 Each strategies will be apply in a random order for a duration of 22 hours. Pulmonary inflammatory and fibrosis pathway will be assess before and after each period using bronchoalveolar lavage BAL samples. Systemic inflammatory cytokines will also be investigate. Main measurements will include respiratory mechanics, transpulmonary pressure, work of breathing, end-expiratory lung volume and tidal ventilation using electrical impedance tomography. 