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

A recruitment maneuver is considered effective if the partial pressure of oxygen in arterial blood PaO2 measured one hour after the completion of recruitment maneuver is 20 % higher than PaO2 before recruitment maneuver.

A recruitment maneuver is considered unsafe if systolic arterial pressure decreases 40 % under its value before recruitment maneuver and/or if systolic arterial pressure decreases under 70 mmHg and/or if arrhythmias (third degree atrio-ventricular block, ventricular tachycardia, ventricular fibrillation, atrial fibrillation)occur during the achievement of recruitment maneuver in patients suffering from Acute Respiratory Distress Syndrome.

Can echocardiography predict the inefficacy and/or unsafeness of recruitment maneuvers in patients suffering from Acute Respiratory Distress Syndrom ?

Collecting echocardiographic criteria exploring the right ventricle is particularly difficult, especially in patients suffering from Acute Respiratory Distress Syndrome.

One of the aims of the study RVSTAR is to evaluate if the measurement of Longitudinal Strain and Strain Rate of the right ventricle is feasible.

At the end of the study, the feasibility of the measurement of Longitudinal Strain and Strain Rate of the right ventricle will be determined by the proportion of patients (among all the patients included) in whom these echocardiographic criteria (Longitudinal Strain and Strain Rate of the right ventricle) have been realised successfully.

Is there any statistical difference in the echocardiographic measurements exploring the right ventricle in the group CONTROL (the recruitment maneuver has been safe and effective) and the group FAILURE (the recruitment maneuver has not been safe and /or has not been effective)? The echocardiographic measurements assessed (and compared between the 2 groups) will be the following ones : right heart dimensions (diameter at the base and at the mid-level of the right ventricle, longitudinal dimension of the right ventricle), right ventricle wall thickness, tricuspid annular plane systolic excursion, two-dimensional fractional area change, two-dimensional right ventricle ejection fraction,tissue Doppler-derived tricuspid lateral annular systolic velocity, longitudinal strain and strain rate, pulsed Doppler of the tricuspid inflow, tissue Doppler of the lateral tricuspid annulus, pulsed Doppler of the hepatic vein, measurements of inferior vena cava, tricuspid regurgitation velocity

One of the aims of the study RVSTAR is to evaluate if there is an effect of the inefficacy and/or the unsafeness of the recruitment maneuver on mortality (proportion of patients who died within 30 days after study enrollment), on the duration of invasive mechanical ventilation (number of days under mechanical ventilation from the study enrollment until discharge from the intensive care unit), on the length of stay in the intensive care unit (number of days spent in the intensive care unit) and on organ failure (renal failure defined by the need for renal replacement therapy, hemodynamic failure defined by the need for vascular filling exceeding 50 ml per kilogram of body weight and/or the need for vasopressors and/or for the need for rising doses of vasopressors) in patients suffering from Acute Respiratory Distress Syndrome.