Diaphragm, Speckle Tracking
Conditions
Brief summary
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.
Interventions
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).
Sponsors
Study design
Eligibility
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Rate of first-attempt weaning failure | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Rescue NIV/HFNC within 48 or 72 hours post-extubation | - 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. |
| - Rescue NIV/HFNC within 48 or 72 hours post-extubation | - 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. |
| - Ventilator-free days at 28 days (D28) | - 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. |
| - Length of stay in the ICU and hospital | 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. |
| - ICU mortality and in-hospital mortality | 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). |
| - Correlation between RDSI and conventional respiratory mechanics/diaphragm ultrasound parameters | 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). |
| - Feasibility and reliability of RDSI image acquisition and speckle tracking | 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). |