What are the effects of positive end-expiratory pressure (PEEP)?

Positive end-expiratory pressure (PEEP) is an important mode of mechanical ventilation that plays a significant role in improving oxygenation in patients with respiratory distress. By maintaining a certain level of pressure in the airways at the end of expiration, PEEP helps to keep alveoli open and prevents their collapse, which can lead to improved gas exchange. The retention of air in the lungs allows for better recruitment of collapsed or partially collapsed alveoli, ultimately enhancing the surface area available for oxygen-carbon dioxide exchange.

When airways are open and alveoli are recruited, the resulting increase in functional residual capacity can lead to improved oxygenation and a reduction in shunting phenomena associated with atelectasis (collapse of lung tissue). Moreover, by improving the distribution of ventilation and perfusion in the lungs, PEEP contributes to enhanced overall respiratory mechanics and can help maintain adequate oxygen levels in the bloodstream.

In contrast, other choices inaccurately depict the effects of PEEP. It does not decrease oxygenation; rather, its primary purpose is to enhance oxygenation. PEEP is typically associated with improving, not reducing, lung compliance by recruiting collapsed lung units rather than increasing discomfort. Furthermore, rather than risking airway collapse during inspiration, PEEP supports airway patency, making