High-frequency oscillatory ventilation (HFOV), as an ideal lung-protecting ventilation method, has been gradually used in neonatal critical care treatment, and is currently recommended as a rescue method for neonatal acute respiratory distress syndrome (ARDS) after failure of conventional mechanical ventilation. . Although its ability to improve oxygenation and enhance carbon dioxide (CO2) scavenging has been repeatedly demonstrated in laboratory studies, its impact on clinical outcomes in these patients remains uncertain. Non-invasive high-frequency oscillatory ventilation (nHFOV) combines the advantages of HFOV and non-invasive ventilation methods, and has become a current research hotspot in this field. It is recommended to be used to avoid intubation after conventional non-invasive ventilation therapy fails. For the treatment of intubation, there is still a lack of large-scale clinical trials to systematically explore its efficacy. The gradual increase in the clinical application of nHFOV has also enriched its use in the treatment of other diseases.

Inclusion Criteria:

1. Age 40-80, males and females;
2. Stage III and IV COPD and PaCO2≥50mmHg;
3. Similar with non-invasive ventilation;
4. Willing to participate in the study;
5. Able to provide informed consent.

Exclusion Criteria:

1. Bronchiectasis; post-tuberculosis sequelae; rib cage deformities; neuromuscular disorders; and bronchial carcinoma.
2. Intolerant with NIV