Reduced lung volume

Total lung capacity: refers to the maximum amount of air that the lung can hold, which is equal to the sum of tidal volume, supplemental inspiration volume, supplemental expiration volume, and residual volume. It is also equal to the sum of deep inspiratory volume and functional residual volume. Adult males average about 5,000ml and females about 3500ml. Vital capacity (VC): Refers to the amount of air exhaled after maximal inspiration. The vital capacity is equal to the sum of the tidal volume, the inspiratory volume, and the expiratory volume, and is also equal to the total lung volume minus the residual volume. The average adult male is about 3500ml and the female is about 2500ml. The vital capacity reflects the maximum capacity of the lung at one time. Generally speaking, the larger the vital capacity, the better the pulmonary ventilation function. During the breathing cycle, the lung volume changes with the amount of gas entering and exiting the lung. The lung volume increases during inhalation and decreases during exhalation. The magnitude of its change is mainly related to the depth of breathing. Certain respiratory diseases or chest surgery can cause pathological lung volume reduction.