An increase in dead space ventilation generally leads to what outcome in V/Q mismatch?

An increase in dead space ventilation typically results in a higher ratio of ventilation to perfusion. This occurs because dead space refers to areas in the lungs where ventilation is taking place but no gas exchange occurs due to inadequate blood flow (perfusion) in those areas.

When dead space increases, there is more air being moved in and out of the lungs without corresponding blood flow. Consequently, while ventilation increases, perfusion may remain the same or even decrease, leading to a greater ventilation-perfusion (V/Q) ratio. In this situation, regions of the lung are ventilated but not perfused, thus contributing to a mismatch that skews the V/Q ratio higher.

This concept is essential for understanding conditions such as pulmonary embolism, where blood flow is obstructed yet ventilation continues, resulting in poor gas exchange despite an increased V/Q ratio.