Proportional Assisted Ventilation and Pressure Support Ventilation in Adult Patients With Prolonged Ventilation

Inclusion Criteria: * Patients with prolonged mechanical ventilation and transfer to respiratory care center, age of 20 years or older, at least 1 time of extubation failure or spontaneous breathing trial failure in ICU, stable hemodynamics, no vasopressor use, FiO2 = 0.40 or less, external positive end-expiratory pressure = 5 cmH2O or less, PaO2 \> 60 mmHg, and body temperature \< 38ºC (within 24 hours). Exclusion Criteria: * Patients with bronchopleural fistulas, central neurological disorders, hemodialysis, and those with pressure support level already \< 15 cmH2O.