A pneumothorax with a small amount of accumulated gas may get better on its own without treatment, while an untreated pneumothorax with a large amount of accumulated gas can affect cardiopulmonary function and can be life-threatening in severe cases. Pneumothorax is a common emergency, and can occur when the pleural cavity breaks down for various reasons and gas enters the pleural cavity. Normally the pleural cavity is a negative pressure space that does not contain air, but after a pneumothorax occurs it becomes a positive pressure, which can lead to compression of the lung tissues and impede the venous return of blood flow to the heart. For a small amount of pneumothorax, usually no special treatment is needed, and the gas in the chest can be absorbed by itself after bed rest. However, for pneumothorax with large amount of accumulated gas, if not treated timely and actively, the accumulated gas will gradually increase in size, which will seriously compress the cardiopulmonary tissues, leading to symptoms of respiratory and circulatory disorders such as chest tightness and dyspnea, and if not decompressed timely, it may lead to sudden death. It is recommended that patients with pneumothorax actively seek medical attention and follow the doctor’s instructions for treatment.