Objective To investigate the changes in respiratory and circulatory functions in chronic obstructive pulmonary disease (COPD) patients during sequential invasive-noninvasive mechanical ventilation therapy, and evaluate the effects of this new technique.Methods Twelve COPD patients with type Ⅱ respiratory failure due to severe pulmonary infection were ventilated through an endotracheal tube. When the pulmonary infection control window (PIC-Window) occurred, the patients were extubated and were ventilated with a facial mask using pressure support ventilation combined with positive end-expiratory pressure. The parameters of hemodynamics, oxygen dynamics, and esophageal pressure were measured at the PIC-Window during invasive mechanical ventilation, one hour after oxygen therapy via a naso-tube, and three hours after non-invasive mechanical ventilation. Results The variation in esophageal pressure was 20.0±6 cmH2O during naso-tube oxygen therapy, and this variation was higher than that during non-invasive mechanical ventilation (10±6 cmH2O, P0.05).Conclusions The respiratory and circulatory functions of COPD patients remained stable during sequential invasive-noninvasive mechanical ventilation therapy using PIC-Window as a switch point for early extubation. The COPD patients can tolerated the transition from invasive mechanical ventilation to noninvasive mechanical ventilation.