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Comparative Study of the Physiological Effects of High Flow Nasal Cannula and Non-invasive Ventilation in Healthy Volunteers
Sponsor study identifier
observational
20
1 country
1
Study Start
April 10, 2019
Actual (reported)Primary Completion
March 30, 2024
Actual (reported)Study Completion
October 1, 2026
Estimated (date passed)This estimate has passed. The registry has not confirmed an actual date for this milestone.
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.
Registry-reported information. Elapsed time and enrollment totals alone do not measure study progress or recruitment pace.
October 1, 2026
Estimated (date passed)This estimate has passed. The registry has not confirmed an actual date for this milestone.
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Dates and qualifiers reported by the registry. Estimated dates do not confirm that a milestone has occurred.
April 2, 2019
Actual (reported)April 4, 2019
Actual (reported)April 10, 2019
Actual (reported)March 30, 2024
Actual (reported)October 1, 2026
Estimated (date passed)This estimate has passed. The registry has not confirmed an actual date for this milestone.
End expiratory nasopharyngeal pressure (NP)
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.
5 minutes
End expiratory nasopharyngeal pressure (NP)
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).
5min
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.
5 minutes
Change in end-expiratory lung impedance
5 minnutes
Dead-space washout in the upper airways
5 minutes
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.
Healthy volunteers responding to advertisement posted through the St. Michael's Hospital Communications board.
St. Michael's Hospital
Toronto, Ontario, M5B1T8, Canada
Wongtirawit N, Butterworth R, Vieira F, Schreiber A, Ko M, Brochard L. Influence of leaks and mask design on CO2 clearance during non-invasive ventilation: a combined bench and physiological study. BMJ Open Respir Res. 2026 Aug 19;13(1):e004135. doi: 10.1136/bmjresp-2026-004135.
Laurent Brochard, MD
Unity Health Toronto
First Submitted
April 2, 2019
First Posted
April 4, 2019
Study Start
April 10, 2019
Actual (reported)Primary Completion
March 30, 2024
Actual (reported)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.
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Study Completion
October 1, 2026
Estimated (date passed)This estimate has passed. The registry has not confirmed an actual date for this milestone.
Last Updated
September 24, 2026
Record last verified: 2026-07
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Source: ClinicalTrials.gov.
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