What condition does auto-PEEP describe?

Auto-PEEP, or intrinsic positive end-expiratory pressure, occurs when there is a failure to fully exhale from the lungs during mechanical ventilation. This results in a build-up of air, causing an increase in lung volume at the end of expiration. Inadequate expiration prevents the lungs from emptying completely before the next breath is initiated, which can lead to increased mean airway pressure and respiratory distress.

This condition is particularly common in patients with obstructive lung diseases, where airflow obstruction leads to prolonged expiration times. If there’s an insufficient respiratory rate or tidal volume set on the ventilator, or if there is a delay in the patient's own efforts to exhale completely, auto-PEEP can develop. Understanding this mechanism helps clinicians adjust ventilatory support to alleviate the difficulties posed by auto-PEEP, ensuring better gas exchange and reducing the work of breathing for patients.