The most commonly used indicators to reflect pulmonary ventilation function are: 1. lung volume: the volume of air exhaled after breathing hard, about 2400-3400ml in normal adults; obstructive emphysema may be normal or mildly increased, restrictive ventilation dysfunction and mixed ventilation dysfunction are mildly decreased to significantly decreased; 2. total lung volume: the amount of air contained in the lungs after breathing hard, mainly including The total lung volume is mildly increased in obstructive ventilatory dysfunction, mildly decreased in restrictive ventilatory dysfunction, and not necessarily in mixed ventilatory dysfunction; 3. Residual air volume/total lung volume ratio: mainly used to determine the presence or absence of emphysema, <25% is normal; 26%-35% is mild emphysema; 36%-45% is moderate emphysema; 46%-55% is severe emphysema; > 55% is very severe. And the ratio of residual air volume to total lung volume is related to age, and the residual air volume increases with age, but should not exceed 35%; 4. Maximum ventilation volume: normal adults are about 80-106L/min, obstructive ventilation dysfunction and respiratory ventilation dysfunction are mildly reduced to significantly reduced, and restrictive ventilation dysfunction is normal or mildly reduced; 5. 1-second forceful breathing volume is abbreviated as FEV1: The ratio of FEV1 to forceful lung volume is often used clinically to determine the percentage of FEV1, the normal value is 83%, obstructive or mixed ventilation dysfunction is mildly reduced to significantly reduced, restrictive ventilation dysfunction is mildly elevated or normal.