End-Expiratory Diaphragmatic Residual Contraction Index for Identifying Intrinsic PEEP and Assisting PEEP Titration: A Prospective Physiological Study

July 5, 2026 updated by: Huiqing Ge, Sir Run Run Shaw Hospital
This study proposes the End-expiratory Diaphragmatic Residual Contraction (EDRC) index to quantify residual diaphragmatic activity at end-expiration during Pressure Support Ventilation (PSV) mode. The study aims to validate the relationship between EDRC and dynamic intrinsic PEEP (PEEPi), triggering load, patient-ventilator asynchrony, and PEEP responsiveness through a brief, standardized PEEP titration trial conducted within a clinically safe range. This will provide a basis for subsequent individualized PEEP setting guided by EDRC.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

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.

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 (Estimated)

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.
100

Contacts and Locations

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

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

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

The study population will consist of adult patients ($\ge$ 18 years) admitted to the Intensive Care Unit (ICU) who are receiving invasive mechanical ventilation in Pressure Support Ventilation (PSV) mode. Participants will be recruited from the ICU at [Insert Name of Hospital/Institution].

The population is characterized by patients who are clinically assessed as having a risk of dynamic intrinsic PEEP (PEEPi,dyn) or are undergoing a spontaneous breathing trial (SBT) as part of the weaning process. All enrolled patients will have an indwelling esophageal balloon catheter placed for the measurement of esophageal pressure (Pes), which serves as the reference standard for respiratory mechanics.

Patients will be screened for eligibility based on hemodynamic stability and the ability to tolerate the study procedures. Specific exclusion criteria include pregnancy, severe esophageal pathology, severe hypoxemia, and conditions precluding diaphragmatic ultrasound imaging (e.g., chest wall tra

Description

Inclusion Criteria:

  • Age ≥ 18 years. Patients receiving invasive mechanical ventilation in Pressure Support Ventilation (PSV) mode.

Clinically assessed as having a risk of dynamic intrinsic PEEP (PEEPi,dyn) or experiencing difficult weaning from mechanical ventilation.

Presence of an indwelling esophageal balloon catheter (for reference standard measurements).

Provision of written informed consent from the patient or legally authorized representative.

Exclusion Criteria:

  • Pregnancy or lactation. Known esophageal diseases (e.g., esophageal varices, strictures, recent esophageal surgery) or contraindications to esophageal catheter placement.

Severe hemodynamic instability (e.g., requiring high-dose vasoactive support, uncontrolled arrhythmias).

Severe hypoxemia (PaO2/FiO2 < 100 mmHg) or severe hypercapnia with hemodynamic compromise at baseline.

Conditions precluding ultrasound assessment of the diaphragm (e.g., extensive chest wall trauma, large pleural effusion, severe subcutaneous emphysema).

Active spontaneous breathing with severe patient-ventilator asynchrony that cannot be stabilized during the trial.

Anticipated extubation or withdrawal of life-sustaining treatment within the next 24 hours.

Participation in another interventional clinical trial within the last 30 days.

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.
Patients Undergoing PEEP Step Trial and EDRC Assessment
All enrolled patients will receive a standardized, short-term PEEP step trial while in Pressure Support Ventilation (PSV) mode. The trial consists of sequentially applying PEEP levels of Baseline, -2, +2, +4, and +6 cmH2O relative to the set PEEP. At each step, respiratory mechanics and patient-ventilator synchrony will be monitored. The primary intervention of interest is the assessment of End-Expiratory Diaphragmatic Residual Contraction (EDRC) via ultrasound to identify the presence of intrinsic PEEP (PEEPi) and to determine the optimal level of extrinsic PEEP that minimizes diaphragmatic effort and asynchrony.
Device: Short-term PEEP Step Trial and EDRC Ultrasound Assessment
This intervention involves a standardized, short-term PEEP step trial combined with a novel physiological assessment. During the trial, external PEEP is systematically adjusted in 2 cmH2O increments (Baseline, -2, +2, +4, +6 cmH2O) while maintaining stable Pressure Support Ventilation (PSV) settings. Simultaneously, the End-Expiratory Diaphragmatic Residual Contraction (EDRC) index is evaluated using diaphragm ultrasound speckle tracking. This distinguishes the intervention by providing a non-invasive, real-time quantification of residual diaphragmatic tension at end-expiration, which serves as a surrogate marker for dynamic intrinsic PEEP (PEEPi) and trigger load, distinguishing it from traditional static measurements or esophageal manometry alone.

