Explain please. An individual with an FEV1 to FVC ratio of less than 0.8: O Is l

Question

Explain please.

An individual with an FEV1 to FVC ratio of less than 0.8: O Is likely suffering from a restrictive lung disease due to bronchoconstriction (a reduction in the diameter of the airways. O Is likely suffering from a restrictive lung disease due to issues with compliance and elasticity of the lungs O Is likely suffering from an obstructive lung disease due to bronchoconstríction (a reduction in the diameter of the airways) Is likely suffering from an obstructive lung disease due to issues with compliance and elasticity of the lungs. O Displays "normal" healthy breathing.

Explanation / Answer

FEV1 is forced expiratory volume in the forst second of forced expiration process.

FVC forced vital capacity of lung is defined as the calculation of vital capacity of lung by forced expiration. It means that the maximum amount of air one can expirate in a single expiration by applying maximum force to their respiratory process.

The ratio between these two entity is the main basis of diagnosing whether the lung disease is restrictive type or obstructive type.

In obstructive lung disease like asthma or COPD there is narrowing of airways but there is no reduction of air space inside the lung interstitium. That means that in obstructive disease alveoli capacity remains normal or near normal (lung compliance not altered). As alveoli contribute to more towards total air capacity of lung, there will be slight or no reduction in total lung air capacity. But there is narrowing of airways (trachea, brochiole etc) due to secretion from lung cells. So vital capacity( How much air lungs can accommodate ) remains same. But as there is obstruction (due to narrowing in airways) in airways, reduced air will be expirated(exhaled) in each second during forced expiration incase of obstructive lung disease than a normal lung, but the total exhaled air amount will same as normal lung as it is a forced expiration. In other wards, in obstructive lung disease FEV1 will be reduced more than FVC. SO in obstruction lung disease FEV1 / FVC ration will be less than normal lung. In obstructive disease lung compliance remains normal (no fibrosis).

In restrictive type lung disease like systemic sclerosis, there is fibrosis of airways as well as fibrosis of alveoli. So airways will be narrow as well as alveolar space will be reduced due to fibrosis. So in restrictive disease lung accommodate significantly less amount of lung. So in restrictive disease total capacity of lung will significantly be reduced due to fibrosis. So in restrictive disease FEV1 will be reduced and FVC will also reduced at same proportion. SO in restrictive disease FEV1 and FVC both will be reduced at same proportion so the ration between them will remain same as normal lung ( though the absolute value will be reduced for both FEV1 and FVC)

In medical practice a FEV1 / FVC ratio less than 0.8 is considered as Obstructive lung disease diagnostic criteria. But in restrictive disease it will remain normal or even more than normal because alveoli contributes to more area of lungs than airways.

So the answer is : option 3

Is likely suffering from obstructive lung disease due to bronchoconstriction ( a reduction in the diameter of the airways)

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