COPD/Chronic Bronchitis

Chronic Bronchitis is classified as an Obstructive lung disease and primarily affects the airways. It is characterized by chronic inflammation of the airways, excess mucous production and cough. These processes act to narrow the airways and increase the work of breathing. Although Chronic Bronchitis by itself does not tend to affect the alveoli, individuals with Chronic Bronchitis tend to hypoventilate (breathe less than they should) because of the increased work of breathing.

Chronic Bronchitis status is best monitored by FEV1.

A typical PFT pattern for Chronic Bronchitis:

Spirometry FVC Normal or reduced
  FEV1 Reduced
  FEV1/FVC Ratio Reduced
  PEF Reduced
Lung Volumes TLC Normal
  RV Elevated
Diffusing Capacity DLCO Normal or reduced
ABG: PaCO2 Elevated

The severity of obstruction is determined by the reduction in FEV1. When the FEV1 or FEV1/FVC ratio are reduced:

FEV1 >= 70% of predicted Mild
FEV1 <70% and >=60% of predicted Moderate
FEV1 <60% and >=50% of predicted Moderately severe
FEV1 <50% and >=35% of predicted Severe
FEV1 <35% of predicted Very severe


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PFT Patient by Richard Johnston is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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