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
Diagnostic Efficacy of EDRC-AUC for Identifying Clinically Significant Dynamic Intrinsic PEEP
Time Frame: During the short-term PEEP step trial (each PEEP level is maintained for 5-10 minutes)
The primary outcome is the diagnostic efficacy of the End-Expiratory Diaphragmatic Residual Contraction Area Under the Curve (EDRC-AUC) in identifying clinically significant dynamic intrinsic PEEP (PEEPi,dyn ≥ 5 cmH2O) in patients undergoing Pressure Support Ventilation (PSV). The diagnostic performance will be evaluated using Receiver Operating Characteristic (ROC) curve analysis, reporting the Area Under the Curve (AUC), optimal cut-off value, sensitivity, specificity, positive predictive value, and negative predictive value, with esophageal manometry and flow curves as the reference standard.
During the short-term PEEP step trial (each PEEP level is maintained for 5-10 minutes)

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
Correlation between EDRC-AUC and Respiratory Drive/Load Indices
Time Frame: During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial
To evaluate the correlation (using Pearson or Spearman correlation coefficients) between the End-Expiratory Diaphragmatic Residual Contraction Area Under the Curve (EDRC-AUC)
During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial
Incidence of Patient-Ventilator Asynchrony Events
Time Frame: During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
To record and compare the total incidence and distribution of patient-ventilator asynchrony events across different PEEP levels. Specific events include:Ineffective triggering;Double triggering;Auto-triggering;Short or long cycling.
During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
Agreement between EDRC-Guided PEEP and Esophageal Manometry-Guided PEEP
Time Frame: During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
To compare the optimal PEEP level determined by the EDRC minimization principle with the optimal PEEP level determined by esophageal manometry (minimizing driving pressure or PTP). Bland-Altman analysis will be used to evaluate the mean bias and limits of agreement between the two methods.
During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
Trends in Diaphragmatic Contraction Dynamics Across PEEP Levels
Time Frame: During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
To observe and describe the dynamic trends of diaphragm thickening fraction (DTF) and the EDRC index across all phases of the PEEP step trial (Baseline, -2, +2, +4, +6 cmH2O), assessing the bidirectional effects of extrinsic PEEP on diaphragmatic load.
During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
Feasibility and Inter-Observer Reliability of EDRC Ultrasound Measurements
Time Frame: During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
Feasibility: The proportion of patients from whom analyzable ultrasound images were successfully obtained; Reproducibility: The intra-class correlation coefficient (ICC) for EDRC-AUC measurements between different operators (inter-observer) and by the same operator at different time points (intra-observer).
During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.
Adverse Events During the PEEP Step Trial
Time Frame: During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.

To document any clinical adverse events occurring during the PEEP titration process, including:

Hemodynamic instability (e.g., systolic blood pressure decrease >20% or increased requirement for vasoactive drugs); Severe hypoxemia (SpO2 < 88% lasting >1 minute); Severe arrhythmias; Significant respiratory distress or intolerance requiring premature termination of the trial.
During the short-term PEEP step trial (each PEEP level maintained for 5-10 minutes) and within 30 minutes post-trial.

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.
Sir Run Run Shaw Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Estimated)

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.
August 21, 2026

Primary Completion (Estimated)

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.
August 24, 2027

Study Completion (Estimated)

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.
September 3, 2027

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).
July 5, 2026

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.
July 5, 2026

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.
July 13, 2026

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.
July 13, 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.
July 5, 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.
July 1, 2026

More Information

Terms related to this study

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.
  • 20260627

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

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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