2. Crotti, et al5 studied five adults with ALI/ARDS with varying plauteau pressures (10, 15, 20, 30, 35, 40, 45 cm H2O) and PEEP levels (5, 10, 15, 20 cm H2O). End-inspiratory and end-expiratory thoracic CT imaging was obtained with each combination of plateau pressure and PEEP. Percentage of lung recruited (as determined radiographically) increased in a nearly linear fashion with increasing plateau pressures (Figure 1). The maximal opening frequency occurred at 20 cm H2O, suggesting that plateau pressures exceeding 20 cm H2O would be most beneficial in lung recruitment. No measures of gas exchange or adverse events were studied.