Why do you need a thoracic puncture? First of all, we should know the role of thoracic puncture in the diagnosis and treatment of chest diseases. Thoracic puncture is a common and convenient diagnosis and treatment method in pulmonary clinical work. For example, if the patient is found to have pleural effusion through examination, the fluid can be pumped out through thoracic puncture, and various examinations can be carried out to find out the cause. If there is a large amount of effusion in the cavity, the lung is pressed or the effusion lasts for too long, the fibrin in it is easy to be organized, and pleural adhesion occurs twice, which affects the respiratory function of the lung. At this time, we also need puncture to take out the effusion. If necessary, you can also inject drugs to achieve the purpose of treatment. For example, pleural effusion caused by cancer, we inject anticancer drugs to play an anti-cancer role. If there is too much gas in the chest cavity and the pleural cavity has changed from negative pressure to positive pressure, then the gas can also be decompressed and pumped out through this operation. If the patient has the situation that the bronchus communicates with the pleural cavity, then we can inject a blue medicine (called methylene blue, which is harmless to human body) into the chest cavity through the puncture needle, so that the patient can cough up blue liquid (including sputum) when coughing, and then we can confirm that the patient has bronchopleural fistula. Bronchopleural fistula is a pathological channel established by lung lesions involving bronchi, alveoli and lung pleura, which is a channel from oral cavity to trachea to bronchi at all levels, alveoli to visceral pleura and then to pleural cavity.