ADULT CCRN CERTIFICATION
MODULE 4
RESPIRATORY
4 PRACTICE TESTS
2024
1. A 65-year-old man with a history of chronic obstructive pulmonary disease (COPD) and
hypertension presents to the emergency department with dyspnea, chest pain, and cough. He
is diagnosed with acute pulmonary embolism (PE) and started on anticoagulation therapy. His
arterial blood gas (ABG) results are: pH 7.32, PaCO2 50 mmHg, PaO2 60 mmHg, HCO3 26
mEq/L, SaO2 90%. Which of the following statements is true about his ABG results?
A) He has respiratory acidosis with partial compensation.
B) He has respiratory alkalosis with partial compensation.
C) He has metabolic acidosis with partial compensation.
D) He has metabolic alkalosis with partial compensation.
Answer: A) He has respiratory acidosis with partial compensation. Rationale: Respiratory
acidosis is caused by hypoventilation, which leads to increased PaCO2 and decreased pH. The
kidneys try to compensate by retaining HCO3, which increases the base excess. However, the
compensation is incomplete because the pH is still below the normal range (7.35-7.45).
2. A 45-year-old woman with a history of asthma and diabetes mellitus is admitted to the
intensive care unit (ICU) with severe acute respiratory distress syndrome (ARDS) due to COVID-
19 infection. She is intubated and mechanically ventilated with a tidal volume of 6 mL/kg, a
positive end-expiratory pressure (PEEP) of 10 cm H2O, and a fraction of inspired oxygen (FiO2)
of 0.8. Her ABG results are: pH 7.28, PaCO2 48 mmHg, PaO2 55 mmHg, HCO3 22 mEq/L, SaO2
88%. Which of the following interventions is most appropriate to improve her oxygenation?
A) Increase the tidal volume to 8 mL/kg.
B) Increase the PEEP to 15 cm H2O.
C) Decrease the FiO2 to 0.6.
D) Decrease the respiratory rate to 10 breaths/min.
Answer: B) Increase the PEEP to 15 cm H2O. Rationale: ARDS is characterized by alveolar
collapse and pulmonary edema, which impair gas exchange and cause hypoxemia. PEEP helps
to recruit collapsed alveoli and increase functional residual capacity, which improves
oxygenation. Increasing the tidal volume or decreasing the respiratory rate would worsen
ventilation-perfusion mismatch and increase the risk of ventilator-induced lung injury.
,Decreasing the FiO2 would lower the oxygen delivery to the tissues.
3. A 55-year-old man with a history of smoking and coronary artery disease undergoes coronary
artery bypass graft surgery. He develops postoperative complications, including atrial
fibrillation, pneumonia, and acute kidney injury. He is transferred to the ICU and placed on
mechanical ventilation. His ABG results are: pH 7.25, PaCO2 40 mmHg, PaO2 70 mmHg, HCO3
18 mEq/L, SaO2 92%. Which of the following statements is true about his ABG results?
A) He has respiratory acidosis with no compensation.
B) He has respiratory alkalosis with no compensation.
C) He has metabolic acidosis with no compensation.
D) He has metabolic alkalosis with no compensation.
Answer: C) He has metabolic acidosis with no compensation. Rationale: Metabolic acidosis is
caused by an excess of nonvolatile acids or a loss of bicarbonate, which leads to decreased
HCO3 and decreased pH. The lungs try to compensate by increasing ventilation, which lowers
PaCO2. However, the compensation is incomplete because the pH is still below the normal
range (7.35-7.45).
4. A 35-year-old woman with a history of systemic lupus erythematosus (SLE) and chronic
kidney disease (CKD) is admitted to the hospital with fever, rash, and joint pain. She is
diagnosed with a lupus flare and started on corticosteroids and immunosuppressants. Her ABG
results are: pH 7.48, PaCO2 32 mmHg, PaO2 80 mmHg, HCO3 24 mEq/L, SaO2 95%. Which of
the following statements is true about her ABG results?
A) She has respiratory acidosis with complete compensation.
B) She has respiratory alkalosis with complete compensation.
C) She has metabolic acidosis with complete compensation.
D) She has metabolic alkalosis with complete compensation.
Answer: B) She has respiratory alkalosis with complete compensation. Rationale: Respiratory
alkalosis is caused by hyperventilation, which leads to decreased PaCO2 and increased pH. The
kidneys try to compensate by excreting HCO3, which decreases the base excess. However, the
compensation is complete because the pH is within the normal range (7.35-7.45).
