If the flow-volume loop does not reach baseline, what is the problem?

• A. Intrinsic PEEP
• B. Air Leak
• C. Bronchospasm
• D. Circuit Kink

Answer: (A)

Not reaching the baseline on the expiratory portion means there is positive pressure remaining in the airways at end expiration, i.e., auto-PEEP (intrinsic PEEP) with air trapping. When expiration ends before the flow decays to zero, the loop ends higher than the zero-flow baseline, signaling incomplete exhalation. This often happens when expiratory time is too short or there is high airway resistance, so air remains trapped and the next breath begins before full exhalation. To address it, allow more time for exhalation (lower respiratory rate or longer I:E ratio), reduce obstruction or bronchospasm if present, and ensure there isn’t an unexpected contributor like mucus plugging.