Pulmonary ventilation is the process of gas exchange between the lungs and the external environment. Lung ventilation is the process of gas exchange between the lungs and the external environment. Lung ventilation can be examined by tidal volume, deep inspiration volume and lung capacity, etc. 1. 1. Tidal volume: it refers to the volume of air inhaled and exhaled at one time during calm breathing, and the reference value for normal adults is about 500 ml. Tidal volume is affected by the function of the inspiratory muscles, especially the movement of the diaphragm, and the tidal volume decreases in the case of respiratory muscle insufficiency. 2. Deep inspiration volume: it refers to the maximum volume of air inhaled at the end of calm expiration with maximum force, i.e., tidal volume plus compensatory inspiration volume. Normal adult reference value is (2617±548) ml for men and (1970±381) ml for women. in general, the normal deep inspiratory volume should account for 2/3 or 4/5 of the lung volume. when respiratory insufficiency, especially the inspiratory muscle strength disorder, as well as the thorax, lung mobility is weakened, and the deep inspiratory volume is reduced when the airway is blocked. 3. Lung volume: It is the maximum volume of air that can be slowly and completely exhaled after inhaling as much as possible, i.e., deep inspiratory volume plus compensatory expiratory volume or tidal volume plus compensatory inspiratory volume plus compensatory expiratory volume. The right lung lung volume accounts for 55% of the total lung volume. The organs that achieve pulmonary ventilation include the airways, alveoli, and thorax. Pulmonary ventilation function tests are the most basic of the respiratory function tests and include alveolar air content, airflow through the airways, and their effects.