Table 1.
Eligibility and exclusion criteria
| Criteria for inclusion and exclusion |
|---|
| Eligibility criteria |
| ∙ Age >20 years |
| ∙ Subjective dyspnea in room air |
| ∙ SaO2 <90% in room air |
| ∙ Oxygen requirement for NC <6 L/min |
| Exclusion criteria |
| ∙ Unstable vital sign |
| - Systolic blood pressure <90 mmHg |
| - Diastolic blood pressure <60 mmHg |
| - Heart rate >120 bpm |
| - Respiratory rate >30 bpm |
| - Persistent dyspnea under oxygen therapy using NC |
| ∙ Severe hypoxia |
| - PaO2/FiO2 <200 mmHg |
| ∙ Unable to cooperate |
| - Delirium |
| - Reduced cognitive function |
| ∙ Symptomatic ischemic heart disease |
| ∙ Use of accessory muscle under oxygen therapy using NC |
| ∙ Impracticality of HFNC or NC application |
| - Facial deformity |
SaO2: oxygen saturation; NC: nasal cannula; HFNC: high flow nasal cannula.