4. Villagra, et al, studied a recruiting maneuver utilizing 2 minutes of ventilation using pressure-controlled ventilation (PCV) in 18 adults with early ARDS. For the RM, PEEP was set 3 cm H2O above the upper inflection point of the PV curve, and peak pressures set to 50. Importantly, RM peak pressures did not differ significantly from baseline ventilation (43.6±7.6 pre-RM, 47±4.5 during RM, and 42.8±7.1 cm H2O post-RM), although PEEP did (14±1.3 pre-RM vs 30±4.9 cm H2O). The investigators did not find a significant difference in PaO2 following the recruiting maneuver (127±63 pre-RM, 162±108 during, and 149±85 cm H2O post-RM). This finding implies several important findings regarding lung recruitment. First, the peak pressure represents a significant determinant in lung recruitment. By contrast, Borges, et al were able to fully recruit all 18 ARDS patients by using driving pressures differed significantly from pre-RM in the maximal recruitment phase (50-60 cm H2O during recruitment vs 30 cm H2O at baseline). Further, the recruiting maneuver utilized here was only 2 minutes, versus the incremental titration utilized by Borges which lasted 4 minutes in each phase. While not systematically studied, the lack of significant improvement in PaO2 post-RM found in this study suggests that recruitment utilizing PCV may be a function of time and peak pressures utilized in the RM.