Effects of High Flow Nasal Cannula on Breathing and the Respiratory System Parameters

Study Overview
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Brief Summary
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The aim of this study is a detailed investigation of the effect of High Flow Nasal Oxygenation (HFNO) on respiratory system characteristics and ventilation parameters in healthy adult subjects and the subsequent use of measured data to answer the following questions: What level of positive end expiratory pressure (PEEP) causes a HFNO with different flow rates? Does HFNO work as pressure support or does it act more like a Continuous Positive Airway Pressure (CPAP) ventilation?

Detailed Description
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High Flow Oxygen through nasal cannula is widely used in the setting of hypoxemic respiratory failure of heterogenous etiology with very good patients compliance. However, the evidence of what level of PEEP or pressure support (if any) with different flow rates is weak. Our goal is to determine these effects and compare them with standard approach with non-invasive ventilation via full face mask.

Official Title
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Effects of High Flow Nasal Cannula on Breathing and the Respiratory System Parameters

Conditions
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Healthy

Intervention / Treatment
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* Device: High Flow Nasal generator (AirVO2)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy volunteers willing to participate Exclusion Criteria: general contraindications for oesophageal catheter insertion: oesophageal varices, bleeding disorders (including anticoagulant medication), diverticulitis, oesophageal tumors, history of recent oesophageal/gastric surgery, recent epistaxis, sinusitis allergy to local anesthetics subject refusal

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: Other
Intervention Model: Single Group Assignment
Interventional Model Description: Approximately 12 volunteers
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental group<br>10-12 young healthy volunteers. Placed on semi-sitting position on the bed (40 deg.elevation). Calibration of electrical impedance tomography (EIT) on defined tidal volume 500ml, done with 500ml syringe connected to closed breathing circuit using full face mask as an interface. Insertion an esophageal and nasopharyngeal catheter for pressures measurement. In the first phase - spontaneous breathing with full face mask at 0, 5 and 10 cm H20 levels of PEEP. In the second phase - high flow oxygenation through nasal cannula, start with flow rate 10 L/min with gradual increase up to 60 L/min. Spirometry to determine functional residual capacity (FRC) before and after procedure is planed. | Device: High Flow Nasal generator (AirVO2)<br>* High Flow Nasal Oxygenation<br>* Other names: Full face mask connected to ventilator (Avea);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measurement of inspiratory pressure, pressure in a hypopharynx and pleural pressure estimation using oesophageal catheter on conventional non-invasive ventilation (NIV). | Using measurement of several pressures - inspiratory, oesophageal, nasopharyngeal (cm of H20 on conventional NIV. | 1 hour | 
| Measurement of inspiratory pressure, pressure in a hypopharynx and pleural pressure estimation using oesophageal catheter on High flow nasal oxygenation (HFNO). | Using measurement of several pressures - inspiratory, oesophageal, nasopharyngeal (cm of H20) on High flow nasal oxygenation (HFNO). | 1 hour | 
| Calculation of Pressure Time Product (PTP) for estimation of Work of Breathing (WOB). | Compare PTP between conventional NIV and HFNO. | up to 8 weeks | 
| Monitoring of EIT during spontaneous ventilation on conventional non-invasive ventilation (NIV). | EIT for description of distribution of ventilation on conventional NIV at different levels of PEEP (cm H20). | 1 hour | 
| Monitoring of EIT during spontaneous ventilation with High flow nasal oxygenation (HFNO). | EIT for description of distribution of ventilation with HFNO with different flow rate levels (litres per minute). | 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High Flow Oxygenation, Electrical Impedance Tomography, Non invasive ventilation