Chapter 17: Acid-Base Imbalances

Question 1

pH range

Answer 1

7.35-7.45

Question 2

PaCO2 range

Answer 2

35-45 mmHg

Question 3

bicarbonate range (HCO3)

Answer 3

22-26 mEq/L

Question 4

PaO2 range

Answer 4

80-100 mmHg

Question 5

SaO2 range

Answer 5

> 95%

Question 6

In respiratory alkalosis, the pH is _____ and the PaCO2 is _____.

Answer 6

↑ ; ↓

Question 7

In respiratory acidosis, the pH is _____ and the PaCO2 is _____.

Answer 7

↓ ; ↑

Question 8

In metabolic alkalosis, the pH and HCO3- are _____ and the PaCO2 is _____ or normal.

Answer 8

↑ ; ↑

Question 9

In metabolic acidosis, the pH and HCO3- are _____ and the PaCO2 is _____ or normal.

Answer 9

↓ ; ↓

Question 10

A client’s arterial blood gas (ABG) results are: pH 7.30, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L. What is the correct interpretation of these results?

A. Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Respiratory alkalosis

Answer 10

B. Respiratory acidosis

Rationale: The pH is below the normal range (7.35–7.45), indicating acidosis. The PaCO2 is elevated (>45 mm Hg), which is consistent with respiratory acidosis. Bicarbonate (HCO3⁻) is within normal limits, so this is uncompensated respiratory acidosis.

Question 11

A client’s ABG results are: pH 7.48, PaCO2 40 mm Hg, HCO3⁻ 30 mEq/L. What is the correct interpretation of these results?

A. Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic alkalosis
D. Combined respiratory and metabolic alkalosis

Answer 11

C. Metabolic alkalosis

Rationale: The pH is above the normal range, indicating alkalosis. The bicarbonate (HCO3⁻) is elevated, indicating metabolic alkalosis. PaCO2 is within normal limits, ruling out a respiratory cause.

Question 12

A client with sepsis has ABG results of: pH 7.32, PaCO2 35 mm Hg, HCO3⁻ 18 mEq/L. What is the underlying condition?

A. Metabolic acidosis
B. Respiratory acidosis
C. Metabolic alkalosis
D. Mixed acidosis

Answer 12

A. Metabolic acidosis

Rationale: The pH is low, indicating acidosis. The bicarbonate (HCO3⁻) is decreased (<22 mEq/L), confirming a metabolic cause. The PaCO2 is normal, ruling out a respiratory component.

Question 13

A client’s ABG results are: pH 7.55, PaCO2 28 mm Hg, HCO3⁻ 24 mEq/L. What is the most likely cause of these results?

A. Prolonged vomiting
B. Hyperventilation
C. Diabetic ketoacidosis
D. Chronic obstructive pulmonary disease (COPD)

Answer 13

B. Hyperventilation

Rationale: The pH is elevated, indicating alkalosis. The PaCO2 is decreased (<35 mm Hg), consistent with respiratory alkalosis. This is often caused by hyperventilation.

Question 14

Which ABG values are most consistent with partially compensated respiratory acidosis?

A. pH 7.38, PaCO2 48 mm Hg, HCO3⁻ 28 mEq/L

B. pH 7.30, PaCO2 50 mm Hg, HCO3⁻ 26 mEq/L

C. pH 7.34, PaCO2 52 mm Hg, HCO3⁻ 29 mEq/L

D. pH 7.50, PaCO2 30 mm Hg, HCO3⁻ 24 mEq/L

Answer 14

C. pH 7.34, PaCO2 52 mm Hg, HCO3⁻ 29 mEq/L

Rationale: The pH is low (indicating acidosis), and the elevated PaCO2 confirms a respiratory cause. The bicarbonate (HCO3⁻) is also elevated, showing partial metabolic compensation.

Question 15

A client is admitted with ABG results of: pH 7.20, PaCO2 60 mm Hg, HCO3⁻ 26 mEq/L. What immediate action should the nurse anticipate?

