The Study of EIT-guided Ventilation Strategy on ARDS Patients

Inclusion Criteria: 1. According to ARDS Berlin standard, ARDS, PaO2 / FiO2 \< 200mmhg, peep \> 5cmh2o; 2. According to clinical judgment, lung recruitment therapy is needed due to hypoxemia; 3. The subjects or their families signed informed consent. 4. Admission to ICU was less than 72 hours; 5. The estimated duration of mechanical ventilation was more than or equal to 48 hours; 6. Age ≥ 18 years old and ≤ 80 years old; Exclusion Criteria: 1. The patients with heart implants could not be monitored by EIT; 2. Patients or their families refused to participate in the study; 3. Hypernatremia