What is the function of PEEP in mechanical ventilation?

PEEP, or Positive End-Expiratory Pressure, plays a crucial role in mechanical ventilation by preventing the collapse of alveoli and aiding in the maintenance of airway patency at the end of expiration. When mechanical ventilation is initiated, patients may not fully empty their lungs, leading to the potential collapse of alveoli, particularly in conditions such as Acute Respiratory Distress Syndrome (ARDS) or pneumonia. By setting PEEP, a certain pressure is maintained in the airways at the end of expiration, which keeps the alveoli open and improves overall lung compliance.

This tactic effectively increases functional residual capacity by allowing more surface area for gas exchange and enhancing oxygenation. It counteracts the effects of atelectasis, which can significantly impair ventilation and gas exchange. As a result, the application of PEEP can improve oxygenation and reduce the work of breathing in patients requiring mechanical ventilation. Through these mechanisms, PEEP contributes to better ventilation-perfusion matching and helps to optimize respiratory function.