This project will conduct a series of analysis of physiological and clinical data on tracheostomy patients who receive prolonged mechanical ventilation, hoping to find out the different manifestations of patients through the investigation by a variety of physiologic measurements, so as to understand whether different types of patients phenotype to derive different clinical strategies for liberation of the mechanical ventilator.

Inclusion Criteria:

• Patients with at least 10 days of mechanical ventilation at the intensive care unit of National Taiwan University Hospital and transferred to the Respiratory Care Center of National Taiwan University Hospital for weaning training
• Patients who have undergone tracheostomy and still have a tracheotomy tube
• Are at least 20 years old
• Stable respiratory condition with inspired oxygen fraction not exceeding 50%

Exclusion Criteria:

• Hemodynamic instability or continuous use of vasopressors
• Pregnancy

Chronic critically ill patients receiving prolonged mechanical ventilation