6.1 Lung Function Testing FINISH

Question 1

Name three reasons for pulmonary function tests?

Answer 1

Diagnosis
Patient assessment
Research

Question 2

When in breathing would an extrathoracic abnormality be evident?

Answer 2

Inspiration

Question 3

When in breathing would an intrathoracic abnormality be evident?

Answer 3

Expiration

Question 4

What may cause a variable upper airway obstruction?

Answer 4

Laryngeal polyp

Question 5

What could cause a fixed upper airway obstruction?

Answer 5

Tracheal stenosis

Question 6

What can the tracings produced by spirometry be used to calculate?

Answer 6

Vital capacity
Tidal volume
Flow rate

Question 7

What is a time-volume graph useful for measuring?

Answer 7

Forced vital capacity

Question 8

What is an example of an obstructive disorder?

Answer 8

Asthma

COPD

Question 9

Why is FEV1 decreased in obstructive disorders?

Answer 9

Narrowed airway reduces the speed that air can be breathed out

Question 10

What spirometry results would you expect in obstructive airways?

Answer 10

FVC nearly normal
FEV1 reduced
FEV1/FVC reduced <70%

Question 11

What is an example of a disease that restricts the airways?

Answer 11

Lung fibrosis

Question 12

Why is FVC reduced in restrictive airways?

Answer 12

Because the lungs are stiff so cant be expanded adequately

Question 13

Why is speed normal in restrictive airways?

Answer 13

Because there is no narrowing

Question 14

What spirometry results would you expect in restrictive airways?

Answer 14

Low FVC
Normal FEV1
FEV1/FVC normal or improved >70%

Question 15

What should a flow volume loop show?

Answer 15

Maximum flow occurs early in expiration
Then small airways become narrowed by compression of the lungs
Results in an early fall in expiratory flow rate

Question 16

Why should PEFR be plotted on a chart?

Answer 16

Because it varies according to height and weight

Question 17

Why is there scalloping of curve in an obstructive defect?

Answer 17

Airways collapse on expiration

This dramatically reduces flow

Question 18

What does vital capacity depend on?

Answer 18

Maximal expiration and maximal inspiration

Question 19

What sort of defect is more sensitively revealed by an expiratory flow-volume loop?

Answer 19

Obstructive

Question 20

What would a mild obstruction of the small airways produce on a flow volume curve?

Answer 20

Scalloping

Question 21

What would indicate a severe obstruction on the flow volume curve?

Answer 21

Reduced PEFR

Question 22

How can we measure residual volume?

Answer 22

Helium dilution test

Question 23

How can you measure dead space?

Answer 23

Nitrogen wash out method

Question 24

How can diffusion capacity be estimated?

Answer 24

Carbon monoxide transfer factor

Question 25

What is diffusion conductance?

Answer 25

The resistance to diffusion across the alveolar membrane

Question 26

What is another name for the nitrogen washout technique?

Answer 26

Fowlers method

Question 27

In addition to measuring dead space, what can the nitrogen washout technique be used to assess?

Answer 27

Mixing efficiency within the lungs

Question 28

How is anatomical dead space determined?

Answer 28

By measuring the volume of gas that is in the conducting airways

Question 29

How is the helium dilution test used to calculate residual volume?

Answer 29

Used to measure the functional residual capacity which can then be used to calculate the residual volume