A. Administering sodium bicarbonate
B. Initiating mechanical ventilation
C. Providing supplemental oxygen
D. Encouraging deep breathing and coughing

Answer 15

B. Initiating mechanical ventilation

Rationale: The pH and PaCO2 values indicate severe respiratory acidosis. Immediate intervention, such as mechanical ventilation, is required to improve gas exchange and lower PaCO2.

Question 16

A client’s ABG results are: pH 7.40, PaCO2 40 mm Hg, HCO3⁻ 24 mEq/L, SaO2 88%. What should the nurse do first?

A. Administer supplemental oxygen
B. Notify the healthcare provider
C. Repeat the ABG test in 30 minutes
D. Document the findings as normal

Answer 16

A. Administer supplemental oxygen

Rationale: Although the pH, PaCO2, and HCO3⁻ are normal, the SaO2 is below the expected range (>95%). The priority is to improve oxygenation by administering supplemental oxygen.

Question 17

A client’s ABG results are: pH 7.36, PaCO2 55 mm Hg, HCO3⁻ 32 mEq/L. What does this indicate?

A. Uncompensated respiratory acidosis
B. Fully compensated respiratory acidosis
C. Partially compensated metabolic alkalosis
D. Normal acid-base balance

Answer 17

B. Fully compensated respiratory acidosis

Rationale: The pH is within the normal range but on the acidic side, suggesting full compensation. The elevated PaCO2 indicates respiratory acidosis, and the elevated HCO3⁻ reflects renal compensation.

Question 18

A client’s ABG results are: pH 7.31, PaCO2 50 mm Hg, HCO3⁻ 25 mEq/L, PaO2 75 mm Hg, SaO2 89%. Based on the 5-step process, what is the correct interpretation?

A. Uncompensated respiratory acidosis with hypoxemia
B. Partially compensated respiratory acidosis with normal oxygenation
C. Fully compensated respiratory acidosis with hypoxemia
D. Uncompensated metabolic acidosis with hypoxemia

Answer 18

A. Uncompensated respiratory acidosis with hypoxemia

Rationale: The pH is low, indicating acidosis. The PaCO2 is elevated, indicating a respiratory cause. HCO3⁻ is normal, showing no compensation. PaO2 and SaO2 are below normal, indicating hypoxemia.

Question 19

A client’s ABG results are: pH 7.52, PaCO2 29 mm Hg, HCO3⁻ 24 mEq/L, PaO2 85 mm Hg, SaO2 96%. Using the ROME method, what is the underlying condition?

A. Respiratory alkalosis
B. Metabolic alkalosis
C. Fully compensated metabolic alkalosis
D. Combined metabolic and respiratory alkalosis

Answer 19

A. Respiratory alkalosis

Rationale: The pH is elevated, indicating alkalosis. The PaCO2 is decreased, consistent with a respiratory cause (respiratory opposite in ROME). HCO3⁻ is normal, indicating no metabolic involvement.

Question 20

A client with renal failure has the following ABG results: pH 7.20, PaCO2 35 mm Hg, HCO3⁻ 15 mEq/L, PaO2 90 mm Hg, SaO2 98%. What is the most likely acid-base disturbance?

A. Uncompensated respiratory acidosis
B. Partially compensated metabolic acidosis
C. Uncompensated metabolic acidosis
D. Fully compensated metabolic acidosis

Answer 20

C. Uncompensated metabolic acidosis

Rationale: The pH is low, indicating acidosis. The HCO3⁻ is low, confirming a metabolic cause. The PaCO2 is normal, ruling out compensation or a respiratory component.

Question 21

A client with pneumonia has ABG results: pH 7.36, PaCO2 48 mm Hg, HCO3⁻ 30 mEq/L, PaO2 68 mm Hg, SaO2 88%. What do these results indicate?

A. Fully compensated respiratory acidosis with hypoxemia
B. Partially compensated metabolic alkalosis with hypoxemia
C. Uncompensated respiratory acidosis with normal oxygenation
D. Fully compensated metabolic alkalosis with normal oxygenation

Answer 21

A. Fully compensated respiratory acidosis with hypoxemia

Rationale: The pH is normal but slightly acidic, indicating full compensation. The elevated PaCO2 and HCO3⁻ reflect respiratory acidosis with metabolic compensation. The low PaO2 and SaO2 indicate hypoxemia.

