RecruitmEnt Assessed by eleCtRical Impedance Tomography

Study Overview
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Brief Summary
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The RECRUIT study is a multinational, multicenter physiological observational study conducted by the PLUG working group. It is a single-day study (1.5-2 hours) associated with specific lung (de)recruitment maneuvers to verify the feasibility of measuring the potential for lung recruitment in mechanically ventilated patients with ARDS by electrical impedance tomography (EIT).

Detailed Description
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Despite higher positive end-expiratory pressure (PEEP) being associated with multiple physiologic benefits, randomized clinical trials comparing higher vs. lower PEEP levels failed to show improved survival of ARDS patients. Higher PEEP should fully exploit its benefits only when implemented in patients with higher potential for alveolar recruitment (i.e., the decrease of non-aerated lung tissue at higher airway pressure) or in patients with airway closure. Retrospective analysis of randomised clinical trials with PEEP suggests that when high PEEP is used in responders (oxygenation), survival may be better. Conversely, in the absence of significant recruitment, higher PEEP should be avoided and lower PEEP might be recommended. Titration of PEEP provided by the mechanical ventilator in patients with severe lung injury should thus be based on bedside information on lung recruitability. However, no valid method exists to define the best PEEP to optimize recruitment and minimize lung overdistention. Recruitability varies and is often not assessed. Electrical impedance tomography (EIT) is a non-invasive bedside imaging technique for measuring the potential for lung recruitment in ARDS patients. By performing lung (de)recruitment maneuvers and in-depth analyses, we will define lung recruitability indices and develop methods for real-time and personalized PEEP selection. This study will prove the feasibility of minimizing risks associated with inadequate mechanical ventilation by EIT.

Official Title
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RecruitmEnt Assessed by eleCtRical Impedance Tomography: Feasibility, Correlation With Clinical oUtcomes and pIloT Data on Personalised PEEP Selection.

Conditions
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Acute Respiratory Distress Syndrome (ARDS)

Intervention / Treatment
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* Other: Specific lung recruitment maneuvers


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Intubated moderate and severe ARDS according to the Berlin definition (PaO2/FiO2 ratio <= 200 mmHg) Under continuous sedation with or without paralysis Exclusion Criteria: Age <18 years Bronchopleural fistula Pure COPD exacerbation Contraindication to EIT monitoring (e.g. burns, pacemaker, thoracic wounds limiting electrode belt placement) Hemodynamic instability (Systolic BP < 75 mmHg or MAP < 60 mmHg despite vasopressors and/or heart rate < 55 bpm) Attending physician deems the transient application of high airway pressures to be unsafe

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Intubated mechanically ventilated ARDS patients<br>Intubated mechanically ventilated patients with moderate to severe ARDS according to the Berlin definition | Other: Specific lung recruitment maneuvers<br>* Specific lung recruitment maneuvers will be performed to measure the potential for lung recruitment at different levels of positive end-expiratory pressure (PEEP) provided by the mechanical ventilator. Electrical impedance tomography signals, synchronized signals of airway pressure and flow, esophageal pressure (if available), and volumetric capnography (if available) will be recorded continuously, during the time span of the protocol for offline analysis.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Potential for lung recruitment | The potential for lung recruitment will be assessed with EIT. Several methods will be used and compared, based on e.g. pixel information of lung aeration, and pressure-volume characteristics at different PEEP steps. | 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Recruitment-to-inflation (R/I) ratio |  | 2 hours | 
| EIT-based optimum PEEP level |  | 2 hours | 
| PEEP level resulting in end-expiratory transpulmonary pressure between 0 and 2 cmH2O | For those patients with esophageal pressure measurements available | 2 hours | 
| Organ dysfunction as per the sequential organ failure assessment (SOFA) score | SOFA score min-max: 0-24; a higher score is associated with poor prognosis. | Day 1, 3, 7 | 
| Vital status at ICU discharge, 28 days, and hospital discharge | Vital status (death/alive) will be assessed via chart review | Through study completion, up to 1 year | 
| Ventilator free days |  | Day 28 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ARDS, Mechanical Ventilation, Lung recruitment, Electrical impedance tomography