Diaphragm Ultrasound and Rapid Shallow Breathing Index for Predicting Extubation Success

The purpose of this study is to find out whether diaphragm ultrasound measurements, alone or combined with the rapid shallow breathing index (RSBI), can better predict successful removal of the breathing tube in adult intensive care unit patients on mechanical ventilation. Diaphragm thickening fraction and diaphragm excursion are measured with bedside ultrasound during the spontaneous breathing trial. Patients are followed after extubation to determine whether they need to be reintubated. The study does not change patient treatment; all measurements are non-invasive.