Background: Long-term oxygen therapy (LTOT) is recommended to be used in stable chronic obstructive pulmonary disease (COPD) patients with severe resting hypoxemia. High-flow nasal oxygen cannula (HFNC) demonstrated benefits in acute hypoxemic respiratory failure. The mechanisms of HFNC by washing out dead space and decreasing work of breathing may be also beneficial in COPD patient who has an indication for LTOT.

Objective: To compare the effect of HFNC versus conventional oxygen therapy (COT) in terms of respiratory rate, gas exchange, and health-related quality of life.

Materials and Methods: A pilot randomized crossover study was conducted in eleven stable COPD patients. Subjects were randomly assigned to HFNC at a flow rate of 30 L/minute or simple nasal cannula at 2 to 4 L/minute for two weeks in a cross-over fashion. The primary outcome was respiratory rate. The secondary outcomes included blood pressure, heart rate, oxygen saturation (SpO₂), transcutaneous carbon dioxide pressure (PtcCO₂), and St.George’s Respiratory Questionnaire (SGRQ) score.

Results: The duration of HFNC and COT use was 8 (IQR 3 to 13) and 14 (IQR 10 to 20) hours/day, respectively (p=0.039). Respiratory rate was significantly lower with HFNC compared to COT at 18 breaths/minute (IQR 16 to 20) versus 22 breaths/minute (IQR 20 to 25) , respectively (p=0.018). SpO₂ was significantly higher with HFNC compared to COT (p=0.046). No differences in blood pressure, heart rate, PtcCO₂, and SGRQ score were observed between the two groups. No serious adverse event from HFNC was observed.

Conclusion: The present pilot study demonstrated that HFNC was tolerable in patients with stable COPD who had an indication for LTOT. Respiratory rate was significantly lower and SpO₂ was significantly higher with HFNC compared to COT. Another study with larger sample size is needed to further clarify the efficacy of HFNC in stable COPD patients.

Keywords: Chronic obstructive pulmonary disease; Dyspnea; High-flow nasal cannula; Oxygen therapy; Respiratory rate

DOI: 10.35755/jmedassocthai.2023.05.13848

Received 5 September 2022 | Revised 5 January 2023 | Accepted 16 January 2023