Resp - Pulmonary Q/V

Question 1

normal V/Q

Answer 1

4/5 = 0.8

Question 2

normal V/Q with abnormal V and Q

Answer 2

lobar pneumonia
V in lobe decreased
hypoxia –> vasoconstriction
Q decreased

Question 3

ventilation and lung regions

Answer 3

highest in base (Pa>Pv>PA)

lowest in apex (PA > Pa)

Question 4

flow and lung regions

Answer 4

highest @ base

lowest @ apex

Question 5

V/Q in lung regions

Answer 5

high in apex (>1)

low in base (<1)

Question 6

Pip in lung regions

Answer 6

more negative @ apex (distend alveoli)

less negative @ base (don’t distend as much)

Question 7

normal P(A-a) O2

Answer 7

< 20 mm Hg
age/4 + 4
(increase w/ age)

Question 8

causes of hypoxemia

Answer 8

hypoventilation
low inspired O2
R/L shunt
V/Q mismatch
diffusion impairment 
(first 2 have normal P(A-a)O2

Question 9

hypoxemia

Answer 9

PaO2 < 80

Question 10

hypoventilation causes

Answer 10

depressed respiration (morphine, sedatives)
neuromuscular diseases

Question 11

hypoventilation Ps

Answer 11

PAO2 down (RR down)
P(A-a)O2 normal (PAO2 and PaO2 lower qually - no lung problem)

Question 12

hypoventilation Tx

Answer 12

supplemental O2

Question 13

low inspired O2 causes

Answer 13

Patm down (altitude)
FIO2 down (improper anesthesia)

Question 14

low inspired O2 Ps

Answer 14

PAO2 down (PIO2 down)
P(A-a)O2 normal (O2 equilibrium normal)

Question 15

low inspired O2 Tx

Answer 15

supplemental O2

Question 16

R/L shunt causes

Answer 16

congenital defect
foramen ovale open
alveolar filling/atelectasis

Question 17

R/L shunt Ps

Answer 17

P(A-a)O2 up (A same, a down)
PaO2 down (added deoxygenated blood)
PaCO2 normal or up

Question 18

R/L shunt Tx

Answer 18

NOT O2

Question 19

V/Q mismatch causes

Answer 19

pneumonia
pulmonary embolism
COPD

Question 20

V/Q mismatch

Answer 20

usually Q normal

P(A-a)O2 increased

Question 21

V/Q mismatch Tx

Answer 21

supplemental O2

Question 22

physiologic response to low V/Q

Answer 22

PaO2 down –> regional pulm vasoconstriction
put blood in good spots
Q goes down to match V

Question 23

physiologic response to high V/Q

Answer 23

PaCO2 down –> regional bronchconstriction
put air in good spots
V goes down to match Q

Question 24

low V/Q and PaO2/CO2

Answer 24

low V/Q - high ventilation or low perfusion –> low PaO2, high PaCO2

Question 25

high V/Q and PaO2/CO2

Answer 25

high V/Q - low ventilation or high persusion –> high PaO2, low PaCO2

Question 26

diffusion impairment cause

Answer 26

interstitial lung disease (scarring
pulmonary fibrosis
** during exercise

Question 27

diffusion impairment Ps

Answer 27

P(A-a)O2 normal @ rest
P(A-a)O2 increased during exercise
PaCO2 is normal

Question 28

diffusion impairment mech

Answer 28

collagen deposition in interstitium prevents O2 diffusion

exercise –> RBCs going by faster than can pick up O2