2024 /2025 | © copyright | This work may not be copied for profit gain Excel!
Pulmonary CCRN study Questions and
Correct Answers | Latest Update
A patient presents with labored breathing and an RR of 40 beats per minute (bpm). The
following ABG is obtained:
PaO2 68
PaCO2 50
pH 7.34
SaO2 91%
HCO3 22
Which of the following is the most accurate interpretation of the above situation?
A. Normal ABG for COPD patient
B. Respiratory failure due to metabolic acidosis
C. Obstructive upper airway most likely causing respiratory failure
D. Respiratory failure due to dead space
✓ -:- D
Normally, as the minute ventilation (MV) increases, the PaCO2 should decrease. The
normal pattern is an inverse relationship. In dead space, the alveolar ventilation decreases
even as the respiratory rate increases. This results in an increase in CO2 and an abnormal
relationship between MV and PaCO2. The patient has respiratory acidosis, not metabolic
1|P a g e | G r a d e A + | 2 0 2 0 2 5
,2024 /2025 | © copyright | This work may not be copied for profit gain Excel!
acidosis. It is not a normal blood gas for a patient with COPD because the pH is abnormal.
There is no indication in this scenario that this would be an upper airway obstruction.
What is the compensatory mechanism for VQ shunting?
A. Decrease MV
B. Bronchoconstriction
C. Pulmonary vasoconstriction
D. Increase cardiac output
✓ -:- C
VQ shunting is perfusion without ventilation. A compensatory mechanism for the VQ shunt
is pulmonary vasoconstriction to redistribute blood flow to ventilated alveolar units. In VQ
shunts, patients increase their respiratory rate, causing an increase in min- ute ventilation.
Bronchoconstriction occurs with dead space in an attempt to shunt ven- tilation to perfused
alveoli. An increase in cardiac output can occur in response to tissue hypoxia but is not
considered a compensatory mechanism for a pulmonary shunt.
Which of the following findings would indicate the presence of obstructive airway disease?
A. FEV1/FVC ratio of < 60%
B. FEV1/FVC ratio 75% to 80%
2|P a g e | G r a d e A + | 2 0 2 0 2 5
, 2024 /2025 | © copyright | This work may not be copied for profit gain Excel!
C. FEV1/FVC ratio > 80%
D. Normal FEV1/FVC ratio
✓ -:- A
An obstructive airway disease causes a decrease in FEV1 with a relatively normal FVC
resulting in a decrease in the FEV1/FVC ratio. A normal ratio is 75% to 80%. The lower the
ratio, the greater the obstruction of airflow. This test is used to assess asthma patients
during bronchodilator treatments. A normal FEV1/FVC ratio would indicate a restrictive
airway disease.
A patient in the ICU is diagnosed with ARDS. The following are the ventilator settings and
ABG results:
SIMV 550 mL TV, Rate 16, 40%, PEEP 5
7.46 pH
48 PaCO2
82 PaO2
94% SaO2
What is the calculated PaO2/FiO2 ratio?
A. 120
B. 20
3|P a g e | G r a d e A + | 2 0 2 0 2 5
Pulmonary CCRN study Questions and
Correct Answers | Latest Update
A patient presents with labored breathing and an RR of 40 beats per minute (bpm). The
following ABG is obtained:
PaO2 68
PaCO2 50
pH 7.34
SaO2 91%
HCO3 22
Which of the following is the most accurate interpretation of the above situation?
A. Normal ABG for COPD patient
B. Respiratory failure due to metabolic acidosis
C. Obstructive upper airway most likely causing respiratory failure
D. Respiratory failure due to dead space
✓ -:- D
Normally, as the minute ventilation (MV) increases, the PaCO2 should decrease. The
normal pattern is an inverse relationship. In dead space, the alveolar ventilation decreases
even as the respiratory rate increases. This results in an increase in CO2 and an abnormal
relationship between MV and PaCO2. The patient has respiratory acidosis, not metabolic
1|P a g e | G r a d e A + | 2 0 2 0 2 5
,2024 /2025 | © copyright | This work may not be copied for profit gain Excel!
acidosis. It is not a normal blood gas for a patient with COPD because the pH is abnormal.
There is no indication in this scenario that this would be an upper airway obstruction.
What is the compensatory mechanism for VQ shunting?
A. Decrease MV
B. Bronchoconstriction
C. Pulmonary vasoconstriction
D. Increase cardiac output
✓ -:- C
VQ shunting is perfusion without ventilation. A compensatory mechanism for the VQ shunt
is pulmonary vasoconstriction to redistribute blood flow to ventilated alveolar units. In VQ
shunts, patients increase their respiratory rate, causing an increase in min- ute ventilation.
Bronchoconstriction occurs with dead space in an attempt to shunt ven- tilation to perfused
alveoli. An increase in cardiac output can occur in response to tissue hypoxia but is not
considered a compensatory mechanism for a pulmonary shunt.
Which of the following findings would indicate the presence of obstructive airway disease?
A. FEV1/FVC ratio of < 60%
B. FEV1/FVC ratio 75% to 80%
2|P a g e | G r a d e A + | 2 0 2 0 2 5
, 2024 /2025 | © copyright | This work may not be copied for profit gain Excel!
C. FEV1/FVC ratio > 80%
D. Normal FEV1/FVC ratio
✓ -:- A
An obstructive airway disease causes a decrease in FEV1 with a relatively normal FVC
resulting in a decrease in the FEV1/FVC ratio. A normal ratio is 75% to 80%. The lower the
ratio, the greater the obstruction of airflow. This test is used to assess asthma patients
during bronchodilator treatments. A normal FEV1/FVC ratio would indicate a restrictive
airway disease.
A patient in the ICU is diagnosed with ARDS. The following are the ventilator settings and
ABG results:
SIMV 550 mL TV, Rate 16, 40%, PEEP 5
7.46 pH
48 PaCO2
82 PaO2
94% SaO2
What is the calculated PaO2/FiO2 ratio?
A. 120
B. 20
3|P a g e | G r a d e A + | 2 0 2 0 2 5
