Effects of Continuous Anterior Chest Compression

Study Overview
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Brief Summary
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The aim is to test the physiological effects of continuous anterior chest compression in patients with severe to moderate ARDS.

Detailed Description
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Acute respiratory distress syndrome (ARDS) is usually characterized by inhomogeneous lesions, leading to an inhomogeneous distribution of the mechanical ventilation with the following several deleterious effects: atelectrauma of dependent posterior areas and overdistension in the anterior ones. Therefore, the gold standard treatment is to prevent VILI with lung protective ventilation : low tidal volume, high positive end expiratory pressure and prone positioning which is a technique that reduces mortality. Prone positioning has several beneficial effects : it relieves cardiac compression of the supporting lung, it stiffens the anterior chest wall thus limiting the risk of overdistension of anterior areas and promotes recruitment of non-dependent posterior pulmonary units. The overall effect is a more uniform distribution of transpulmonary pressures and improved ventilation to perfusion ratios. Similar to prone positioning, continuous anterior chest wall compression stiffens the anterior chest wall. The investigators hypothesize that such reduction in anterior chest wall compliance may protect against overdistension and promote the redistribution of the ventilation in posterior areas.

Official Title
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 Effects of Continuous Anterior Chest Compression (CACC) & Comparision With Prone Position in ARDS Patients  The StrapVent Study 

Conditions
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Evaluable

Intervention / Treatment
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* Device: Continuous anterior chest compression


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 ans Intubated moderate and severe ARDS according to the Berlin definition (PaO2/FiO2 ratio <= 200 mmHg) The patent must be sedated and paralyzed Informed consent from patient or family members Exclusion Criteria: Extracorporeal membrane oxygenation (ECMO) Pneumothorax Thoracic trauma during the last 3 months Refractory shock Contraindication to EIT monitoring (e.g. burns, pacemaker, thoracic wounds limiting electrode belt placement) Pregnancy Any contra-indication to esophageal manometry (less than one month esophagus surgery, bronchopleural or esotracheal fistula, latex allergy) No social care Adults under Guardianship, curatorship or protection of the court

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: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: Clinical trials with a single arm
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: A description of each arm of the clinical trial that indicates its role in the clinical trial<br>Arm 1 Description: The study will consitent of recording the measurments of ventilatory settings, respiratory mechanics, flow and pressure curves, gaz exchange, haemodynamics and ventilation distribution in 5 consecutive conditions in adult patients with moderate to severe ARDS : After 16 hours of prone position In supine position 1 hour after the prone position 15mn after CACC with a pressure equal to the one observed in the prone position 15mn after CACC with a pressure set at 60 - 80 cmH20 15mn after taking of the CACC | Device: Continuous anterior chest compression<br>* Patients with severe to moderate ARDS who were placed in prone position by the attending physician : First CACC : the applied pressure is equal to the one observed in the prone position Second CACC : The applied pressure is set at 60 - 80 cmH20<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The end inspiratory transpulmonary pressure (PL-insp) in centimetre of water | The transpulmonary pressure will be measured by using an esophageal catheter connected to a differential pressure transducer. The PL-insp will be calculated using the ratio between the elastance of the lung (El) and of the respiratory system (Ers) expressed in centimetre of water thanks to this formula PL-insp = Plateau pressure x (El/Ers). The PL-insp between the different protocol conditions will be compared (After 16 hours of prone position, in supine position, 15mn after CACC with a pressure equal to the one observed in the prone position, 15mn after CACC with a pressure set at 60 - 80 cmH20, 15mn after taking off the CACC in supine position ). CACC will be considered protective if there is a decrease in Pl-insp. | Through study completion (up to 6 hours) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Regional pulmonary compliances in centimetre of water | Evaluation and comparison of pulmonary compliances in the different regions of interest (ROI) measured by Electrical Impedance Tomography (EIT) in the different protocol conditions. | Through study completion (up to 6 hours) | 
| Lung mechanics : Airways pressure, Flow curves and Esophageal pressure | Airways pressure (Paw) will be measured in cmH2O and recorded by the mean of a differential pressure transducer. Flow curves will be measured in L/mn and recorded by the mean of a pneumotachograph connected to the ventilator circuit. Esophageal pressure (Pes) will be measured in cmH2O and recorded thanks to an esophageal balloon catheter introduced in the mid-esophagus of the patient and connected to differential pressure transducer. Evaluation and comparison of respiratory mechanics in the different protocol conditions. | Through study completion (up to 6 hours) | 
| Pulmonary ventilation distribution in percentage | Evaluation and comparison of the distribution of ventilation in the different regions of interest (ROI) measured by Electrical Impedance Tomography (EIT) in the different protocol conditions | Through study completion (up to 6 hours) | 
| Recruitment-to-inflation (R/I) ratio | Evaluation and comparaison of R/I in the different protocol conditions | Through study completion (up to 6 hours) | 
| Hemodynamics | Heart rate will be expressed in beats per minute, arterial blood pressure will be expressed in millimetre of mercury and norepinephrine perfusion will be expressed in milligrams per hour. | Through study completion (up to 6 hours) | 
| Arterial blood gazes (ABG | pH, PaCO2 and PaO2 will be measured by standard clinical technique using the ICU blood gaz analyzer. PaCO2 and PaO2 will be expressed in millimetre of mercury. | Through study completion (up to 6 hours) | 
| Incidence of CACC adverse events | CACC will be interrupted if : Reduction in oxygen saturation (SpO2) beneath 88% despite FiO2 optimisation. Reduction in mean arterial pressure beneath 60 mmHg Increase in norepinephrine perfusion beyond 0.5 mg/h | Through study completion (up to 6 hours) | 
| End expiratory lung impedance (EELZ) expressed in arbitrary units | Evaluation and comparison of EELZ using EIT in the different protocol conditions. | Through study completion (up to 6 hours) ] | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ARDS : Acute Respiratory Distress Syndrome, CACC : Continuous Anterior Chest Compression, VILI : Ventilator-Induced Lung Injury, ARDS,Human: Adult Respiratory Distress Syndrome