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

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.

Study Overview

• Status: Recruiting
• Conditions: Acute Respiratory Failure (ARF)
• Intervention / Treatment: Diagnostic test: The lung recruitment potential assessed and PEEP titration by ventilator and 2D/3D EIT

• Study Type: Observational
• Enrollment (Estimated): 50

Contacts and Locations

• Study Contact: Name: Huaiwu He; Phone Number: 010-6915-2300; Email: tjmuhhw@126.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China, 100730
      • Recruiting
      • Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences
      • Contact: Huaiwu He; Phone Number: 010-6915-2300; Email: tjmuhhw@126.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients with acute respiratory failure who are intubated, under sedation and analgesia with controlled ventilation and no spontaneous breathing will be recruited from the Department of Critical Care Medicine, Peking Union Medical College Hospital. Additional inclusion criteria include an oxygenation index of less than 300 mmHg, clinical judgment indicating the need for PEEP titration, and no contraindications to PEEP titration or EIT examination.

Description

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.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Mechanically ventilated patients with hypoxemia requiring clinical PEEP optimization; The study will enroll mechanically ventilated patients under sedation/analgesia without spontaneous breathing, exhibiting a oxygenation index (PaO₂/FiO₂ ratio) <300 mmHg, and deemed clinically eligible for PEEP titration by attending physicians.	Diagnostic test: The lung recruitment potential assessed and PEEP titration by ventilator and 2D/3D EIT; The patient will undergo a standardized PEEP titration procedure and determination of the Recruitment-to-Inflation ratio (R/I ratio), with concurrent monitoring by both 2D- and 3D- EIT.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lung recruitment assessed by R/I ratio and 2D/3D-EIT （PEEP titration）	Lung recruitment potential can be predicted by the R/I ratio and the lung collapse rate calculated from 2D/3D-EIT.	Within 24 hours post-enrollment

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
R/I ratio measured by 2D/3D-EIT	The R/I ratio can be calculated from 2D/3D-EIT.	Within 24 hours after enrollment
V/Q monitored by EIT	Ventilation and perfusion monitored by 2D/3D-EIT at different PEEP levels. To evaluate the V/Q match, deadspace and shunt lung region.	Within 24 hours after enrollment
SpO₂ at different PEEP levels	Pulse oxygen saturation at different PEEP levels	Within 24 hours after enrollment
Lung compliance at different PEEP levels	Lung compliance at different PEEP levels measured via ventilator parameters	Within 24 hours after enrollment
Mechanical power	Mechanical power measured via ventilator parameters	Within 24 hours after enrollment

Collaborators and Investigators

• Sponsor: Peking Union Medical College Hospital
• Investigators: Study Chair: Huaiwu He, Peking Union Medical College Hospital

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2025
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): September 30, 2026

Study Registration Dates

• First Submitted: January 21, 2026
• First Submitted That Met QC Criteria: January 23, 2026
• First Posted (Actual): January 30, 2026

Study Record Updates

• Last Update Posted (Actual): January 30, 2026
• Last Update Submitted That Met QC Criteria: January 23, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Acute respiratory failure; PEEP titration; Lung recruitability; 3D-EIT; 2D-EIT; R/I ratio
• Other Study ID Numbers: 3D EIT-based PEEP & R/I ratio

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No