Emphysema is an abnormal and persistent dilatation of the distal air spaces of the terminal fine bronchi in the lungs, accompanied by destruction of alveoli and fine bronchi, without obvious pulmonary fibrosis. Clinically, emphysema is generally divided into the following five stages: 1. Stage 1: early stage of emphysema, patients may have no obvious conscious symptoms; 2. Stage 2: chronic cough and sputum appear, often with obvious cough in the morning and paroxysmal cough or sputum discharge at night; symptoms of shortness of breath or dyspnea may appear during more strenuous activities in the early stage; 3. Stage 3: shortness of breath or dyspnea gradually worsens to the point that it occurs during daily activities or even It also occurs at rest, accompanied by weight loss, loss of appetite, etc.; 4. Stage 4: Hypoxia and carbon dioxide retention occur, and different degrees of hypoxemia and hypercapnia occur; 5. Stage 5: Pulmonary heart disease occurs, which can gradually develop from the compensated stage of pulmonary and cardiac function to the decompensated stage of pulmonary and cardiac function, and patients develop chest tightness, cough, cough with blood, telangiectatic breathing, lower limb edema, etc. symptoms of heart failure.