5. A 25-year-old man with a history of cystic fibrosis and bronchiectasis is admitted to the
hospital with an acute exacerbation of his chronic respiratory failure. He is treated with
antibiotics, bronchodilators, and chest physiotherapy. His ABG results are: pH 7.38, PaCO2 60
mmHg, PaO2 65 mmHg, HCO3 35 mEq/L, SaO2 90%. Which of the following statements is true
about his ABG results?
A) He has respiratory acidosis with chronic compensation.
B) He has respiratory alkalosis with chronic compensation.
C) He has metabolic acidosis with chronic compensation.
D) He has metabolic alkalosis with chronic compensation.
Answer: A) He has respiratory acidosis with chronic compensation. Rationale: Respiratory
acidosis is caused by hypoventilation, which leads to increased PaCO2 and decreased pH. The
kidneys try to compensate by retaining HCO3, which increases the base excess. The
compensation is chronic because the pH is within the normal range (7.35-7.45), but the PaCO2
,and HCO3 are both elevated.
6. A 75-year-old woman with a history of congestive heart failure and diabetes mellitus is
admitted to the hospital with acute pulmonary edema and hyperglycemia. She is treated with
diuretics, insulin, and oxygen therapy. Her ABG results are: pH 7.30, PaCO2 35 mmHg, PaO2 75
mmHg, HCO3 18 mEq/L, SaO2 93%. Which of the following statements is true about her ABG
results?
A) She has mixed respiratory and metabolic acidosis.
B) She has mixed respiratory and metabolic alkalosis.
C) She has mixed respiratory acidosis and metabolic alkalosis.
D) She has mixed respiratory alkalosis and metabolic acidosis.
Answer: D) She has mixed respiratory alkalosis and metabolic acidosis. Rationale: Mixed
disorders are caused by a combination of two or more primary acid-base disturbances that
affect the pH in opposite directions. In this case, the patient has respiratory alkalosis due to
hyperventilation from pulmonary edema, which lowers PaCO2 and raises pH; and metabolic
acidosis due to hyperglycemia from diabetes mellitus, which lowers HCO3 and lowers pH. The
net effect is a low pH with a normal or low PaCO2 and a low HCO3.
7. A 50-year-old man with a history of alcohol abuse and cirrhosis is admitted to the hospital
with ascites, jaundice, and hepatic encephalopathy. He is treated with lactulose, antibiotics,
and paracentesis. His ABG results are: pH 7.45, PaCO2 45 mmHg, PaO2 85 mmHg, HCO3 32
mEq/L, SaO2 96%. Which of the following statements is true about his ABG results?
A) He has respiratory acidosis with acute compensation.
B) He has respiratory alkalosis with acute compensation.
C) He has metabolic acidosis with acute compensation.
D) He has metabolic alkalosis with acute compensation.
Answer: D)
Question 1: Arterial Blood Gas Analysis
A patient presents with the following ABG values: pH 7.25, PaCO2 50 mmHg, HCO3- 24 mEq/L,
PaO2 85 mmHg. What is the primary acid-base disorder?
A. Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Metabolic alkalosis
Answer: A. Respiratory acidosis
Rationale: The low pH and elevated PaCO2 indicate respiratory acidosis, characterized by
inadequate alveolar ventilation leading to CO2 retention and subsequent acidosis.
, Question 2: Acute Respiratory Distress Syndrome
Which of the following is a hallmark clinical feature of acute respiratory distress syndrome
(ARDS)?
A. Normal pulmonary capillary wedge pressure
B. Hypercapnia
C. Hypoxemia with normal chest radiograph
D. Increased lung compliance
Answer: C. Hypoxemia with normal chest radiograph
Rationale: ARDS is characterized by severe hypoxemia with a normal or non-specific chest
radiograph and is often associated with non-cardiogenic pulmonary edema.
Question 3: Acute Pulmonary Embolus
A patient presents with sudden onset dyspnea, pleuritic chest pain, and hemoptysis. Which
diagnostic test is most appropriate for confirming the presence of acute pulmonary embolus
(APE)?
A. Ventilation-perfusion (V/Q) scan
B. D-dimer assay
C. Chest x-ray
D. Echocardiography
Answer: A. Ventilation-perfusion (V/Q) scan
Rationale: V/Q scan is a sensitive and specific test for diagnosing APE by demonstrating
ventilation-perfusion mismatch in the lungs.
Question 4: Respiratory Failure
In type I respiratory failure, which ABG finding is most characteristic?
