A patient’s blood pH is decreasing.
    The nurse realizes that this patient’s hydrogen ion concentration is:
  • 122. Increasing
    Being affected by oxygen concentration
  • 123. A patient is admitted with the diagnosis of diabetic ketoacidosis.
    The nurse realizes that this patient’s body will attempt to attain acid-base balance by:
  • 124. Decreasing its respiratory rate.
    Increasing the reabsorption of hydrogen ions.
    Increasing the secretion of hydrogen ions.
    Decreasing the reabsorption of bicarbonate.
  • 125. A patient has a respiratory rate of 20.
    The nurse calculates this patient’s minute ventilation to be:
  • 126. 1 L/min
    2 L/min
    5 L/min
    10 L/min
  • 127. The nurse, admitting a patient with diabetes, believes the patient is attempting to correct an acidotic condition.
    Which of the following did this nurse most likely observe while assessing this patient?
  • 128. Slow methodical respirations
    Deep rapid respirations
    Change in level of consciousness
    Intact extraocular movements
  • 129. The nurse is caring for a patient with metabolic acidosis.
    The nurse realizes that which of the following laboratory values might be altered for this patient?
  • 130. Ammonia
  • 131. The nurse is reviewing a patient’s arterial blood gas results.
    Which of the following values should the nurse study first?
  • 132. PaCO2
  • 133. The nurse is caring for a patient with pneumonia who has arterial blood gas values of: pH 7.20, PaCO2 75, HCO3- 28, PaO2 44.
    Which of the following would be a priority for this patient?
  • 134. Assisting the patient to breathe into a paper bag.
    Preparing to administer Sodium Bicarbonate IV.
    Placement of the patient in high Fowler’s position.
    Administration of the prn sedative available.
  • 135. A patient is admitted in respiratory acidosis secondary to barbiturate overdose.
    Which of the following will the nurse most likely assess in this patient?
  • 136. Kussmaul’s respirations
    Slow, shallow respirations
    Increased deep tendon reflexes
  • 137. The nurse is providing discharge instructions to a patient with respiratory alkalosis.
    Which of the following statements indicates the patient understands the instructions?
  • 138. “I will not take my Lasix without a potassium supplement.”
    “I will not use Mylanta 5-6 times a day like I used to.”
    “I will take a stress management class or seek counseling.”
    “I will call my MD the next time I have diarrhea for a few days.”