A Pilot Study Comparing Oxygen Delivery Via Helmet Interface Versus High Flow Nasal Cannula

Study Overview
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Brief Summary
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Our main objective is to collect feasibility data on helmet NIPPV and other clinical elements in to eventually prepare for a full scale randomized trial based on findings of this pilot study.

Detailed Description
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Patients with acute hypoxemia leading to respiratory failure are frequently supported by endotracheal intubation and mechanical ventilation. Unfortunately an invasive approach to support is associated with risks of lung injury, infection, need for heavy sedation, and increased mortality. Non-invasive oxygen delivery, by mask (BiPAP or CPAP), high flow nasal cannula or helmet interface, is better tolerated and reduces risks associated with invasive mechanical ventilation. A growing body of medical literature and clinical experience suggests that non-invasive oxygen delivery can prevent the need for endotracheal intubation in some patients. This proposal will compare two different modes of non-invasive oxygen delivery: helmet and high flow nasal cannula.

Official Title
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A Pilot Randomized Controlled Study of Non-invasive Oxygenation and Ventilation in Patients With Acute Hypoxemic Respiratory Failure (AHRF): A Comparison of Oxygen Delivery Via Helmet Interface Versus High Flow Nasal Cannula (HFNC)

Conditions
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Hypoxemic Respiratory Failure

Intervention / Treatment
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* Device: Helmet
* Device: High Flow Nasal Oxygen


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years AHRF defined as: A ratio of partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2) between 100 - 250 mm Hg while breathing O2 from Venturi mask, or other delivery system that allows quantification of FiO2 such as Mask-NIPPV or HFNC. When no arterial blood gas (ABG) result available, use transcutaneous oxygen saturation measurement (SpO2) to impute PaO2 (Appendix A.2 for Table of PaO2 / FiO2 imputed from SpO2 [Brown 2017]. If no oxygenation data prior to use of Mask-NIPPV or HFNC are available, then P/F ratio 100 - 250 on Mask-NIPPV or HFNC meets this criterion. Respiratory rate (RR) ≥24 /min and/or subjective shortness of breath (Modified Borg Dyspnea Scale ≥ 2) Exclusion Criteria: P/F Ratio < 100 (Severe ARDS) on quantifiable FiO2 More than 24 hours has elapsed since the patient met criteria for AHRF (Inclusion #2 and 3, above) Urgent need for intubation Criteria for intubation: i. RR>40 ii. Lack of improvement of respiratory muscle fatigue iii. Copious tracheal secretions that require frequent suctioning iv. Acidosis with a potential Hydrogen (pH) <7.35 v. Acute hypercarbia (PaCO2 > 45 mm Hg) vi. SpO2 < 88% for more than 5 minutes despite FiO2 and non-invasive support vii. Respiratory or cardiac arrest viii. Glasgow Coma Scale ≤ 8 Contraindication to HFNC, Helmet-NIPPV, or Mask-NIPPV Upper airway obstruction, facial trauma Copious secretions, airway bleeding, epistaxis or vomiting Primary cause of respiratory failure is exacerbation of chronic obstructive pulmonary disease (COPD) or asthma Elevated intracranial pressure >20 mm Hg Home mechanical ventilation except for CPAP/BiPAP used solely for sleep disordered breathing Persistent hemodynamic instability (systolic blood pressure (SBP)<90 or mean arterial pressure (MAP)<60 despite IV fluid resuscitation, or norepinephrine dose > 0.1 mcg/kg/min or equivalent vasopressor dose) Plan for procedure during which NIPPV or HFNC is contraindicated. Okay to enroll if procedure is complete and AHRF persists within 24 hours. Absence of airway protective gag reflex or cough Tracheostomy Lack of informed consent Pregnancy Actual body weight exceeding 1 kg per cm of height Diffuse alveolar hemorrhage Severe acute pancreatitis as etiology for hypoxemia Recent upper gastrointestinal surgical anastomosis within the past 30 days Enrollment in another clinical trial within the past 30 days Unsuitable for non-invasive ventilation in the judgment of the treating MD Decision to withhold life-sustaining treatment. Patients with Do-Not-Resuscitate (DNR) or No Cardiopulmonary resuscitation (No CPR) order may be enrolled. Do not intubate order

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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Helmet oxygenation group<br>Patients randomized to helmet NIPPV will receive noninvasive oxygenation and ventilation via a latex free helmet | Device: Helmet<br>* The helmet encloses the head and neck of the patient, has a rigid ring and is secured by 2 armpit braces. A soft collar adheres to the neck and ensures a sealed connection once the helmet is inflated.<br>|
| Active Comparator: High Flow Nasal Oxygen<br>Oxygen will be passed through a heated humidifier and applied continuously through large-bore nasal prongs | Device: High Flow Nasal Oxygen<br>* Large-bore nasal prongs through which oxygen is delivered at high flow rates<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rate of intubation | To determine the rates of intubation for subjects with Acute Hypoxemic Respiratory Failure (AHRF) managed by non-invasive modalities High Flow Nasal Cannula (HFNC) and Helmet NIPPV. | 28 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to intubation | Hours and minutes from time of initiation of protocol until intubation | 28 days | 
| Intubation-free days through day 28 | number of days from the time of randomization to day 28 after randomization on which the patient is not intubated and does not require invasive mechanical ventilation | 28 days | 
| Organ-failure-free days through day 28 | Daily determination of presence or absence of Cardiovascular, Kidney, Liver, Central Nervous System, and Hematological Dysfunction. | 28 days | 
| Mortality prior to discharge from hospital (up to study day 90 whichever comes first) | hospital mortality | 90 days | 
| Hospital mortality to day 28 | hospital mortality | 28 days | 
| ICU free-days to day 28 | days not in ICU | 28 days | 
| Hospital length of stay | duration of hospital stay | 28 days | 
| Rate of cross-over between groups | The percentage of patients in each group crossed over to the alternative group or another form of noninvasive ventilation. | 28 days | 
| Complications | Adverse events other than failure of the noninvasive oxygenation device | 28 days | 
| Ventilator associated pneumonia, barotrauma | Complications due to mechanical ventilation | 28 days | 
| Total daily dose of sedative medications (milligram) | Assessment of Sedation medications | 7 days | 
| Highest level of daily mobility through day 7 | Activity level | 7 days | 
| Tolerance of the devices | Daily assessment with visual analog scale for comfort, range 0-5, with 0= no discomfort and 5=unable to tolerate | 28 days | 
| Rate and reason for exclusion from enrollment to this trial of Helmet-NIPPV vs. HFNC | Reasons for exclusion of patients meeting inclusion criteria | through study completion, an average of 1 year | 
| Rate of intubation in non-enrolled patients that meet inclusion and exclusion criteria | Usual care comparison | 28 days | 
| Richmond Agitation and Sedation Scale (RASS) | Highest daily RASS score. The scale range is -5 to +4 in integer increments, Where -5 is unarousable, 0 is alert and calm, and +4 is combative | 7 days | 
| Confusion Assessment Method for the ICU (CAM-ICU) | Daily assessment of presence or absence of delirium | 7 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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non-invasive ventilation