Exercise Capacity Under Various FiO2 and Oxygen Flow Rates Using HFNC

Examination of Exercise Capacity Under Various Oxygen Concentrations and Oxygen Flow Rates Using High Flow Nasal Cannula

The purpose of this study is to compare the exercise capacity (6-min walking distance) under the following 4 conditions using High-flow nasal cannula (HFNC); 1. FIO2 value that the minimum SpO2 value in a 6-minute walking test (6MWT) is 86-88%, and a flow of 10 L/min 2. FIO2 value that the minimum SpO2 value in a 6MWT is 86-88%, and a flow of 40-50 L/min 3. FIO2 value that the minimum SpO2 value in a 6MWT is 92-94%, and a flow of 10 L/min 4. FIO2 value that the minimum SpO2 value in a 6MWT is 92-94%, and a flow of 40-50 L/min

In the pervious study, the investigators demonstrated that 4 weeks of training using both high FIO2 and high flow through an HFNC significantly improved the 6MWD compared with training using a 6 L/min nasal cannula. However, it was unclear whether the effects of pulmonary rehabilitation under HFNC were due to high FIO2, high flow rate, or a synergistic effect. It is also unknown whether there are differences in the effects of pulmonary rehabilitation under HFNC for each underlying disease.

Inclusion Criteria:

• Subjects with a minimum SPO2 of 88% or less during performing 6MWT under HFNC (FIO2 0.21 and a flow rate of 10L/min)
• Subjects who have been clinically stable for the last 2 weeks
• Subjects with written informed consent to participate in this study

Exclusion Criteria:

• Subjects with severe cardiovascular disease, liver disease, neurological disease, and renal failure
• Subjects who needed antimicrobial agent or steroid administration for pneumonia and exacerbation of respiratory disease in the last 2 weeks
• Subjects who cannot undergo 6MWT due to severe heart failure, arteriosclerosis obliterans or spinal disease