Comparison of Sarcopenia Index, Diaphragm Ultrasonography, and Traditional Weaning Parameters in Predicting Successful Weaning From Mechanical Ventilation

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.