There are often multiple-choice questions about the comparison of lung function of several respiratory diseases, so I have made some summaries of the relevant contents, including the introduction of basic concepts, which I am familiar with.
1, chronic bronchitis: no abnormality in the early stage. If there is small airway obstruction, the expiratory flow rate-volume curve (MEFV curve) will obviously decrease at 75% and 50% volume, and the volume of breath closure will obviously increase. When COPD develops, obstructive ventilation dysfunction and lung function may occur. For example, the ratio of forced expiratory volume to forced vital capacity decreased in the first second, the ventilation decreased, and the MEFV curve decreased more obviously.
2. Obstructive emphysema: Pulmonary function examination has diagnostic significance for emphysema, and its characteristic change is that functional residual volume, residual volume and total lung volume all increase, and the proportion of residual volume to total lung volume increases (> 40%). When the lesion develops into COPD, the indexes reflecting airway obstruction and airflow limitation decrease, such as compulsory medicine = education network-original expiratory flow rate.
3.COPD: Pulmonary function examination is the main objective index to judge airflow limitation, which is of great significance to the diagnosis, severity evaluation, disease progress, prevention and treatment response judgment of COPD. The airflow restriction is determined by the decrease of forced expiratory volume (FEV 1% predicted value) and forced expiratory volume (FEV 1/FVC) in the first second. FEV 1/FVC is a sensitive index of COPD, which can detect mild airflow restriction. The predicted value of FEV 1% is a good indicator of moderate and severe airflow restriction, with small variability and easy operation, and should be used as a basic item for pulmonary function examination of COPD. After inhaling bronchodilator, fev 1