Spirometry

Question 1

What is vital capacity (VC)?

Answer 1

The greatest volume of air that can be expelled from the lungs after taking the deepest possible breath

Question 2

What is forced vital capacity (FVC)?

Answer 2

The maximum amount of air that can be exhaled when blowing out as fast as possible

Question 3

What is forced expiratory volume (FEV1)?

Answer 3

Measures how much air a person can exhale during a forced breath

Question 4

What is the FEV1, FVC and FEV1/FVC ratio like in obstructive lung disease?

Answer 4

FEV1

• Normal: mild obstruction
• Decreased: moderate/severe obstruction

FVC

• Normal: mild/moderate obstruction
• Decreased: severe obstruction

FEV1/FVC ratio
- Decreased (<70%)

Question 5

What is obstructive lung disease?

Answer 5

Difficulty exhaling due to airway narrowing

Question 6

What is the FEV1, FVC and FEV1/FVC ratio like in restrictive lung disease?

Answer 6

FEV1
- Normal or Decreased

FVC
- Decreased

FEV1/FVC ratio
- Normal or increased (≥70%)

Question 7

What is restrictive lung disease?

Answer 7

Restrict lung expansion, resulting in a decreased lung volume, an increased work of breathing, and inadequate ventilation and/or oxygenation
Difficulty inhaling

Question 8

What is not included in the generalised category of obstructive lung disease?

Answer 8

• Upper airway obstruction

Question 9

What is variable extra-thoracic airway obstruction?

Answer 9

During inspiration, intra-tracheal pressure decreases below atmospheric pressure
Extra-thoracic airway collapses

Question 10

What is variable extra-thoracic airway obstruction?

Answer 10

During forced expiration, the intra-pleural pressure is higher than intra-tracheal pressure
Intra-tracheal airway collapses during expiration