Evaluation of the Hemodynamic Effects of Transvenous Phrenic Stimulation

Study Overview
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Brief Summary
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Mechanical ventilation is a cornerstone in the management of severe forms of pneumonia, acute respiratory distress syndrome. It provides essential oxygen to patients, ventilates the lungs but also has deleterious effects like any treatment, in particular by reducing cardiac output by reducing venous return. Mechanical ventilation also has effects on the diaphragm: diaphragmatic dysfunction. It is explained by a prolonged inactivity of this muscle with a reduction of muscle fibers that can settle down quickly, after only a few days of mechanical ventilation. This dysfunction results in a reduction in the latter's ability to generate intrathoracic pressure necessary for ventilation, slows the withdrawal of mechanical ventilation and lengthens the duration of stay in intensive care unit. To reduce this dysfunction, phrenic stimulation has been proposed as an alternative to remuscler the diaphragm thanks to electrodes located on a central venous catheter, also used to deliver the usual therapies in intensive care unit. The HEMOSTIM study is interested in the effects of phrenic stimulation on regional ventilation, cardiac output and cerebral perfusion: investigator hypothesize that diaphragmatic stimulation allows an improvement of these parameters.

Official Title
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Evaluation of the Hemodynamic Effects of Transvenous Phrenic Stimulation

Conditions
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Mechanical Ventilation

Intervention / Treatment
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* Procedure: phrenic stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient included in RESCUE 3 study, interventional arm with phrenic stimulation Patient or family consent Exclusion Criteria: Patient not affiliated or not benefiting from a social security scheme

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: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: phrenic stimulation<br> | Procedure: phrenic stimulation<br>* measurements of the hemodynamic effects of phrenic stimulation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| measurement of integral time speed by cardiac transthoracic ultrasound | to assess the effects of phrenic stimulation on cardiac output | 1 minute | 
| Measurement of increased venous return gradient in percentage (variation between the value before phrenic stimulation and the value after phrenic stimulation) | To specify the mechanisms of the effect of phrenic stimulation on cardiac output | 1 minute | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| variation in ventilation distribution before and after phrenic stimulation measured in electrical impedance tomography | To assess the effects of diaphragmatic stimulation on ventilation and pulmonary recruitment measured in electrical impedance tomography | 1 minute | 
| Measurement of diaphragmatic stimulation on cerebral oxygenation evaluated by the Near infrared spectrometry technique |  | 1 minute |