Question 22

A client with prolonged vomiting presents with the following ABG results: pH 7.48, PaCO2 46 mm Hg, HCO3⁻ 30 mEq/L, PaO2 92 mm Hg, SaO2 97%. What is the correct interpretation?

A. Uncompensated respiratory alkalosis
B. Fully compensated metabolic alkalosis
C. Partially compensated metabolic alkalosis
D. Uncompensated metabolic alkalosis

Answer 22

C. Partially compensated metabolic alkalosis

Rationale: The pH is elevated, indicating alkalosis. The HCO3⁻ is elevated, confirming a metabolic cause. The PaCO2 is elevated, suggesting partial respiratory compensation.

Question 23

A client’s ABG results are: pH 7.43, PaCO2 50 mm Hg, HCO3⁻ 30 mEq/L, PaO2 88 mm Hg, SaO2 90%. Using the 5-step process, how should the nurse interpret these results?

A. Fully compensated respiratory acidosis with normal oxygenation
B. Uncompensated metabolic alkalosis with normal oxygenation
C. Partially compensated respiratory alkalosis with hypoxemia
D. Fully compensated metabolic alkalosis with hypoxemia

Answer 23

D. Fully compensated metabolic alkalosis with hypoxemia

Rationale: The pH is normal but slightly alkaline, indicating full compensation. The HCO3⁻ is elevated, reflecting metabolic alkalosis, and the PaCO2 is elevated, indicating compensation. The low PaO2 and SaO2 indicate hypoxemia.

Question 24

A client’s ABG results are: pH 7.30, PaCO2 60 mm Hg, HCO3⁻ 32 mEq/L, PaO2 55 mm Hg, SaO2 75%. What is the priority nursing intervention?

A. Administer sodium bicarbonate
B. Initiate oxygen therapy
C. Prepare for intubation and mechanical ventilation
D. Encourage the client to use an incentive spirometer

Answer 24

C. Prepare for intubation and mechanical ventilation

Rationale: The pH and elevated PaCO2 indicate respiratory acidosis with partial compensation. The PaO2 and SaO2 values indicate severe hypoxemia, necessitating immediate respiratory support such as intubation and ventilation.

Question 25

A client with pneumonia is admitted with the following ABG results: pH 7.28, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L. What is the pathophysiology underlying the respiratory acidosis?

A. Alveolar hyperventilation causing CO2 retention
B. Decreased alveolar ventilation leading to CO2 retention
C. Increased renal excretion of bicarbonate
D. Excessive elimination of CO2

Answer 25

B. Decreased alveolar ventilation leading to CO2 retention

Rationale: Severe pneumonia can impair gas exchange and reduce alveolar ventilation, leading to CO2 retention and respiratory acidosis.

Question 26

A client with Guillain-Barré syndrome develops progressive respiratory muscle weakness. Which ABG pattern is most concerning for this client?

A. pH 7.45, PaCO2 32 mm Hg, HCO3⁻ 22 mEq/L

B. pH 7.36, PaCO2 45 mm Hg, HCO3⁻ 25 mEq/L

C. pH 7.30, PaCO2 55 mm Hg, HCO3⁻ 24 mEq/L

D. pH 7.60, PaCO2 28 mm Hg, HCO3⁻ 20 mEq/L

Answer 26

C. pH 7.30, PaCO2 55 mm Hg, HCO3⁻ 24 mEq/L

Rationale: The low pH and elevated PaCO2 indicate uncompensated respiratory acidosis, which can occur due to respiratory muscle weakness and hypoventilation.

Question 27

A client is admitted after a suspected sedative overdose. What initial ABG results would the nurse expect to see?

A. pH 7.52, PaCO2 28 mm Hg, HCO3⁻ 24 mEq/L

B. pH 7.28, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L

C. pH 7.38, PaCO2 40 mm Hg, HCO3⁻ 26 mEq/L

D. pH 7.48, PaCO2 35 mm Hg, HCO3⁻ 30 mEq/L

Answer 27

B. pH 7.28, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L

Rationale: Sedative overdose often causes respiratory depression, leading to hypoventilation, CO2 retention, and respiratory acidosis.

