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NCT Number: NCT03902639

Examining the Effects of Nasal High Flow Oxygen Therapy Compared to Non-invasive Ventilation in Health Volunteers

Respiratory failure is characterized by low levels of oxygen and high levels of carbon dioxide in the blood which causes difficulty breathing. The management of patients with respiratory failure aims at improving oxygenation and changing the effort required to breathe. Mechanical ventilation is a life-saving treatment but may be associated with a high mortality rate, prolonged stay in the intensive care unit (ICU), and infection. Oxygenation techniques to avoid mechanical ventilation include standard oxygen therapy, continuous positive pressure (CPAP), and high-flow nasal cannula oxygen therapy (HFNC). CPAP consists of delivering oxygen through a mask. As compared to standard oxygen therapy, CPAP can promote lung recruitment leading to improved oxygenation and the effect in work of breathing in patients with respiratory failure. Conversely, high-flow nasal cannula oxygen therapy (HFNC) delivers oxygen through nasal prongs. Oxygen is heated and humidified and can be delivered at different flows (from 10 - 60 L/min). As compared to standard oxygen therapy, HFNC can promote some lung recruitment leading to mofiy oxygenation and work of breathing. Therefore, the present study will have 2 phases:

Phase 1:Comparison of the physiological effects of different flows of HFNC to CPAP in healthy volunteers. The investigators hypothesized that the physiological effects of HFNC in the nasopharynx are comparable to that of CPAP at 4 cm H2O.

Phase 2: Comparison of the physiological effects of different nasal interfaces of HFNC (Standard cannula vs. Asymmetrical cannula vs. Single-nostril adapted cannula) in healthy volunteers. The investigators hypothesized that the physiological effects of HFNC in the nasopharynx are comparable to that of CPAP at 4 cm H2O. It was hypothesized that asymmetrical which is the cannula that has a higher cross-sectional area generates higher nasal pharyngeal pressure.

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Key information

Conditions

Healthy Volunteers

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

St. Michael's Hospital

Toronto, Ontario, M5B1T8, Canada

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy volunteers ≥ 18 y-o,
  • No evidence of acute or chronic cardiopulmonary disease

Exclusion criteria

  • Active epistaxis, sinus problem, nasal trauma, or deviated septum that would preclude the nasopharyngeal catheter insertion,
  • Pregnancy, clinical evidence of respiratory illness, history of respiratory disease, body mass of over 50 kg/m2, ribcage malformation,
  • Cardiac pace maker or implantable cardioverter-defibrillator according to EIT manufacturer,
  • Allergy to topical lidocaine,
  • Claustrophobia that would preclude the use of CPAP or HFNC.

Treatment and study plan

Phase 1 and 2

Other

First, participant will be randomized to a protocol during our study. Participant will breathe normally at different flows of HFNC (20, 40 or 60 L/min) with their mouth open and mouth closed at each flow. They will breathe normally with CPAP at a positive pressure of 4 cm H2O. A lubricated catheter is inserted above the glottis through the nostril to measure ventilatory parameters. EIT is applied to measure inflation of the lung using electromagnetic waves that are not perceptible and are harmless. An ultrasound is done to measure the thickening of your diaphragm and of your abdominal muscles during inspiration and expiration and vocal cords position with and without HFNC (single measurement - around 3 min).During the second step, second catheter is inserted through the nostril to measure esophageal pressure. They will breathe for one additional minute during the closed mouth portions of the experiment while watching the esophageal pressure to ensure steady effort.

Phase 3

Other

In the 3rd phase, according to randomization, volunteers will be masked with either RT041, RT043 or ONIV117 first, followed by the second mask then third mask, also randomize mouth position set to open or closed. The fitting of the masks will be determined based on the manufacturer guidelines and healthy volunteer tolerance. The mask will be adjusted to minimize leaks. At each step, EIT measurements will be recorded at regular breathing over a 10-minute period with an 8-minute washout between devices and 5-minute washout period between mouth positions. The transcutaneous CO2 will be continuously monitored from the earlobe throughout the protocol.

Primary outcomes

  1. End expiratory nasopharyngeal pressure (NP)

    Time frame: 5 minutes

    The primary endpoint is to compare the end expiratory nasopharyngeal pressure (NP) under 60 L/min of high flow nasal cannula (HFNC) to continuous positive airway pressure (CPAP 4 cmH2O).This will be assessed using a nasopharyngeal catheter.

  2. End expiratory nasopharyngeal pressure (NP)

    Time frame: 5min

    The primary endpoint is to compare the end expiratory nasopharyngeal pressure (NP) of high flow nasal cannula (HFNC) among the 3 different nasal cannulas (Symmetrical, Asymmetrical, Single-nostril adapted).

Secondary outcomes

  1. Change in physiologic variables of airway pressure at different flows of HFNC (20, 40, and 60 L/min) and CPAP (4 cmH20). In the phase#2; HFNC 2, and 50 L/min.

    Time frame: 5 minutes

    One of the secondary endpoints is to compare variables of airway pressure at different flows of HFNC to CPAP. The investigators will measure the end expiratory NP, mean NP, mean peak inspiratory pressure, mean peak expiratory pressure, delta inspiratory pressure and delta expiratory pressure.

    Each of these variables will be measured for 1 minute using a nasopharyngeal catheter. Furthermore, at each flow of HFNC, the investigators will ask the patient to breathe with their mouth open and mouth closed.

  2. Change in end-expiratory lung impedance

    Time frame: 5 minnutes

    The other secondary endpoint is to compare the change in ventilation distribution and end-expiratory lung impedance at different flows of HFNC and CPAP (Different nasal cannulas in the 2nd phase). These variables will be measured using electrical impedance tomography (EIT) by placing a band around the chest of each participant.

  3. Dead-space washout in the upper airways

    Time frame: 5 minutes

    Assess whether the transcutaneous CO2 is modified by HFNC, while comparing 3 different nasal cannulas (Symmetrical, Asymmetrical, Single-nostril adapted).

Interested in participating?

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This study is active but is not currently recruiting participants.

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Sponsors and collaborators

Lead sponsor

Unity Health Toronto

Other

Registry information

Official study title

Comparative Study of the Physiological Effects of High Flow Nasal Cannula and Non-invasive Ventilation in Healthy Volunteers

Important dates

Study start
2019
Primary completion
2024
Study completion
2026
First posted
Apr 4, 2019
Registry last updated
Sep 24, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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