Ventilation-Perfusion Relationships Flashcards Preview

Pulmonology > Ventilation-Perfusion Relationships > Flashcards

Flashcards in Ventilation-Perfusion Relationships Deck (10):
0

How can the body compensate for low V in an area to maintain V/Q balance?

Hypoxic vasoconstriction- lowers Q.

1

What does a pulmonary embolus do to V/Q?

Dead space is created -> "infinite" V/Q

2

Does low V/Q (e.g. from pneumonia, edema) cause predominately hypoxia or hypercarbia?

Hypoxia, predominately.
(Hyperventilation can compensate for the hypercarbia... and CO2 has an easier time diffusing out across fluid in the alveoli?)

3

Does high V/Q cause predominately hypoxia or hypercarbia?

Predominately hypercarbia. (though hypoxia also occurs.)

4

What effect does low V/Q have on neighboring segments?

Hyperventilation -> increased ventilation to neighboring segments.

5

What effect does increased V/Q (dead space) have on neighboring, healthy statements?

Blood flow is increased to healthy segments.

6

In an upright perfusion, where in the lung are ventilation and perfusion the greatest.

Ventilation and perfusion are both greatest in the lower lungs.

7

In an upright person, how does V/Q ratio compare high in the lung vs. low in the lung?

V/Q is high at the top, low at the bottom.

8

If you have an area of high V/Q and an area of low V/Q, why do you still get hypoxemia?

Because of the shape of the hemoglobin O2-binding curve, increased V/Q won't increase arterial pO2 as much as low V/Q will lower it.

9

What is a typical acid/base status for a person with PE blocking one part of the lung?

Respiratory alkalosis. (dead space -> hypercarbia...)