Which of the following is a factor that increases physiologic dead space?

The correct answer is anticholinergic agents because these medications have a specific impact on the respiratory system. Anticholinergic drugs work by blocking the action of the neurotransmitter acetylcholine in the central and peripheral nervous systems. In the context of respiratory physiology, anticholinergics can lead to bronchodilation and decreased secretions in the airways, which can contribute to increased physiologic dead space.

Physiologic dead space refers to the portion of the tidal volume that does not participate in gas exchange, which occurs in the respiratory system when parts of the lungs are ventilated but not perfused with blood. By influencing airway resistance and potentially leading to ventilation-perfusion mismatches, anticholinergic agents can increase the amount of air that enters the alveoli but does not participate in gas exchange, thereby increasing dead space.

The other factors have different effects or do not specifically increase physiologic dead space. For instance, the supine position typically decreases dead space due to improved lung mechanics. An increased respiratory rate may help reduce the impact of dead space by facilitating more effective gas exchange. Hypoxia, while it affects oxygenation, does not directly correlate with an increase in physiologic dead space in the same way anticholinergic agents