Effect of PEEP Titration on the EELV Measured by the Nitrogen Dilution Technique in ARDS

Inclusion Criteria:

• Patients admitted to intensive care with a diagnosis of moderate to severe ARDS inaccordance with the Berlin criteria, i.e. a PAFI <200 and PEEP >5cm H20 ratio

• Diagnosis of ARDS made within 72 hours

• Age over 18 years

• Informed consent of the patient and/or trusted person where applicable

Exclusion Criteria:

• Start of mechanical ventilation more than 72 hours prior to inclusion.

• SDRA evolving for more than 72 hours

• Presence of major hemodynamic instability with mean blood pressure <60mmhg, and/orheart rate <45 bpm or >150bpm with an increase in vasopressor amine dosage of morethan 20% over the last 6 hours.

• Intracranial hypertension with CPP<60mmhg

• Massive hemoptysis requiring immediate surgical or interventional radiology procedure

• Tracheal surgery (except intensive care tracheotomy) or sternotomy within the previous 15 days

• Trauma or surgery of the face in the previous 15 days.

• Deep vein thrombosis treated for less than 2 days

• Pacemaker implantation in the last 2 days

• Unstable fracture (spine, femur or pelvis)

• Respiratory reasons

• use of extracorporeal oxygenation

• nitric oxide

• pleural drainage system with bronchopleural gap

• pulmonary transplantation

• Poor respiratory tolerance per procedure with desaturation Spo2<85%.

• Poor hemodynamic tolerability per procedure combining hypotension with MAP<65mmhg anda 20% increase in norepinephrine dosage.

• Lack of patient consent to proceed

• minor patient

• lack of consent