Tidal volume, PaO2/PAO2, respiratory rate, occlusion pressure (P0.1), maximal inspiratory pressure (MIP) and ABG measurements were recorded. Only the values from the last 20 min of the successful 2-h period before extubation were averaged and analysed. The primary outcome variable was discontinuation from mechanical ventilation, which was defined as independence from ventilatory support >48 hours following extubation.