Asymmetric High-Flow Nasal Cannula During Pulmonary Rehabilitation in COPD (A-HFNC-PR)

March 26, 2026 updated by: Manuel Gálvez Reyes, Universidad de Santiago de Chile

Feasibility and Preliminary Effects of Asymmetric High-flow Nasal Cannula During Exercise-based Pulmonary Rehabilitation in Patients With COPD: a Randomized Pilot Trial

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Actual)

30

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Chile
      • Santiago, Chile
        • Hospital Clínico San José

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 40 years or older
  • Spirometry-confirmed COPD diagnosis (post-bronchodilator FEV1/FVC ratio less than 0.70)
  • Modified Medical Research Council (mMRC) dyspnea grade 2 or higher
  • Spirometry performed within the preceding 12 months

Exclusion Criteria:

  • Acute respiratory exacerbation within the preceding three months
  • Uncontrolled respiratory symptoms or any acute condition compromising clinical stability
  • Current use of home non-invasive mechanical ventilation or artificial airway
  • Hospitalization within the preceding three months
  • Neuromuscular or osteoarticular conditions limiting physical activity
  • Cognitive or communication difficulties precluding adherence to instructions
  • Recent acute cardiovascular events
  • Decompensated comorbidities

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Experimental Group
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)

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.
Active Comparator: Control Group
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
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incremental Load Test Duration
Time Frame: Baseline and post-intervention (week 6)
Total exercise duration in seconds achieved during an incremental load test using the modified Bruce protocol on a treadmill. Reflects maximal cardiorespiratory exercise capacity.
Baseline and post-intervention (week 6)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Universidad de Santiago de Chile

Investigators

  • Principal Investigator: Manuel A GAlvez, MSc, Universidad de Santiago de Chile

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 2, 2025

Primary Completion (Actual)

September 20, 2025

Study Completion (Actual)

September 20, 2025

Study Registration Dates

First Submitted

March 22, 2026

First Submitted That Met QC Criteria

March 22, 2026

First Posted (Actual)

March 27, 2026

Study Record Updates

Last Update Posted (Actual)

April 1, 2026

Last Update Submitted That Met QC Criteria

March 26, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 276/2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared publicly due to the small sample size, which could compromise participant confidentiality despite anonymization procedures.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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