Physiological Effects of High-flow Nasal Cannula During Exercise

Study Overview
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Brief Summary
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The high-flow nasal cannula (HFNC) has increased its evidence in patients during pulmonary rehabilitation. These studies hypothesize that the physiological effects of HFNC (positive expiratory pressure, anatomical dead space lavage, thermo-humidification) lead to an increase in exercise time. This is believed to be due to improvements that the device can generate in the respiratory system and muscles. However, the physiological effects of HFNC on respiratory effort and distribution of pulmonary ventilation during exercise are unknown. The aim of this study is to determine the acute effect of high flow nasal cannula on the distribution of pulmonary ventilation and respiratory effort during physical exercise in healthy subjects.

Detailed Description
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A randomized, cross-over clinical trial in which either HFNC or Sham may be used as an adjunct on a cycle ergometer in random order will be performed to compare the respiratory effort and distribution of pulmonary ventilation continuously. Measurements will be taken in a warm-up, exercise, and recovery phase for both groups.

Official Title
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Effects of High-flow Nasal Cannula on the Distribution of Pulmonary Ventilation and Respiratory Effort in Healthy Subjects During Exercise.

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Device: High-flow Nasal Cannula


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adults volunteers Physically inactive (according to World Health Organization criteria). Exclusion Criteria: Refusal to participate Smokers History of acute cardiorespiratory or musculoskeletal disease during the last year (including COVID-19 when hospitalization or supplemental oxygen was required without any other disease) Any neuromuscular or cardiovascular or condition that limits test performance. Contraindication for esophageal catheter installation (recent epistaxis, severe coagulopathy, among other).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants receive one of two alternative interventions during the initial phase of the study and receive the other intervention during the second phase of the study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HFNC Group<br>Healthy subject will perform one Constant Work-Rate Exercise Test at respiratory compensation point as determined by a cardiopulmonary exercise test with High Flow Nasal at 60L/min (without additional oxygen) | Device: High-flow Nasal Cannula<br>* HFNC is a device that, in this study, will give the maximum flow (60 L/min), with minimum adjusted temperature (31°C) and FiO2 of 21% or room air.<br>* Other names: HFNC;|
| Sham Comparator: Control Group<br>Healthy subject will perform one Constant Work-Rate Exercise Test at respiratory compensation point as determined by a cardiopulmonary exercise test with High Flow Nasal at 2L/min (without additional oxygen) | Device: High-flow Nasal Cannula<br>* HFNC is a device that, in this study, will give the maximum flow (60 L/min), with minimum adjusted temperature (31°C) and FiO2 of 21% or room air.<br>* Other names: HFNC;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inspiratory effort | The average esophageal pressure swings during inspiration (ΔPes) defined as the absolute differences between end-expiratory and end-inspiratory Pes over a period of 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Standard deviation of regional ventilation delay index (RVDsd) | as a measure of temporal distribution of ventilation: defined as the average of 10 breaths representative of the 60 seconds evaluated in each period. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Work of breathing | The average pressure time product over a minute (PTPmin), defined as the sum of the areas subtended by the Pes waveform during inspiration over 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Work of breathing per single breath | The average per-breath pressure time product (PTP), defined as the area subtended by the Pes waveform during inspiration in a series of representative and valid breaths divided by the number of breaths (at least five to ten) over 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Respiratory drive | The average of negative pressure measured 500 ms after the initiation of an inspiratory effort defined as the defection in Pes during the first 0.5 s during inspiration in a series of representative and valid breaths divided by the number of breaths (at least five to ten) over 60 seconds. Also, The average slope of the inspiratory negative Pes swings from the start of inspiration to the minimum pressure (ΔPes/Δt) in a series of representative and valid breaths divided by the number of breaths (at least five to ten) over 60 seconds. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Tidal Variation (TV) as a measure of variation during tidal breathing | defined as the average of differences between end-expiratory lung impedance (EELI) and end-inspiratory lung impedance (EILV) in 60 seconds for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| End-Expiratory Lung Impedance (EELI), as a measure lung aeration | average of end-expiratory lung impedance respectively, in 60 seconds for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Normalized Tidal Variation (TV) as a measure of variation during tidal breathing | defined as the average of differences between end-expiratory lung impedance (EELI) and end-inspiratory lung impedance (EILV) divided by the number of breaths evaluated in each period (60 seconds).Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Normalized End-Expiratory Lung Impedance (EELI) | as a measure lung aeration: defined as the average of end-expiratory lung impedance divided by the number of breaths evaluated in each period (60 seconds). Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Global inhomogeneity index (GI) as a measure of spatial distribution of tidal ventilation | defined as the value of the tidal image in 60 seconds for each period evaluated. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Center of ventilation (COV), dorsal fraction of ventilation (TVd) and anterior-to-posterior ventilation ratio (Impedance ratio), most dorsal region of interest (ROI4) (TVroi4), as a measure of ventilation distribution influenced by gravity. | defined as the value of the tidal image in 60 seconds for each period evaluated. Measurements will be during warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Dyspnea and leg fatigue | : using Modified Borg Scale (0 - 10 points) for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Heart rate | using a pulse oximetry for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Pulse oxygen saturation | using a pulse oximetry for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Respiratory rate | using a electrical impedance tomography for each period evaluated warm-up (one minute of five minutes), exercise (minutes: 0-1'; 3-4'; 5-6'), and the recovery phase (minutes: 0-1'; 1-2'; 3-4'; 5-6';7-8';9-10') for both groups. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during warm-up, exercise, and recovery | 
| Blood pressure | Using a sphygmomanometer and stethoscope will be evaluated at the beginning (basal), end of the exercise, and during the recovery phase by the same operator. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately seven days, for a total time frame of 3 weeks maximum per participant. Data will be collected during the basal and recovery phase | 
| Comfort scale associated with dispositive | using visual analog likert scale (0-5: 0: nothing comfortable to 5: totally comfortable) evaluated before and at the end of the exercise. | at 3 weeks. Outcome will be measured during the CWRET and will be carried out on different days, separate from approximately 7 days, for a total time frame of 3 weeks maximum per participant. Data will be collected during the basal and end-exercise | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High-Flow Nasal Cannula, Electrical Impedance Tomography, Respiratory Physiology, Exercise