Introduction:
Chronic Obstructive Pulmonary Disease (COPD) is a chronic disorder with many systematic complications and one of the most important reasons for patients to require mechanical ventilation, admission in intensive care unit and prolonged mechanical ventilation. Although the first attempt in separation of mechanical ventilation is failed in half of chronic obstructive pulmonary disease (COPD) patients, but delaying in the weaning process in these patients also cause ventilator dependence. PaCO2 = 35 - 60 mm/Hg is one of the most important indexes for predicting a successful extubation.