End-expiratory Transpulmonary Pressure-guided vs Electrical Impedance Tomography-guided PEEP Titration Methods in Patients With Intra-abdominal Hypertension Combined With Acute Respiratory Distress Syndrome: a Randomized Crossover Controlled Study

Inclusion criteria

• age: 18-80 years;
• meets IAH ≥12 mmHg;
• meets the diagnostic criteria of the Berlin definition of ARDS;
• PaO2/FiO2 ≤ 200;
• within 36 hours of invasive mechanical ventilation;
• patients or their family members were consulted, agreed to participate in the trial, and signed an informed consent form.

Exclusion criteria

• Age <18 years or age >80 years;
• uncorrected shock of any type;
• chronic obstructive pulmonary disease, interstitial lung disease, pulmonary embolism, right heart failure, pulmonary hypertension, or severe cardiac arrhythmia;
• pneumothorax or bronchopleural fistula or lobectomy or other surgery of the lungs within 2 weeks of surgery;
• non-invasive ventilation or transnasal high-flow oxygen;
• with relevant contraindications to the application of EIT (large chest skin injuries, infections, pacemaker implanters, in vivo automatic defibrillator implantation, etc.) pneumothorax, mediastinal emphysema, massive pleural effusion;
• oesophageal obstruction, oesophageal perforation, severe oesophageal variceal bleeding, upper gastrointestinal surgery, and other factors that make it impossible to place an oesophageal pressure catheter;
• diaphragmatic hernia, thoracic deformity; patients with obvious pulmonary hernias;
• prolongation of prothrombin time (PT), activated partial thromboplastin time (APTT) to two times the high limit of normal values or with active bleeding in the nasopharynx;
• severe neurological disease: intracranial hypertension or neuromuscular disease, etc;
• pregnant and lactating women;
• patients to be treated with ECMO;
• re-admission to the ICU of patients who have already been included in this study, or who are participating in other clinical studies;