Purpose of research:to explore a reasonable programmed withdrawal process of noninvasive ventilation and thereby reduce the duration of noninvasive mechanical ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease.

This is a single-center, prospective, randomized controlled study. The study subjects were patients with acute exacerbation of chronic obstructive pulmonary disease admitted to the intensive care unit, who were randomized into the study group, that is, the programmed withdrawal unit, and the control group was the traditional withdrawal unit (the attending physician decided the NIV regimen according to the condition). The primary study endpoints of the trial were complete evacuation of noninvasive ventilation (i. e. from the start of the patient to noninvasive ventilation) . Secondary study endpoints include length of stay in ICU, length of stay in hospital and failure of non-invasive ventilation (failure of non-invasive ventilation was defined as the patient underwent NIV again within 48 hours after being weaned off the ventilator;During NIV, endotracheal intubation was required, and invasive mechanical ventilation was used instead;The patient could not discontinue NIV completely and needed to use home non-invasive ventilation; The patient died.).

Inclusion Criteria:

• It is defined that in patients with acute exacerbation of chronic obstructive pulmonary disease, the arterial blood gas analysis was decompensation of respiratory acidosis, and the pH value was 7.20-7.35
• Non-invasive mechanical ventilation was performed and it was well tolerated

Exclusion Criteria:

• younger than 40 years old
• pregnancy
• Human immunodeficiency virus (HIV) antibody was positive
• Hemodynamic instability
• Long-term use of home non-invasive ventilators
• Mechanical ventilation for endotracheal intubation and cardiopulmonary resuscitation were disagreed