Question 28

A client is diagnosed with pulmonary edema and has ABG results showing respiratory acidosis. What is the primary cause of the acidosis in this client?

A. Retention of bicarbonate by the kidneys
B. Impaired alveolar gas exchange
C. Excessive CO2 elimination
D. Decreased production of hydrogen ions

Answer 28

B. Impaired alveolar gas exchange

Rationale: Pulmonary edema causes fluid accumulation in the alveoli, impairing gas exchange and leading to CO2 retention, which causes respiratory acidosis.

Question 29

A client with COPD presents with chronic respiratory acidosis. What compensatory mechanism would the nurse expect?

A. Increased bicarbonate excretion by the kidneys
B. Decreased renal hydrogen ion excretion
C. Decreased respiratory rate
D. Increased renal retention of bicarbonate

Answer 29

D. Increased renal retention of bicarbonate

Rationale: In chronic respiratory acidosis, the kidneys compensate by retaining bicarbonate to buffer the excess hydrogen ions caused by elevated PaCO2.

Question 30

Which of the following clinical conditions is least likely to cause respiratory acidosis?

A. Atelectasis
B. Chronic obstructive pulmonary disease (COPD)
C. Hyperventilation due to anxiety
D. Mechanical hypoventilation

Answer 30

C. Hyperventilation due to anxiety

Rationale: Hyperventilation leads to excessive CO2 elimination and respiratory alkalosis, not acidosis. Atelectasis, COPD, and hypoventilation can all cause CO2 retention and respiratory acidosis.

Question 31

A client with severe scoliosis is at risk for developing respiratory acidosis due to:

A. Reduced lung compliance and hypoventilation
B. Increased alveolar hyperventilation
C. Excessive use of accessory muscles for breathing
D. Elevated PaO2 levels impairing gas exchange

Answer 31

A. Reduced lung compliance and hypoventilation

Rationale: Severe scoliosis can restrict lung expansion, reduce compliance, and impair ventilation, leading to CO2 retention and respiratory acidosis.

Question 32

A client presents with lightheadedness, dizziness, and tachypnea following an anxiety attack. ABG results are: pH 7.50, PaCO2 30 mm Hg, HCO3⁻ 24 mEq/L. What is the correct interpretation of these findings?

A. Uncompensated respiratory alkalosis
B. Uncompensated metabolic alkalosis
C. Partially compensated respiratory alkalosis
D. Fully compensated respiratory alkalosis

Answer 32

A. Uncompensated respiratory alkalosis

Rationale: The elevated pH and decreased PaCO2 indicate respiratory alkalosis. The normal HCO3⁻ indicates no compensation. This is commonly seen in anxiety-induced hyperventilation.

Question 33

A nurse is caring for a client with liver failure who is breathing rapidly. The nurse anticipates which ABG result consistent with respiratory alkalosis?

A. pH 7.32, PaCO2 48 mm Hg, HCO3⁻ 26 mEq/L

B. pH 7.46, PaCO2 32 mm Hg, HCO3⁻ 23 mEq/L

C. pH 7.36, PaCO2 40 mm Hg, HCO3⁻ 24 mEq/L

D. pH 7.20, PaCO2 55 mm Hg, HCO3⁻ 22 mEq/L

Answer 33

B. pH 7.46, PaCO2 32 mm Hg, HCO3⁻ 23 mEq/L

Rationale: The elevated pH and low PaCO2 indicate respiratory alkalosis, which can result from hyperventilation due to liver failure. The normal HCO3⁻ indicates no compensation.

Question 34

A client with a recent stroke is hyperventilating and has ABG results showing respiratory alkalosis. What physiological mechanism explains this finding?

A. Increased renal retention of bicarbonate
B. Stimulated respiratory center in the brainstem
C. Increased alveolar CO2 production
D. Decreased oxygen demand at the tissue level

Answer 34

B. Stimulated respiratory center in the brainstem

Rationale: Conditions like stroke can stimulate the respiratory center, leading to hyperventilation and excessive CO2 elimination, which causes respiratory alkalosis.

