The pleura is a double-layer membrane that surrounds the lungs and the inner chest wall. Essentially, it is a closed, airtight system. However, when air enters the pleural space between the lungs and chest wall as the result of disease or injury, a pneumothorax, or collapsed lung can occur. If this occurs, more often than not, it will require medical attention. If the collapse is extremely small or minor, a physician may allow it to resolve on its own, requiring no additional intervention. If a pneumothorax is the result of an injury or total lung collapse, it can be life threatening and require immediate medical intervention.
The visceral pleura is the muscular layer that adheres directly to each lung. Another pleural membrane, the parietal pleura, adheres to the inside of the chest wall. A thin layer of lubrication lies between the two pleural layers, allowing them to easily slide against each other when the lungs inflate during inhalation.
Both lungs and the chest wall are elastic and pull in opposite directions, causing a subtle balance of opposing pressures between the pleural membranes. This balance enables the lungs to inflate. If air enters the pleural space, it upsets the balance between the pleural membranes, and the balance in pressure becomes uneven. When this happens, the lung collapses inward, and the chest wall springs outward. According to the Mayo Clinic, ruptures often occur at the top of the lung, but can essentially occur anywhere there is a weak spot in the pleura.
Treatment of a pneumothorax depends on the amount of air in the chest, the extent of the collapse and whether disease is present. A small pneumothorax may not require treatment. Doctors treat others by releasing the air with a needle and syringe called aspiration. If a small pneumothorax recurs, doctors may introduce an irritant that causes an inflammation, making the two pleural membranes fuse together as they heal.
Doctors will drain larger pneumothoraces with a chest tube and a water seal bottle. The patient receives a local anesthetic before the doctor makes a small incision in the general area of the collapse. She inserts a tube through the chest wall into the pleural space. She then connects the tube to a device called a water seal bottle that allows air in the chest to move into the bottle, but prevents air in the room from entering the pleural space. The pressure balance created in the pleural space helps to reinflate the lung.
If the pneumothorax does not resolve either on its own or with minimal intervention, surgery may be considered. During the procedure, the surgeon scrapes the surface of the pleura to cause scar formation, causing the two pleural layers to stick together. A second surgical procedure involves removing the section of the lung that has ruptured.