The goal of this prospective interventional crossover randomized physiological study is to investigate the reliability of Pressure Muscle Index (PMI) - as an estimation of inspiratory effort - at different levels of expiratory cycling during pressure support ventilation. PMI will be compared with the esophageal pressure swing that is considered the gold standard technique. This study aims to answer to the following questions: * which is the optimal expiratory cycling threshold where PMI better correlates with the esophageal pressure swing? * what is the optimal correlation between the occlusion pressure (Poc) estimated by an expiratory occlusion manoeuvre and P0.1 with PMI obtained at various degrees of expiratory cycling threshold? * does airway resistance - evaluated by using esophageal pressure - correlate with the estimation of airway resistance on the pressure-time waveform by a high percentage of expiratory cycling mimicking the interrupter technique?
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Pressure muscle index (PMI) as a bedside estimation of inspiratory effort at different expiratory cycling levels during different levels of pressure support.
Timeframe: After at least 6 hours after and within 72 hours since switch from controlled ventilation to pressure support ventilation.