In emphysema, the walls of the alveoli are eaten away and lose elasticity. Ruptured alveoli combine to form larger sacs that restrict the exchange of air and gas to and from the lungs. As a result, respiratory muscles work harder to bring in enough oxygen for tissue and to rid the body of carbon dioxide. Chronic Bronchitis Chronic bronchitis affects about 14 million people. Other symptoms include yellow or green sputum, shortness of breath and periods of exacerbation with increased cough, sputum production and shortness of breath.
Cigarette smoking is the most common cause of chronic bronchitis.
Air pollution also may cause chronic bronchitis. In the early stages of chronic bronchitis, a cough usually occurs in the morning. As the disease progresses, coughing persists throughout the day. Infection can cause further inflammation of bronchial tubes, which results in a reduced amount of air flowing in and out of the lungs, and shortness of breath. The National Emphysema Treatment Trial, a seven-year grant awarded to National Jewish and the University of Colorado Health Sciences Center by the National Heart, Lung and Blood Institute at the National Institutes of Health and the Health Care Financing Administration, is studying the benefits of lung volume reduction surgery.