High Flow Nasal Cannula in Patients Undergoing Colonoscopy

Study Overview
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Brief Summary
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During colonoscopy, the insertion of the fiberscope and colon distension required to perform the examination may induce modifications to respiratory mechanics, respiratory effort and breathing pattern. High-flow nasal cannula (HFNC) therapy is a mixed air-oxygen supply system able to deliver heated humidified gas up to 60 L/min of flow rate, with an inspiratory oxygen fraction (FiO2) ranging from 21% to 100%. Increasing evidence supports the use of HFNC in several clinical conditions and settings. When compared to standard therapy (ST), HFNC results in enhanced gas exchange and improved comfort. No studies have yet assessed the benefits of HFNC versus ST during and after colonoscopy. The investigators designed this unblinded randomized controlled trial to assess whether HFNC, compared to ST, improves oxygenation at the end of the procedure (primary endpoint). Additional endpoints were: 1) the lowest peripheral saturation of oxygen (SpO2) and the number of oxygen desaturations; 2) the changes of end-expiratory lung impedance and tidal impedance assessed by Electrical Impedance Tomography (EIT); 3) the effects on diaphragm function assessed by ultrasound (DUS).

Official Title
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High-flow Nasal Cannula Oxygen Therapy for Outpatients Undergoing Colonoscopy: a Randomized Controlled Trial

Conditions
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Colonoscopy

Intervention / Treatment
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* Device: High Flow Nasal Cannula
* Device: Conventional Oxygen Therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: outpatients with the indication to diagnostic colonoscopy Exclusion Criteria: life-threatening cardiac aritmia or acute miocardical infarction within 6 weeks need for invasive or non invasive ventilation presence of pneumothorax or pulmonary enphisema or bullae recent (within 1 week) thoracic surgery presence of chest burns presence of tracheostomy pregnancy nasal or nasopharyngeal diseases dementia lack of consent or its withdrawal

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High Flow Nasal Cannula<br>High Flow Nasal cannula is a system to deliver heated and humidified oxygen with an inspired oxygen fraction between 21 and 100% through large bore nasal cannula. The system delivers a flow up to 60 liters/min. | Device: High Flow Nasal Cannula<br>* High Flow Nasal Cannula will be set at 60 liters per minute of air/oxygen admixture to reach a peripheral oxygen saturation equal or greater than 94%<br>|
| Active Comparator: Standard Treatment<br>If peripheral oxygen saturation will be < 95%, conventional oxygen therapy will be administered through common nasal cannula with a flow up to 6 Liters per minute | Device: Conventional Oxygen Therapy<br>* Conventional Oxygen Therapy will be administered through nasal cannula with a oxygen flow set to achieve a peripheral oxygen saturation equal or greater than 94%<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Arterial blood gases at end of the procedure | Arterial blood will be sample for gas analysis | At the end of the endoscopy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Respiratory effort at end of the procedure | The respiratory effort will be assessed through the ultrasonographic assessment of the diaphragm thickening fraction | At the end of the endoscopy | 
| Respiratory effort at baseline | The respiratory effort will be assessed through the ultrasonographic assessment of the diaphragm thickening fraction | At enrollment | 
| Respiratory effort at the beginning of the colonoscopy | The respiratory effort will be assessed through the ultrasonographic assessment of the diaphragm thickening fraction | At 5 minutes after the beginning of the procedure | 
| Respiratory effort after the colonoscopy | The respiratory effort will be assessed through the ultrasonographic assessment of the diaphragm thickening fraction | After 10 minute from the end of the endoscopy | 
| Change of end-expiratory lung impedance (dEELI) from baseline at the beginning of the colonoscopy | change from baseline, expressed in mL, of the end expiratory lung volume as assessed through electrical impedance tomography | At 5 minutes after the beginning of the procedure | 
| Change of end-expiratory lung impedance (dEELI) from baseline at end of the procedure | change from baseline, expressed in mL, of the end expiratory lung volume as assessed through electrical impedance tomography | At the end of the endoscopy, compared to baseline | 
| Change of end-expiratory lung impedance (dEELI) from baseline after colonoscopy | change from baseline, expressed in mL, of the end expiratory lung volume as assessed through electrical impedance tomography | After 10 minute from the end of the endoscopy, compared to baseline | 
| Arterial blood gases at baseline | Arterial blood will be sample for gas analysis | At enrollment | 

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