Impact of Dyspnea, Regional Lung Ventilation, and Diaphragmatic Function During de Novo Acute Respiratory Failure

Study Overview
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Brief Summary
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Modern management of acute respiratory failure aims to relieve dyspnea and anxiety by providing a non-invasive respiratory support. This approach tries to avoid endotracheal intubation, patient self inflicted lung injuries (PSILI) and diaphragmatic dysfunction. The present study aims to evaluate dyspnea, pulmonary regional ventilation and diaphragmatic function in patients with hypoxemic acute respiratory failure by different observations, and to bring risk factor for intubation out.

Detailed Description
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Patients aged of 18 years or more, presenting with an acute respiratory failure without hypercapnia will be included in the study. Clinical and biological variables, dyspnea assessment, regional lung ventilation (electrical impedance tomography) and diaphragm function (ultrasound) will be evaluated at inclusion and at 2 hours, 4 hours and 48 hours after inclusion. In case of intubation, diaphragmatic function will be also evaluated with phrenic nerve stimulation technique. Primary endpoint is intubation at day 7. Secondary endpoints are measurement of dyspnea, pulmonary ventilation and diaphragmatic function, also ventilator free days, ICU length of stay and mortality.

Official Title
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Evaluation of Dyspnea, Pulmonary VentIlation and DIaphragmatic Function in de Novo Adult Acute Respiratory Failure.

Conditions
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Acute Respiratory Failure

Intervention / Treatment
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* Other: Diaphragmatic ultrasound and electrical impedance tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 18 Acute respiratory insufficiency defined by the three following items : PaO2/ FiO2 <300 Respiratory rate > 25/min Oxygen support > 10L/min or High Flow nasal oxygen (HFNO) Non opposition by the patient to be included Social insurance Exclusion Criteria: Respiratory acidosis (pH < 7,35 PaCO2 > 45mmHg or 6kPa) Chronic respiratory disease ( COPD, bronchiectasis…) Cardiogenic Acute lung oedema Non intubation decision at randomisation Contraindication for Electro-impedance tomography-belt placement (chest trauma with rib fractures, thoracic wound, chest tube). Uncommunicative patient (Glasgow coma scale <12) Guardianship or curators for vulnerable patients.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with de novo acute respiratory failure<br>The following tests will be performed as part of the research (these tests are usually performed as part of routine care but not routinely and comprehensively): A diaphragmatic ultrasound in the half-seated position. Diaphragmatic excursion and thickening fraction will be measured in the right hemi-diaphragm. A 10-minute reference acquisition. They will be performed at inclusion, H2, H4 and H48. | Other: Diaphragmatic ultrasound and electrical impedance tomography<br>* A diaphragmatic ultrasound in a half sitting position. The diaphragmatic excursion and the thickening fraction of the right hemi-diaphragm will be measured. - Acquisition of 10 minutes of regional pulmonary ventilation by electrical impedance tomography.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oro-tracheal intubation | Patients who will be intubated within the 7 days after admission in the ICU | 7 days after admission in the ICU | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diaphragmatic function | using ultrasonography, measure of diaphragmatic excursion and diaphragmatic thickening in Hertz (Hz) | 2 days after inclusion | 
| Diaphragmatic function | Diaphragmatic function evaluation by phrenic nerve stimulation (only for intubated patients). | 2 days after inclusion | 
| lung regional ventilation | As measured with Electric Impedance Tomography index measures (inhomogeneity index, end expiratory lung impedance change) | 2 days after inclusion | 
| Dyspnea evaluation | Dyspnea evaluation using visual analogue scale applied to dyspnea: from 1 to 10, 1 corresponding to no breathlessness and 10 to maximum breathlessness. | 28 days after inclusion | 
| Dyspnea evaluation | Dyspnea evaluation using Respiratory Distress Observation Scale (RDOS) | 28 days after inclusion | 
| Mechanical ventilation duration | (only for intubated patients). | 28 days after inclusion | 
| ICU length of stay | for all patients | 28 days after inclusion | 
| ICU mortality | for all patients | 28 days after inclusion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Acute respiratory failure, diaphragm, dyspnea, EIT