Mechanical Vent 2 Exam 2 Practice 2026 - Free Mechanical Ventilation Practice Questions and Study Guide

High PEEP raises alveolar pressures; when pushed too high, some alveoli become overdistended rather than simply recruited. Overdistension compresses the surrounding pulmonary capillaries, reducing blood flow to those ventilated units. Ventilated but poorly perfused alveoli become alveolar dead space, so the physiologic dead space increases. Moderate PEEP can recruit collapsed units and reduce dead space, but excessive PEEP shifts the balance toward increased dead space due to capillary compression and reduced perfusion of ventilated areas.