PFTs

Question 1

There will be a question on the graph of FEV1% as a function of age - comparing normal decline in FEV1 to the accelerated decline in COPD

Answer 1

just know it

Question 2

know your lung volumes, capacities, and how to calculate

Answer 2

will be on test (TV, IRV, ERV, RV, VC, FRC, TLC)

Question 3

in the ICU, we can use PEEP to oxygenate patients. what lung volume or capacity does PEEP affect in order to be effective?

Answer 3

PEEP increases FRC

Question 4

when you evaluate a spirometry, you compare to predicted normal. what are the factors (3) that go in to predicting normal, and how do they correlate

Answer 4

1) sex (male larger lungs)
2) age (negative correlation)
3) Height (positive correlation)

Question 5

what one key factor is NOT a predictor of normal for lung function measured by spirometry?

Answer 5

weight

Question 6

what is the definition of a positive bronchodilator response seen on PFT

Answer 6

an increase in FEV1 of 200 mL AND 12%
or
15% from basal FEV1

Question 7

does obstructive lung disease reduce FVC?

Answer 7

yes

Question 8

does restrictive lung disease reduce FVC?

Answer 8

yes

Question 9

how does obstructive lung disease affect FEV1/FVC ratio?

Answer 9

obstructive lung disease dec FEV1/FVC

Question 10

how does restrictive lung disease affect FEV1/FVC ratio?

Answer 10

restrictive lung dz inc FEV1/FVC

Question 11

what volume can you not measure with spirometry? what capacity can you not measure with spirometry?

Answer 11

cannot measure RV

so cannot measure FRC or TLC

Question 12

how do you measure RV and FRC?

Answer 12

body box (plethysmograph)

Question 13

what 4 factors will reduce TLC?

Answer 13

1) dz of thorax
2) inspiratory muscles
3) pleural dz
4) loss of functioning alveoli

Question 14

what 3 factors will reduce VC?

Answer 14

1) chest pain
2) fatigue
3) poor effort

Question 15

what is the mechanism of dyspnea in COPD, especially upon exercise?

Answer 15

dynamic hyperinflation - at baseline, a COPD pt has an inc FRC, which means their inspiratory capacity is already less. Once start exercising, they inc breathing rate, so they start trapping more air, stacking more air into their lungs on each breath, until their FRC is essentially at TLC, i.e. there is no more inspiratory capacity left and they can no longer breathe

Question 16

define compliance

Answer 16

the change in volume a lung has for a given change in pressure

Question 17

does asthma dec or inc compliance?

Answer 17

there is no change in compliance, if there are no complications

Question 18

emphysema compliance?

Answer 18

compliance is inc

Question 19

fibrosis compliance

Answer 19

compliance is dec

Question 20

a normal VC excludes what kind of disorder?

Answer 20

a normal VC excludes a significant restrictive disorder - i.e. in restriction, volumes must be dec

Question 21

restrictive lung diseases have hyperflows - define this and what does this mean about the elasticity of the lung

Answer 21

flow velocities are higher for each given instantaneous volume - thus there is greater elastic recoil

Question 22

what is the characteristic shape of expiratory arm of flow volume loop for COPD? what does this indicate?

Answer 22

scooping - indicates slower flow rates for the effort independent portion of the curve

Question 23

if you see a hamburger shape of the flow volume loop (both the inhalation and exhalation arms are dec) what does this indicate

Answer 23

fixed obstruction of upper airways

Question 24

what is the diffusion capacity of CO compared to O2?

Answer 24

Diffusion capacity of CO 210x the diff cap of O2

Question 25

what is a functioning capillary bed? how do we measure?

Answer 25

a capillary bed that is perfused that is in contact with ventilated alveoli
the DLCO measures this components - of diffusion

Question 26

what does the DLCO “single breath” technique require

Answer 26

an inhaled VC of more than 1L and 10 sec of breath holding

Question 27

Muthiah - how do we determine a spirometry was of good quality

Answer 27

exhalation time greater than 6 seconds

Question 28

Muthiah - what are 3 conditions that will dec FRC

Answer 28

1) obesity
2) ascites
3) pregnancy

Question 29

Muthiah - which part of flow volume loop is effort dependent

Answer 29

the first part of the exhalation arm, the peak flow, is effort dependent

Question 30

Muthiah - on the flow volume loop what indicates obstruction

Answer 30

scooping

Question 31

Muthiah - what cannot you not measure by spirometry

Answer 31

RV

Question 32

Muthiah - define RV

Answer 32

the air that is left after complete exhalation

Question 33

Muthiah - what is the mechanism of dyspnea in pts w/ obstructive lung dz

Answer 33

dynamic hyperinflation

Question 34

Muthiah - what indicates dynamic hyperinflation on spiromtery/ in life

Answer 34

a reduction in the inspiratory capacity

Question 35

Muthiah - what composes the inspiratory capacity

Answer 35

TV + IRV

Question 36

Muthiah - what happens to TLC in restrictive lung dz

Answer 36

TLC decreases

Question 37

Muthiah - what appearance do you see in flow volume loop when there is a fixed upper airway obstruction

Answer 37

hamburger

Question 38

Muthiah - what does an isolated decrease in DLCO indicate

Answer 38

pulmonary vascular disease