When the patients have reached satisfactory neurological status, clinical and biochemical parameters with improvement or resolution of the underlying cause of acute respiratory failure. In addition, if the patients showed good tolerance with an acceptable ABG analysis (pH >7.35, SaO2 of 88% or more for FiO2 of 40% or less) after a minimum of 24 hours of ventilation and other criteria according to Raoof (2003) [21]. Patients were randomized equally into two groups to receive either adaptive support ventilation (group I) or with pressure support ventilation (group II). Weaning and extubation were performed by the pulmonary and critical care physicians who were not aware of the study. When the patients have reached satisfactory neurological status, clinical and biochemical parameters with improvement or resolution of the underlying cause of acute respiratory failure. In addition, if the patients showed good tolerance with an acceptable ABG analysis (pH >7.35, SaO2 of 88% or more for FiO2 of 40% or less) after a minimum of 24 hours of ventilation and other criteria according to Raoof (2003) [21]. Patients were randomized equally into two groups to receive either adaptive support ventilation (group I) or with pressure support ventilation (group II). Weaning and extubation were performed by the pulmonary and critical care physicians who were not aware of the study.