Regional Diaphragmatic Synchrony Index for Predicting Weaning Outcomes During Pressure Support Ventilation Spontaneous Breathing Trials

July 23, 2026 updated by: Huiqing Ge, Sir Run Run Shaw Hospital

Regional Diaphragmatic Synchrony Index for Predicting Weaning Outcomes During Pressure Support Ventilation Spontaneous Breathing Trials: A Prospective Observational Study

The primary aim of this study is to evaluate the predictive value of the inspiratory regional diaphragmatic synchrony index (RDSI-insp) during PSV-SBT for first-attempt weaning failure. Secondary objectives include: (1) assessing the correlation between RDSI-insp and conventional respiratory mechanics and diaphragmatic ultrasound parameters such as RSBI, MIP/NIF, VC, CPF, P0.1, DE, and DTF; (2) comparing differences in RDSI and DPSI between successful and failed weaning groups during inspiration, end-inspiration, and expiration; (3) exploring the association of anterior diaphragmatic dyssynchrony index, posterior/crural dyssynchrony index, and regional time-to-peak dispersion with weaning outcomes; and (4) evaluating the feasibility, analyzable image rate, and repeatability of diaphragmatic speckle-tracking and RDSI calculation in patients undergoing PSV-SBT.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Estimated)

110

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 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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

The study population will consist of adult patients (aged 18 years and older) who have received invasive mechanical ventilation for at least 24 hours and are clinically ready for their first Spontaneous Breathing Trial (SBT) under Pressure Support Ventilation (PSV) mode. Eligible participants must be hemodynamically stable (MAP ≥ 65 mmHg with or without low-dose vasopressors) and have adequate oxygenation (FiO2 ≤ 0.60 and PEEP ≤ 10 cmH2O) to safely undergo the SBT. Patients with known diaphragm paralysis, inadequate ultrasound windows, severe agitation, or those who are pregnant will be excluded. Written informed consent will be obtained from the patient or their legally authorized representative prior to enrollment.

Description

Inclusion Criteria:

  • Age: Age ≥ 18 years.
  • Mechanical Ventilation Duration: Receiving invasive mechanical ventilation for ≥ 24 hours.
  • Weaning Readiness: The attending physician has determined that the patient meets the criteria for weaning assessment and plans to conduct a Spontaneous Breathing Trial (SBT) under Pressure Support Ventilation (PSV) mode.
  • Hemodynamic Stability: Hemodynamically stable prior to the SBT, defined as a mean arterial pressure (MAP) ≥ 65 mmHg, or requiring only low-dose vasopressor support.
  • Oxygenation Criteria: Oxygenation status permits an SBT, typically defined as FiO2 ≤ 0.60 and PEEP ≤ 10 cmH2O, or meeting the standard weaning assessment criteria of the participating institution.

Exclusion Criteria:

  • Known or highly suspected phrenic nerve injury, or unilateral/bilateral diaphragmatic paralysis.
  • Neuromuscular diseases causing severely restricted spontaneous breathing capacity, as judged by the investigator to be unsuitable for RDSI analysis.
  • Recent chest or upper abdominal surgery, open trauma, skin infection, or extensive dressing coverage that prevents obtaining a reliable diaphragm ultrasound window.
  • Significant agitation or severe patient-ventilator asynchrony that prevents the acquisition of continuous and stable respiratory cycles.
  • Undrained pneumothorax, or conditions deemed unsuitable for ultrasound examination as judged by the attending physician.
  • Pregnant patients.
  • The patient or their legally authorized representative refuses to participate in the study.

