What is the primary purpose of PEEP in ARDS management?

• A. To increase venous return
• B. To prevent alveolar collapse and improve oxygenation
• C. To raise blood pressure
• D. To promote dehydration

Answer: (B)

Positive end-expiratory pressure (PEEP) is used in ARDS to keep the lungs from collapsing at the end of exhalation. In ARDS, the alveoli are damaged and prone to collapse, which leads to areas that are poorly ventilated and contribute to hypoxemia through intrapulmonary shunting. By maintaining a baseline positive pressure at the end of expiration, PEEP helps recruit and keep alveoli open, increasing the amount of aerated lung (functional residual capacity) and improving ventilation-perfusion matching. The result is better oxygenation. While higher PEEP can affect heart filling due to increased intrathoracic pressure, its primary purpose in ARDS management is to prevent alveolar collapse and enhance oxygenation.