Pulmonary function tests
Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and the FEV1/FVC ratio were measured by a computerized spirometer. The spirometer was calibrated before use to ensure that it worked properly. Before the examination, we understood the patient’s medical history and treatment in detail, determined whether the indication for spirometry was met, and paid attention to exclude relevant contraindications. Introduce the procedure and movement to the patient and guide the patient to practice to master the movement more quickly. The patient takes a sitting position with his chest straight, feet relaxed and the head naturally level or slightly tilted. According to the test curve and indicators, patients were guided to perform measurement procedures and corresponding actions. The measurement is repeated, and the best result is selected.