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
Intervention / Treatment
Weaning Success
Patients who successfully pass the first PSV-SBT and remain free from reintubation or rescue non-invasive ventilation (NIV)/high-flow nasal cannula (HFNC) for at least 48 hours post-extubation due to respiratory failure or failure of airway protection.
Patients undergoing their first Spontaneous Breathing Trial (SBT) under Pressure Support Ventilation (PSV) will receive diaphragm ultrasound examinations. The investigators will measure diaphragm excursion (DE) and thickening fraction (DTF) to calculate the Respiratory Diaphragm-SB Index (RDSI). Conventional weaning parameters (RSBI, MIP, P0.1, etc.) will also be recorded simultaneously. The results will be compared to predict weaning outcomes (successful extubation vs. failure/reintubation).
Weaning Failure
Patients who fail the first PSV-SBT, or those who pass the SBT but require reintubation or rescue NIV/HFNC within 48 hours post-extubation due to respiratory failure or failure of airway protection.
Patients undergoing their first Spontaneous Breathing Trial (SBT) under Pressure Support Ventilation (PSV) will receive diaphragm ultrasound examinations. The investigators will measure diaphragm excursion (DE) and thickening fraction (DTF) to calculate the Respiratory Diaphragm-SB Index (RDSI). Conventional weaning parameters (RSBI, MIP, P0.1, etc.) will also be recorded simultaneously. The results will be compared to predict weaning outcomes (successful extubation vs. failure/reintubation).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rate of first-attempt weaning failure
Time Frame: Up to 48 hours post-extubation (or duration of the first PSV-SBT if failed)
First-attempt weaning failure, defined as failure of the first PSV-SBT, or extubation following a successful SBT but requiring reintubation within 48 hours due to respiratory failure or failure of airway protection.
Up to 48 hours post-extubation (or duration of the first PSV-SBT if failed)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rescue NIV/HFNC within 48 or 72 hours post-extubation
Time Frame: - Up to 72 hours post-extubation
- Proportion of patients requiring reintubation for any reason (e.g., respiratory failure, decreased airway protection) within 72 hours after extubation.
- Up to 72 hours post-extubation
- Rescue NIV/HFNC within 48 or 72 hours post-extubation
Time Frame: - Up to 48 hours or 72 hours post-extubation
- Proportion of patients requiring urgent initiation of non-invasive ventilation (NIV) or high-flow nasal cannula (HFNC) due to respiratory distress or hypoxemia within 48 or 72 hours after extubation.
- Up to 48 hours or 72 hours post-extubation
- Ventilator-free days at 28 days (D28)
Time Frame: - Up to 28 days post-enrollment
- The number of days from the first successful weaning and extubation until day 28, during which the patient is alive and free from invasive mechanical ventilation. If the patient dies or remains on mechanical ventilation for more than 28 days, it is recorded as 0 days.
- Up to 28 days post-enrollment
- Length of stay in the ICU and hospital
Time Frame: From the date of randomization until the date of ICU discharge or hospital discharge, whichever came first, assessed up to 12 months.
- The number of days from enrollment (day of first SBT) to ICU discharge, and from enrollment to final hospital discharge.
From the date of randomization until the date of ICU discharge or hospital discharge, whichever came first, assessed up to 12 months.
- ICU mortality and in-hospital mortality
Time Frame: From the date of randomization until the date of ICU discharge or death, whichever came first, assessed up to 12 months.
- The proportion of patients who die during their ICU stay and during the entire hospital stay (until discharge).
From the date of randomization until the date of ICU discharge or death, whichever came first, assessed up to 12 months.
- Correlation between RDSI and conventional respiratory mechanics/diaphragm ultrasound parameters
Time Frame: At the end of the first PSV-SBT (approximately 30 to 120 minutes post-initiation)
- Assessment of the statistical correlation between the novel RDSI index and conventional weaning predictors, including Rapid Shallow Breathing Index (RSBI), Maximum Inspiratory Pressure (MIP/NIF), Vital Capacity (VC), Cough Peak Flow (CPF), Airway Occlusion Pressure (P0.1), Diaphragmatic Excursion (DE), and Diaphragm Thickening Fraction (DTF).
At the end of the first PSV-SBT (approximately 30 to 120 minutes post-initiation)
- Feasibility and reliability of RDSI image acquisition and speckle tracking
Time Frame: At the end of the first PSV-SBT, up to 120 minutes post-initiation (upon image completion)
- Assessment of the acquisition rate of diaphragm ultrasound images, the analyzability rate (proportion of successful speckle tracking analysis), and the inter-observer and intra-observer measurement agreement (Intraclass Correlation Coefficient, ICC).
At the end of the first PSV-SBT, up to 120 minutes post-initiation (upon image completion)

Collaborators and Investigators

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

Sponsor

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)

August 23, 2026

Primary Completion (Estimated)

August 21, 2027

Study Completion (Estimated)

August 30, 2027

Study Registration Dates

First Submitted

July 5, 2026

First Submitted That Met QC Criteria

July 23, 2026

First Posted (Actual)

July 29, 2026

Study Record Updates

Last Update Posted (Actual)

July 29, 2026

Last Update Submitted That Met QC Criteria

July 23, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • 20260625

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

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