A. PaO2 50 mmHg
C. pH 30 mEq/L
Answer: A. PaO2 50 mmHg
C. pH 30 mEq/L
Answer: B. PaCO2 > 50 mmHg
Rationale: Type II respiratory failure is characterized by hypercapnia, indicated by a PaCO2 > 50
MODULE 4
RESPIRATORY
4 PRACTICE TESTS
2024
1. A 65-year-old man with a history of chronic obstructive pulmonary disease (COPD) and
hypertension presents to the emergency department with dyspnea, chest pain, and cough. He
is diagnosed with acute pulmonary embolism (PE) and started on anticoagulation therapy. His
arterial blood gas (ABG) results are: pH 7.32, PaCO2 50 mmHg, PaO2 60 mmHg, HCO3 26
mEq/L, SaO2 90%. Which of the following statements is true about his ABG results?
A) He has respiratory acidosis with partial compensation.
B) He has respiratory alkalosis with partial compensation.
C) He has metabolic acidosis with partial compensation.
D) He has metabolic alkalosis with partial compensation.
Answer: A) He has respiratory acidosis with partial compensation. Rationale: Respiratory
acidosis is caused by hypoventilation, which leads to increased PaCO2 and decreased pH. The
kidneys try to compensate by retaining HCO3, which increases the base excess. However, the
compensation is incomplete because the pH is still below the normal range (7.35-7.45).
2. A 45-year-old woman with a history of asthma and diabetes mellitus is admitted to the
intensive care unit (ICU) with severe acute respiratory distress syndrome (ARDS) due to COVID-
19 infection. She is intubated and mechanically ventilated with a tidal volume of 6 mL/kg, a
positive end-expiratory pressure (PEEP) of 10 cm H2O, and a fraction of inspired oxygen (FiO2)
of 0.8. Her ABG results are: pH 7.28, PaCO2 48 mmHg, PaO2 55 mmHg, HCO3 22 mEq/L, SaO2
88%. Which of the following interventions is most appropriate to improve her oxygenation?
A) Increase the tidal volume to 8 mL/kg.
B) Increase the PEEP to 15 cm H2O.
C) Decrease the FiO2 to 0.6.
D) Decrease the respiratory rate to 10 breaths/min.
Answer: B) Increase the PEEP to 15 cm H2O. Rationale: ARDS is characterized by alveolar
collapse and pulmonary edema, which impair gas exchange and cause hypoxemia. PEEP helps
to recruit collapsed alveoli and increase functional residual capacity, which improves
oxygenation. Increasing the tidal volume or decreasing the respiratory rate would worsen
ventilation-perfusion mismatch and increase the risk of ventilator-induced lung injury.
,Decreasing the FiO2 would lower the oxygen delivery to the tissues.
3. A 55-year-old man with a history of smoking and coronary artery disease undergoes coronary
artery bypass graft surgery. He develops postoperative complications, including atrial
fibrillation, pneumonia, and acute kidney injury. He is transferred to the ICU and placed on
mechanical ventilation. His ABG results are: pH 7.25, PaCO2 40 mmHg, PaO2 70 mmHg, HCO3
18 mEq/L, SaO2 92%. Which of the following statements is true about his ABG results?
A) He has respiratory acidosis with no compensation.
B) He has respiratory alkalosis with no compensation.
C) He has metabolic acidosis with no compensation.
D) He has metabolic alkalosis with no compensation.
Answer: C) He has metabolic acidosis with no compensation. Rationale: Metabolic acidosis is
caused by an excess of nonvolatile acids or a loss of bicarbonate, which leads to decreased
HCO3 and decreased pH. The lungs try to compensate by increasing ventilation, which lowers
PaCO2. However, the compensation is incomplete because the pH is still below the normal
range (7.35-7.45).
4. A 35-year-old woman with a history of systemic lupus erythematosus (SLE) and chronic
kidney disease (CKD) is admitted to the hospital with fever, rash, and joint pain. She is
diagnosed with a lupus flare and started on corticosteroids and immunosuppressants. Her ABG
results are: pH 7.48, PaCO2 32 mmHg, PaO2 80 mmHg, HCO3 24 mEq/L, SaO2 95%. Which of
the following statements is true about her ABG results?
A) She has respiratory acidosis with complete compensation.
B) She has respiratory alkalosis with complete compensation.
C) She has metabolic acidosis with complete compensation.
D) She has metabolic alkalosis with complete compensation.
Answer: B) She has respiratory alkalosis with complete compensation. Rationale: Respiratory
alkalosis is caused by hyperventilation, which leads to decreased PaCO2 and increased pH. The
kidneys try to compensate by excreting HCO3, which decreases the base excess. However, the
compensation is complete because the pH is within the normal range (7.35-7.45).
5. A 25-year-old man with a history of cystic fibrosis and bronchiectasis is admitted to the
hospital with an acute exacerbation of his chronic respiratory failure. He is treated with
antibiotics, bronchodilators, and chest physiotherapy. His ABG results are: pH 7.38, PaCO2 60
mmHg, PaO2 65 mmHg, HCO3 35 mEq/L, SaO2 90%. Which of the following statements is true
about his ABG results?
