What is intrinsic PEEP caused by?

Intrinsic PEEP, also known as auto-PEEP, occurs when there is insufficient time for complete exhalation between breaths, causing a buildup of pressure in the lungs. This can happen in cases of increased respiratory rates or decreased lung compliance, leading to incomplete emptying of the alveoli before the next breath is initiated. When the patient inhales again before fully exhaling, trapped air increases lung volume and can elevate intrathoracic pressure, which can ultimately impair hemodynamics and gas exchange.

Inadequate time to exhale is directly linked to the mechanics of breathing and ventilatory support, where the normal exhalation phase does not allow the lungs to return to baseline pressure. This situation can adversely affect ventilation, contributing to further complications such as decreased oxygenation or increased work of breathing. Therefore, recognizing intrinsic PEEP is important for effective mechanical ventilation management.