Based on the phase III ARDSnet trial, which was randomized for low versus high levels of PEEP in ALI patients, what outcome was obtained?

A. Patients who were ventilated with high tidal volumes and low PEEP were at a higher risk for developing VILI.
B. Patients who were ventilated with low tidal volumes and low PEEP were at a higher risk for developing VILI.
C. Patients who were ventilated with low VTs and whose Pplateau were maintained at or below 30 cm H2O were at a lower risk for developing VILI.
D. No benefit was found for ALI patients receiving low tidal volumes and higher levels of PEEP.

?ANS: D
A. Incorrect response: See explanation D.
B. Incorrect response: See explanation D.
C. Incorrect response: See explanation D.
D. Correct response: The ARDSNetwork conducted a phase III randomized controlled trial of higher versus lower PEEP in ALI patients. In that study, 549 patients were randomly assigned to either higher or lower PEEP levels in combination with FIO2, according to a priori tables. All patients were ventilated with tidal volumes of 6 ml/kg predicted body weight and a goal of limiting plateau pressures to 30 cm H2O. Mean PEEP in the high PEEP group was 13.2 cm H2O, and 8.2 cm H2O in the low PEEP group. This study suggests that when ALI patients receive ventilation with low VT, no benefit from the use of higher levels of PEEP appears to occur.