Breathe Easier
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death and could be almost entirely prevented if people didn’t smoke. By Rear Adm. Joyce Johnson, D.O.

Deep in the lungs are tiny air sacs, called alveoli, that bring oxygen from the air into our blood in exchange for carbon dioxide, which we exhale. The alveoli have several characteristics that facilitate gas exchange. First, sheer quantity — if you laid them flat, they would cover a football field. This extensive surface area enables more gas to be exchanged. Second, the alveoli are very elastic, so as you breathe they can expand to take in air and shrink to push it out. Third, these air sacs have many tiny capillaries, each filled with a single row of red blood cells where the actual gases are exchanged.

There are two types of COPD — emphysema and chronic bronchitis. With emphysema the walls between the air sacs are destroyed and the alveoli lose their elasticity, reducing the surface area and leaving large, inefficient air sacs. Someone with emphysema can’t get enough oxygen and (eventually) is always gasping for air. Chronic bronchitis causes an increase in mucus production that reduces the exchange of gases, leaving you short of breath. This mucus results in a chronic productive cough with sputum.

Most people are at least 40 before they begin to notice COPD. Initial symptoms include increased shortness of breath during exercise, while climbing steps, etcetera. Over time these symptoms worsen. In the late stages of COPD, a patient is on oxygen constantly and out of breath without any exertion. Just moving enough to feed oneself becomes difficult.

Doctors diagnose COPD by measuring how much air the lungs breathe in and out and how fast that air moves; COPD is characterized by a decrease in both the amount and the speed of air moved. A chest X-ray and measuring the amount of oxygen in your blood, as well as other tests, are used to diagnose COPD before the symptoms affect daily activities.

Cigarette smoking is by far the biggest risk factor for COPD; over time, most smokers develop some degree of COPD. Some people have an alpha 1 antitrypsin deficiency that leaves the body less able to destroy harmful proteins in the blood and thus more vulnerable to COPD. Other risk factors include secondhand smoke, severe air pollution, and exposure to chemical gases and dusts (from jobs or hobbies).

A major goal of COPD treatment is to increase gas exchange. Inhalers with bronchodilators help the lungs work better, while inhaled steroids reduce lung inflammation. Supplemental oxygen, carried in a tank, also can be useful. Other respiratory diseases are especially dangerous for patients with COPD, who should get vaccinated for flu and pneumonia.

COPD is a dangerous, chronic disease. If you don’t smoke, your risk is very low. There are many programs to help you quit smoking; for information, visit www.smokefree.gov or see your doctor.

— Rear Adm. Joyce Johnson, USPHS-Ret., D.O., M.A., is vice president, Health Sciences, Battelle Memorial Institute, Arlington, Va.