REstricted Versus Liberal Positive End-Expiratory Pressure in Patients Without ARDS

The 'REstricted versus Liberal positive end-expiratory pressure in patients without Acute respiratory distress syndrome' (RELAx) trial is a national multicenter, open randomized controlled trial in ICU patients without ARDS at start of ventilation. It will be the first RCT comparing ventilation with the lowest possible positive end-expiratory pressure (PEEP) level with ventilation with the median PEEP level currently practiced in the Netherlands that recruits a sufficient number of patients to test the hypothesis that ventilation with the lowest possible PEEP level is non-inferior to ventilation with a PEEP level of 8 cm H2O with regard to objective and patient-relevant clinical endpoints.