Pulmonary Function Test Quiz

Pulmonary Function Tests

• Pulmonary function tests measure how well the lungs take in and release air.
• Spirometry is the most common type of pulmonary function test.

Lung Volumes and Capacities

• Lung volumes are divided into 4 defined volumes and 4 capacities.
• Volumes are integral units, whereas capacities consist of 2 or more volumes.
• Static lung volumes do not depend on the rate at which air flows.

Lung Volumes

• Tidal Volume (TV): volume of air inspired or expired during normal quiet breathing (0.5L).
• Inspiratory Reserve Volume (IRV): maximum amount of air that can be forcefully inspired after a normal tidal volume (3L).
• Expiratory Reserve Volume (ERV): maximum amount of air that can be forcefully expired after a normal or resting expiration (1.2L).
• Residual Volume (RV): volume of air remaining in the lungs after a forceful expiration (1.2L).

Lung Capacities

• Vital Capacity (VC): volume of air that can be exhaled from the lungs after a maximum inspiration (VC = IRV + TV + ERV = 4.7L).
• Inspiratory Capacity (IC): amount of air that the lung can hold after normal expiration (IC = IRV + TV = 3.5L).
• Functional Residual Capacity (FRC): volume of air remaining in the lungs after normal expiration (FRC = ERV + RV = 2.4L).
• Total Lung Capacity (TLC): volume of air in the lungs after a maximum inspiration (TLC = IRV + TV + ERV + RV = 5.9L).

Spirometry Tests

• Forced Vital Capacity (FVC): total volume of air that can be exhaled forcefully and rapidly after maximum inhalation.
• Slow Vital Capacity (SVC): maximum volume of air that can be exhaled slowly after slow maximum inhalation.
• Maximum Voluntary Ventilation (MVV): largest volume of air that can be breathed out of the lungs in 1 minute.
• Minute Ventilation (MV): volume of expired air in liters per minute measured over a minimum of one minute while breathing normally (MV = respiratory rate x tidal volume).