1. NCLEX Review Questions
Acid Base Balance
NCLEX Review Questions

2. Acid Base Balance An arterial blood gas (ABG) sample reports the status of oxygenation and acid-base balance in the blood.
An arterial blood gas (ABG) sample reports the status of oxygenation and acid-base balance in the blood.

3. Acid Base Balance An ABG measures:
pH – the amount of free hydrogen ions in the (H+)
PaO2 – the partial pressure of oxygen
PaCO2 – the partial pressure of carbon dioxide
HCO3 – the concentration of bicarbonate
SaO2 – percentage of oxygen bound to hemoglobin as compared to the total amount that can possible be carried

4. Acid Base Balance ABG Measure Normal Range pH 7.35 – 7.45 PaO2
80 – 100 mmHg
PaCO2
mmHg
HCO3
22 – 26 mEq/L
SaO2 %

5. Acid Base Balance
Blood pH levels may be affected by any number of disease processes (respiratory, endocrine, or neurologic).
Blood pH levels below 7.35 reflect acidosis, while levels above 7.45 reflect alkalosis.
ABGs can be obtained by an arterial puncture or through an arterial line.

6. Acid Base Balance
If you can remember the following pyramid points and steps, you will be able to analyze any blood gas report.
Pyramid Points
In acidosis, the pH is down.
In alkalosis, the pH is up.
The respiratory function indicator is the PCO2 value.
The metabolic function indicator is the HCO3 level.

7. Pyramid Steps Step 1 Step 2
Look at the pH. Is it up or down? If it is up, it reflects alkalosis. If it is down, it reflects acidosis.
Step 2
Look at the PCO2 level. Is it up or down? If it reflects an opposite relationship to the pH, then you know that the condition is a respiratory imbalance. If it does not reflect an opposite relationship to the pH, then move to step 3

8. Pyramid Steps
Step 3
Look at the HCO3 level. Does the HCO3 level reflect a corresponding relationship to the pH? If it does, then the condition is a metabolic imbalance.

9. Acid Base Balance Respiratory Acidosis Respiratory alkalosis
The pH is down.
The PCO2 is up.
Respiratory alkalosis
The pH is up.
The PCO2 is down.

10. Acid Base Balance Metabolic acidosis Metabolic Alkalosis
The pH is down.
The HCO3 is down.
Metabolic Alkalosis
The pH is up.
The HCO3 is up.

11. Acid Base Balance
A client with diabetes mellitus has a blood glucose on admission of 596 mg/dL. The nurse anticipates that this client would be experiencing which of the following types of acid-base imbalance?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis

12. Acid Base Balance
A client with diabetes mellitus has a blood glucose on admission of 596 mg/dL. The nurse anticipates that this client would be experiencing which of the following types of acid-base imbalance?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis
1. ANS: A
Rationale: Diabetes mellitus can lead to metabolic acidosis. When the body does not have sufficient circulating insulin, the blood glucose level rises while the cells of the body use all available glucose and then break down glycogen and fat for fuel. The by-products of fat metabolism are acidotic, leading to the complication called diabetic ketoacidosis.
Test-Taking Strategy: The strategic words in the question are “diabetes mellitus.” This tells you that the primary problem is metabolic in nature rather than respiratory. Therefore, eliminate options 3 and 4. Use knowledge of acid-base concepts to choose correctly between the two remaining options, remembering that metabolic acidosis is a concern in diabetes mellitus. Review the complications of diabetes mellitus if you had difficulty with this question.

13. Acid Base Balance
A nurse is assisting to admit a client with a diagnosis of Guillain-Barré syndrome. The nurse knows that if the disease is severe enough, the client will be at risk for which of the following acid-base imbalances? a. Metabolic acidosis b. Metabolic alkalosis c. Respiratory acidosis d. Respiratory alkalosis

14. Acid Base Balance
A nurse is assisting to admit a client with a diagnosis of Guillain-Barré syndrome. The nurse knows that if the disease is severe enough, the client will be at risk for which of the following acid-base imbalances?
a. Metabolic acidosis
b. Metabolic alkalosis
c. Respiratory acidosis
d. Respiratory alkalosis
ANS: C
Rationale: Guillain-Barré is a neuromuscular disorder in which the client may experience weakening or paralysis of the muscles used for respiration. This could cause the client to retain carbon dioxide, leading to respiratory acidosis due to ventilatory failure as the paralysis ensues.
Test-Taking Strategy: Recall that this disorder impairs the client’s respirations to eliminate options 1 and 2 first. Thinking through the effects of reduced ventilation will help you choose correctly between the remaining two options. Review the complications of Guillain-Barré syndrome if you had difficulty with this question.

