Spirometry measurements

Question 1

What is tidal volume (V(T))?

Answer 1

Volume of air inspired/expired during quiet respiration.

Question 2

What is inspiratory reserve volume (IRV)?

Answer 2

Volume above normal inspiratory lung volume at rest during forced inspiration.

Question 3

What is expiratory reserve volume (ERV)?

Answer 3

Volume below normal expiratory lung volume at rest during forced expiration.

Question 4

What is vital capacity (VC)?

Answer 4

Total volume of air moved into and out of the lungs during forced inspiration followed by forced expiration.
VC = IRV + V(T) + ERV.

Question 5

What is inspiratory capacity (IC)?

Answer 5

The total amount the lungs can be expanded by from end of quiet expiration.
IC = V(T) + IRV.

Question 6

What is residual volume (RV)?

Answer 6

Volume of air left in lungs after forced expiration.

Question 7

What is functional residual capacity (FRC)?

Answer 7

Volume of lungs at the end of quiet expiration.

FRC = RV + ERV.

Question 8

What is total lung capacity (TLC)?

Answer 8

Volume of lungs at the end of forced inspiration.

TLC = RV + ERV + V(T) + IRV.

Question 9

What flow-dependent values can be measured using spirometer?

Answer 9

1. Forced vital capacity (FVC)
2. Forced expiratory volume of air in 1 second (FEV1)
3. Forced expiratory volume of air over middle 50% of FVC (FEV25-75%)

Question 10

What are the effects of obstructive pulmonary diseases on spirometry measurements?

Answer 10

1. Normal TLC
2. ↑ RV
3. ↓ FEV1
4. ↓ FEV1/FVC
5. ↓ FEF25-75%
6. ↓FVC

Question 11

What are the effects of restrictive pulmonary diseases on spirometry measurements?

Answer 11

1. ↓ TLC
2. Normal RV
3. ↓ FEV1
4. Normal FEV1/FVC
5. Normal FEF25-75%