Pulmonary CCRN study questions 2025
with Answers
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 - ANSWER-D
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,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 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 - ANSWER-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.
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, 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%
C. FEV1/FVC ratio > 80%
D. Normal FEV1/FVC ratio - ANSWER-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?
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with Answers
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 - ANSWER-D
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
,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 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 - ANSWER-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.
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
, 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%
C. FEV1/FVC ratio > 80%
D. Normal FEV1/FVC ratio - ANSWER-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?
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 3
