Heated Humidified Nasal High-Flow Therapy: Therapy is initiated at 15 L/min and 34 °C. After 3 minutes, the temperature is increased to 37 °C if tolerated; otherwise it is returned to or maintained at 34 °C. Flow is increased every 3 minutes to an individualized clinically used level, up to 40 L/min. In participants receiving long-term oxygen therapy, supplemental oxygen is titrated to maintain a saturation comparable to the usual saturation without nasal high-flow therapy. Total exposure duration is 4 hours. The intervention is briefly interrupted for respiratory oscillometry immediately after titration and at 30, 60, 120, 180, and 240 minutes.
Study summary
Chronic obstructive pulmonary disease (COPD) can affect the small airways and alter respiratory mechanics. Nasal high-flow therapy delivers warmed and humidified gas through nasal cannulas and may change airway resistance. Respiratory oscillometry is a noninvasive test that measures respiratory resistance and reactance during quiet breathing.
This prospective, single-center study will enroll 20 adults with severe or very severe stable COPD who have never used nasal high-flow therapy. During a single study visit lasting approximately 6 hours, participants will receive individualized nasal high-flow therapy for 4 hours. Respiratory oscillometry will be measured before exposure, immediately after device titration, and after 30, 60, 120, 180, and 240 minutes.
The primary objective is to describe the time course of the difference between respiratory resistance measured at 5 hertz and at 20 hertz (R5-R20), an indirect index of peripheral airway mechanical abnormalities. Secondary objectives are to describe changes in total and proximal respiratory resistance, respiratory reactance, resonant frequency, and area of reactance. The hypothesis is that nasal high-flow exposure will produce measurable, time-dependent changes in respiratory oscillometry parameters.
Eligibility
Sex
ALL
Min age
18 Years
Max age
85 Years
Healthy volunteers
No
Inclusion Criteria:
* Age \>18 years and \<85 years;
* Chronic obstructive pulmonary disease classified as Global Initiative for Chronic Obstructive Lung Disease (GOLD) spirometric grade III or IV;
* Modified Medical Research Council dyspnea score ≥2;
* Completed a pulmonary rehabilitation program at the study center;
* Clinically stable, defined as no exacerbation and no treatment change during the previous 4 weeks;
* With or without long-term oxygen therapy;
* Never previously used nasal high-flow therapy;
* Affiliated with a French social security system;
* Able to read and understand the participant information and provide written informed consent.
Non-inclusion Criteria:
* Under legal guardianship or curatorship;
* Confirmed or suspected pregnancy;
* Unable to provide informed consent;
* Primary diagnosis of another chronic obstructive respiratory disease, such as asthma or primary bronchiectasis;
* Severe or unstable cardiovascular disease, including uncontrolled cardiac arrhythmia, severe heart failure, recent myocardial infarction, or unstable angina;
* Hemodynamic instability.
Exclusion Criteria:
• None
Primary outcome measure(s)
Change From Baseline in Frequency Dependence of Respiratory Resistance (R5-R20) — Baseline; immediately after individualized nasal high-flow titration; and 30, 60, 120, 180, and 240 minutes after starting nasal high-flow therapy. Frequency dependence of respiratory resistance is calculated as respiratory resistance measured at 5 hertz minus respiratory resistance measured at 20 hertz (R5-R20). It is measured by impulse oscillometry using the Vyntus impulse oscillometry system (IOS) and expressed in kilopascals per liter per second (kPa/L/s). Percent-predicted values will also be reported when appropriate reference equations are available. The outcome is the change from the pre-exposure baseline at each post-baseline assessment during the exposure period. The registered measure is the repeated change from the pre-exposure baseline across the exposure period.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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