A) He has respiratory acidosis with chronic compensation.
B) He has respiratory alkalosis with chronic compensation.
C) He has metabolic acidosis with chronic compensation.
D) He has metabolic alkalosis with chronic compensation.
Answer: A) He has respiratory acidosis with chronic compensation. Rationale: Respiratory
acidosis is caused by hypoventilation, which leads to increased PaCO2 and decreased pH. The
kidneys try to compensate by retaining HCO3, which increases the base excess. The
compensation is chronic because the pH is within the normal range (7.35-7.45), but the PaCO2
,and HCO3 are both elevated.
6. A 75-year-old woman with a history of congestive heart failure and diabetes mellitus is
admitted to the hospital with acute pulmonary edema and hyperglycemia. She is treated with
diuretics, insulin, and oxygen therapy. Her ABG results are: pH 7.30, PaCO2 35 mmHg, PaO2 75
mmHg, HCO3 18 mEq/L, SaO2 93%. Which of the following statements is true about her ABG
results?
A) She has mixed respiratory and metabolic acidosis.
B) She has mixed respiratory and metabolic alkalosis.
C) She has mixed respiratory acidosis and metabolic alkalosis.
D) She has mixed respiratory alkalosis and metabolic acidosis.
Answer: D) She has mixed respiratory alkalosis and metabolic acidosis. Rationale: Mixed
disorders are caused by a combination of two or more primary acid-base disturbances that
affect the pH in opposite directions. In this case, the patient has respiratory alkalosis due to
hyperventilation from pulmonary edema, which lowers PaCO2 and raises pH; and metabolic
acidosis due to hyperglycemia from diabetes mellitus, which lowers HCO3 and lowers pH. The
net effect is a low pH with a normal or low PaCO2 and a low HCO3.
7. A 50-year-old man with a history of alcohol abuse and cirrhosis is admitted to the hospital
with ascites, jaundice, and hepatic encephalopathy. He is treated with lactulose, antibiotics,
and paracentesis. His ABG results are: pH 7.45, PaCO2 45 mmHg, PaO2 85 mmHg, HCO3 32
mEq/L, SaO2 96%. Which of the following statements is true about his ABG results?
A) He has respiratory acidosis with acute compensation.
B) He has respiratory alkalosis with acute compensation.
C) He has metabolic acidosis with acute compensation.
D) He has metabolic alkalosis with acute compensation.
Answer: D)
Question 1: Arterial Blood Gas Analysis
A patient presents with the following ABG values: pH 7.25, PaCO2 50 mmHg, HCO3- 24 mEq/L,
PaO2 85 mmHg. What is the primary acid-base disorder?
A. Respiratory acidosis
B. Respiratory alkalosis
C. Metabolic acidosis
D. Metabolic alkalosis
Answer: A. Respiratory acidosis
Rationale: The low pH and elevated PaCO2 indicate respiratory acidosis, characterized by
inadequate alveolar ventilation leading to CO2 retention and subsequent acidosis.
, Question 2: Acute Respiratory Distress Syndrome
Which of the following is a hallmark clinical feature of acute respiratory distress syndrome
(ARDS)?
A. Normal pulmonary capillary wedge pressure
B. Hypercapnia
C. Hypoxemia with normal chest radiograph
D. Increased lung compliance
Answer: C. Hypoxemia with normal chest radiograph
Rationale: ARDS is characterized by severe hypoxemia with a normal or non-specific chest
radiograph and is often associated with non-cardiogenic pulmonary edema.
Question 3: Acute Pulmonary Embolus
A patient presents with sudden onset dyspnea, pleuritic chest pain, and hemoptysis. Which
diagnostic test is most appropriate for confirming the presence of acute pulmonary embolus
(APE)?
A. Ventilation-perfusion (V/Q) scan
B. D-dimer assay
C. Chest x-ray
D. Echocardiography
Answer: A. Ventilation-perfusion (V/Q) scan
Rationale: V/Q scan is a sensitive and specific test for diagnosing APE by demonstrating
ventilation-perfusion mismatch in the lungs.
Question 4: Respiratory Failure
In type I respiratory failure, which ABG finding is most characteristic?
A. PaO2 50 mmHg
C. pH 30 mEq/L
Answer: A. PaO2 50 mmHg
C. pH 30 mEq/L
Answer: B. PaCO2 > 50 mmHg
Rationale: Type II respiratory failure is characterized by hypercapnia, indicated by a PaCO2 > 50
