High flow nasal oxygen feasible in pulmonary rehabilitation of COPD patients

Use of high flow nasal oxygen (HFO) is feasible during early pulmonary rehabilitation for improving exercise capacity in chronic obstructive pulmonary disease (COPD) patients after an exacerbation, results of a pilot randomized controlled trial (RCT) have shown. Additionally, HFO has high patient acceptability.

“The clinical significance of our study is its potential to address a longstanding challenge in COPD pulmonary rehabilitation and change rehabilitation practice,” said the researchers, led by Yingjuan Mok from the Department of Respiratory and Critical Care Medicine, Changi General Hospital, Singapore.

Mok and colleagues conducted this RCT to assess the impact of HFO in improving pulmonary rehabilitation outcomes of COPD patients postexacerbation. Twenty-two patients recently hospitalized for COPD exacerbation were enrolled and randomized to either HFO or usual care during an early 6-week, outpatient pulmonary rehabilitation program.

Of the 22 patients randomized between May 2019 and December 2019, 18 completed the study. Improvements in exercise capacity were greater in the HFO arm than in the usual care arm, with a mean difference in 6-min walk distance (6MWD) of 30 m (95 percent confidence interval, ‒23 to 84). However, this did not reach statistical significance. [Proc Singap Healthc 2023;doi:10.1177/20101058231204705]

All 18 patients in either group showed compliance to the rehabilitation program. Compliance was defined by attending at least 75 percent of the exercise sessions. In addition, HFO exhibited good tolerability, with no adverse events reported.

“Having demonstrated feasibility in this pilot study, we hope to further this research in a larger, adequately powered RCT to ascertain the benefits of HFO use during exercise training in early pulmonary rehabilitation for COPD patients posthospitalization for COPD exacerbation,” the researchers said.

Previous research

A study by Vitacca and colleagues comparing HFO to oxygen delivered via a Venturi mask during exercise training in COPD patients showed a greater improvement in 6MWD, but not in endurance time, in the HFO arm after 20 exercise sessions. [Phys Ther 2020;100:1249]

A similar study involving 32 stable advanced COPD patients on long-term oxygen therapy compared HFO to oxygen delivered via usual cannula at flow rate of 6 L/min during a 4-week, inpatient pulmonary rehabilitation program. The results demonstrated a greater improvement in 6MWD, but not in the duration of the constant-load exercise test, in the HFO arm. [Respir Investig 2022;60:658]

“Regardless, these two studies had limited generalizability as their 1-month, five sessions/week, intensive pulmonary rehabilitation program was conducted inpatient, a high-resource care model that would not be suitable for many healthcare systems including Singapore’s,” the researchers said.

Guidelines recommend early pulmonary rehabilitation for all COPD patients following hospitalization for COPD exacerbation, but many patients experience difficulties participating in this program due to breathlessness, according to the researchers.

“HFO has been shown to improve ventilatory efficiency in stable COPD patients, but there is little data on HFO use during exercise training in pulmonary rehabilitation post-COPD exacerbation,” they added.