High Flow Oxygen Therapy Effect on Healthy Subjects

Study Overview
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Brief Summary
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The use of high-flow nasal cannula (HFNC) has increased. Diaphragmatic ultrasonography is a tool that, as a noninvasive complement to esophageal pressure (Pes) measurement, allows the evaluation of diaphragm function and reflects, through the diaphragm thickening fraction (DTf), the magnitude of diaphragmatic fiber recruitment. The objective of this study was to evaluate the impact of HFNC therapy on the DTf in healthy subjects. Second, this study aimed to assess the behavior of the respiratory rate (RR) and the work of breathing in these subjects.

Official Title
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Impact of High Flow Oxygen Therapy on Diaphragm Thickening Fraction in Healthy Subjects. A Prospective Cohort Study

Conditions
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Healthy Volunteers, Diaphragm, Respiratory Rate

Intervention / Treatment
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* Device: High flow nasal canula


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy subjects over 18 years old Exclusion Criteria: contraindication for esophageal balloon placement diagnosis of lung disease smokers

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Intervention/Treatment |
| --- |
|Device: High flow nasal canula|Measurement of diaphragm thickening fraction, respiratory rate and esophageal pressure swing with calculation of diaphragmatic pressure-time product without the use of HFNC and with the use of HFNC at 20 and 40 Liters per minute|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diaphragm thickening fraction. | ultrasound measurements were performed by an expert operator (the same in all cases). The ultrasound measurement was performed using a high-resolution linear transducer in real-time in B-mode. The diaphragm thickness was measured at the end of expiration and the end of inspiration of the same ventilatory cycle and the average value of 3 ventilatory cycles was recorded. A 2-minute washout period was allowed between each test condition to avoid the summation of effects. The DTf and PTPes/min were calculated for each subject in each available condition (baseline - without flow- , wtih 20 and 40 liters per minute): DTf = End Inspiratory Diaphragm thickening - End Expiratory Diaphragm thickening / End Expiratory Diaphragm thickening x 100 | Immediately after 5 min of each condition (baseline, 20 and 40 liters per minute) the diaphragmatic thickness was measured at the end of inspiration y de la expiration during 3 consecutive respiratory cycles (each cycle is between 3 and 10 seconds) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Respiratory Rate | The number of breaths per minute was recorded in 60 seconds. | The number of breaths per minute was recorded in 60 seconds. | 
| Esophageal pressure swing (Pes). | Difference between basal Pes and maximum inspiratory Pes deflection. | 5 minutes each condition | 
| Esophageal pressure-time product per minute (PTPes/min). | It was calculated as the area determined by esophageal deflection multiplied by respiratory rate. An ad hoc software developed in MATLAB R2018b (The MathWorks, Inc. Massachusetts, United States) was used for this purpose. | Through study completion, an average of 24 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High flow nasal canula, High flow nasal canula therapy, Diaphragm thickening fraction, Work of breathing, Respiratory rate