Emphysema is classified as an Obstructive lung disease and affects the lung structure, airways and alveoli. It is characterized by a loss of lung elasticity, hyperinflation (lung overinflation) and a loss of functional alveolar surface area. The loss of elasticity causes the airways to collapse during exhalation which reduces the rate at which air can flow. The hyperinflation decreases the turnover of fresh air in the lung during breathing and can limit how deep a breath that can be taken. The decrease in alveolar surface area reduces the ability of the lungs to transfer oxygen and carbon dioxide.
Emphysema status is best monitored by FEV1, DLCO and Oximetry.
A typical PFT pattern for Emphysema:
|Spirometry||FVC||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|
An additional factor that can be used to assess the severity of emphysema is the reduction in DLCO:
|DLCO >=60% and <80% of predicted||Mild reduction|
|DLCO >=40% and <60% of predicted||Moderate reduction|
|DLCO <40% of predicted||Severe reduction|
PFT Patient by Richard Johnston is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.