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NCT Number: NCT07697703

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

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.

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Key information

Conditions

Speckle Tracking Diaphragm

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Short-term PEEP Step Trial and EDRC Ultrasound Assessment

Device

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.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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)

  2. 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.

  3. 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.

  4. 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.

  5. 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).

  6. 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Huiqing Ge, MD

CONTACT

[email protected]

+8613588706787

YIqing Xu, Master

CONTACT

[email protected]

+86 13634115344

Sponsors and collaborators

Lead sponsor

Sir Run Run Shaw Hospital

Other

Registry information

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jul 13, 2026
Registry last updated
Jul 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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