To determine whether the prevention of atelectrauma by setting PEEP (CMV) to obtain 0 cmH2O of transpulmonary pressure at end-expiratory occlusion and mPaw (HFOV) to obtain 0 cmH2O of mean transpulmonary pressure is less injurious than lung recruitment limiting tidal overdistension by setting PEEP (CMV) and mPaw (HFOV) at a threshold of 15 cmH2O of transpulmonary pressure. Plasma cytokines will be used to define the ventilator induced lung injury.