What's Up Doc? Coping with COPD
Q: My mother was just diagnosed with COPD. What is this?
A: Chronic obstructive pulmonary disease affects over 10 percent of Americans over age 40 and is the fourth leading cause of death. Evidence of COPD is found in two-thirds of men and over a quarter of women (this is increasing) at autopsy, so it is more common than this 10 percent figure suggests.
Normally, air enters through the nose and/or mouth and travels through the trachea to the main, lobar and finally the segmental bronchi. The bronchi branch into thousands of smaller bronchioles, which end in alveolar sacs. These sacs have capillaries running through their walls allowing oxygen to enter the blood and carbon dioxide to be exhaled.
The two main forms of COPD are chronic bronchitis (causing increased mucous, inflammation and thickening of the airways) and emphysema (causing abnormal enlargement of the airspaces and loss of elasticity of the alveoli), though chronic active asthma (where, in addition to inflammation, airway hyper-reactivity is also present) may also lead to COPD.
Most patients with COPD have some components of both emphysema and chronic bronchitis, causing shortness of breath (especially with exertion), cough, wheezing and/or acute chest illness (manifesting as chest pain, acute bronchitis, pneumonia, etc.).
Over 80 percent of patients with COPD have a smoking history. Although COPD is diagnosed in only 20 percent of long-time smokers, many more are affected and adjust their lifestyle because of their shortness of breath, consistent with the under-diagnosis from the discrepancy of diagnosed COPD and autopsy findings.
Other risk factors for developing COPD include occupational exposure to dust or chemicals, a hereditary condition called alpha-1 antitrypsin deficiency, tuberculosis, bronchopulmonary dysplasia and others. COPD may be more severe in those with airway hyper-responsiveness, HIV and those with high or low body mass index (obese and very skinny patients).
COPD is diagnosed by lung function testing; patients breathe into a machine that measures how much and how quickly they mobilize air. Specifically, the forced expiratory volume in one second (FEV1, the maximum volume of air exhaled in one second) and the forced vital capacity (FVC, the volume of air between maximum inspiration and maximum expiration) are measured. These are compared to the predicted normal volumes expected based on the patient's characteristics (age, sex and body characteristics).
Normally, FEV1/FVC is over 80 percent. The decreased elasticity and other changes from COPD don't allow patients to "blow out" this high a percentage of their lung volume over one second, so FEV1/FVC is less than 70 percent. FEV1, compared to the predicted normal for the patient, is then used to stage COPD:
- Mild has FEV1 over 80 percent of that predicted for the patient
- Moderate has FEV1 between 50 and 80 percent
- Severe has FEV1 between 30 and 50 percent
- Very severe has FEV1 less than 30 percent (or less than 50 percent with chronic respiratory failure)
The patient's symptoms and stage of COPD help determine what treatment is best for them. In general, short-acting bronchodilators (to dilate the airways) are the first line of treatment and are used when needed. This is usually sufficient for patients with mild COPD. The next line of treatment adds regular doses of long-acting bronchodilators, continuing the short-acting bronchodilators as needed. Pulmonary rehabilitation (to improve lung function) may be utilized for these patients as well.
More than one type of bronchodilator may be needed; in general, medications with different mechanisms of action are added sequentially to help control symptoms.
Patients with severe COPD would utilize the above treatments and add inhaled steroid medications. Supplemental oxygen therapy may also be needed. Finally, patients with very severe COPD may require all the above and, in some cases, need surgery to remove the parts of their lungs that are compromising breathing because of poor productive functioning.
Patients with COPD periodically have acute flare-ups, further compromising their breathing. Depending on the severity of the flare-up, they may require antibiotics, intensified bronchodilator therapy, more aggressive steroid therapy and/or other treatments (for example, supplemental oxygen and/or machines to facilitate breathing, such as bipap machines or even intubation).
Although there are COPD treatments, there is no cure, so preventing this condition is a priority:
- If you smoke, stop
- Avoid exposure to chemical and other respiratory irritants
- Keep your weight at a healthy level
People with severe COPD should consult their health care provider to see if it is safe for them to fly on an airplane; air cabin pressure is similar to more than 5,000 feet of air pressure, like in Denver, and can exacerbate respiratory illnesses for people not accustomed to it.
Jeff Hersh, Ph.D., M.D., F.A.A.P., F.A.C.P., F.A.A.E.P., can be reached at DrHersh@juno.com.