In vivo hysteresis of airspace dimensions measured by aerosol recovery

Optimal peep in ARDS. Changing concepts and current controversies

From many recently performed studies, it is clear that a criterion standard for determining the optimal positive end-expiratory pressure (PEEP) level in patients with acquired respiratory distress syndrome (ARDS) does not exist. What is evident and consistent, however, are several points such the optimal PEEP level ultimately represents a balance between regional areas of overstretching and regional derecruitment; higher levels of PEEP may be required early in ARDS, independent of oxygenation requirements; and the exact method for titrating PEEP in patients with ARDS remains to be determined. These points and others are delineated and discussed in this article.