V/Q Defects

Question 1

V/Q ratio

Answer 1

V - ventilation (alveolar ventilation)

Q - perfusion (pulmonary blood flow)

NORMAL - 0.8 mL

Question 2

HIGH V/Q

Answer 2

high PO2
low PCO2 (lung apex)

Question 3

LOW V/Q

Answer 3

low PO2
high PCO2 (lung base)

Question 4

V/Q = ZERO

Answer 4

shunt (R-L shunt, airway obstructions)

100% O2 does NOT improve PaO2

i.e. foreign body obstruction

Question 5

V/Q = INFINITE

Answer 5

dead space (pulmonary embolism)

100

Question 6

In an upright position which area of the lung will have a HIGHER compliance

Answer 6

BASE of the lungs

100% O2 improves PaO2