Diaphragm, Speckle Tracking
Conditions
Brief summary
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.
Interventions
DEVICEShort-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.
Sponsors
Sir Run Run Shaw Hospital
Study design
Observational model
OTHER
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Diagnostic Efficacy of EDRC-AUC for Identifying Clinically Significant Dynamic Intrinsic PEEP | 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
| Measure | Time frame | Description |
|---|---|---|
| Correlation between EDRC-AUC and Respiratory Drive/Load Indices | 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) |
| Incidence of Patient-Ventilator Asynchrony Events | 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. |
| Agreement between EDRC-Guided PEEP and Esophageal Manometry-Guided PEEP | 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. |
| Trends in Diaphragmatic Contraction Dynamics Across PEEP Levels | 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. |
| Feasibility and Inter-Observer Reliability of EDRC Ultrasound Measurements | 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). |
| Adverse Events During the PEEP Step Trial | 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. |
Contacts
CONTACTHuiqing Ge, MD
CONTACTYIqing Xu, Master
Outcome results
None listed