Randomized Controlled Study of Programmed Weaning From NIV for AECOPD

Programmed withdrawal unit: daily morning review arterial blood gas analysis (since the 2nd, daily morning stop non-invasive ventilation 1 hours, 2 hours, 3 hours, 4 hours after check arterial blood gas analysis), blood gas results suggest respiratory acidosis compensatory period (pH value greater than 7.35) can reduce daily noninvasive ventilation time, namely the noninvasive ventilation use time for 24 hours, 20 hours, the third day 16 hours, the fourth 12 hours, fifth day 8 hours. If ABG indicates still acid decompensation, continue the non-invasive ventilation regimen of the previous day. If noninvasive ventilation failed, invasive mechanical ventilation was performed.