S2: Pulmonary Function Testing

Question 1

Describe spirometry

Answer 1

• A non invasive diagnostic test
• Quick
• Gives measure of lung function
• 5+ years age
• Patient exhales (and inhales) into a spirometer
• Required to exhale as fast and as long as possible from a position of full inspiration
• Measure volume of air in litres that is exhaled as function of time

Question 2

What key measurement are recorded in spirometry?

Answer 2

• · Measures the volumes of air (in litres) that are exhaled as a function of time

FEV1
FVC (forced vital capacity)
FEV1/FVC (%) –> <70% suggests obstructive lung disease

Question 3

Why do we need to perform spirometry?

Answer 3

• Aids in diagnosis of lung disorders (obstructive and restrictive lung disorders)
• Excludes lung disease
• Monitors severity of disease and their progression
• Assesses response to medications
• Preoperative asessment
• Prognosis of disease

Question 4

What is needed to make a diagnosis?

Answer 4

History
Diagnostic tests
Clinical examination

Question 5

Describe how to perform spirometry

Answer 5

• Patient is seated / wearing nose clips
• Blows into a Spirometer
• Need to blow out as fast as possible / as long as possible
• At least 3 measurements are recorded and give patients a rest between measurements
• Measures the volumes of air that can be exhaled by the patient
• Volitional
  May be repeated after administration of a bronchodilator drug to see if there is significant improvement

Question 6

What is Force Vital Capcity (FVC)?

Answer 6

It gives an indication of lung size
- measured in litres

Forced vital capacity, or FVC, is the amount of air which can be forcibly exhaled from the lungs after taking the deepest breath possible.

Question 7

What is FEV1?

Answer 7

• Forced Expiratory Volume in 1 second

- measured in litres

Question 8

Factors affecting spirometry values

Answer 8

• Age
• Height
• Gender

Question 9

Common causes of airflow obstruction

Answer 9

• COPD (emphysema, bronchitis)
• Asthma
• Cystic Fibrosis

Question 10

Do flow volume loops differ in obstructive and restrictive diseases?

Answer 10

Yes

Question 11

Why is having high quality measurements important?

Answer 11

• Essential that diagnostic tests are performed correctly
• Facilitates accurate results
• Ensures correct patient diagnosis/management
  o Medication/therapy
  o Surgery
  o Occupation
• Performed by skilled trained operators
  o Clinical physiologists (BSc Healthcare Science)
• Equipment should be calibrated prior to measurements
• Tests should also be performed safely
  o Infection Control
  o Test Contraindications