What is the purpose of Positive End Expiratory Pressure (PEEP)?

The purpose of Positive End Expiratory Pressure (PEEP) is to prevent atelectasis by keeping the alveoli open. PEEP achieves this by maintaining a certain amount of positive pressure in the airways at the end of expiration, which helps to ensure that the alveoli do not fully collapse. This is crucial, especially in patients with compromised lung function, as it improves ventilation and promotes better gas exchange. By keeping the alveoli open, PEEP can enhance oxygenation, as more areas of the lung remain available for gas exchange, thereby improving overall respiratory efficiency.

The other choices address related concepts but do not capture the fundamental role of PEEP. While PEEP may contribute to improved oxygenation and may influence lung volume positively, its primary role is to prevent the complete collapse of alveoli, which is essential for maintaining adequate lung function and preventing complications associated with insufficient air exchange.