Echocardiography Predictive of the Inefficacy and/or of the Unsafeness of Recruitment Maneuvers in Patients With Acute Respiratory Distress Syndrome.

Inclusion Criteria: * Endotracheal mechanical ventilation for acute hypoxemic respiratory failure lasting for one week or less * A ratio of the partial pressure of arterial oxygen (PaO2 measured in millimeters of mercury) to the fraction of inspired oxygen (FiO2 which is unitless) of 300 mmHg or less and inspired fraction of oxygen FiO2 of more than 50 % * A positive end-expiratory pressure of 5 cm of water or higher * A tidal volume of 6 to 8 ml per kilogram of predicted body weight * Bilateral opacities on chest radiography not fully explained by effusions, lobar/lung collapse, or nodules * Respiratory failure not fully explained by cardiac failure or fluid overload * Written and informed consent * Adult patients at least 18 years of age * Ventilatory criteria (PaO2/FiO2 of 300 mmHg or less and Positive End Expiratory Pressure of 5 cm of water or higher) and radiologic criteria (Bilateral opacities on chest radiography not fully explained by effusions, lobar/lung collapse, or nodules) lasting more than 24 hours Exclusion Criteria: * Endotracheal mechanical ventilation for acute hypoxemic respiratory failure lasting for more than one week * Age younger than 18 years old * No written and informed consent * Known pregnancy and/or breastfeeding * Increased intracranial pressure * A ratio of the partial pressure of arterial oxygen (PaO2 measured in millimeters of mercury) to the fraction of inspired oxygen (FiO2 which is unitless) higher than 300 mmHg * Positive end expiratory pressure of less than 5 mmHg * Ventilatory criteria (PaO2/FiO2 of 300 mmHg or less and Positive End Expiratory Pressure of 5 cm of water or higher) and radiologic criteria (Bilateral opacities on chest radiography not fully explained by effusions, lobar/lung collapse, or nodules) lasting less than 24 hours * Severe chronic respiratory disease requiring long-term oxygen therapy or mechanical ventilation at home * Severe chronic liver disease * Barotrauma such as pneumothorax * Hemodynamic failure needing more than 3 milligrams per hour of noradrenalin and/or more than 2 milligrams per hour of adrenalin and or rising doses of vasopressors and/or vascular filling exceeding 500 milliliters in the preceding hour * Arrhythmias such as : ventricular tachycardia, ventricular fibrillation, third degree atrioventricular block * Atrial fibrillation