Overview
The purpose of this observational study is to assess the differences and consistency in evaluating lung recruitment potential between the recruitment-to-inflation ratio (R/I ratio) and three-dimensional electrical impedance tomography (3D-EIT) and two-dimensional EIT (2D-EIT) in mechanically ventilated patients with acute respiratory failure. The main questions it aims to answer is:
Are the lung recruitment potentials predicted by 3D-EIT, 2D-EIT and the R/I ratio consistent? Participants will: Undergo a standardized PEEP titration protocol with synchronized EIT monitoring; Have R/I ratios measured at high and low PEEP levels.
Eligibility
Inclusion Criteria:
- Mechanically ventilated patients under sedation and analgesia with no spontaneous breathing.
- Oxygenation index \< 300 mmHg.
- Patients who are clinically judged by the attending doctor to require the PEEP titration.
Exclusion Criteria:
- Aged under 18 years.
- Pregnancy.
- Contraindications for EIT examination (e.g. automatic implantable cardioverter defibrillator, implantable pumps, chest wounds limiting electrode belt placement, severe thoracic deformity, and others).
- No informed consent obtained.
- Hemodynamic instability with intolerance to high PEEP levels determined by the attending doctor.
- High-risk populations with pneumothorax, mediastinal emphysema, and other such conditions determined by the attending doctor.