Effect of EIT-guided PEEP in ARDS Patients

Inclusion Criteria: 1. Age≥18 years 2. Moderate-to-severe ARDS, defined by the ARDS Definition Task Force in the Berlin definition (partial pressure of arterial oxygen \[PaO2\]:FiO2 ratio ≤200 mmHg with a PEEP ≥5 cmH2O) 3. Diagnosis of ARDS less than 72 hours Exclusion Criteria: 1. Expected to be mechanically ventilated for less than 48 hours 2. Severe chronic respiratory diseases requiring long-term home oxygen therapy or noninvasive MV 3. Undrained pneumothorax or subcutaneous emphysema 4. Contraindication to the use of EIT (pacemaker, automatic implantable cardioverter defibrillator, and implantable pumps) 5. Severe neuromuscular disease 6. Hemodynamic instability 7. Contraindications to hypercapnia, such as intracranial hypertension or acute coronary syndrome 8. Severe other organs dysfunction with a low expected survival (7 days) or palliative care 9. Severe liver disease (Child-Pugh Score ≥10) 10. Pregnancy 11. Refusal to sign the informed consent