Weaning and Decannulation Protocol: Attempts to discontinue mechanical ventilation (MV) will be initiated when the tracheostomized patients fulfill the criteria (recovery from the precipitating illness; respiratory criteria consisting of a PaO2/fraction of inspired oxygen ratio of >150 mm Hg with a positive end-expiratory pressure <8 cm H2O, and an arterial pH >7.32; and clinical criteria consisting of the absence of myocardial ischemia determined by ECG, no need for vasoactive drugs or dopamine ≤5 µg/kg/min, a heart rate <140 beats/min, haemoglobin concentration >8 g/dL, temperature <38°C, no need for sedative drugs, presence of respiratory stimulus and spontaneous cough deemed clinically appropriate. Patients will be screened daily for these criteria).