2. Toth, et al17 described a decremental PEEP titration following a SI recruiting maneuver. Following SI at 40 cm H2O for 40 seconds, PEEP was set at 26 cm H2O, then decreased by 2 cm H2O every 4 minutes until the PaO2 decreased by >10% of its peak value. The PEEP 2 cm H2O above this was defined as optimal PEEP. Optimal PEEP was found to actually be lower than the patients' baseline PEEP (prior to protocol initiation, 17±3 vs 15±4 cm H2O). The PaO2 following the recruiting maneuver (203±108 at baseline PEEP vs 328±132 cm H2O) sustained at the 30 minute followup period (266±121 cm H2O, p<0.05 compared to baseline).