Comparing 3D/2D electrical impedance tomography and the R/I ratio to measure lung recruitability during mechanical ventilation

Lung Recruitment Assessed by Two-Dimensional/Three-Dimensional Electrical Impedance Tomography and Recruitment-to-Inflation Ratio in Acute Respiratory Failure Patients With Mechanical Ventilation

This test tries to see if two imaging methods (3D and 2D electrical impedance tomography) and a pressure-based recruitment-to-inflation (R/I) ratio give consistent estimates of how much the lungs can be recruited in sedated adults on mechanical ventilation for acute respiratory failure.

Quick facts

• Study type: Observational
• Enrollment: 50 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Peking Union Medical College Hospital (Academic / other)
• Locations: 1 site (Beijing, Beijing Municipality)
• Trial ID: NCT07379242 on ClinicalTrials.gov

What this trial studies

This is an observational protocol that compares lung recruitability estimates from 3D-EIT, 2D-EIT, and the recruitment-to-inflation (R/I) ratio in mechanically ventilated adults with acute respiratory failure. Participants undergo a standardized PEEP titration while synchronized EIT monitoring records regional impedance changes and R/I ratios are measured at high and low PEEP levels. The study examines agreement and differences between the techniques rather than testing a therapeutic intervention. Patients with contraindications to EIT, hemodynamic intolerance to high PEEP, or other predefined exclusions are not enrolled.

Who should consider this trial

Good fit: Mechanically ventilated adults with acute respiratory failure who are sedated without spontaneous breathing, have a PaO2/FiO2 (oxygenation index) below 300 mmHg, and whose treating team plans a PEEP titration are ideal candidates.

Not a fit: Patients under 18, pregnant patients, those with contraindications to EIT (for example implanted cardiac devices or chest wounds), or those with hemodynamic instability or high-risk pneumothorax/mediastinal emphysema are unlikely to benefit or be eligible.

Why it matters

Potential benefit: If successful, clinicians could have clearer guidance on which bedside measurement best predicts lung recruitability, helping tailor PEEP settings to improve oxygenation and reduce ventilator-induced lung injury.

How similar studies have performed: Previous work using 2D-EIT and the R/I ratio has shown promise for estimating recruitability, but direct comparisons that include 3D-EIT are limited, so this study builds on existing methods while adding 3D data.

Eligibility criteria

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.

Where this trial is running

Beijing, Beijing Municipality

• Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences — Beijing, Beijing Municipality, China (Recruiting)

Study contacts

• Study coordinator: Huaiwu He

Conditions Acute Respiratory Failure; Acute respiratory failure; PEEP titration; 3D-EIT; 2D-EIT; Lung recruitability; R/I ratio