Hypoxic Pulmonary Vasoconstriction Flashcards Preview

Apex 1 - 2 Respiratory II: Physiology (24) > Hypoxic Pulmonary Vasoconstriction > Flashcards

Flashcards in Hypoxic Pulmonary Vasoconstriction Deck (25)
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1

What physiologic process minimizes shunt by diverting pulmonary blood flow away from unventilated alveoli?

Hypoxic Pulmonary Vasoconstriction (HPV)

2

Agents that impair HPV

A. increase the shunt fraction & reduce PaO2

B. decrease the shunt fraction & increase PaO2

Increase the shunt fraction

&

Reduce PaO2

3

Agents that impair HPV

A. Halogenated anesthetics

B. IV anesthetic agents

Halogenated anesthetics

4

Halogenated anesthetics impair HPV at which MAC?

> 1 - 1.5 MAC

5

Agents that preserve HPV

A. Halogenated anesthetics

B. IV anesthetic agents

IV anesthetic agents

6

Hypoxic pulmonary vasoconstriction (HPV) is a local reaction that occurs in response to a reduction in

A. alveolar oxygen tension

B. arterial P02

alveolar oxygen tension

7

What's the only region in the body that responds to hypoxia with vasoconstriction?

Pulmonary vascular bed

8

HPV selectively increases the pulmonary vascular resistance in poorly ventilated areas to

A. minimize shunt flow to these regions

B. Increase shunt flow to these regions

minimize shunt flow to these regions

9

HPV selectively increases the pulmonary vascular resistance in poorly ventilated areas to minimize shunt flow to these regions. The response begins within

A. seconds

B. minutes

 

seconds

10

HPV selectively increases the pulmonary vascular resistance in poorly ventilated areas to minimize shunt flow to these regions. The response begins within seconds and achieves its full effect in about

A. 15 minutes

B. 90 minutes

15 minutes

11

Which protective mechanism minimizes shunt flow during atelectasis or one-lung ventilation?

 

HPV

12

Which two factors Impair HPV?

Drugs

Altered physiology

13

Which drug categories impair HPV?

Volatile anesthetics

Vasodilators, phosphodiesterase inhibitors, dobutamine, and some calcium channel blockers

Vasoconstrictive drugs

14

At which concentration do Volatile anesthetics  reduce the effectiveness of HPV?

> 1.5 MAC

(some texts say 1 MAC)

15

True or False

IV anesthetics affect HPV

False

IV anesthetics do NOT affect HPV

Ketamine, propofol, fentanyl, etc. will not increase shunt

16

Vasodilators, phosphodiesterase inhibitors, dobutamine, and some calcium channel blockers increase shunt flow by

A. facilitating HPV

B. inhibiting HPV

inhibiting HPV

17

Vasoconstrictive drugs such as phenylephrine, epinephrine, and dopamine may constrict well-oxygenated vessels. How would this affect shunt flow

increase shunt flow

18

Hypervolemia could be defined as LAP of which value?

 

LAP> 25 mmHg

19

How do Hypervolemia (LAP> 25 mmHg) and elevated cardiac output affect constricted vessels and shunt flow?

Distend constricted vessels

&

Increase shunt flow

20

How does hypovolemia affect vasculature in well ventilated alveolar units?

A. pulmonary vasoconstriction

B. pulmonary vasodilation

Pulmonary vasoconstriction

21

Which volume status is best to prevent HPV

A. Hypervolemia

B. Hypovolemia

C. Euvolemia

Euvolemia

22

Excessive PEEP or high tidal volumes

A. increase dead space (zone 1)

B.  decrease dead space (zone 1)

Increase dead space (zone 1)

 

23

Excessive PEEP or high tidal volumes

A. increase optimal V/Q matching

B. reduce optimal V/Q matching

Reduce optimal V/Q matching

24

Reference:

 

Nagelhout. Nurse Anesthesia. 6th ed. 2018. p. 637-638.

25

Excessive PEEP or high tidal volumes impair HPV by

A. increasing dead space (zone 1) and reducing optimal V/Q matching

B. reducing dead space (zone 1) and increasing optimal V/Q matching

increasing dead space (zone 1)

and

reducing optimal V/Q matching