Personalized Tidal Volume in ARDS (VT4HEMOD)

Study Overview
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Brief Summary
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Treatment of acute respiratory distress syndrome (ARDS) relies on invasive mechanical ventilation with supposedly protective settings (low tidal volume ventilation). Mortality of ARDS remains high in observational studies (40 to 50%). Approximately 30% of ARDS patients exhibit tidal hyperinflation despite low tidal volume ventilation, suggesting that personalization of tidal volume is required to improve ARDS prognostic. To date, reliable bedside tools to adjust tidal volume are lacking. Excessive tidal volume can be detected using computed tomography by quantification of tidal hyperinflation, but this technique is reserved to research studies and requires patient transport to imaging facility. Mechanical ventilation generates cardio-pulmonary interaction, whose magnitude is influenced by tidal volume and respiratory system characteristics. Pulse pressure variation is a bedside tool with potential to quantify cardio-pulmonary interactions. Increasing tidal volume will decrease right ventricular preload and increase right ventricular afterload, hence maximizing cardio-pulmonary interactions. The investigators hypothesize that pulse pressure variation might help to detect excessive tidal volume during a tidal volume challenge (i.e. stepwise increase in tidal volume)

Official Title
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Personalized Tidal Volume According to Cardiopulmonary Interactions in ARDS

Conditions
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Acute Respiratory Distress Syndrome

Intervention / Treatment
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* Procedure: Standardized ventilation
* Procedure: Personalized ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age greater then 18 years old ARDS according to the BERLIN definition with PaO2/FiO2 ratio ≤ 150 mm Hg invasive mechanical ventilation in volume controlled mode with tidal volume set to 6 ml/kg predicted body weight use of sedation and neuromuscular-blocking agents arterial catheter allowing computation of pulse contour cardiac output calibrated with thermodilution central venous catheter implanted in the superior vena cava territory esophageal balloon Computed tomography planned by attending physician Exclusion Criteria: Previous inclusion in current study Acute cor pulmonale ECMO Arterial pH < 7.21 despite respiratory rate set to a maximum of 35/min Pneumothorax or bronchopleural fistula Decision to withdraw or withhold life sustaining treatment with 24 hours from inclusion Contra-indication of transport to imaging facility Intracranial hypertension Tricuspid or pulmonary mechanical valve Tricuspid or pulmonary infective endocarditis Pace maker with intracardiac leads Right ventricle tumor Complete left bundle block Intrathoracic metallic device COPD Cardiac arrythmia Vesical pressure > 15 mm Hg Lower limb amputation Inferior vena cava thrombosis Patient under an exclusion period relative to participation to another clinical trial Patient under a legal protective measure Patient not affiliated to social security lac of patient/representative consent Pregnancy Breast feeding

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: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standardized tidal volume<br>Ventilation with tidal volume 6 ml/kg | Procedure: Standardized ventilation<br>* Patient will be ventilated with tidal volume 6 mL/kg predicted body weight (PBW) and positive end-expiratory pressure (PEEP) according to the PEEP-FiO2 table of the ARMA trial. A CT scan will be performed with this ventilatory setting and the patients will be switched to the other group<br>Procedure: Personalized ventilation<br>* Patient will be ventilated with PEEP according to the PEEP-FiO2 table of the ARMA trial. Tidal volume will be selected as the tidal volume minimizing cardiopulmonary interactions as assessed on arterial pressure tracing, during a VT trial. A CT scan will be performed with this ventilatory setting and the patients will be switched to the other group.<br>|
| Experimental: Personalized tidal volume<br>Ventilation with tidal volume aiming to minimize cardiopulmonary interactions as assessed by pulse pressure variation | Procedure: Standardized ventilation<br>* Patient will be ventilated with tidal volume 6 mL/kg predicted body weight (PBW) and positive end-expiratory pressure (PEEP) according to the PEEP-FiO2 table of the ARMA trial. A CT scan will be performed with this ventilatory setting and the patients will be switched to the other group<br>Procedure: Personalized ventilation<br>* Patient will be ventilated with PEEP according to the PEEP-FiO2 table of the ARMA trial. Tidal volume will be selected as the tidal volume minimizing cardiopulmonary interactions as assessed on arterial pressure tracing, during a VT trial. A CT scan will be performed with this ventilatory setting and the patients will be switched to the other group.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tidal hyperinflation | Difference between hyperinflated volume in computed tomography images acquired at end-inspiration (defined by the volume of voxels with CT-number < -900) and hyperinflated volume in computed tomography images acquired at end-expiration (defined by the volume of voxels with CT-number < -900). This difference will be standardized to predicted body weight using the formula of the ARMA trial. | 5 minutes - This endpoint will be assessed 5 minutes after ventilatory adjustment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tidal volume | Standardized versus personalized tidal volume | 5 hours - This endpoint will be assessed through study completion (approximately 4-5 hours after study inclusion) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Acute Respiratory Distress Syndrome, cardiopulmonary interaction, tidal volume, computed tomography