Chronic obstructive pulmonary disease (COPD) weakens the structure of the lung and may also damage the tiny air sacs (alveoli) in the lung. When these air sacs break down, larger airspaces known as bullae are formed. Bullae sometimes can become so large that they interfere with breathing and may cause complications: They can burst, leading to a collapsed lung (pneumothorax). A collapsed lung will often need treatment with a chest tube. They can become infected, leading to an abscess in the lung that can spread to the pleural cavity (the space between the lung and the membrane that surrounds it). This condition (empyema) can be difficult to resolve and often requires extensive treatment with antibiotics. For some people, surgically removing the enlarged air sacs—known as a bullectomy—makes breathing easier. But few people are considered good candidates for a bullectomy. It may work best for people with COPD who are young, have large bullae that are grouped in just one area of the lung, and do not have severe blockage in their airways. A bullectomy may be considered if the bullae: Are larger than one-third of a lung. Prevent the lung from expanding so the person cannot move enough air into his or her lungs. Bullectomy may make the lungs work better so more oxygen gets into the blood.