What happens to Functional Residual Capacity (FRC) in emphysema?

• A. Increases
• B. Decreases
• C. Remains unchanged
• D. Varies with activity level

Answer: (A)

In emphysema, Functional Residual Capacity (FRC) is known to increase. FRC is the volume of air remaining in the lungs after a normal expiration, and it serves as an important measure of lung function.

In emphysema, the destruction of alveolar walls leads to a loss of elastic recoil in the lung tissue. This results in a decreased ability of the lungs to revert to their resting volume after exhalation. The loss of elasticity allows for air trapping during expiration, causing an accumulation of air in the lungs. Consequently, this air accumulation raises the FRC because more air is left in the lungs after normal exhalation compared to healthy lung function.

As lung mechanics are altered in emphysema, the increased FRC reflects the pathological changes in lung structure and function, impacting gas exchange and overall respiratory efficiency. This situation creates a scenario where patients often have difficulty fully expelling air, leading to the characteristic overinflation of the lungs observed in emphysema.