15. Acid Base Balance
A client is determined to be in respiratory alkalosis by blood gas analysis. The nurse would monitor this client for signs of which of the following electrolyte disorders that could accompany the acid- base imbalance?
a. Hypercalcemia
b. Hypochloremia
c. Hypernatremia
d. Hypokalemia

16. Acid Base Balance
A client is determined to be in respiratory alkalosis by blood gas analysis. The nurse would monitor this client for signs of which of the following electrolyte disorders that could accompany the acid- base imbalance?
a. Hypercalcemia
b. Hypochloremia
c. Hypernatremia
d. Hypokalemia
ANS: D
Rationale: Clinical manifestations of respiratory alkalosis include tachypnea, hyperpnea, weakness, paresthesias, tetany, dizziness, convulsions, coma, hypokalemia, and hypocalcemia. The clinical picture does not include hypernatremia, hypercalcemia, or hypochloremia.
Test-Taking Strategy: Focus on the subject, respiratory alkalosis. Remember that the clinical manifestations of respiratory alkalosis include tachypnea, hyperpnea, weakness, paresthesias, tetany, dizziness, convulsions, coma, hypokalemia, and hypocalcemia. If this question was difficult, review this acid-base disorder.

17. Acid Base Balance
A nurse is caring for a client who is nervous and is hyperventilating. The nurse would monitor the client for signs of which of the following acid-base imbalances?
a. Respiratory acidosis
b. Respiratory alkalosis
c. Metabolic alkalosis
d. Metabolic acidosis

18. Acid Base Balance
A nurse is caring for a client who is nervous and is hyperventilating. The nurse would monitor the client for signs of which of the following acid-base imbalances?
a. Respiratory acidosis
b. Respiratory alkalosis
c. Metabolic alkalosis
d. Metabolic acidosis
ANS: B
Rationale: A client who hyperventilates blows off excessive carbon dioxide. This would have the effect of inducing alkalosis. Because a respiratory problem is triggering the alteration, it is called a respiratory alkalosis.
Test-Taking Strategy: Note the strategic word “hyperventilating” in the question. This tells you that the correct option is more likely to be respiratory in origin. Recalling that blowing off carbon dioxide triggers alkalosis will help you choose correctly from the remaining two options. Review the basics of acid-base imbalance if you had difficulty with this question.

19. Acid Base Balance
A nurse is assisting in the care of a client for whom an arterial blood gas (ABG) must be drawn. The nurse notes that the person who draws the blood sample from the radial artery performs Allen’s test first. The nurse understands that this is being done to determine the adequacy of the:
a. Carotid circulation
b. Ulnar circulation
c. Femoral circulation
d.Brachial circulation

20. Acid Base Balance
A nurse is assisting in the care of a client for whom an arterial blood gas (ABG) must be drawn. The nurse notes that the person who draws the blood sample from the radial artery performs Allen’s test first. The nurse understands that this is being done to determine the adequacy of the: a. Carotid circulation b. Ulnar circulation c. Femoral circulation d.Brachial circulation
ANS: B
Rationale: Allen’s test is done to test the adequacy of the ulnar circulation before drawing an ABG. This is necessary to ensure that the client has adequate circulation to the hand in case the radial artery becomes occluded. Failure to assess collateral circulation could result in severe ischemic injury to the hand if damage to the radial artery occurs with arterial puncture.
Test-Taking Strategy: Recall the concepts of anatomy to answer this question. Recalling that the two blood vessels that supply the hand are the radial and the ulnar arteries will help you choose correctly. Review the purpose and procedure of Allen’s test if you had difficulty with this question.

21. Acid Base Balance
A nurse is assisting in the care of a client who had an ileostomy created a few days ago. Owing to the normally high output of drainage from this type of ostomy, the nurse monitors the client for signs of:
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis

22. Acid Base Balance
A nurse is assisting in the care of a client who had an ileostomy created a few days ago. Owing to the normally high output of drainage from this type of ostomy, the nurse monitors the client for signs of:
A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis
ANS: A
Rationale: Intestinal secretions are high in bicarbonate because of the effects of pancreatic secretions. These fluids may be lost from the body before they can be reabsorbed in conditions such as diarrhea or creation of ileostomy. The decreased bicarbonate level creates the actual base deficit of metabolic acidosis.
Test-Taking Strategy: Begin to answer this question by eliminating options 2 and 4 first. Intestinal fluids are alkaline in nature, and their loss would produce an acidotic state. Note that the client condition is a gastrointestinal disorder to eliminate the option that deals with a respiratory problem. If you had difficulty with this question, review the causes of metabolic acidosis.

23. Acid Base Balance
A client with a chronic airflow limitation is experiencing respiratory acidosis as a complication. The nurse who is trying to enhance the client’s respiratory status would avoid doing which of the following?
a. Keeping the head of the bed elevated
b. Monitoring the flow rate of supplemental oxygen
c. Assisting the client to turn, cough, and deep breathe
d. Encouraging the client to breathe slowly and shallowly

24. Acid Base Balance
A client with a chronic airflow limitation is experiencing respiratory acidosis as a complication. The nurse who is trying to enhance the client’s respiratory status would avoid doing which of the following?
a. Keeping the head of the bed elevated
b. Monitoring the flow rate of supplemental oxygen
c. Assisting the client to turn, cough, and deep breathe
d. Encouraging the client to breathe slowly and shallowly
ANS: D
Rationale: The client with respiratory acidosis is experiencing elevated carbon dioxide levels due to insufficient ventilation. The nurse would encourage the client to breathe slowly and deeply (not shallowly) to expand alveoli and to promote better gas exchange. The actions listed in options 1, 2, and 3 are helpful actions on the part of the nurse.
Test-Taking Strategy: Note that the question contains the strategic word “avoid.” With this in mind, eliminate options that are beneficial to airway status, and choose the one that would cause further impairment. Review care of the client with respiratory acidosis if you had difficulty with this question.

