Pulmonary function testing

Question 1

PFT

Answer 1

pulmonary function testing

Question 2

TV

Answer 2

tidal volume

volume of air pt brings in and out w/ each breath during tidal (resting) breathing

Question 3

TLC

Answer 3

total lung capacity

how much air pt can inhale

Question 4

FRC

Answer 4

functional residual capacity

amount of air left in lungs after exhalation during tidal (resting) breathing (what’s left –> residual)

depends on battle b/n lungs (wants to recoil to lower volume) and chest wall (wants to recoil to higher volume)

Question 5

RV

Answer 5

residual volume

volume of air left in lungs after complete exhalation (what’s left –> residual)

Question 6

FEV1

Answer 6

forced expiratory volume in 1 second

volume exhaled in 1st second of exhalation

Question 7

VC

Answer 7

vital capacity

total volume exhaled during spirometry in 1 breath

Question 8

FVC

Answer 8

forced vital capacity

total volume exhaled during forced exhalation

Question 9

normal FEV1/VC ratio

Answer 9

> 70% or 0.7

Question 10

why would FEV1/VC ratio be low?

Answer 10

obstruction –> harder to exhale a lot during 1st second –> lower FEV1 –> lower FEV1/VC ratio

Question 11

3 major functional abnormalities ID on PFT

Answer 11

1) obstructive disease
2) restrictive diseases
3) pulmonary vascular diseases

Question 12

PFT of obstructive disease

Answer 12

low FEV1/FVC

airflow obstructed, usually on exhalation
can’t exhale as much air during 1st second

Question 13

PFT of restrictive disease

Answer 13

low TLC

can’t expand lung enough when inhaling
d/t: intrapulmonary (bad lung parenchyma, ex: pulmonary fibrosis) or extrapulmonary (ex: paralysis)

Question 14

PFT of pulmonary vascular diseases

Answer 14

low DLCO

problem w/ pulmonary vasculature –> less blood flow through pulmonary capillary network –> less surface area for diffusion

ex: pulmonary arterial hypertension