The twang sound is a very fine and uniform wet rales. Mostly heard at the end of inspiration, it is similar to the sound made when twisting a bunch of hair with a finger in the ear. This is due to the presence of secretions in the bronchial and alveolar walls that are stuck to each other and are re-inflated by the airflow during inspiration, resulting in a high-pitched, high-frequency, small bursting sound. Pulmonary examination is a complex examination with many items, such as: pulmonary function test: pulmonary function test includes ventilation function, ventilation function, respiratory regulation function and pulmonary circulation function, etc. There are many examination items and measurement indexes. This test can detect lung and respiratory pathologies at an early stage, which is especially important for smokers and people who are engaged in highly polluting work, to determine how well you can tolerate and what kind of work you can do. It is also very sensitive and does not cause any damage to the body. Pulmonary capillary wedge pressure: Pulmonary capillary wedge pressure is one of the most common and important indicators used in clinical hemodynamic monitoring. It is also known as pulmonary artery wedge pressure (PAWP). Pulmonary artery wedge pressure is usually measured by floating a Swan-Ganz balloon catheter through the bloodstream and wedging it into the small pulmonary artery, blocking the antegrade blood flow there, at which time the pressure measured at the tip of the catheter is the pulmonary artery wedge pressure (PAWP). Bronchoscopy: Bronchoscopy is an examination method that includes electronic bronchoscopy, pediatric bronchoscopy, and transbronchoscopic lung biopsy. Selective bronchoscopy is performed with the patient in a supine or semi-recumbent position, with intravenous access, intermittent blood pressure monitoring, and continuous oximetry and ECG monitoring. Fluoroscopy is not necessary but can be helpful in many cases. Color video imaging bronchoscopy is useful for visualization and for photographing airway lesions.