Lung Volumes Definitions and Spirometry

Total lung capacity (TLC): the volume in the lungs at maximal inflation, the sum of VC and RV.

Residual volume (RV): the volume of air remaining in the lungs after a maximal exhalation

Expiratory Reserve Volume (ERV): the maximal volume of air that can be exhaled from the end-expiratory position

Inspiratory Reserve Volume (IRV): the maximal volume that can be inhaled from the end-inspiratory level

Inspiratory Capacity (IC): the sum of IRV and TV

Inspiratory Vital Capacity (IVC): the maximum volume of air inhaled from the point of maximum expiration

Vital Capacity (VC): the volume of air breathed out after the deepest inhalation.

Tidal Volume (VT): that volume of air moved into or out of the lungs during quiet breathing

Functional Residual Capacity (FRC): the volume in the lungs at the end-expiratory position

Forced Vital Capacity (FVC): the determination of the vital capacity from a maximally forced expiratory effort

Forced Expiratory Volume (time) (FEVt): a generic term indicating the volume of air exhaled under forced conditions in the first (t) seconds
FEV1 – Volume that has been exhaled at the end of the first second of forced expiration

Peak Expiratory Flow (PEF): The highest forced expiratory flow measured with a peak flow meter