The Effect of Asymmetrical vs. Symmetrical High Flow Nasal Cannula on the Work of Breathing

NCT ID: NCT07066566

Last Updated: 2025-07-18

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

30 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-04-09

Study Completion Date

2025-09-01

Brief Summary

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The goal of this study randomized single-center crossover study is to evaluate the impact of asymmetrical versus symmetrical nasal high flow (NHF) therapy on work of breathing (WOB). The main question it aims to answer are:

1\. Does the asymmetrical NHF interface improve the work of breathing compared to the symmetrical NHF interface? Researchers will compare the symmetrical NHF interface to the symmetrical NHF interface to see if the the asymmetrical interface has a greater impact on the work of breathing.

Participants will :

1. receive NHF via both interfaces (FiO₂ 0.21, 50 L/min) for 15 minutes, in random order, with esophageal pressure monitoring and bioelectrical impedance analysis performed.
2. baseline characteristics will me monitored throughout the interventions
3. Esophageal pressure and minute ventilation will be monitored.

Detailed Description

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Each participant will undergo all phases of the study while seated comfortably, breathing room air. Vital signs, including blood pressure, heart rate, and peripheral oxygen saturation (%SpO₂), will be continuously monitored and recorded throughout.

Respiratory mechanics will be assessed using esophageal pressure (Pes) monitoring. A thin latex balloon catheter (10 cm long, 3-5 cm circumference; Cooper surgical, USA), filled with 0.5 mL of air, will be placed in the mid-esophagus (\~45 cm from the nares) and will be connected to a pressure transducer (RSS-100HR, Hans Rudolph Inc., USA). Correct positioning will be confirmed by observing equal fluctuations in Pes and airway pressure (Paw) during occluded breaths. Balloon integrity will be verified before, after, and as needed during the procedure.

Participants will be instructed to breathe quietly on room air (FiO₂ 0.21) to allow for baseline assessment. Volume will be recorded using a heated pneumotachometer (Series 3813; Hans Rudolph Inc., USA) and the Research Pneumotach System (RSS100-HR), sampling at 50 Hz, a sampling rate exceeding the Nyquist criterion for respiratory signals. A bioelectrical impedance technology device (ExSpiron, Respiratory Motion Inc., Waltham, MA) will then be attached around the chest to assess lung volume changes.

Participants will then be randomized in a 1:1 ratio to one of two intervention sequences using a computer-generated randomization schedule.

* Sequence 1: Symmetrical NHF Interface - 3-minute washout period - Asymmetrical NHF Interface
* Sequence 2: Asymmetrical NHF Interface - 3-minute washout period - Symmetrical NHF Interface In the seated position, participants will both 15-minute phases, separated by a 3-minute washout period to prevent residual effects. During the "Symmetrical Interface" phase, participants will breathe using the conventional symmetrical NHF cannula, and during the asymmetrical phase, the asymmetrical interface (DUET, Fisher and Paykel Healthcare, Auckland, New Zealand) will be used. High-flow oxygen will be delivered using a commercial system (AIRVO 3; Fisher and Paykel Healthcare, Auckland, New Zealand) set at a flow of 50 L/min, temperature of 37°C, and FiO₂ of 0.21.

Conditions

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Respiratory Disease (Clinically Stable Individuals - Patients Recovered From Respiratory Disease)

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Outcome Assessors

Study Groups

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Recovery patients from respiratory disease - Asymmetric or conventional nasal high flow cannula

Patients recovered from acute respiratory disease will be randomized to NHF oxygen therapy with asymmetrical cannula or conventional cannula

Group Type EXPERIMENTAL

Asymmetric nasal cannula - DUET

Intervention Type DEVICE

DUET asymmetric nasal high flow interface that fits best to patients' nostrils (size: one nostril of the patient should be fully occluded) Patients will be crossed - over between the 2 interventions

Conventional nasal high flow cannula

Intervention Type DEVICE

Well - established conventional nasal high flow cannula (size: medium) Patients will be cross - over between the 2 interventions

Recovery patients from respiratory disease - Conventional or asymmetric nasal high flow cannula

Patients recovered from acute respiratory disease will be randomized to NHF oxygen therapy with conventional cannula or asymmetrical cannula

Group Type ACTIVE_COMPARATOR

Asymmetric nasal cannula - DUET

Intervention Type DEVICE

DUET asymmetric nasal high flow interface that fits best to patients' nostrils (size: one nostril of the patient should be fully occluded) Patients will be crossed - over between the 2 interventions

Conventional nasal high flow cannula

Intervention Type DEVICE

Well - established conventional nasal high flow cannula (size: medium) Patients will be cross - over between the 2 interventions

Interventions

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Asymmetric nasal cannula - DUET

DUET asymmetric nasal high flow interface that fits best to patients' nostrils (size: one nostril of the patient should be fully occluded) Patients will be crossed - over between the 2 interventions

Intervention Type DEVICE

Conventional nasal high flow cannula

Well - established conventional nasal high flow cannula (size: medium) Patients will be cross - over between the 2 interventions

Intervention Type DEVICE

Eligibility Criteria

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Inclusion Criteria

1. age ≥18 years old
2. absence of symptoms and signs of respiratory failure (SpO2\>95% at FiΟ2 0.21)

Exclusion Criteria

1. pregnancy
2. SpO2\<94% at FiΟ2 0.21
3. neuromuscular disease
4. contraindications to esophageal pressure monitoring (e.g., uncontrolled coagulopathy, esophageal disease, nasal trauma, allergy to local lidocaine)
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Larissa University Hospital

OTHER

Sponsor Role lead

Responsible Party

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Ioannis Pantazopoulos

Associate Professor of Respiratory & Emergency Medicine Faculty of Medicine, University of Thessaly, Greece

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Demosthenes Makris

Role: STUDY_CHAIR

Professor of Intensive Care Unit, University Hospital of Larissa

Locations

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University Hospital of Larissa, Department of Pulmonary Medicine

Larissa, , Greece

Site Status RECRUITING

Countries

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Greece

Central Contacts

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Ioannis Dr. Pantazopoulos, Associate Professor

Role: CONTACT

+30- 6945661525

Facility Contacts

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Ioannis Dr Pantazopoulos, Associate Professor

Role: primary

+30 - 69445661525

Provided Documents

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Document Type: Study Protocol and Statistical Analysis Plan

View Document

Document Type: Informed Consent Form

View Document

Other Identifiers

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16171

Identifier Type: -

Identifier Source: org_study_id

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