Question 35

A client with a fever and septicemia is admitted to the ICU. Which ABG pattern would the nurse expect due to hyperventilation caused by the fever?

A. pH 7.30, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L

B. pH 7.50, PaCO2 28 mm Hg, HCO3⁻ 22 mEq/L

C. pH 7.35, PaCO2 40 mm Hg, HCO3⁻ 24 mEq/L

D. pH 7.20, PaCO2 60 mm Hg, HCO3⁻ 26 mEq/L

Answer 35

B. pH 7.50, PaCO2 28 mm Hg, HCO3⁻ 22 mEq/L

Rationale: Hyperventilation from fever and septicemia leads to excessive CO2 elimination, causing an elevated pH and decreased PaCO2, consistent with respiratory alkalosis.

Question 36

A client is admitted for salicylate poisoning. The nurse notes ABG results of pH 7.48, PaCO2 28 mm Hg, HCO3⁻ 22 mEq/L. Which nursing intervention is most appropriate?

A. Administer IV sodium bicarbonate
B. Encourage deep breathing exercises
C. Administer activated charcoal as prescribed
D. Decrease oxygen flow rate

Answer 36

C. Administer activated charcoal as prescribed

Rationale: Salicylate poisoning can stimulate the respiratory center, leading to hyperventilation and respiratory alkalosis. Activated charcoal is given to limit salicylate absorption, addressing the underlying cause.

Question 37

A client with diabetic ketoacidosis (DKA) presents with the following ABG results: pH 7.30, PaCO2 36 mm Hg, HCO3⁻ 18 mEq/L. Which physiological process is responsible for the development of metabolic acidosis in this condition?

A. Excessive CO2 retention due to hypoventilation
B. Increased production of ketones as an alternative energy source
C. Excessive renal bicarbonate retention
D. Increased lactate production secondary to tissue hypoxia

Answer 37

B. Increased production of ketones as an alternative energy source

Rationale: In DKA, the body breaks down fats for energy due to a lack of insulin, leading to the production of ketones, which are acidic and result in metabolic acidosis.

Question 38

A client is admitted with chronic diarrhea and metabolic acidosis. Which laboratory finding is consistent with this condition?

A. Elevated serum bicarbonate
B. Decreased anion gap
C. Decreased serum bicarbonate
D. Increased PaCO2

Answer 38

C. Decreased serum bicarbonate

Rationale: Chronic diarrhea causes a loss of bicarbonate, resulting in metabolic acidosis. The serum bicarbonate level will be reduced in this condition.

Question 39

A nurse is caring for a client with lactic acidosis secondary to shock. What is the primary cause of lactic acid buildup in this condition?

A. Hypoxia-induced anaerobic metabolism
B. Excessive production of ketone bodies
C. Impaired excretion of hydrogen ions by the kidneys
D. Increased loss of bicarbonate through the GI tract

Answer 39

A. Hypoxia-induced anaerobic metabolism

Rationale: In shock, tissue hypoxia leads to anaerobic metabolism, which results in the production and accumulation of lactic acid, causing metabolic acidosis.

Question 40

A client with renal failure has ABG results indicating metabolic acidosis. What is the underlying pathophysiology for this condition?

A. Decreased hydrogen ion excretion and impaired bicarbonate reabsorption

B. Excessive ketone production from fat metabolism

C. Increased gastrointestinal loss of bicarbonate

D. Prolonged hypoxia resulting in lactate accumulation

Answer 40

A. Decreased hydrogen ion excretion and impaired bicarbonate reabsorption

Rationale: In renal failure, the kidneys are unable to excrete hydrogen ions or reabsorb bicarbonate efficiently, leading to metabolic acidosis.

Question 41

A client with starvation is admitted with metabolic acidosis. Which assessment finding supports this diagnosis?

A. Increased blood glucose levels
B. Presence of ketones in the urine
C. Decreased respiratory rate
D. Elevated serum bicarbonate levels

Answer 41

B. Presence of ketones in the urine

Rationale: Starvation causes the body to break down fats for energy, leading to the production of ketones. The resulting ketoacidosis contributes to metabolic acidosis.

