Certified Respiratory Therapist Practice Exam

Which patient characteristic is a common finding in those suffering from emphysema based on pulmonary function testing?

1. Increased FEV1

2. Reduction in DLCO

3. Normal Residuary Volume

4. Decreased lung volumes

The correct answer is: Reduction in DLCO

In patients suffering from emphysema, a reduction in DLCO (Diffusing Capacity of the Lung for Carbon Monoxide) is commonly observed during pulmonary function testing. This measurement assesses how well gases can diffuse across the alveolar-capillary membrane. In emphysema, the destruction of the alveolar walls leads to a decrease in surface area for gas exchange, which impairs the diffusion process. Consequently, patients exhibit a lower DLCO value, indicating an impairment in their lungs’ ability to transfer oxygen and carbon dioxide effectively. The other options reflect characteristics not typically associated with emphysema. An increased FEV1 (Forced Expiratory Volume in one second) is not a common finding since patients generally have obstructive patterns that lead to a decrease in FEV1. Normal Residual Volume (RV) would not accurately represent emphysema, as patients typically exhibit increased RV due to air trapping. Lastly, decreased lung volumes could suggest restrictive lung disease, while emphysema usually presents with hyperinflation, leading to increased lung volumes rather than a decrease. Therefore, the reduction in DLCO is the hallmark of the impaired gas exchange characteristic of emphysema.