Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by airflow limitation that is not fully reversible and develops progressively; COPD is associated with an abnormal inflammatory response of the lung to harmful gases or harmful particles. Chronic obstructive pulmonary disease is closely related to chronic bronchitis and emphysema; chronic bronchitis and emphysema are characterized by irreversible airflow limitation; early asthma has reversible airflow limitation and is not considered to be chronic obstructive pulmonary disease. Chronic obstructive pulmonary etiology and pathogenesis: 1, smoking: tar, nicotine damage to epithelial cells, cilia hypokinesis and reduced macrophage function. Mucus gland hypertrophy, cupular cell hyperplasia, parasympathetic N excitation, airway constriction; 2, occupational dust and chemicals, allergens, industrial exhaust; air pollution: sulfur dioxide, nitrogen dioxide, etc.; 3, infection: viruses, mycoplasma secondary to bacterial infection; 4, protease-anti-protease imbalance: tissue structure destruction; 5, autonomic dysfunction, temperature mutation, etc. Pathophysiology of chronic obstructive pulmonary disease: early small airway narrowing, increased closed volume, decreased dynamic lung compliance, increased static lung compliance; emphysematous stage: increased RV and RV/TLC%; pulmonary ventilation dysfunction: hypercapnia. Pulmonary diffusion dysfunction: ventilation/blood flow ratio imbalance, massive loss of alveoli and capillaries, reduced diffusion area, hypoxia. Clinical manifestations of chronic obstructive pulmonary disease: I. Symptoms; Chronic coughing sputum: sleep parasympathetic excitation at night, increased secretion, sputum accumulation, stimulated by change of position when getting up, so heavier in the morning. Mucus or plasma foamy; shortness of breath or dyspnea; wheezing and chest tightness: caused by airway constriction, congestion edema and increased secretion; weight loss. II. Signs; 1. Visual and palpation: increased anteroposterior diameter of the thorax, shallow breathing, constricted lip breathing, diminished verbal fibrillation; 2. Percussion: lung hyperclear sounds; 3. Auscultation: diminished breath sounds, prolonged expiration, and dry and moist rales are heard. Chronic obstructive pulmonary diagnosis: 1. presence of risk factors, incomplete reversible airflow limitation; 2. monitoring: chronic cough and sputum with a history of risk factor exposure, airflow limitation test should be performed; pulmonary function measurement is the gold standard; FEV1