A pathological state of decreased airway elasticity, hyperinflation, inflation and increased lung volume or concomitant airway wall destruction in the distal end fine bronchi (respiratory fine bronchi, alveolar ducts, alveolar sacs and alveoli). There are several types of emphysema according to their pathogenesis: senile emphysema, compensatory emphysema, interstitial emphysema, focal emphysema, paracentral emphysema, and obstructive emphysema). Patient’s physical signs, heart in a pendulous pattern. During inspiration, the lumen of the fine bronchial tubes dilates and air enters the alveoli; during exhalation, the lumen narrows, air is retained, and the intra-alveolar pressure keeps increasing, leading to hyperinflation or rupture of the alveoli. How to check it? 1.X-ray examination The thorax is dilated, the rib space is widened, the ribs are parallel, the activity is weakened, the diaphragm is lowered and flattened, and the translucency of the two lung fields is increased. 2.Electrocardiogram examination Generally there is no abnormality, sometimes it may show low voltage. 3.Respiratory function test It is important to diagnose obstructive emphysema. 4.Blood gas analysis If there is obvious hypoxic carbon dioxide retention, the partial pressure of arterial blood oxygen (PaO2) decreases and the partial pressure of carbon dioxide (PaCO2) increases, and there may be loss of compensatory respiratory acidosis and pH decreases. 5.Blood and sputum examination Generally, there is no abnormality, and when secondary infection is present, it looks like an acute exacerbation of LSI. Diagnosis is based on history, physical examination, X-ray examination and pulmonary function measurement. X-ray examination shows enlarged anterior and posterior diameter of the chest cavity, anterior protrusion of the sternum, widening of the posterior sternal space, low flattening of the diaphragm, reduced lung texture, increased lung field translucency, overhanging heart, widening of the pulmonary artery and major branches, and small peripheral blood vessels. Pulmonary function measurements showed increased residual air and total lung volume, increased residual air/total lung volume ratio, significantly decreased 1-second rate, and decreased diffusion function.