Why should PEEP be set above the lower inflection point on the deflation limb of the PV loop?

• A. To prevent alveolar collapse and reopening
• B. To recruit alveoli during deflation
• C. To increase overdistension risk
• D. To decrease compliance

Answer: (A)

Setting PEEP above the lower inflection point on the deflation limb keeps alveoli from collapsing as pressure falls during expiration. That LIP marks the pressure where derecruitment begins; by maintaining airway pressure above this point, alveoli stay open throughout expiration and on the next breath, they don’t repeatedly collapse and reopen. This reduces atelectrauma and improves overall lung stability and oxygenation.

Higher PEEP beyond this point isn’t about actively recruiting during deflation; it’s about preventing collapse. Increasing PEEP can risk overdistension if taken too far, and isn’t intended to decrease compliance—that potential side effect isn’t the goal here.