QuestionSBA
QuestionChoice
This is incorrect because a pulmonary embolism causes a blockage in the blood vessels of the lung, leading to a decrease in perfusion but no change in ventilation. This leads to a greater V/Q ratio.
10007105
e
Causes an increase in both ventilation and perfusion, leading to an increase in the ratio
QuestionChoice
This is incorrect because a pulmonary embolism causes a blockage in the blood vessels of the lung, leading to a decrease in perfusion but no change in ventilation. This results in a increase in the V/Q ratio.
10007102
b
Causes a decrease in both ventilation and perfusion, leading to a decrease in the V/Q ratio
QuestionChoice
If the blood flow within the lungs is obstructed due to an embolus, perfusion to the lung is decreased. The ventilation is divided by a smaller number, hence the increase in V/Q ratio. If the embolus completely occluded a pulmonary artery, leading to zero perfusion, the ratio would theoretically be infinite.
10007101
a
Causes a decrease in perfusion but no change in ventilation, leading to an increase in the V/Q ratio
QuestionChoice
This is incorrect because a pulmonary embolism causes a blockage in the blood vessels of the lung, leading to a decrease in perfusion but no change in ventilation. This leads to a greater V/Q ratio.
10007103
c
Causes a decrease in perfusion but an increase in ventilation, leading to an decrease in the ratio
QuestionChoice
This is incorrect because a pulmonary embolism causes a blockage in the blood vessels of the lung, leading to a decrease in perfusion but no change in ventilation. This leads to a greater V/Q ratio.
10007104
d
Causes an increase in perfusion but a decrease in ventilation, leading to a decrease in the ratio
Concept
Chapter
2693
4567
V/Q ratio
Topic
150
Respiratory physiology
13967
A 43-year-old woman attends the emergency department with pain in her chest that occurs when she breaths deeply. Her observations show saturations of 90% on room air, but are otherwise unremarkable. Her respiratory rate is 16.

A CTPA demonstrates a pulmonary embolism (PE).

Which of the following best explains the effect of a PE on the ventilation perfusion ratio (V/Q)?
a