CCRN Exam: Respiratory 2025
Questions and Answers
What is minute ventilation? What is the normal value for minute ventilation? -
ANSWER-Minute ventilation = Tidal Volume x Respiratory Rate
Normal MV = 5-8 L/minute
What is the optimal body position for ventilation? - ANSWER-Upright sitting
position - low Fowler's
Why is high Fowler's not optimal for ventilation? - ANSWER-High Fowler's
position increases pressure of abdominal contents against the diaphragm, which
decreases diaphragmatic excursion.
Do you want the good or bad lung down? - ANSWER-Want the GOOD lung
DOWN = think of the effect of gravity on pulmonary perfusion
Example: If you turn a patient with a right lung pneumonia to the right side (bad
lung down), more blood goes to the right side and the patient may become
hypoxic. (There is a decrease in blood flow past the alveoli due to the pneumonia.)
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,What is dead space ventilation? - ANSWER-The volume of air that does not
participate in gas exchange
What is anatomic dead space? - ANSWER-2 mL/kg of tidal volume
We all have this, it is normal. There is no gas exchange at the level of the nose
down to the terminal bronchioles/alveoli. This area has air (ventilation), but no
alveolar-capillary membrane.
What is alveolar dead space? What is an example of alveolar dead space? -
ANSWER-Pathologic, non-perfused alveoli
A pulmonary embolism causes alveolar dead space. There is air the alveolus, but
no blood is available to that area to pick up the oxygen in the alveolus.
What is physiologic dead space? - ANSWER-Anatomic dead space + alveolar dead
space
What is V/Q ratio and what is the ideal lung unit (V/Q ratio number)? -
ANSWER-V/Q ratio = ventilation/perfusion ratio
4 L ventilation/min (V) ÷ 5 L perfusion/min (Q) =
0.8 normal V/Q ratio
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, A normal V/Q ratio is when there are no problems with either ventilation or
perfusion, the patient will have normal gas exchange on room air.
What does a negative V/Q scan tell us? - ANSWER-Effectively rules out a
pulmonary embolism
What does an intermediate V/Q scan indicate? - ANSWER-< 60% change of a
pulmonary embolism
Does not rule out a PE
What does a low V/Q scan indicate? - ANSWER-< 40% chance of a pulmonary
embolism
Does not rule out a PE
What does a high probability V/Q scan indicate? - ANSWER-97% chance of a
pulmonary embolism
What increases the specificity for pulmonary embolism with a low or intermediate
V/Q scan? - ANSWER-A positive D-dimer
What is a shunt? - ANSWER-An extreme V/Q mismatch
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Questions and Answers
What is minute ventilation? What is the normal value for minute ventilation? -
ANSWER-Minute ventilation = Tidal Volume x Respiratory Rate
Normal MV = 5-8 L/minute
What is the optimal body position for ventilation? - ANSWER-Upright sitting
position - low Fowler's
Why is high Fowler's not optimal for ventilation? - ANSWER-High Fowler's
position increases pressure of abdominal contents against the diaphragm, which
decreases diaphragmatic excursion.
Do you want the good or bad lung down? - ANSWER-Want the GOOD lung
DOWN = think of the effect of gravity on pulmonary perfusion
Example: If you turn a patient with a right lung pneumonia to the right side (bad
lung down), more blood goes to the right side and the patient may become
hypoxic. (There is a decrease in blood flow past the alveoli due to the pneumonia.)
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
,What is dead space ventilation? - ANSWER-The volume of air that does not
participate in gas exchange
What is anatomic dead space? - ANSWER-2 mL/kg of tidal volume
We all have this, it is normal. There is no gas exchange at the level of the nose
down to the terminal bronchioles/alveoli. This area has air (ventilation), but no
alveolar-capillary membrane.
What is alveolar dead space? What is an example of alveolar dead space? -
ANSWER-Pathologic, non-perfused alveoli
A pulmonary embolism causes alveolar dead space. There is air the alveolus, but
no blood is available to that area to pick up the oxygen in the alveolus.
What is physiologic dead space? - ANSWER-Anatomic dead space + alveolar dead
space
What is V/Q ratio and what is the ideal lung unit (V/Q ratio number)? -
ANSWER-V/Q ratio = ventilation/perfusion ratio
4 L ventilation/min (V) ÷ 5 L perfusion/min (Q) =
0.8 normal V/Q ratio
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
, A normal V/Q ratio is when there are no problems with either ventilation or
perfusion, the patient will have normal gas exchange on room air.
What does a negative V/Q scan tell us? - ANSWER-Effectively rules out a
pulmonary embolism
What does an intermediate V/Q scan indicate? - ANSWER-< 60% change of a
pulmonary embolism
Does not rule out a PE
What does a low V/Q scan indicate? - ANSWER-< 40% chance of a pulmonary
embolism
Does not rule out a PE
What does a high probability V/Q scan indicate? - ANSWER-97% chance of a
pulmonary embolism
What increases the specificity for pulmonary embolism with a low or intermediate
V/Q scan? - ANSWER-A positive D-dimer
What is a shunt? - ANSWER-An extreme V/Q mismatch
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 3
