Preventive Strategies in Acute Respiratory Distress Syndrome (ARDS)

"Ventilation mode: volume control, pressure control, dual modes (It is allowed to change to a spontaneous mode; a minimum of 5 cmH2O level of support should be used; in case the resulting tidal volume exceeds 6 mL/kg PBW this is accepted. This is not a reason to use more sedation and/or muscle relaxants, or to switch the ventilator to a controlled mode of ventilation).~* Tidal volume: 6 mL/Kg PBW, decreasing 1 mL/kg PBW each step if necessary (steps of 5 minutes), to maintain plateau pressure \< 25 cmH2O until a minimum tidal volume of 4 mL/Kg PBW, unless the patient suffers from severe dyspnea or unacceptable acidosis.~* Fraction of inspired oxygen inspired oxygen fraction (FiO2) \> 0.21 to maintain oxygen saturation 90-92%.~* PEEP ≥ 5 cmH2O, and optimized to maintain Oxygen saturation (SpO2) 90-92% (left to the discretion of the attending physician).~* Plateau pressure ≤ 25 cmH2O"

"Ventilation mode: volume control, pressure control, dual modes (It is allowed to change to a spontaneous mode, with the level of support adjusted to reach tidal volumes minimum of 8 mL/kg predicted body weight PBW; if it is not possible, the data collection should be continue and an intention-to-treat analysis will be done).~* Tidal volume: minimum 8 mL/kg PBW. It is possible to increase until 10 mL/kg PBW unless plateau pressure increases above 25 cmH2O.~ · FiO2 \> 0.21 to maintain oxygen saturation 90-92%.~* PEEP ≥ 5 cmH2O, and optimized to maintain SpO2 90-92% (left to the discretion of the attending physician).~* Plateau pressure ≤ 25 cm H2O."

Volumetric capnography will be used. Dead space (Vd/Vt) measurements will be taken at baseline and daily after initiation of mechanical ventilation. Nursing and respiratory care activities (including changes to ventilator settings) will be suspended for at least 5 minutes prior to all Vd/Vt measurements.