ObjectiveTo investigate the effects of arterial blood gas index control during invasive mechanical ventilation on prognosis in COPD patients with type Ⅱ respiratory failure. MethodsSeventy-six COPD patients with hypercapnic respiratory failure who underwent invasive mechanical ventilation were recruited in the study. The patients were divided into group A with conventional arterial blood gas index control [pH of 7.40±0.05,PaO2 of (70±5)mm Hg,PaCO2 of (55±5)mm Hg],and group B with low index control [pH of 7.35±0.05,PaO2 of (60±5)mm Hg,PaCO2 of (60±5)mm Hg]. Two groups were compared on the required parameters of invasive mechanical ventilation,the duration of invasive mechanical ventilation,the incidence rate of sequential therapy in noninvasive mechanical ventilation,ventilator associated pneumonia and secondary intubation,etc. ResultsThe required parameters of invasive mechanical ventilation in group B including tidal volume (VT) and pressure support (PS),the duration of invasive mechanical ventilation,the incidence rate of sequential therapy in noninvasive mechanical ventilation,ventilator associated pneumonia and secondary intubation were all significantly lower than those in group A (P<0.05). ConclusionThe strategy to permit a lower PaO2 and carbon dioxide retention to a certain extent at lower FiO2,VT and PS levels in invasive mechanical ventilation can reduce the duration of invasive mechanical ventilation and the occurrence of ventilator associated complications,and improve the prognosis in COPD patients with type Ⅱ respiratory failure.