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Respiriatory: Airway Disease > Pulmonary Function Testing > Flashcards

Flashcards in Pulmonary Function Testing Deck (47)
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1

What are 3 types of pulmonary function test?

* Effort dependent tests
* Effort independent tests
* Gas diffusion tests

2

What are examples of effort dependent tests?

* Forced expiratory volumes/flow rates

3

How are forced expiratory volumes measured?

Spirometry

4

What are examples of effort independent tests?

* Relaxed vital capacity
* Helium/N2 without static lung volumes
* Whole body plethysmography
* Impulse oscillometry
* Exhaled breath nitric oxide

5

What are examples of gas diffusion tests?

* CO transfer factor
* Arterial blood gases (resting)
* SaO2 during exercise

6

How is relaxed vital capacity measured?

Spirometry

7

What is a forced expiratory manoeuvre?

From TLC to RV

8

What is the forced expiratory volume in 1 second?

FEV1 (litres)

9

What is the forced expiratory ratio?

FER = FEV1/FVC

10

What is relaxed vital capacity?

Patient breathes out in their own time

11

What is the normal value of FER?

>75%

12

In asthma, how does FEV1, FVC and FER compare with a normal individual?

* FEV1 is reduced
* FVC is the same (just takes longer)
* FEV1/FVC is reduced

13

In COPD, how does FEV1, FVC and FER compare with a normal individual?

* FEV1 is reduced
* FVC is reduced
* FEV1/FVC is the same

14

Why is FEV1/FVC ratio preserved in COPD?

FEV1 is reduced in proportion to FVC

15

What is a volume-time curve?

Plots volume in litres (FVC and FEV1) against time (s)

16

What is a flow-volume curve?

Flow rate (l/s) plotted against forced expiratory volume (l)

17

What affects the shape of the expiratory flow-volume curve?

* Volume dependent expiratory airway closure - asthma, chronic bronchitis
* Pressure dependent expiratory airway closure - emphysema

18

What causes volume dependent expiratory airway closure in asthma?

Small airways close off earlier in expiration (wheeze)

19

What causes pressure dependent expiratory airway closure in COPD?

Small airways close off extremely early in expiration

20

How is peak expiratory flow rate (PEF) measured?

Peak flow meter

21

What are the units of peak expiratory flow rate?

l/min

22

How does obstructive airway disease affect peak expiratory flow rate?

Peak expiratory flow rate is reduced in obstructive disease

23

What is the FEV1/FVC ratio of someone with asthma?

<75%

24

What is the FEV1 response to B2-agonist in asthma?

Increases by approx 15%

25

How does restrictive airway disease affect peak expiratory flow rate?

Peak expiratory flow rate is normal in restrictive airway disease

26

Why is peak expiratory flow rate not affected in restive airway disease?

In restrictive disease, no problem with conducting airways so flow rate is normal

27

Why is there no FEV1 response to B2 agonist (e.g. salbutamol) in restrictive airway disease?

Conducting airways are normal

28

What are methods of bronchial challenge testing?

* Exercise (will produce bronchoconstriction - cold air)
* Metacholine/histamine/mannitol (markers of airway hyper-responsiveness)
* Allergens/chemicals (early and late responses)

29

How is metacholine/histamine/mannitol used in bronchial challenge testing?

Provocative dose to produce 20% fall in FEV1

30

How is exercise testing used to diagnose respiratory disease?

* Fall in FEV1 or peak expiratory flow rate = asthma
* Decrease in SaO2 during exercise in interstitial lung disease - to monitor treatment response
* Full cardiopulmonary exercise test (CPET) - differentiate cardiac vs respiratory dyspnoea (HR vs oxygen uptake vs ventilatory rate)