Deck 23: Ventilation

Question 1

Which of the following is not a primary cause of hypoxemia (low oxygen level in the blood)?

A)Anatomical shunt
B)Physiological shunt
C)Low V̇/Q̇
D)Increased dead space

Answer 1

D

Question 2

In comparison with pulmonary blood flow at rest in the upright position,pulmonary blood flow when upright during exercise in normal individuals is:

A)Distributed more to the bottom of the lung than to the top.
B)Distributed more to the top of the lung than to the bottom.
C)Distributed essentially evenly between the top and the bottom of the lung.
D)Is too highly variable to be determined.

Answer 2

C

Question 3

If the oxygen consumption is 200 mL/minute and the carbon dioxide production is 140 mL/minute,what is the respiratory quotient?

A)60 mL/minute
B)0.8
C)0.7
D)143 mL/minute

Answer 3

C

Question 4

Which of the following does not directly affect the alveolar partial pressure of oxygen?

A)Arterial partial pressure of carbon dioxide (Paco₂)
B)Atmospheric pressure
C)Tidal volume
D)Fraction of inspired oxygen
E)Oxygen consumption and carbon dioxide production (R)

Question 5

A twofold increase in the blood flow through a pulmonary arteriole is associated with:

A)No significant change in pulmonary vascular resistance.
B)A twofold increase in pulmonary vascular resistance.
C)A fourfold increase in pulmonary vascular resistance.
D)A 15-fold increase in pulmonary vascular resistance.

Question 6

A patient is admitted to the hospital because of hypoxemia.While the patient breathes ambient air,the arterial partial pressure of oxygen (Pao₂)is 50 mm Hg with an oxygen saturation of 82%.When the patient breathes 100% oxygen through a non-rebreathing mask,the Pao₂ is 83 mm Hg with an oxygen saturation of 92%.The cause of this patient's hypoxemia is probably:

A)A physiological shunt.
B)Low V̇/Q̇.
C)Hypoventilation.
D)Decreased inspired oxygen.

Question 7

When the respiratory rate is 15 breaths per minute,tidal volume is 500 mL,and anatomical dead space volume is 150 mL,what is the minute ventilation?

A)2.25 L/minute
B)5.25 L/minute
C)7.50 L/minute
D)9.75 L/minute

Question 8

An individual with early lung disease has a tidal volume of 500 mL.What is the alveolar volume if the dead space doubles and the tidal volume remains the same? (Assume that the normal ratio of dead space ventilation per minute to tidal volume [V_D/V_T] = 0.25.)

A)150 mL
B)250 mL
C)300 mL
D)400 mL

Question 9

When alveolar ventilation (V_A)is reduced from 5 L/minute to 2.5 L/minute,the Paco₂ changes from 40 mm Hg to:

A)20 mm Hg.
B)60 mm Hg.
C)80 mm Hg .
D)100 mm Hg.
E)250 mm Hg.

Question 10

The Paco₂ decreases when:

A)Alveolar ventilation and CO₂ production are increased and dead space is increased.
B)Alveolar ventilation is decreased,CO₂ production is unchanged,and dead space is increased.
C)Alveolar ventilation is increased and CO₂ production and dead space are decreased.
D)Both alveolar ventilation and CO₂ production are decreased and dead space is increased.