Auto-PEEP occurs when exhalation is not fully completed before inspiration, leading to what outcome?

• A. Retained volume and increased end expiratory pressure in the alveoli
• B. Decreased respiratory rate
• C. Reduced tidal volume
• D. Decreased blood oxygen levels

Answer: (A)

Auto-PEEP happens when expiration isn’t finished before the next breath starts, so air gets trapped in the lungs. That trapped air raises the volume at the end of expiration and increases the end-expiratory pressure in the alveoli. This retained volume is the defining feature and leads to dynamic hyperinflation, which makes breathing work harder and can affect how well blood returns to the heart and how gases are exchanged. The other options don’t capture this air trapping: the rate isn’t determined by auto-PEEP, tidal volume isn’t inherently reduced by it, and while oxygen levels can be affected, the hallmark outcome described here is the increased end-expiratory pressure from retained air.