Study design: Unblinded, randomized controlled trial. Patients were randomized to standard low tidal volume ventilation with low PEEP or low tidal volume ventilation with higher PEEP (intervention group). PEEP was increased in the intervention group to attain a plateau pressure of 28-30 cm H2O
Setting: 37 intensive care units in France.
Synopsis: Though PEEP, total PEEP, and plateau pressure were considerably higher in the experimental group, there was no difference in 28-day mortality compared with the control group, 27.8% vs. 31.2% (95% CI 0.90-1.40, p=0.31). There was, however, an increase in the number of ventilator-free days (seven vs. three, p=0.04) and organ-failure-free days (six vs. two, p=0.04) in the experimental group compared with the control group. Criteria were used to evaluate patients for readiness for extubation, but the differential application of PEEP between arms may have altered the timing of these evaluations in the two arms and may be at least partly responsible for the difference in ventilator-free days.
Throughout patient recruitment, the primary end point was monitored, resulting in 18 interim analyses of the data. No statistical adjustments were made for these frequent examinations of the data.
Bottom line: The use of higher PEEP and maximum plateau pressure to increase alveolar recruitment while limiting hyperinflation results in more ventilator-free and organ failure-free days in patients with acute lung injury and ARDS. These maneuvers do not, however, alter mortality.
Citation: Mercat A, Richard JCM, Vielle B, et al. Positive end-expiratory pressure setting in adults with acute lung injury and acute respiratory distress syndrome. A randomized controlled trial. JAMA 2008;299(6):646-655.