Objective To assess whether AECOPD patients can breathe independently at the PIC window and thus whether NPPV was necessary after extubation.Methods We performed a prospective observational study, we used the spontaneous breathing trial (SBT)to assess whether each patient could breathe independently at the PIC window,then performed extubation.Patients who passed the SBT received oxygen therapy only,whereas those who failed received NPPV.However,if the former showed respiratory distress,they also received NPPV.The primary out-come variables were SBT pass/fail,the demand for NPPV and rate of reintubation within 72h following extubation. Results In all,23 patients were enrolled,15cases(65.2%)of which passed the SBT.Of these,12cases (80.0%) patients developed respiratory distress after extubation and required NPPV (one of whom required reintubation).Of the eight patients that failed,one received reintubation after NPPV.The reintubation rates within 72h following extuba-tion of SBT-pass(7.0%)and SBT-fail (13.0%)(χ2 =1.476,P>0.05)patients were comparable.Conclusion Most AECOPD patients can breathe independently at the PIC window,but nonetheless develop respiratory distress and thus require NPPV following extubation.