This study compare the efficacy of high flow nasal cannula with nasal continuous positive airway pressure. All of participants will be randomized to receive one night high flow nasal cannula therapy and another night for nasal continuous positive airway pressure.

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common medical condition. Nasal continuous positive airway pressure (CPAP) is mainstay of treatment for OSAHS, but CPAP has some limitations. Patient who has bulbar dysfunction and poor consciousness are contraindications for CPAP. They are also not suitable for other therapy. There are still large number of patients could not accept CPAP. Alternative treatment method transnasal high flow was developed and previous study showed moderately reduce respiratory event. It is deliver 20 L/minute constant room air by nasal cannula. Because the technical limitation, the maximal flow rate is also 20 L/minute and it limit the effectiveness.

Recently, new high flow nasal cannula(HFNC) is developed. This HFNC has already widely been used for respiratory disease. It can deliver air flow up to 60 L/mins. It is also can maintain high humidifier and adequate temperature. The every 10 L/min air flow could generate approximately 1 cmH2O positive end expiratory pressure (PEEP). The higher air flow could generate more high PEEP and may have better effect than previous HFNC, but there are no study to evaluate the efficacy in OSAHS patient. Thus, the purpose of our study is to compare the efficacy of HFNC with standard CPAP therapy.

All of the participants were randomized into two groups for minimized first night effects. All of them would receive one-night HFNC therapy and another night for CPAP titration under PSG monitoring. The duration between these two treatments was approximately one week apart. The first group underwent CPAP titration on the first night and HFNC titration on the second night. Conversely, the second group was subjected to HFNC on the first night and CPAP titration on the second night. All of the participants were asked and recorded their side effects following completion of an HFNC or CPAP.

Inclusion Criteria:

• Apnea hypopnea index greater than 5 times per hour
• Age greater than 18 years old.

Exclusion Criteria:

• Central sleep apnea
• Hypoventilation syndrome
• Chronic obstructive airway disease
• Receive soft palate surgery or used an oral appliance
• Intolerance to transnasal high flow or CPAP
• Pregnant women
• Unstable hemodynamic state
• Eastern Cooperative Oncology Group Performance Status higher than grade 2

De-identified participants raw data will be made available.

Data will available within 12 months of study completion

Requestors need application and explain the purpose. The data access will be provided after approved by review panel.

2 days; All of the participants were asked and recorded their side effects following completion of an HFNC or CPAP.

CPAP and HFNC have been widely used in clinical practice for long time, but the serious adverse effects or mortality events are rarely reported . Our study excluded the participants who have unstable clinical condition. Therefore, there was no serious adverse events or mortality in our study.