This study only enrolled patients with tracheotomy. When a patient is eligible to this study, he or she is randomly assigned to intervention or control group.A patient in intervention group is switched to noninvasive ventilation by masking the tracheotomy tube. If the patient presents distress in noninvasive ventilation, he or she is switched to invasive ventilation. If the distress relieves, patient is switched to noninvasive ventilation again until the patient successfully weans from ventilator. In control group, the patient is weaned as the conventional methods.