Pulmonary Function Tests

Question 1

What does spirometry allow you to differentiate between?

Answer 1

Obstructive and restrictive lung diseases

Question 2

In healthy individuals what is the normal FEV1/FVC ratio?

Answer 2

Around 75%

Question 3

Asthma pattern?

Answer 3

Reduced FEV1
Normal FVC
Reduced FEV1/FVC ratio
Reduced PEF

Question 4

COPD pattern?

Answer 4

Reduced FEV1
Reduced FVC
Reduced FEV1/ FVC
Reduced PEF

Question 5

When is it useful to assess reversibility with bronchodilator in spirometry? What will the results be?

Answer 5

Useful if considering asthma a cause of obstruction

The presence of reversibility suggests asthma and absence suggests fixed obstructive disease such as COPD

Question 6

What is a restrictive pattern?

Answer 6

FEV1 reduced, FVC reduced, FEV1/FVC normal

Question 7

Who is peak expiratory flow usually measured in?

Answer 7

Asthmatics

Question 8

How is total lung capacity (TLC) measured?

Answer 8

Inhale a known concentration of helium and then measure the change in concentration

Question 9

When is TLC increased?

Answer 9

Hyperinflation- Emphysema

Question 10

When is TLC decreased?

Answer 10

Restrictive Lung Disease

Question 11

What is transfer factor/ TLCO/ DLCO? What gas is used and why?

Answer 11

This is used to measure the efficiency of gas transfer across the alveolar membrane. CO is used as a surrogate since the diffusion rate is similar to oxygen

Question 12

What conditions is TLCO reduced in?

Answer 12

Anaemia, emphysema, interstitial lung diseases, pulmonary oedema, pulmonary emboli and bronchiectasis.