Conventional Low Flow Oxygenation Versus High Flow Nasal Cannula in Hypercapnic Respiratory Failure

Study Overview
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Brief Summary
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Current evidence suggests a mechanistic and physiological rationale for the use of high flow nasal cannula (HFNC) in acute respiratory hypoxemic failure (AHRF) based on physiological studies in airway models, healthy volunteers and patients with Chronic Obstructive Respiratory Disease (COPD). This is supported by observational studies in patients with AHRF with reductions in a range of respiratory and other physiological parameters. Observational studies also suggest similar intubation rates and lower failure rates with HFNC when compared to non-invasive ventilation (NIV) with improved patient acceptance and tolerance for HFNC. The role of HFNC is less clear in acute hypercapnic respiratory failure. Although non-invasive ventilation is the recommended treatment, it is associated with discomfort, and a significant proportion (up to 25% in some reports) cannot tolerate non-invasive ventilation. Observational reports and limited data from randomized controlled trials suggests that HFNC is effective in treating patients with hypercapnic respiratory failure. We designed this trial to assess whether early application of HFNC in patients with non-severe hypercapnic respiratory failure can correct barometric abnormalities, and prevent progression to non-invasive ventilation or tracheal intubation and mechanical ventilation.

Official Title
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Conventional Low Flow Oxygenation Versus High Flow Nasal Cannula in Hypercapnic Respiratory Failure

Conditions
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Hypercapnic Respiratory Failure, Acute Copd Exacerbation

Intervention / Treatment
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* Device: High flow nasal cannula
* Device: Conventional low flow oxygenation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients > 18 years of age Acute Hypercapnic respiratory failure with pH < 7.35 and pCO2 > 45 mmHg Exclusion Criteria: Pregnant or Breast-Feeding Patients who cannot read and understand French or English Hypercapnia secondary to a drug toxicity or non-pulmonary aetiology Hypercapnia secondary to exacerbation of asthma Contraindication to NIV Contraindication to HFNC Not for escalation to NIV based on a ceiling of care pH < 7.15 GCS 8 or less Shock defined as systolic < 90 mmHg or a reduction by 20mmHg from usual systolic BP despite volume resuscitation Respiratory or cardio-respiratory arrest Any other indication that requires immediate invasive/non-invasive mechanical ventilation

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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High Flow Nasal Cannula<br> | Device: High flow nasal cannula<br>* HFNC with the maximum tolerated flow (up to 60 L/min). Titration of supplemental oxygen to a SpO2 between 88 - 92%.<br>* Other names: High flow oxygen therapy;|
| Active Comparator: Conventional Oxygenation with low flow cannula<br> | Device: Conventional low flow oxygenation<br>* Conventional oxygenation through nasal prongs or a facemask, with supplemental oxygen titrated to a SpO2 between 88 - 92%.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients progressing to NIV in each cohort |  | 6 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Venous blood gas PCO2 |  | 1 hour, 6 hours, and 24 hours | 
| Venous blood gas pH |  | 1 hour, 6 hours, and 24 hours | 
| Respiratory rate | Number of breaths per minute, as documented in the medical chart | 1 hour, 6 hours, 24 hours, and daily until study completion | 
| Heart rate | Number of heart beats per minute, as documented in the medical chart | 1 hour, 6 hours, 24 hours, and daily until study completion | 
| Mean arterial pressure | Mean arterial pressure, as documented in the medical chart | 1 hour, 6 hours, 24 hours, and daily until study completion | 
| Incidence of intubation |  | Up to 90 days after enrolment, or until hospital discharge | 
| Admission to the intensive care unit |  | Up to 90 days after enrolment, or until hospital discharge | 
| In-hospital mortality |  | Up to 90 days after enrolment, or until hospital discharge | 
| Intensive care unit length of stay |  | Up to 90 days after enrolment, or until discharge from the intensive care unit | 
| Hospital length of stay |  | Up to 90 days after enrolment, or until hospital discharge | 
| Patient comfort | Level of comfort assessed on a visual analogue scale by the patient | 1 hour, 6 hours, 24 hours, and daily until cessation of oxygen therapy, up to a maximum of 7 days | 
| Shortness of breath | Severity of the shortness of breath assessed on a visual analogue scale by the patient | 1 hour, 6 hours, 24 hours, and daily until cessation of oxygen therapy, up to a maximum of 7 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High Flow Nasal Cannula, High Flow Nasal Insufflation, High Flow Oxygen Therapy, High Flow Oxygenation