Respiratory Rate Measured by Pressure Variation During HFNC

Study Overview
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Brief Summary
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Monitoring the respiratory rate is important during procedural sedation. Several methods of measuring the respiratory rate are available, but most are unreliable and the most reliable method (capnography) is not available during the use of High Flow Nasal Cannula (HFNC) oxygen. We hypothesize that measuring the pressure variation in the HFNC-circuit is a reliable method of measuring the respiratory rate. An experimental study, using healthy volunteers that will breath in three guided respiratory rates, compares the measurements of respiratory rate by the pressure variation in the HFNC circuit with measurements of respiratory rate by an ECG-derived method and a manual count by an physician. A secondary outcome will be the ability to measure the size of pressure difference, in order to determine its feasiblity to use it as a surrogate for tidal volume or respiratory effort.

Detailed Description
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The healthy volunteers will be administered HFNC-oxygen and will be instructed to breath normally, rapidly and slowly for 30 seconds. This will be done at two HFNC flow rates (35 L/min and 70 L/min) and with an open and a closed mouth. During these 30 seconds the respiratory rate will be measured by pressure variation in the HFNC circuit, ECG-derived impedance difference and a manual count by a physician. This will lead to 12 conditions, depending on HFNC flow (35 and 70 L/min), open or closed mouth and respiratory rate (normally, rapidly, slowly). The measurements of the respiratory rates wil be compared per HFNC flow and per open or closed mouth. A secondary outcome will be the ability to measure the size of pressure difference, in order to determine its feasiblity to use it as a surrogate for tidal volume or respiratory effort.

Official Title
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Is it Possible to Measure an Adequate Respiration Rate Using Pressure Variation During HFNC

Conditions
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Respiratory Rate

Intervention / Treatment
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* Behavioral: Instructions of breathing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy volunteers Exclusion Criteria: known neurodegenerative diseases Pregnancy Children (age <18) Upper airway obstruction

Ages Eligible for Study
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Minimum Age: 18 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: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study cohort<br>The cohort of healthy volunteers, who will breath at three different respiratory rates, as guided by normal, slowly and rapid. | Behavioral: Instructions of breathing<br>* Breathing normally, slowly and rapidly for 30 seconds with an open and a closed mouth.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Respiratory rate by pressure variation | Respiratory rate as measured by the pressure variation in the HFNC circuit. | 30 seconds | 
| Respiratory rate by manual count | Respiratory rate as measured by a physician | 30 seconds | 
| Respiratory rate by ECG-derived measurement | Respiratory rate as measured by the ECG-derived impedance difference | 30 seconds. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure difference during breathing | The pressure difference measured in the HFNC-circuit between inspiration and expiration in cmH2O as the mean value over the 30 seconds. | 30 seconds. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High Flow Nasal Cannula, Thrive