Lung Volumes & Capacities

Question 1

Anatomic Dead Space Volume (VD)

Answer 1

The volume of air that occupies the non-respiratory conducting airways

Question 2

Expiratory Reserve Volume (ERV)

Answer 2

The max volume of air that can be exhaled after a normal tidal exhalation. ERV ~15% of TLC

Question 3

Forced Expiratory Volume (FEV)

Answer 3

The max volume of air exhaled in a specified period of time: usually the 1st, 2nd and 3rd second of a forced vital capacity maneuver

Question 4

Forced Vital Capacity (FVC)

Answer 4

The volume of air expired during a forced maximal expiration after a forced maximal inspiration

Question 5

Functional Residual Capacity (FRC)

Answer 5

The volume of air in the lungs after normal exhalation. FRC= ERV + RV; FRC ~40% TLC

Question 6

Inspiratory Capacity (IC)

Answer 6

The max volume of air that can be inspired after a normal tidal exhalation. IC= TV + IRV; IC ~60% of TLC

Question 7

Inspiratory Reserve Volume (IRV)

Answer 7

The max volume of air that can be inspired after normal tidal volume inspiration. IRV ~50% of TLC

Question 8

Minute Volume Ventilation (VE)

Answer 8

The volume of air expired in one minute. VE= TV x RR (respiratory rate)

Question 9

Peak Expiratory Flow (PEF)

Answer 9

The max flow of air during the beginning of a forced expiratory maneuver

Question 10

Residual Volume (RV)

Answer 10

The volume of gas remaining in the lungs at the end of a maximal expiration. RV ~25% TLC

Question 11

Tidal Volume (TV)

Answer 11

Total volume inspired and expired with each breath during quiet breathing. TV ~10% TLC

Question 12

Total Lung Capacity (TLC)

Answer 12

Volume of air in the lungs after a maximal inspiration; the sum of all lung volumes. TLC = RV + VC or TLC = FRC + IC

Question 13

Vital Capacity (VC)

Answer 13

The volume change that occurs between maximal inspiration and maximal expiration; VC = TV + IRV. VC ~75% of TLC