Effect of intrinsic positive end-expiratory pressure on respiratory compliance.

We evaluated the influence of intrinsic positive end-expiratory pressure (PEEPi) on the measurement of static respiratory compliance in 15 adult patients with acute respiratory failure under mechanical ventilation. Modifying the inspiratory/expiratory ratio from 1:2 to 2:1, and the respiratory frequency from 15 to 20 and 25 breath/min significantly changed compliance values. Because PEEPi can increase the work of breathing, we suggest adjusting ventilatory variables to minimize PEEPi.