What is the role of PEEP in lung-protective ventilation?

• A. Increases risk of barotrauma; always avoided
• B. Has no effect on gas exchange
• C. Maintains open alveoli and improves oxygenation
• D. Worsens oxygenation by collapsing alveoli

Answer: (C)

PEEP keeps alveoli open at the end of expiration, preventing collapse and the repetitive reopening that hurts gas exchange. By maintaining recruitment, it increases functional residual capacity and enhances the surface area for oxygen diffusion, which improves arterial oxygenation. It also reduces atelectrauma from cyclic collapse. In lung-protective ventilation, PEEP is carefully titrated to sustain recruitment while avoiding overdistension and hemodynamic effects. That’s why this option—maintaining open alveoli and improving oxygenation—best fits. The other statements aren’t correct because PEEP does affect gas exchange, it doesn’t inherently worsen oxygenation by collapsing alveoli, and while high PEEP can have risks, it is not simply “always avoided” in protective strategies.