Pulmonary Function Tests

Question 1

What is the key spirometric pattern in obstructive lung disease?

Answer 1

FEV1 ↓↓↓, FVC normal/↓, FEV1/FVC ↓ (<0.7).

Question 2

What is the key spirometric pattern in restrictive lung disease?

Answer 2

FEV1 ↓, FVC ↓↓↓, FEV1/FVC normal or ↑.

Question 3

Which conditions cause obstructive patterns?

Answer 3

Asthma, COPD, bronchiectasis, bronchiolitis obliterans.

Question 4

Which conditions cause restrictive patterns?

Answer 4

Pulmonary fibrosis, asbestosis, sarcoidosis, ARDS, scoliosis, neuromuscular disease, severe obesity.

Question 5

Which volumes increase in obstructive disease?

Answer 5

RV, FRC, TLC (air trapping).

Question 6

Which volumes decrease in restrictive disease?

Answer 6

IRV, IC, ERV, RV, FRC, TLC (reduced compliance).

Question 7

Which lung volume cannot be measured on spirometry?

Answer 7

Residual volume (RV).

Question 8

Name two ways to measure residual volume.

Answer 8

Helium dilution or body plethysmography.

Question 9

What is vital capacity (VC)?

Answer 9

IRV + TV + ERV.

Question 10

What is total lung capacity (TLC)?

Answer 10

VC + RV.

Question 11

What does FEV1 measure?

Answer 11

Volume forcibly exhaled in 1 second.

Question 12

What does FVC measure?

Answer 12

Total volume forcibly exhaled after full inspiration.

Question 13

What defines airway reversibility?

Answer 13

≥10% increase in FEV1/FVC/VC OR ≥15% rise in FEV1/FVC ratio after bronchodilator.

Question 14

Which disease typically shows reversibility?

Answer 14

Asthma.

Question 15

What does a “scooped-out” expiratory curve indicate?

Answer 15

Obstructive disease.

Question 16

What pattern suggests fixed large airway obstruction (e.g. tracheal stenosis)?

Answer 16

Flattened inspiratory and expiratory limbs.

Question 17

What pattern suggests extrathoracic obstruction?

Answer 17

Flattened inspiratory loop.

Question 18

What is minute ventilation?

Answer 18

Tidal volume × respiratory rate.

Question 19

What is anatomical dead space?

Answer 19

~150 mL of conducting airways.

Question 20

What determines alveolar ventilation?

Answer 20

Minute ventilation − dead space ventilation.

Question 21

What happens to physiological dead space in COPD?

Answer 21

Increases (due to poorly perfused alveoli).

Question 22

Asthma vs COPD on PFTs?

Answer 22

Both obstructive; asthma shows reversibility, COPD does not.

Question 23

What PFT pattern is seen in obesity?

Answer 23

Restrictive (reduced TLC and FRC).

Question 24

Which condition classically increases TLC the most?

Answer 24

Emphysema (hyperinflation).

Question 25

What does an increased FEV1/FVC ratio strongly suggest?

Answer 25

Restriction, not improvement.