Pulmonary pneumatic pressure injury is a disease caused by the internal pressure of the lung being too high or too low compared to the external pressure, causing lung tissue and pulmonary vessels to tear, resulting in gas entering the vessels and adjacent areas, producing air bubble embolism and emphysema compression. There are many factors that cause the disease in daily life, and early understanding of these causes can help in the early detection and treatment of the disease. The causes are as follows: The lungs are connected to the outside world through the trachea, larynx, and nasopharyngeal cavity. Only the vocal cords can be switched on and off in this channel. If the vocal cords close when pressurized, this can cause external pressure to be greater than the pressure in the trachea and lungs. Pneumatic pressure injuries to the lungs are only seen in divers, sunken staff, patients undergoing hyperbaric oxygen therapy inappropriate breath holding, coughing, and convulsions during decompression (grand mal seizures, cerebral type oxygen poisoning) to close the vocal cords, causing the pressure in the trachea and lungs to be greater than the dry external pressure. Due to the poor pressure-bearing capacity of lung tissue, when the pressure difference between inside and outside the lung is greater than 10.6 kPa (80 mmHg), the lung tissue will over-expand, resulting in pneumothorax, mediastinal emphysema, subcutaneous emphysema due to tearing of alveolar walls, blood vessels, and interstitium, and gas embolism if gas enters the ruptured blood vessels.