Question 42

A client is diagnosed with a GI fistula and metabolic acidosis. What is the most likely cause of the acidosis?

A. Decreased reabsorption of hydrogen ions
B. Excessive retention of carbon dioxide
C. Increased lactic acid production from tissue hypoxia
D. Increased loss of bicarbonate through GI secretions

Answer 42

D. Increased loss of bicarbonate through GI secretions

Rationale: GI fistulas can result in the loss of bicarbonate-rich fluids, particularly from the intestines, leading to metabolic acidosis.

Question 43

A nurse is reviewing ABG results for a client with shock. The values are: pH 7.25, PaCO2 38 mm Hg, HCO3⁻ 16 mEq/L. What is the body’s compensatory mechanism for this acid-base imbalance?

A. Increased renal excretion of hydrogen ions
B. Increased respiratory rate to eliminate CO2
C. Decreased renal production of bicarbonate
D. Decreased respiratory rate to retain CO2

Answer 43

B. Increased respiratory rate to eliminate CO2

Rationale: In metabolic acidosis, the body compensates by increasing respiratory rate (Kussmaul respirations) to eliminate CO2 and reduce acidity.

Question 44

A client is admitted with metabolic alkalosis from excessive bicarbonate ingestion. Which nursing intervention is most appropriate to correct the underlying cause?

A. Administer sodium bicarbonate to neutralize gastric acid
B. Infuse IV potassium chloride to replace deficits
C. Monitor and treat for fluid volume deficit
D. Educate the client on limiting antacid use

Answer 44

D. Educate the client on limiting antacid use

Rationale: Excessive bicarbonate ingestion (e.g., from antacids) is a common cause of metabolic alkalosis. Education on proper antacid use addresses the underlying issue.

Question 45

A client has been taking a loop diuretic for congestive heart failure and is diagnosed with metabolic alkalosis. What is the primary cause of the acid-base imbalance in this client?

A. Excessive loss of hydrogen ions through the kidneys

B. Increased production of bicarbonate by the kidneys

C. Impaired excretion of carbon dioxide

D. Excessive loss of bicarbonate through the GI tract

Answer 45

A. Excessive loss of hydrogen ions through the kidneys

Rationale: Loop diuretics promote the excretion of hydrogen ions and potassium in the urine, leading to a loss of acid and the development of metabolic alkalosis.

Question 46

A nurse is caring for a client with prolonged vomiting. The client’s ABG results are: pH 7.48, PaCO2 45 mm Hg, HCO3⁻ 30 mEq/L. What is the correct interpretation of these findings?

A. Uncompensated metabolic alkalosis
B. Partially compensated metabolic alkalosis
C. Uncompensated respiratory alkalosis
D. Fully compensated metabolic alkalosis

Answer 46

A. Uncompensated metabolic alkalosis

Rationale: Elevated pH and HCO3⁻ with normal PaCO2 indicate metabolic alkalosis without compensation. Vomiting leads to the loss of hydrogen ions, contributing to alkalosis.

Question 47

A client receiving NG suctioning for several days develops metabolic alkalosis. What is the likely cause of this acid-base imbalance?

A. Loss of bicarbonate-rich pancreatic secretions
B. Excessive retention of carbon dioxide
C. Loss of gastric acid through suctioning
D. Increased hydrogen ion excretion by the kidneys

Answer 47

C. Loss of gastric acid through suctioning

Rationale: NG suctioning removes hydrochloric acid from the stomach, decreasing the body’s hydrogen ion concentration and leading to metabolic alkalosis.

Question 48

A client with mineralocorticoid excess is diagnosed with metabolic alkalosis. Which electrolyte imbalance is most likely to accompany this condition?

A. Hyperkalemia
B. Hypokalemia
C. Hypercalcemia
D. Hyponatremia

Answer 48

B. Hypokalemia

Rationale: Mineralocorticoid excess (e.g., from conditions like hyperaldosteronism) promotes renal excretion of potassium and hydrogen ions, resulting in hypokalemia and metabolic alkalosis.

Question 49

A client with chronic hypokalemia is admitted to the hospital. ABG results show: pH 7.50, PaCO2 46 mm Hg, HCO3⁻ 28 mEq/L. Which clinical finding supports the diagnosis of metabolic alkalosis?