25. Acid Base Balance
An anxious client is experiencing respiratory alkalosis from hyperventilation due to anxiety. The nurse would do which of the following to help the client experiencing this acid-base disorder?
A. Withhold all sedative or antianxiety medications.
B. Provide emotional support and reassurance.
C. Tell the client to breathe very deeply but more slowly.
D. Put the client in a supine position.

26. Acid Base Balance
An anxious client is experiencing respiratory alkalosis from hyperventilation due to anxiety. The nurse would do which of the following to help the client experiencing this acid-base disorder? A. Withhold all sedative or antianxiety medications. B. Provide emotional support and reassurance. C. Tell the client to breathe very deeply but more slowly. D. Put the client in a supine position.
ANS: B
Rationale: An anxious client benefits from emotional support and reassurance, which in turn reduces anxiety and may lower the respiratory rate. The client may benefit from the administration of a sedative or antianxiety medication, if it is prescribed. The client should try to breathe more slowly and shallowly. Lying supine provides no benefit to the client.
Test-Taking Strategy: Visualize the items in each of the options and their anticipated effect on the client’s respiratory status. Use the process of elimination to choose the umbrella option, which is providing support and reassurance. If you had difficulty with this question, review care of the client with respiratory alkalosis.

27. Acid Base Balance
A client is being treated for metabolic acidosis with medication therapy and other measures. The nurse would plan to most carefully note the levels of which of the following electrolytes, which could dramatically decline with effective treatment of the acidosis?
A. Sodium
B. Potassium
C. Magnesium
D. Phosphorus

28. Acid Base Balance
A client is being treated for metabolic acidosis with medication therapy and other measures. The nurse would plan to most carefully note the levels of which of the following electrolytes, which could dramatically decline with effective treatment of the acidosis? A. Sodium B. Potassium C. Magnesium D. Phosphorus
ANS: B
Rationale: During treatment of metabolic acidosis, potassium moves out of the bloodstream and back into the cells. This can cause a rapid drop in the serum potassium level. Because of the effects of potassium on the heart, this electrolyte should be monitored closely as the client is treated.
Test-Taking Strategy: Specific knowledge about electrolyte changes that accompany acid-base disturbances is needed to answer the question. In the question, note the strategic words “most carefully,” which tell you that more than one option may be partially correct. Recall the roles of the various electrolytes in the body, and remember that during treatment of metabolic acidosis, potassium moves out of the bloodstream and back into the cells. Review metabolic acidosis if you had difficulty with this question.

29. Acid Base Balance
A licensed practical nurse (LPN) is assisting in the care of a client who overdosed on aspirin 24 hours ago. The LPN would report to the registered nurse (RN) which of the following findings associated with an anticipated acid-base disturbance?
a. Drowsiness, headache, and tachypnea
b. Decreased respiratory rate and depth, cardiac irregularities
c. Disorientation and dyspnea
d. Tachypnea, dizziness, and paresthesias

30. Acid Base Balance
A licensed practical nurse (LPN) is assisting in the care of a client who overdosed on aspirin 24 hours ago. The LPN would report to the registered nurse (RN) which of the following findings associated with an anticipated acid-base disturbance?
a. Drowsiness, headache, and tachypnea
b. Decreased respiratory rate and depth, cardiac irregularities
c. Disorientation and dyspnea
d. Tachypnea, dizziness, and paresthesias
ANS: A
Rationale: The client who ingests a large amount of aspirin (acetylsalicylic acid) is at risk for developing metabolic acidosis 24 hours later. If metabolic acidosis occurs, the client is likely to exhibit drowsiness, headache, and tachypnea. In the very early hours following aspirin overdose, the client may exhibit respiratory alkalosis as a compensatory mechanism. By 24 hours postoverdose, however, the compensatory mechanism fails and the client reverts to metabolic acidosis. The client with metabolic alkalosis (option 2) is likely to experience cardiac irregularities and a compensatory decreased respiratory rate and depth. Options 3 and 4 indicate respiratory acidosis and alkalosis, respectively.
Test-Taking Strategy: Note that the strategic words in the question are “24 hours later.” To answer this question accurately, you must be familiar with signs of aspirin poisoning and the signs and symptoms exhibited with various acid-base disturbances. Remember that if metabolic acidosis occurs, the client is likely to exhibit drowsiness, headache, and tachypnea. Review the manifestations of metabolic acidosis if you had difficulty with this question.