What is the role of positive end-expiratory pressure (PEEP) in mechanical ventilation?

Positive end-expiratory pressure (PEEP) plays a crucial role in mechanical ventilation by preventing alveolar collapse at the end of expiration. When PEEP is applied, it maintains a certain pressure in the airways at the end of expiration, which keeps the alveoli open and helps improve gas exchange. This is particularly important in patients with conditions such as Acute Respiratory Distress Syndrome (ARDS), where alveolar collapse can significantly hinder oxygenation.

By keeping the alveoli open, PEEP increases the surface area available for gas exchange, enhancing oxygen saturation and preventing atelectasis (the collapse or closure of a lung). It also helps to recruit collapsed alveoli that may be filled with fluid or other debris, thus improving overall lung function during mechanical ventilation. The benefits of PEEP extend to enhancing lung compliance and reducing the work of breathing, which is vital for patients with compromised respiratory function.