Session 6: Spirometry and Lung Function Measurements

Question 1

What is spirometry?

Answer 1

Measuring of breath. It records the volume of air that is breathed in and out and generates tracings of air flow.

Question 2

What are the tracings generated by the spirometer used for?

Answer 2

To calculate vital capacity, tidal volume and the flow rate of air movement.

Also forced expiration volume.

Question 3

Why would you use a spirometer?

Answer 3

Diagnosis, however the tests are rarely diagnostic on their own.

Patient assessment

Research purposes

Question 4

What should be higher, FVC when seated or standing?

Answer 4

FVC standing > FVC seated

Question 5

Answer 5

Question 6

What will forced flow-volume measurements show us?

Answer 6

How much air can the subject blow out?

How fast is the air expelled?

Pattern of change in flow-volume curve

Response to treatment

Change with age and growth

Progression of a disease

Question 7

What is FVC?

Answer 7

Forced vital capacity

The maximal amount of air that the patient can forcibly exhale after taking a maximal inhalation.

Only thing left is the residual volume

Question 8

What is FEV1?

Answer 8

Forced expiration volume

Volume exhaled in the first second of forced exhalation.

Question 9

What is peak expiratory flow?

Answer 9

Maximal speed of airflow as the patient exhales

Question 10

Explain what a time volume graph is.

Answer 10

When volume exhaled is matched against time.

Question 11

What is the FEV1:FVC ratio?

Answer 11

A ratio of how much air is exhaled in the first second of forced exhalation (FEV1) compared to how much can possible be exhaled (FVC).

Question 12

What is a normal FEV1:FVC ratio?

Answer 12

When FEV1 is above 70% of FVC.

Question 13

How does the FEV1:FVC ratio help?

Answer 13

It can determine what type of lung disease a patient might have.

Question 14

If FEV1 <70% of FVC. What is this in indication of?

Answer 14

Obstructive defect.

Question 15

What is the FEV1:FVC ratio in restrictive disease?

Answer 15

Normal

Question 16

How can the FEV1:FVC ratio be normal in restrictive lung disease?

Answer 16

Because both FEV1 and FVC are reduced proportionately.

Question 17

Typical conditions where an obstructive pattern can be seen.

Answer 17

COPD

Asthma

Question 18

Typical conditions where a restrictive pattern can be seen.

Answer 18

Diffuse lung fibrosis

Question 19

In normal individual, what is the peak flow mostly affected by?

Answer 19

Resistance of the large airways

Question 20

In individuals with severe obstruction of the smaller airways like in asthma. What will be affected?

Answer 20

The peak expiratory flow rate.

Question 21

Explain the flow volume curve in mild obstructive disease.

Answer 21

The curve gets scooped out

Question 22

Explain the flow volume curve in severe obstruction.

Answer 22

The curve is scooped out but the PEFR is also reduced.

Question 23

Explain the flow volume loop in restrictive lung disease.

Answer 23

It is characterised by a decrease in FVC.

This leads to a narrow flow volume loop where PEFR is not significantly reduced because there is no obstruction.

This leads to a narrow and tall flow loop.

Question 24

In order to determine whether an obstructive condition is due to asthma or COPD, how can the spirometry test be conducted further?

Answer 24

By giving B2 agonists like salbutamol.

Question 25

How would B2 agonists differ in the spirometer test between asthma and COPD?

Answer 25

There will be a significant improvement of FEV1:FVC in asthma as well of the flow volume loop. No significant change in COPD.

Question 26

Why is spirometry tests done sitting down even though FVCstanding\>FVCsitting?

Answer 26

Because high intrathoracic presure can lead to reduced CO and cerebral outflow. This can lead to fainting.

Question 27

What does this indicate?

Answer 27

**Variable upper** airway obstruction of airways like a laryngeal polyp.

Question 28

What does this indicate?

Answer 28

**Fixed upper** airway obstruction like tracheal stenosis

Question 29

Movement of trace in inspiration.

Answer 29

Upward deflection

Question 30

Movement of trace in expiration.

Answer 30

Downwards deflection

Question 31

How to measure residual volume.

Answer 31

Diane hudman says this can't be measured. Work book says: Helium dilution test

Question 32

How to measure dead space.

Answer 32

Nitrogen washout method

Question 33

How to measure diffusion capacity.

Answer 33

Carbon monoxide transfer factor

Question 34

What is a normogram?

Answer 34

A diagram to standardise FVC and predict it. The measured value is compared to that of healthy people of the same gender, age and height.

Question 35

What is the right diagram an indication of?

Answer 35

Asthma