The Effects of Flow Settings During High Flow Nasal Cannula for Adult Hypoxemia Patients

Study Overview
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Brief Summary
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High flow nasal cannula (HFNC) delivers oxygen at a flow which exceeds the patient's inspiratory flow demand in order to improve oxygenation. Numerous randomized control trials and meta-analyses have shown that HFNC improves oxygenation and helps avoid intubation in hypoxemic patients, as well as reduce work of breathing, improve ventilation, and decrease hypercapnia in COPD patients. Flow settings play a critical role when using HFNC, as increased flow can reduce inspiratory effort, improve ventilation, and dynamic lung compliance. However, flow rates used in many studies vary widely. The clinical effects of different HFNC flow setting, specifically to match or over than a patients' own inspiratory flow, is still unknown.

Detailed Description
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High flow nasal cannula (HFNC) delivers oxygen at a flow which exceeds the patient's inspiratory flow demand in order to improve oxygenation. Numerous randomized control trials and meta-analyses have shown that HFNC improves oxygenation and helps avoid intubation in hypoxemic patients, as well as reduce work of breathing, improve ventilation, and decrease hypercapnia in COPD patients. Flow settings play a critical role when using HFNC, as increased flow can reduce inspiratory effort, improve ventilation, and dynamic lung compliance. However, flow rates used in many studies vary widely, from 20-40 LPM in COPD patients and 30-60 LPM in hypoxemic patients. The clinical effects of different HFNC flow setting, specifically to match or over than a patients' own inspiratory flow, is still unknown.

Official Title
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The Effects of Flow Settings During High Flow Nasal Cannula for Adult Hypoxemia Patients

Conditions
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Hypoxemia

Intervention / Treatment
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* Other: HFNC flow


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients (Age > 18yrs and < 90yrs) who need nasal cannula oxygen flow ≥ 5 L/min to maintain SpO2 at 90-97%. Exclusion Criteria (Common): - Unable to use resuscitation mask, such as facial trauma, claustrophobia Inability to verbally communicate; Pregnant Inability to breathe via nose, such as nasosinusitis, stuffy nose or nasal obstruction, etc. Ordered SpO2 goal is above 97% FIO2 needs ≤ 0.4 Using inhaled pulmonary vasodilator via HFNC

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 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: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Oxygenation on hypoxemia patients<br>Adult patients with hypoxemia will be recruited, their own breathing profiles (inspiratory flow, respiratory rates and tidal volume) will be measured. Then patients will be placed on high flow nasal cannula (HFNC), HFNC flow will be titrated based on the hospital's policy or protocol and patient's comfort, patient's clinical effects on oxygenation will be monitored and recorded during the titration process. | Other: HFNC flow<br>* HFNC flow will be titrated based on the hospital's policy or protocol for hypoxemic patients and research protocol for healthy volunteers<br>|
| Experimental: Lung expansion on healthy volunteer<br>Adult healthy volunteers will be recruited, their own breathing profiles (inspiratory flow, respiratory rates and tidal volume) will be measured. Then they will be placed on HFNC, HFNC flow will be increased sequentially by research protocol and their comfort, subjects' lung expansion effects in different flow will be quantified by Electrical impedance tomography (EIT), a noninvasive assessment tool. Their comfort will also be assessed using a visual scale. | Other: HFNC flow<br>* HFNC flow will be titrated based on the hospital's policy or protocol for hypoxemic patients and research protocol for healthy volunteers<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| SpO2/FIO2 increment for hypoxemic patients | SpO2/FIO2 at the optimal/maximum /tolerable/ HFNC flow setting compared to the SpO2/FIO2 at HFNC flow matching patient's inspiratory flow or 30 L/min for hypoxemic patients | 30 minutes | 
| RR change for hypoxemic patients | Respiratory rates at the optimal/maximum /tolerable/ HFNC flow setting compared to the SpO2/FIO2 at HFNC flow matching patient's inspiratory flow or 30 L/min for hypoxemic patients | 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| comfort scores | comfort will be self-evaluation using a visual analog scale with measured score of 0 is the worst and 10 is the best | 30 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High flow nasal cannula, Hypoxemia, Flow setting