A. Muscle weakness and decreased deep tendon reflexes
B. Kussmaul respirations and warm, flushed skin
C. Increased respiratory rate and decreased urine output
D. Cyanosis and peripheral edema

Answer 49

A. Muscle weakness and decreased deep tendon reflexes

Rationale: Metabolic alkalosis and hypokalemia are often associated. Hypokalemia causes muscle weakness and reduced reflexes, while metabolic alkalosis itself can cause neuromuscular excitability.

Question 50

A nurse reviews the ABG values: pH 7.45, PaCO2 50 mm Hg, HCO3⁻ 30 mEq/L. What condition is indicated?

A. Fully compensated metabolic alkalosis
B. Fully compensated respiratory acidosis
C. Partially compensated metabolic alkalosis
D. Fully compensated respiratory alkalosis

Answer 50

A. Fully compensated metabolic alkalosis

Rationale: The normal pH is slightly alkalotic. Elevated HCO3⁻ indicates metabolic alkalosis. The high PaCO2 reflects respiratory compensation.

Question 51

A client with renal failure has the following ABG results: pH 7.18, PaCO2 32 mm Hg, HCO3⁻ 15 mEq/L. How should the nurse interpret these values?

A. Fully compensated metabolic acidosis
B. Uncompensated respiratory acidosis
C. Partially compensated metabolic acidosis
D. Uncompensated metabolic acidosis

Answer 51

C. Partially compensated metabolic acidosis

Rationale: The low pH and low HCO3⁻ indicate metabolic acidosis. Low PaCO2 reflects respiratory compensation, though it has not fully normalized the pH.

Question 52

A nurse is assessing ABG values: pH 7.50, PaCO2 25 mm Hg, HCO3⁻ 24 mEq/L. Which condition is indicated by these findings?

A. Uncompensated metabolic alkalosis
B. Uncompensated respiratory alkalosis
C. Fully compensated respiratory alkalosis
D. Partially compensated respiratory alkalosis

Answer 52

B. Uncompensated respiratory alkalosis

Rationale: The elevated pH indicates alkalosis. The low PaCO2 points to a respiratory origin. Normal HCO3⁻ suggests no metabolic compensation.

Question 53

A client’s ABG values are as follows: pH 7.44, PaCO2 30 mm Hg, HCO3⁻ 20 mEq/L. What do these results suggest?

A. Fully compensated respiratory alkalosis
B. Fully compensated metabolic acidosis
C. Partially compensated respiratory alkalosis
D. Fully compensated respiratory acidosis

Answer 53

A. Fully compensated respiratory alkalosis

Rationale: The normal pH is slightly alkalotic. Low PaCO2 indicates respiratory alkalosis, and the low HCO3⁻ shows compensation by the kidneys.

Question 54

A client’s ABG results show: pH 7.32, PaCO2 48 mm Hg, HCO3⁻ 28 mEq/L. What is the correct interpretation?

A. Uncompensated metabolic acidosis
B. Partially compensated respiratory acidosis
C. Uncompensated respiratory acidosis
D. Fully compensated respiratory acidosis

Answer 54

B. Partially compensated respiratory acidosis

Rationale: The low pH indicates acidosis. The elevated PaCO2 points to a respiratory cause. Elevated HCO3⁻ indicates the kidneys are attempting to compensate.

Question 55

A client presents with ABG values: pH 7.58, PaCO2 45 mm Hg, HCO3⁻ 35 mEq/L. Which condition do these findings indicate?

A. Uncompensated metabolic alkalosis
B. Partially compensated metabolic alkalosis
C. Fully compensated metabolic alkalosis
D. Uncompensated respiratory alkalosis

Answer 55

A. Uncompensated metabolic alkalosis

Rationale: The elevated pH and HCO3⁻ point to metabolic alkalosis. A normal PaCO2 shows no respiratory compensation.

Question 56

A client in shock has ABG results of: pH 7.20, PaCO2 38 mm Hg, HCO3⁻ 15 mEq/L. What is the correct interpretation of these results?

