In emphysema, what is typically observed in pulmonary function tests?

In emphysema, pulmonary function tests typically reveal a decreased diffusing capacity for carbon monoxide (DLCO). This is due to the destruction of alveolar walls and the associated loss of surface area available for gas exchange. As emphysema progresses, the integrity of the alveolar-capillary membrane is compromised, leading to a reduction in the efficiency of gas exchange and a subsequent decrease in DLCO.

The decreased diffusing capacity indicates that the lung’s ability to transfer gases from the alveoli into the bloodstream is impaired, which is a hallmark of emphysema. This contrasts with normal DLCO, which would suggest that gas exchange effectiveness has not been significantly compromised.

In terms of lung volumes, emphysema typically leads to increased lung volumes due to air trapping, particularly noted in total lung capacity (TLC) and residual volume (RV), making the observation of decreased lung volume incorrect in this context. Additionally, the FEV1/FVC ratio is typically decreased in emphysema, reflecting obstructive patterns of airflow limitation rather than an increase. Therefore, understanding the pulmonary function test outcomes is crucial for the diagnosis and management of emphysema, and recognizing that decreased DLCO is an important feature of this condition helps clarify the physiological implications of the