What position is known to decrease physiologic dead space?

The position known to decrease physiologic dead space is the prone position. This is because when a patient is placed in the prone position, the lung bases, which are more compliant and better perfused, typically receive more ventilation. This helps improve overall ventilation-perfusion matching, which effectively reduces the amount of dead space in the lungs.

Furthermore, the prone position can enhance the expansion of the lung fields, particularly in individuals with certain types of lung pathology or in patients undergoing mechanical ventilation. In contrast, positions like sitting or standing may not facilitate as much improvement in lung function or perfusion in certain contexts compared to the prone position. The supine position tends to increase the potential for atelectasis and can lead to increased dead space due to the potential for diminished aeration of certain lung regions.