November 29, 2015
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COPD (Chronic Obstructive Pulmonary Disease) (cont.)

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What are the four stages of COPD?

One way to stage COPD is the Global Initiative for Chronic Obstructive Lung Disease program (GOLD). The staging is based on the results of a pulmonary function test. Specifically, the forced expiratory volume (how much air one can exhale forcibly) in one second (FEV1) of a standard predicted value is measured, based on the individual patient's physical parameters. The staging of COPD by this method is as follows:

  • Stage I is FEV1 of equal or more than 80% of the predicted value
  • Stage II is FEV1 of 50% to 79% of the predicted value
  • Stage III is FEV1 of 30% to 49% of the predicted value
  • Stage IV is FEV1 of less than 30% of predicted value or an FEV1 less than 50% of predicted value plus respiratory failure

Other staging methods are similar but are based on the severity of the shortness of breath symptom that is sometimes subjective. The above staging is measurable objectively, providing the patient is putting forth their best effort.

What other diseases or conditions contribute to COPD?

In general, three other non-genetic problems related to the lung tissue play a role in COPD. 1) chronic bronchitis, 2) emphysema, and 3) infectious diseases of the lung.

  • Chronic bronchitis and emphysema, are thought by many to be variations of COPD and considered part of the progression of COPD by many researchers. Chronic bronchitis is defined as a chronic cough that produces sputum for three or more months during two consecutive years.
  • Emphysema is an abnormal and permanent enlargement of the air spaces (alveoli) located at the end of the terminal bronchioles in the lungs.
  • Infectious diseases of the lung may damage areas of the lung tissue and contribute to COPD.
Medically Reviewed by a Doctor on 11/4/2015


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