Lung Recruitment Assessed by 2D/3D-EIT and R/I Ratio in Acute Respiratory Failure Patients With Mechanical Ventilation

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.