PFTs Flashcards Preview

Pulmonary > PFTs > Flashcards

Flashcards in PFTs Deck (24):
1

Indications for performing PFT

dyspnea, cough
pre-op
occupational exposure, disability
severity
Treatment response

2

in spirometery, expiratory effort must be maintained for ___ seconds

6

3

What is MVV?

maximal voluntary ventilation: maximum amount of air that can be inhaled and exhaled within one minute

4

What is the clinical use of MVV?

1. used to determine if person is a candidate for lung resection
2. look for weakness/fatigue that would suggest neuromuscular disorder
3. determine breathing reserve

5

MVV > 55%

pneumonectomy candidate

6

MVV > 45 %

lobectomy candidate

7

FEV1/FVC pattern for
normal lungs
restrictive lung disease
restrictive lung disease

nlm: 80%
obt: < 80%
rest: > 80%

8

WHy is the FEV1/FVC > normal in restrictive lung disease?

fibrosis increases the elasticity/recoil of the lung and since expiration is passive and depends on the recoil, inc recoil = inc expiration

9

What is the gold std for measuring TLC?

body plethymograph (sit in the box and breathe, use PV=PV to calculate volume changes)

10

Describe the effects exercise on hyperinflated lungs

hyper-inflated lungs = air trapping = inc FRC = raises TV baseline

this means that there is a smaller inspiratory reserve volume left n, so when this person will have decreased exercise tolerance because they are unable to take in enough fresh air to meet their needs

11

air trapping inc or dec in COPD pts that are exercising

increases
**called dynamic inflation

12

How does lung compliance change in asthma

no change

13

How does lung compliance change in emphysema?

increased
*can hold more volume with a smaller change in pressure

14

How does lung compliance change in (what should be here?)?

decreased
*can hold less volume with inc pressure

15

normal compliance
increased TLC
increased VC
increased FRC
decreased FEV1/FRC but reversible

asthma

16

inc compliance
increased TLC
increased VC
increased FRC
decreased FEV1/FRC and not reversible

emphysema

17

dec compliance
dec TLC
dec VC
dec FRC
inc FEV1/FRC

fibrosis

18

How is the diffusing capacity of the lung measured?
What is the problem with this test?

CO has a higher affinity for Hb than O2 so pt breathes it in and back out and the amt that diffused can be measured
**but it requires the pt to inhale > 1L anf hold it for 10 s

19

What is the normal DLCO?

81-140%

20

increased TLC
increased VC
increased FRC
decreased FEV1/FRC and not reversible
Low DLCO

emphysema

21

increased TLC
increased VC
increased FRC
decreased FEV1/FRC and not reversible
nml DLCO

chronic bronchitis

22

dec TLC
dec VC
dec FRC
inc FEV1/FRC
normal DLCO

kyphosis, muscle weakness, obesity, pregnancy

23

nml compliance
normal lung volumes/capacities
dec DLCO

PE
PAH

24

What are predictors of airflow?

sex, age, height