A. Uncompensated metabolic acidosis
B. Uncompensated respiratory acidosis
C. Partially compensated metabolic acidosis
D. Fully compensated metabolic acidosis

Answer 56

A. Uncompensated metabolic acidosis

Rationale: The low pH and low HCO3⁻ point to metabolic acidosis. Normal PaCO2 indicates no respiratory compensation.

Question 57

ABG results for a client are as follows: pH 7.47, PaCO2 32 mm Hg, HCO3⁻ 22 mEq/L. What is the likely condition?

A. Partially compensated metabolic alkalosis
B. Uncompensated metabolic alkalosis
C. Uncompensated respiratory alkalosis
D. Uncompensated respiratory acidosis

Answer 57

C. Uncompensated respiratory alkalosis

Rationale: The elevated pH indicates alkalosis. Low PaCO2 indicates respiratory origin. Normal HCO3⁻ suggests no metabolic compensation.

Question 58

A nurse reviews ABG results: pH 7.38, PaCO2 48 mm Hg, HCO3⁻ 30 mEq/L. What do these values indicate?

A. Uncompensated respiratory alkalosis
B. Fully compensated respiratory acidosis
C. Fully compensated metabolic alkalosis
D. Partially compensated respiratory acidosis

Answer 58

B. Fully compensated respiratory acidosis

Rationale: The pH is normal but slightly acidic, PaCO2 is high (indicating acidosis), and HCO3⁻ is elevated, showing compensation. Full compensation is indicated by the normal pH.

Question 59

A client’s ABG results are as follows: pH 7.25, PaCO2 50 mm Hg, HCO3⁻ 24 mEq/L. What is the correct interpretation of this ABG?

A. Uncompensated respiratory acidosis
B. Partially compensated respiratory acidosis
C. Uncompensated metabolic acidosis
D. Fully compensated respiratory acidosis

Answer 59

A. Uncompensated respiratory acidosis

Rationale: The low pH indicates acidosis. The elevated PaCO2 points to a respiratory origin. Normal HCO3⁻ levels indicate no compensation has occurred.

Question 60

A patient who was involved in a motor vehicle crash has had a tracheostomy placed to allow for continued mechanical ventilation. How would the nurse interpret the following arterial blood gas results: pH 7.48, PaO 2 85 mm Hg, PaCO 2 32 mm Hg, and HCO 3 25 mEq/L?

a. Metabolic acidosis

b. Metabolic alkalosis

c. Respiratory acidosis

d. Respiratory alkalosis

Answer 60

d. Respiratory alkalosis

Rationale: The pH indicates that the patient has alkalosis and the low PaCO2 indicates a respiratory cause. The other responses are incorrect based on the pH and the normal HCO3 .

Question 61

A patient who is lethargic with deep, rapid respirations has the following arterial blood gas (ABG) results: pH 7.32, PaO2 88 mm Hg, PaCO2 35 mm Hg, and HCO3 16 mEq/L. How would the nurse interpret these results?

a. Metabolic acidosis

b. Metabolic alkalosis

c. Respiratory acidosis

d. Respiratory alkalosis

Answer 61

a. Metabolic acidosis

Rationale: The pH and HCO3 indicate the patient has a metabolic acidosis. The ABGs are inconsistent with the other responses.

Question 62

The laboratory technician calls with arterial blood gas (ABG) results on four patients. Which result is most important for the nurse to report immediately to the health care provider?

a. pH 7.34, PaO2 82 mm Hg, PaCO2 40 mm Hg, and O2 sat 97%

b. pH 7.35, PaO2 85 mm Hg, PaC 2 50 mm Hg, and O2 sat 95%

c. pH 7.46, PaO2 90 mm Hg, PaCO 2 32 mm Hg, and O2 sat 98%

d. pH 7.31, PaO2 91 mm Hg, PaCO2 50 mm Hg, and O2 sat 96%

Answer 62

d. pH 7.31, PaO2 91 mm Hg, PaCO2 50 mm Hg, and O2 sat 96%

Rationale: ABGs with a decreased pH and increased PaCO 2 indicate uncompensated respiratory acidosis and should be reported to the health care provider. the other values are normal, close to normal, or compensated.