Evaluation of the Diagnostic Performance of Electrical Impedance Tomography to Detect Situations at Risk of Lesions Induced by Conventional Mechanical Ventilation in ARDS

"Different ventilatory conditions are studied and measures are acquired with scanner and EIT~Time A: measure under basal conditions (TVbasal=6ml/kg of predicted weight), basal PEP, basal inspiratory time / total time = 30%)~Time B: different PEP are applied for 4 minutes: 5, 10, 15, 20 cm of H2O conserving the basal TV~Time C: different TV are applied for 4 minutes: 4, 7, 10 ml/kg of predicted weight conserving the basal PEP and the basal inspiratory time~Time D: recruitment in continuous positive airway pressure at 45 cm of H2O is performed for 30 seconds~Time E: return to adjustment period A"