inclusion criteria: subjects admitted in icu for \>72hs, undergoing orotracheal intubation and on mechanical ventilation for \>48hs, with a diagnosis of acute respiratory distress syndrome (ards) according to berlin definition secondary to covid-19, with shock or organ failure, according to the diagnosis and treatment protocol for novel coronavirus pneumonia (7th interim edition) guideline, and clinical stability: * mean arterial pressure \< 60 mmhg; * heart rate \>60 and \<120 beats/minute; * respiratory rate \<30 breaths/minute; * oxygen saturation ≥ 92%; * fraction of inspired oxygen (fio2) ≤0.6; * absence of vasopressor dose increase * absence of dysrhythmia (except for chronic atrial fibrillation); * controlled sepsis; * hemoglobin (hb) \> 8g m/d, plaquettes \>20.000, glucemia \>70 e \<180; * without nmbs

inclusion criteria: subjects admitted in icu for \>72hs, undergoing orotracheal intubation and on mechanical ventilation for \>48hs, with a diagnosis of acute respiratory distress syndrome (ards) according to berlin definition secondary to covid-19, with shock or organ failure, according to the diagnosis and treatment protocol for novel coronavirus pneumonia (7th interim edition) guideline, and clinical stability: * mean arterial pressure \< 60 mmhg; * heart rate \>60 and \<120 beats/minute; * respiratory rate \<30 breaths/minute; * oxygen saturation ≥ 92%; * fraction of inspired oxygen (fio2) ≤0.6; * absence of vasopressor dose increase * absence of dysrhythmia (except for chronic atrial fibrillation); * controlled sepsis; * hemoglobin (hb) \> 8g m/d, plaquettes \>20.000, glucemia \>70 e \<180; * without nmbs

inclusion criteria: subjects admitted in icu for >72hs, undergoing orotracheal intubation and on mechanical ventilation for >48hs, with a diagnosis of acute respiratory distress syndrome (ards) according to berlin definition secondary to covid-19, with shock or organ failure, according to the diagnosis and treatment protocol for novel coronavirus pneumonia (7th interim edition) guideline, and clinical stability: mean arterial pressure < 60 mmhg; heart rate >60 and <120 beats/minute; respiratory rate <30 breaths/minute; oxygen saturation ≥ 92%; fraction of inspired oxygen (fio2) ≤0.6; absence of vasopressor dose increase absence of dysrhythmia (except for chronic atrial fibrillation); controlled sepsis; hemoglobin (hb) > 8g m/d, plaquettes >20.000, glucemia >70 e <180; without nmbs

inclusion criteria: subjects admitted in icu for >72hs, undergoing orotracheal intubation and on mechanical ventilation for >48hs, with a diagnosis of acute respiratory distress syndrome (ards) according to berlin definition secondary to covid-19, with shock or organ failure, according to the diagnosis and treatment protocol for novel coronavirus pneumonia (7th interim edition) guideline, and clinical stability: mean arterial pressure < 60 mmhg; heart rate >60 and <120 beats/minute; respiratory rate <30 breaths/minute; oxygen saturation ≥ 92%; fraction of inspired oxygen (fio2) ≤0.6; absence of vasopressor dose increase absence of dysrhythmia (except for chronic atrial fibrillation); controlled sepsis; hemoglobin (hb) > 8g m/d, plaquettes >20.000, glucemia >70 e <180; without nmbs