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|
|Diffusing Capacity||DLCO||Normal or reduced|
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|
PFT Patient by Richard Johnston is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.