There have been multiple strategies to determine the “optimal PEEP” in acute respiratory distress syndrome (ARDS). One strategy is to perform a recruitment maneuver using an “Open Lung” approach and neuromuscular blockade (with pressures as high as 60 cm H2O), followed by PEEP titration to the highest lung compliance, followed by a second recruitment maneuver. Another strategy is to follow the traditional PEEP-FiO2 tables outlined by the ARDSNet group from the ALVEOLI trial published in 2004. In this trial the “high PEEP” and “low PEEP” groups had similar outcomes.
In the effort to identify the optimal PEEP for a patient, investigators have used strategies to titrate using the pressure–volume curves, using esophageal balloons, and empirical trials. No approach has proven to be superior.
In this well-designed study, investigators randomized 1010 patients with moderate-to-severe ARDS either to standard PEEP, based on the PEEP protocol from the ARDSnet trial group or to lung recruitment with PEEP set by respiratory-system compliance as described above. Mortality at 28 days was significantly higher in the recruitment-maneuver group than in the standard group (55% vs. 49%); recruitment patients were more likely to receive neuromuscular blockade and sedatives (P=0.05). Barotrauma and hypotension immediately after PEEP titration were significantly more common in the recruitment group.
