Chronic Obstructive Pulmonary Disease (COPD) is the abbreviation for Chronic Obstructive Pulmonary Disease. Most long-term heavy smokers gradually exhibit chronic bronchitis, emphysema, dyspnea and reduced lung ventilation after middle-age and old age, which are the main manifestations of what is known medically as chronic obstructive pulmonary disease (COPD). In fact, COPD has a specific meaning, traditionally defined as a disease state characterized by airflow limitation (difficulty in expiration, slowing down of expiratory flow rate), and its diagnostic criteria are: exertion expiratory volume in the first second after inhalation of bronchodilator (FEV1) <80% of the expected value (expected value is the normal value that should be achieved according to the patient's height and weight, and the normal value is 80%~120%), and with the exertion spirometry (FVC) ratio (FEV1/FVC) <70% (i.e., the ratio is 0.7), and normal should be ≥75% (i.e., the ratio is 0.75). Primary Recognition of Chronic Obstructive Lung In clinical practice, there are many conditions that show ventilatory dysfunction, the most common being emphysema, but patients with alveoli, asthma, bronchiectasis, cystic fibrosis, and occupational pneumoconiosis (commonly referred to as silicosis) can all have airflow limitation, thus showing that chronic obstructive lung is actually a syndrome. Pulmonary function tests are important in determining airflow limitation. After inhalation of bronchodilators, FEV1/FVC <70% indicates airflow limitation that is not completely reversible. Chronic cough and sputum often precede airflow limitation by many years and persist, but not all patients with cough and sputum symptoms will develop COPD. Some patients may have irreversible airflow limitation without chronic cough and sputum. Diseases with airflow limitation of known etiology or characteristic pathology, such as bronchiectasis, fibrotic lesions of tuberculosis, cystic fibrosis, diffuse panbronchiolitis (DPB), and occlusive bronchiolitis (OB), are not considered to be chronic obstructive pulmonary disease (COPD). Only "chronic bronchitis" and/or "emphysema" without airflow limitation is not diagnostic of COPD. The relationship between COPD and asthma The definition of COPD and the new understanding of asthma increasingly suggest that COPD is similar to chronic persistent asthma. Certain patients with asthma can have mixed or irreversible airflow obstruction, making it impossible to make a clear distinction between asthma with incompletely reversible airflow obstruction and chronic bronchitis and emphysema with partially reversible airflow obstruction. 1, similarities: chronic obstructive pulmonary and bronchial asthma are both obstructive airway diseases, the two main common or similar points are: ① both have chronic inflammation of the airways; ② both have a genetic basis and the role of environmental factors in the background; ③ both have the pathophysiological abnormality of bronchial spasm and hypersecretion; ④ both can be manifested in dyspnea, chest tightness, breath-holding, wheezing, coughing; ⑤ part of the patients with chronic obstructive pulmonary can be manifested in the airway hyper-responsiveness; ⑥ part of the patients with chronic obstructive pulmonary can be manifested in airway hyper-reactivity; ⑥ Some patients with chronic obstructive pulmonary disease have reversible airflow limitation; (7) Airway remodeling can occur to varying degrees; (8) Inhaled glucocorticosteroids and long-acting bronchodilators are effective in moderate-to-severe persistent asthma and chronic obstructive pulmonary disease, especially when they are combined in the same inhaler, which further proves that there is a similarity in the nature of the lesions in chronic obstructive pulmonary disease and asthma. 2, the difference: there are many differences between chronic obstructive pulmonary disease and asthma, the most important are: ① asthma has an early onset, the onset of disease in infancy and early childhood, while chronic obstructive pulmonary disease usually starts after middle age, the vast majority of smokers or exposure to hazardous gases or particles related to the population, and into the old age, most of the symptoms are very typical of the significant impairment of lung function; ② asthma is obvious familial, reflecting the close relationship between asthma and the genetics, although chronic obstructive pulmonary disease has a close relationship with the genes, but not with the genes. Although chronic obstructive pulmonary disease (COPD) also has a family distribution of phenomena, but most of them are related to the same smoking habit or the environment, it is difficult to explain the genetic susceptibility; ③ most asthma patients with other allergic diseases, especially allergic rhinitis (commonly known as allergic rhinitis) and dermatitis (eg, eczema), and the probability of patients with COPD associated with these allergic diseases is much lower; ④ the airway provocation and diastolic test showed that asthma patients have a significant bronchial constriction. The airway provocation test and diastolic test show that the bronchial tubes of asthmatics are markedly constrictible and diastolic, whereas the response of patients with chronic obstructive pulmonary disease (COPD) to these tests is usually weak; ⑤ Asthma onset or exacerbation is episodic, cyclical, seasonal, and may resolve on its own or with treatment, whereas COPD patients have basically persistent and progressive symptoms, and it is the leading cause of disease, death, and depletion of health care resources globally, with approximately 2.75 million deaths attributed to COPD each year. and death each year due to COPD.