An observational study in Ventilator Weaning, Sarcopenia and Diaphragm Ultrasonography, sponsored by Kocaeli City Hospital. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-28.
Sponsored by Kocaeli City Hospital · Observational
This study investigates whether the Sarcopenia Index (SI = serum creatinine/cystatin C × 100), a simple biomarker derived from routine blood tests, can predict weaning success in critically ill patients undergoing invasive mechanical ventilation in the intensive care unit. SI will be measured at the spontaneous breathing trial (SBT), and its predictive value will be compared with diaphragm ultrasound parameters - diaphragm thickening fraction (DTF) and diaphragm excursion (DE) - as well as other established weaning parameters. The goal is to determine whether SI can serve as an accessible, low-cost alternative or complement to ultrasound-based assessment in predicting successful liberation from mechanical ventilation, and to establish a population-specific SI cutoff value for this setting.
This study will enroll adult patients undergoing invasive mechanical ventilation in the ICU. Serum creatinine and cystatin C will be measured at the time of the spontaneous breathing trial (SBT) to calculate SI . Diaphragm ultrasound parameters (DTF and DE) will be obtained at the SBT, along with other standard weaning parameters (e.g., rapid shallow breathing index, and other clinically used indices). Weaning success will be defined as the absence of reintubation or need for ventilatory support within 48-72 hours after extubation.
The primary aim is to evaluate the diagnostic accuracy of SI, alone and in combination with diaphragm ultrasound parameters, in predicting weaning success using receiver operating characteristic (ROC) curve analysis, and to derive a population-specific SI cutoff value for this setting. Secondary aims include comparing SI's predictive performance to established weaning parameters and assessing correlations between SI and diaphragm ultrasound measurements. If validated, SI could offer clinicians a low-cost, widely available, and less operator-dependent adjunct or alternative to ultrasound-based assessment of weaning readiness.
Adult patients admitted to the intensive care unit at Kocaeli City Hospital who require invasive mechanical ventilation for at least 24 hours and undergo a spontaneous breathing trial for weaning.
Exclusion Criteria:
Patients who met weaning criteria and were successfully extubated following a spontaneous breathing trial (SBT), without reintubation or need for non-invasive mechanical ventilation (NIMV) within 48 hours post-extubation. In this group, diaphragm ultrasonography (diaphragm excursion, end-expiratory and end-inspiratory diaphragm thickness, diaphragm thickening fraction), classical weaning parameters (RSBI, NIF, P0.1), and the Sarcopenia Index (serum creatinine/serum cystatin C × 100) were recorded at the time of the SBT.
Other: sarcopenia index · Other: diaphragma ultrasound · Other: parameters of mechanical ventilation (MV)
Patients who, despite meeting weaning criteria and undergoing an SBT, required reintubation or new NIMV support within 48 hours post-extubation, classified as unsuccessful weaning. The same diaphragm ultrasonography parameters, classical weaning parameters, and Sarcopenia Index measurements were recorded at the time of the SBT for comparison with the Weaning Success group.
Other: sarcopenia index · Other: diaphragma ultrasound · Other: parameters of mechanical ventilation (MV)
A calculated biomarker derived from routinely measured serum creatinine and serum cystatin C values \[(creatinine/cystatin C) × 100\], obtained at the time of the spontaneous breathing trial.
Non-invasive, point-of-care bedside ultrasonography of the diaphragm performed at the time of the spontaneous breathing trial using a linear high-frequency probe (3-14 MHz) at the 8th-10th intercostal space between the anterior and mid-axillary lines. Diaphragm excursion (DE) is measured with a curvilinear probe (1.3-5.7 MHz) in M-mode. End-expiratory and end-inspiratory diaphragm thickness are measured, and the diaphragm thickening fraction (DTF) is calculated as \[(inspiratory thickness - expiratory thickness) / expiratory thickness\] × 100. This is a diagnostic imaging assessment, not a therapeutic intervention, and involves no ionizing radiation or additional risk to the patient.
Standard bedside weaning parameters recorded by the investigator at the time of the spontaneous breathing trial: Rapid Shallow Breathing Index (RSBI, respiratory rate/tidal volume ratio), Negative Inspiratory Force (NIF/PImax, maximal inspiratory pressure), and Airway Occlusion Pressure at 0.1 seconds (P0.1). These are routine, non-invasive respiratory mechanics measurements obtained as part of standard weaning assessment, with no additional risk or intervention beyond usual ICU care.
Predictive Value of the Sarcopenia Index for Predicting Weaning Success
Area under the ROC curve (AUC), sensitivity, and specificity of the Sarcopenia Index (serum creatinine/serum cystatin C × 100) in predicting successful weaning from invasive mechanical ventilation.
Time frame: Through study completion, an avarage of 1 year
Association Between Sarcopenia Index and Reintubation
Comparison of Sarcopenia Index values (serum creatinine/serum cystatin C × 100) measured at the spontaneous breathing trial between patients who required reintubation or new non-invasive mechanical ventilation (NIMV) support and those who did not, within 48 hours post-extubation.
Time frame: Within 48 hours after extubation
No study locations are listed for this record.
Plan to share: No — No formal plan for sharing individual participant data (IPD) with other researchers has been established at this time. Data will be reported in aggregate form in accordance with the study's ethics committee approval and institutional data protection policies.
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Kocaeli City Hospital