An interventional study of Asymmetric High-Flow Nasal Cannula (A-HFNC) and Conventional Pulmonary Rehabilitation Program in Pulmonary Disease, Chronic Obstructive (COPD), Dyspnea and Exercise Tolerance, sponsored by Universidad de Santiago de Chile. Completed at 1 site in Chile. Open to participants aged 40 Years and older. Per ClinicalTrials.gov, last updated 2026-04-01.
Sponsored by Universidad de Santiago de Chile · Not applicable, Interventional, and Treatment
This randomized pilot trial evaluated the feasibility and preliminary effects of using asymmetric high-flow nasal cannula (A-HFNC) during exercise-based pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD). Thirty patients were randomly assigned to conventional PR or PR supplemented with A-HFNC during aerobic training, completing 12 supervised sessions. The study assessed whether A-HFNC could be safely and acceptably incorporated into PR, and whether it enabled higher training intensity and improved exercise performance. Results showed that the intervention was feasible and safe, with 83% adherence in both groups and no adverse events. Patients in the A-HFNC group trained at significantly higher treadmill inclination and showed a clinically meaningful trend toward greater improvement in maximal exercise tolerance. These findings support the design of a larger definitive trial.
Chronic obstructive pulmonary disease (COPD) is a major cause of disability worldwide. Pulmonary rehabilitation (PR) is the most effective non-pharmacological intervention for COPD, but adherence is limited by exercise intolerance and dyspnea. Strategies that reduce ventilatory demand during exercise may help patients tolerate higher training intensities, potentially improving outcomes.
Asymmetric high-flow nasal cannula (A-HFNC) delivers heated and humidified gas at high flow rates through an asymmetric nasal interface, promoting dead-space washout and reducing the work of breathing. These mechanisms may facilitate higher exercise intensity during PR.
This pilot trial randomized 30 patients with COPD to two groups. The control group received a conventional 12-session supervised PR program including treadmill aerobic exercise, resistance training, and patient education. The experimental group followed the same program with A-HFNC applied during all aerobic training sessions. Flow rate, temperature, and fraction of inspired oxygen were individualized according to oxygen saturation and patient tolerance.
Primary feasibility outcomes were recruitment rate, protocol adherence, and absence of serious adverse events. Exploratory clinical outcomes included six-minute walk distance, incremental load test performance (modified Bruce protocol), and COPD Assessment Test score, assessed at baseline and after the 12-session program. Secondary outcomes included heart rate, blood pressure, oxygen saturation, rate-pressure product, and perceived dyspnea.
The study was conducted at the cardiopulmonary rehabilitation center of Hospital Clínico San José, Santiago, Chile, between May and September 2025. Ethics approval was obtained from the institutional review board (No. 276/2025). The trial was registered retrospectively upon manuscript preparation.
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Exclusion Criteria:
Conventional pulmonary rehabilitation program (12 supervised sessions) supplemented with asymmetric high-flow nasal cannula (A-HFNC) during aerobic training. Flow rate, temperature, and FiO₂ were individualized according to oxygen saturation and patient tolerance.
Device: Asymmetric High-Flow Nasal Cannula (A-HFNC)
Conventional pulmonary rehabilitation program (12 supervised sessions) including treadmill aerobic exercise, upper and lower limb resistance training, and patient education, without any supplemental device during training.
Other: Conventional Pulmonary Rehabilitation Program
Experimental: Asymmetric high-flow nasal cannula (A-HFNC) applied during aerobic training sessions of a 12-session supervised pulmonary rehabilitation program. Flow rate was set at 50 L/min, temperature at 31-34°C, and FiO₂ at 21-36%, individualized according to oxygen saturation and patient tolerance. Aerobic exercise was performed on a treadmill with progressive intensity adjustment based on cardiorespiratory response. Control: Conventional 12-session supervised pulmonary rehabilitation program including treadmill aerobic exercise, upper and lower limb resistance training, and patient education. Aerobic workload was determined from baseline incremental load test and progressively adjusted based on cardiorespiratory response. No supplemental device was used during training.
Twelve supervised pulmonary rehabilitation sessions including treadmill-based aerobic exercise, upper and lower limb resistance training, and patient education. Aerobic workload was determined from baseline incremental load test results and progressively adjusted according to each participant's cardiorespiratory response. Heart rate, oxygen saturation, and perceived dyspnea were continuously monitored during all sessions. No supplemental device was used during training.
Incremental Load Test Duration
Total exercise duration in seconds achieved during an incremental load test using the modified Bruce protocol on a treadmill. Reflects maximal cardiorespiratory exercise capacity.
Time frame: Baseline and post-intervention (week 6)
Plan to share: No — Individual participant data will not be shared publicly due to the small sample size, which could compromise participant confidentiality despite anonymization procedures.
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This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Universidad de Santiago de Chile