Electrical Impedance Tomography-Derived Dorsal Recruitment-to-Inflation Ratio Identifies PEEP Responsiveness and Risk Phenotypes in ARDS

April 20, 2026 updated by: Ruijin Hospital
In the treatment of critically ill patients, mechanical ventilation is a key link, and appropriate mechanical ventilation strategies can open the alveoli and improve oxygenation, while inappropriate mechanical ventilation can increase lung injury and seriously affect the prognosis. Ventilator-related lung injury is mainly concentrated in barotrauma, volumetric injury, shear injury, and biological injury, and the monitoring of respiratory ventilation to the level of local ventilation can help to better assess the state of alveolar opening and alveolar collapse, and help to understand the uniformity of gas distribution in the lungs, which is closely related to lung injury. However, how to achieve simple, bedside and real-time lung ventilation and lung volume assessment in clinical work has always been a difficult problem to be overcome. This study intends to explore the changes of local ventilation and blood flow in the lungs during PEEP trail in patients with ARDS monitored by EIT.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

  1. Background and Rationale ARDS is associated with heterogeneous lung collapse. The recruitment-to inflation (R/I) ratio has emerged as an index of recruitability, but is usually assessed globally. Electrical impedance tomography (EIT) enables regional assessment of ventilation and may provide more precise determinations of recruitable lung regions, particularly dorsal areas.
  2. Objectives Primary objective: To compare the predictive value of regional (dorsal and ventral) versus global R/I for recruitment success in moderate-severe ARDS. Secondary objectives: To classify recruitment phenotypes and evaluate associations with oxygenation, compliance improvement, ventilator-free days, ICU length of stay, and 28-day mortality.
  3. Study Design Prospective, single-centre observational cohort study in ICU patients with moderate-severe ARDS. All eligible patients undergo standardised recruitment maneuver and EIT monitoring.
  4. Study Setting Ruijin Hospital, Shanghai Jiao Tong University School of Medicine ICU, December 2022 - December 2024.
  5. Intervention Standardized PEEP step maneuver from 5 → 15 cmH₂O, maintained for 3 minutes. Continuous EIT monitoring of regional compliance, oxygenation, hemodynamics. Dynamic strain cutoff (>0.6) or adverse events terminate the maneuver. Ventilation mode: volume control, tidal volume 4-6 mL/kg predicted body weight, plateau ≤28-30 cmH₂O, FiO₂ titrated for SpO₂ 88-92%.
  6. Measurements EIT-derived ΔEELI in dorsal and ventral regions Regional and global compliance (Crec and Crs) R/I calculated: Crec/Crs at baseline PEEP Airway opening pressure by low-flow inflation method Primary outcome: recruitment success (≥10% compliance improvement + ≥20 mmHg PaO₂/FiO₂ increase) Secondary: ventilator-free days, ICU LOS, 28-day mortality, dynamic strain
  7. Statistical Analysis Plan Distribution check by Shapiro-Wilk. Paired tests for within-patient comparisons. ROC curves and Youden index for cut-off selection. Multivariate regression for mortality risk factors. Bonferroni correction for multiple comparisons.
  8. Safety Monitoring Terminate RM if: MAP <65 mmHg, SpO₂ <88%, arrhythmia onset, dynamic strain >0.6.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
120

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Shanghai Municipality
      • Shanghai, Shanghai Municipality, China, 200025
        • Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine，Shanghai，China.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

This study included adult patients (≥18 years) with moderate-to-severe acute respiratory distress syndrome (ARDS) who were receiving invasive mechanical ventilation in the intensive care unit (ICU) of Ruijin Hospital. All enrolled patients met the Berlin definition of ARDS and had a PaO₂/FiO₂ ratio ≤200 mmHg within 6 hours of screening. A total of 120 patients were consecutively enrolled from December 2022 to December 2024. Patients were stratified by airway closure status for subgroup analyses.

Description

Inclusion Criteria:

  • Patients who meet the Berlin definition of ARDS and have been treated with mechanical ventilation (clinical diagnosis of ARDS by the attending ICU physician)
  • PaO₂/FiO₂ ≤200 mmHg

Exclusion Criteria:

  • Age< 18 or >90 years
  • Pneumothorax, pneumomediastinum
  • Hemodynamic instability (rising vasopressor need in <6h)
  • Contraindications to RM or EIT

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
evaluate the feasibility of using EIT to calculate regional recruitment-to-inflation (R/I) ratios
Regional R/I ratios were computed for the global lung, dorsal (dependent), and ventral (non-dependent) regions of interest (ROIs), which were defined as 50% of the ventro-dorsal lung diameter based on EIT imaging.compare the predictive value of regional (dorsal and ventral) versus global R/I for recruitment success in moderate-severe ARDS.
Diagnostic test: Electrical Impedance tomography Monitoring

Standardized PEEP step maneuver from 5 → 15 cmH₂O, maintained for 3 minutes. Continuous EIT monitoring of regional compliance, oxygenation, hemodynamics. Dynamic strain cutoff (>0.6) or adverse events terminate the maneuver.

Ventilation mode: volume control, tidal volume 4-6 mL/kg predicted body weight, plateau ≤28-30 cmH₂O, FiO₂ titrated for SpO₂ 88-92%.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
recruitment success percent
Time Frame: From enrollment to the end of treatment at 7 days
recruitment( ≥10% compliance improvement ) and Re-check the blood gas ≥20 mmHg PaO₂/FiO₂ increase mean success
From enrollment to the end of treatment at 7 days

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
28-day mortality
Time Frame: From enrollment to the end of treatment at 28 days
Statistical analysis of 28-day mortality
From enrollment to the end of treatment at 28 days
Change in Sequential Organ Failure Assessment (SOFA) score from baseline to day 7
Time Frame: From enrollment to the end of treatment at 7 days
Change in Sequential Organ Failure Assessment (SOFA) score from baseline to day 7
From enrollment to the end of treatment at 7 days
Length of ICU stay
Time Frame: From enrollment to the end of treatment at 7 days
Length of ICU stay in days
From enrollment to the end of treatment at 7 days
Ventilator-free days at Day 28
Time Frame: From enrollment to the end of treatment at 28 days
Number of days alive and free from mechanical Ventilation with in the first days after enrollment
From enrollment to the end of treatment at 28 days

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in IL-6/IL-10 ratio
Time Frame: From enrollment to the end of treatment at 5 days
Change in IL-6/IL-10 ratio from baseline to day 5 measured by immunoassay
From enrollment to the end of treatment at 5 days
Percentage of patients achieving ventilator-free days
Time Frame: From enrollment to the end of treatment at 7 days
Percentage of patients achieving ventilator-free days
From enrollment to the end of treatment at 7 days
Hospital costs during ICU stay
Time Frame: From enrollment to the end of treatment at 7 days
Hospital costs in USD during ICU stay
From enrollment to the end of treatment at 7 days
Quality of life score at discharge
Time Frame: From enrollment to the end of treatment at 28 days
Quality of life score at discharge measured by EQ-5D-5L instrument (range 0-1)
From enrollment to the end of treatment at 28 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ruijin Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Hongping Qu, Department of Critical Care Medicine，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine
  • Principal Investigator: Jialin Liu, Department of Geriatrics，Ruijin Hospital，Shanghai Jiao Tong University School of Medicine
  • Study Director: rui zhang, Department of Critical Care Medicine，Ruijin Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 25, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 8, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 12, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 23, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 20, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2022325

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

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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