Chronic Obstructive Pulmonary Disease, or COPD, is diagnosed and treated according to the GOLD guidelines. The GOLD staging system is based on pulmonary function tests, first measuring the volume of air in a one-second forced exhalation and then measuring the total volume of exhaled breath. In people with normal lung function, the forced one-second volume is at least 70 percent of the total exhaled breath, according to WebMD.
Patients with COPD take longer to completely empty the lungs. Stage I is classified as mild COPD. Stage II is moderate. Stage III is severe. Stage IV is very severe and requires long-term oxygen therapy, according to WebMD. Since GOLD only measures airflow obstruction, it is not considered the sole diagnostic criterion. Other factors including obesity, smoking, medical conditions such as heart disease and physical fitness also influence breathing and life expectancy.
There is no cure for COPD, but lifestyle changes such as quitting smoking can relieve symptoms, according to the National Heart, Lung and Blood Institute. Some patients benefit from bronchodilators administered by inhalers that deliver medication directly to the lungs. In severe cases of COPD, a steroid can be added to the bronchodilator. Other treatments include vaccinations against pneumonia and the flu, pulmonary rehabilitation programs and oxygen. Surgery is considered a last resort.