What is one consequence of diffusion limitation in gas exchange?

• A. Increased oxygen saturation
• B. Reduced efficiency in CO2 removal
• C. Enhanced lung compliance
• D. Improved respiratory rate

Answer: (B)

Diffusion limitation in gas exchange occurs when there is an impairment in the ability of gases to pass across the alveolar-capillary membrane. When this limitation occurs, particularly with carbon dioxide (CO2), it means that CO2 is not being effectively removed from the bloodstream. As a result, elevated levels of CO2 can accumulate in the blood, leading to reduced efficiency in CO2 removal. This impairment can be attributed to various factors, such as decreased surface area for gas exchange, increased thickness of the membrane, or altered ventilation-perfusion ratios.

In the context of gas exchange, while increased oxygen saturation, enhanced lung compliance, and improved respiratory rate may seem beneficial, they do not address the fundamental issue of diffusion limitation. For instance, increased oxygen saturation typically reflects improved oxygen delivery, while enhanced lung compliance indicates greater ease of lung expansion during breathing. Improved respiratory rate may temporarily aid ventilation but does not resolve the underlying limitations presented by diffusion issues. Thus, the consequence of diffusion limitation is directly linked to reduced efficiency in CO2 removal, confirming the correct choice in this scenario.