I Definition Bronchial asthma is a chronic inflammatory disorder of the airways involving a variety of cells (e.g., eosinophils, mast cells, T lymphocytes, neutrophils, airway epithelial cells, etc.) and cellular components. This chronic inflammation leads to increased airway hyperresponsiveness and causes recurrent episodes of wheezing, shortness of breath, chest tightness, or coughing, which often flare up and worsen at night and/or early in the morning, usually with widespread variable and reversible airflow limitation, and most patients can resolve on their own or with treatment. Second, the diagnosis of bronchial asthma is a chronic inflammatory disorder of the airways involving a variety of cells (e.g., eosinophils, mast cells, T lymphocytes, neutrophils, airway epithelial cells, etc.) and cellular components. This chronic inflammation leads to increased airway hyperresponsiveness and causes recurrent episodes of wheezing, shortness of breath, chest tightness, or coughing, which often flare up and intensify at night and/or early in the morning, usually with widespread variable and reversible airflow limitation, which can resolve spontaneously or with treatment in most patients. (A) Diagnostic criteria 1. Recurrent episodes of wheezing, shortness of breath, chest tightness or cough are mostly associated with exposure to allergens, cold air, physical or chemical irritation, viral upper respiratory tract infection, and exercise. 2. During the attack, scattered or diffuse, expiratory phase dominated croup can be heard in both lungs with prolonged expiratory phase. 3. The above symptoms may be relieved by treatment or may resolve on their own. 4, Those with atypical symptoms (such as no obvious wheezing or signs) should have at least one of the following positive tests. (1) positive bronchial excitation test or exercise test; (2) positive bronchial diastolic test [force expiratory volume in one second (FEV1) increased by more than 15%, and the absolute value of FEV1 increase >200m1]; (3) maximum expiratory flow (PEF) intra-day variability or diurnal fluctuation rate ≥20%. 5, except wheezing, shortness of breath, chest tightness and cough caused by other diseases. (B) Staging According to clinical manifestations bronchial asthma can be divided into acute exacerbation, chronic persistence and remission. The remission period refers to the disappearance of symptoms and signs with or without treatment, and the return of pulmonary function to the pre-acute attack level, which is maintained for more than 4 weeks. The severity of asthma should be graded into three parts. 1.Grading of the severity of asthma before treatment: including patients with new onset asthma and patients with previously diagnosed asthma who have not applied medication for a long time. See Table 1. Table 1 Grading of pre-treatment asthma severity grading clinical characteristics intermittent episodes (grade 1) symptoms < 1 brief episode per week nocturnal asthma symptoms ≤ 2 episodes per month FEV1 ≥ 80% of expected value or PEF ≥ 80% of personal best, PEF or FEV1 variability < 20% mild persistent (grade 2) symptoms ≥ 1 episode per week but < 1 episode per day may affect activity and Sleep nocturnal asthma symptoms >2 times per month but <1 time per week FEV1 ≥80% expected or PEF ≥80% personal best, PEF or FEV1 variability 20%-30% Moderately persistent (level 3) daily symptomatic episodes interfering with activity and sleep nocturnal asthma symptoms ≥1 time per week FEV160%-79% expected or PEF 60%-79 personal best, PEF or FEV1 variability > 30% severe persistent (grade 4) frequent daily symptomatic episodes frequent nocturnal asthma symptoms physical activity limitation FEV1 < 60% expected or PEF < 60% personal best, PEF or FEV1 variability > 30% 2. Grading of asthma severity during treatment: When the patient is already in standardized graded treatment, the severity of asthma Grading should then be based on a combination of clinical presentation and the level of the current daily treatment regimen. Original set treatment level Intermittent episodes (level 1) Mildly persistent (level 2) Moderately persistent (level 3) Current patient’s symptoms and lung function severity grading Intermittent episodes (level 1) Symptoms < 1 transient episode per week Nocturnal asthma symptoms ≤ 2 episodes per month Normal lung function during intermittent episodes Mildly persistent Moderately persistent Mildly persistent (level 2) Symptoms ≥ 1 per week but < 1 per day Nocturnal Asthma symptoms > 2 episodes per month but < 1 episode per week during normal lung function mild persistent moderate persistent severe persistent moderate persistent (level 3) daily symptomatic episodes interfering with activity and sleep nocturnal asthma symptoms ≥ 1 episode per week FEV 160% to 79% expected or PEF 60% to 79% personal best moderate persistent severe persistent severe persistent severe persistent (level 4) frequent daily symptoms Seizures frequent nocturnal asthma FEV1 < 60% predicted or PEF < 60% personal best severe persistent severe persistent severe persistent