Core Tip: The most commonly used lung function indicators reflecting lung ventilation function. The most commonly used lung function indicators reflecting pulmonary ventilation function are as follows: 1. Spirometry: is the volume of air exhaled at the end of deep inspiration as best as possible, normal adults are about 2400-3400 ml. The value is normal or mildly reduced in obstructive ventilation disorders; the value is mildly reduced in restrictive and mixed ventilation disorders and significantly reduced. 2.Total lung volume: It is the total amount of gas contained in the lungs after deep inspiration, and it is equal to the lung volume plus the residual gas volume. This value is mildly increased in obstructive ventilation disorder; restrictive: mildly decreased, mixed: variable. 3, residual gas volume / total lung volume: the ratio of residual gas volume to lung volume is used to determine the presence or absence of emphysema.