Inclusion Criteria:  Willing to participate after informed consent Males and females, any race and aged≥18yeras Objectively confirmed central sleep apnea/Cheyne Stokes Respiration with an apnoea-hypopnoea- index (AHI)≥5/h by overnight polysomnography  Exclusion Criteria:  Obstructive sleep apnea Severe COPD，FEV1/FVC<70% and FEV1<60% Chronic CO2 retention with unknown reason Severe nasal congestion Poor understanding