Dynamic Non-invasive Monitoring of Inspiratory Effort

This prospective, observational cohort study aims to evaluate whether the dynamic monitoring of a patient's breathing effort can predict successful liberation from invasive mechanical ventilation. The study will include 120 patients who have undergone 36 hours or more of controlled mechanical ventilation and deep sedation. Patient monitoring will commence immediately upon their transition to an assisted spontaneous breathing mode with pressure support. Starting from this clinical milestone, the researchers will track the patients' longitudinal inspiratory effort daily through four specific variables: maximum occlusion pressure, muscle pressure index, flow index via visual waveform inspection, and diaphragmatic thickening fraction via ultrasound. Concurrently, ventilator safety parameters (plateau pressure, driving pressure, transpulmonary pressure, and compliance) will be recorded. The primary outcome is the time from PSV initiation to successful weaning (defined as 72 hours without ventilator support). Clinical events such as death or return to a controlled mode due to PSV failure will be statistically treated as competing risks. Secondary outcomes include the incidence of pneumonia, ICU-acquired weakness, delirium, mortality, and PSV failure. Data will be analyzed using multivariate joint modeling within a Bayesian framework.