Which statement about PEEP is correct?

• A. PEEP reduces the need for oxygen therapy
• B. PEEP helps keep alveoli open at end expiration to improve oxygenation
• C. PEEP directly removes carbon dioxide
• D. PEEP eliminates the risk of barotrauma

Answer: (B)

PEEP works by keeping small airways and alveoli open at the end of expiration, preventing collapse. This recruitment raises the surface area for gas exchange and increases functional residual capacity, which helps maintain better oxygenation by reducing intrapulmonary shunting. It doesn’t directly remove carbon dioxide; CO2 clearance depends on how well you ventilate (tidal volume and respiratory rate), not on PEEP itself. It can also raise intrathoracic pressure and, if used inappropriately, contribute to barotrauma or reduce venous return. So the statement that PEEP helps keep alveoli open at end expiration to improve oxygenation best describes its primary effect.