Inclusion Criteria:

- Diagnosis of ALI/ARDS within the first 72 hours based on all of the following
criteria:

- Respiratory failure requiring mechanical ventilation - via endotracheal
intubation or noninvasive positive pressure ventilation;

- Acute onset of bilateral pulmonary densities on chest radiograph in the context
of appropriate predisposing injury or illness with no evidence of left
ventricular failure;

- Ratio of partial pressure of arterial oxygen to fraction of inspired oxygen
(PaO2:FiO2 ) ≤ 300 (criteria for ALI) or 200 (criteria for ARDS) with FiO2 ≥ 0,5
and PEEP = 5 cmH2O.

- To sign the Informed Consent to participate.

Exclusion Criteria:

- ALI/ARDS with more than 72 hours of diagnosis

- Failure to obtain written informed consent to participate in the study;

- Condition requiring > 0.5mg/Kg/day of prednisone equivalent (i.e., acute asthma or
bronchopulmonary dysplasia)

- Patients enrolled in another experimental (interventional) protocol within the past
30 days, which might adversely impact on the results of this study as determined by
the investigators;

- Primary or secondary neuromuscular dysfunction

- Patients using aminoglycosides combined with neuromuscular blockers

- Cardiopulmonary arrest within 7 days or anytime during present hospitalization prior
to enrollment;

- Irreversible cessation of all brain function;

- Immunosuppression, including HIV+ status, history of bone marrow or solid organ
transplantation, current malignancy, neutropenia, receiving cytotoxic therapy for any
reason, and acute burn injury;

- Severe chronic liver disease (Child-Pugh Class C score > 10 points).