Assessment of Human Diaphragm Strength by Magnetic and Electric Stimulation After Ultrasonography Phrenic Nerve Tracking

Study Overview
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Brief Summary
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Development and validation of a new affordable and easy-to-use phrenic nerve stimulation tool for diaphragm strength assessment in intensive care unit

Detailed Description
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In intensive care unit, various forms of sepsis, undernutrition, surgery, global inflammation, iatrogeny, and mechanical ventilation, contribute to the overall muscular involvement including the diaphragm. Assessment of diaphragm dysfunction is a critical issue for patients under mechanical ventilation, providing prognosis information and leading to the best therapeutic choices. Up to now, for sedated ventilated critical care patient, expensive magnetic phrenic nerve stimulation equipment is needed to evaluate diaphragm strength. In this study, the investigators aim to develop an affordable easy-to-use phrenic nerve stimulation tool, with ultrasonography and a nerve stimulator usually used for neuromuscular transmission monitoring. Hypothesis is that phrenic pacing using this new method is equivalent to the Gold Standard.

Official Title
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Assessment of Human Diaphragm Strength by Magnetic and Electric Stimulation After Ultrasonography Phrenic Nerve Tracking : a Randomized, Cross Over, Physiologic Study in Critically Ill Patients Requiring Invasive Mechanical Ventilation

Conditions
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Intensive Care Unit, Invasive Mechanical Ventilation

Intervention / Treatment
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* Procedure: Magnetic stimulation
* Procedure: Electric stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ICU patient with invasive mechanical ventilation Sedated patient with a Richmond Agitation-Sedation Scale of -4 or -5 Exclusion Criteria: Contraindication for magnetic stimulation (Pacemaker) Hemodynamic or respiratory instability : PaO2/FiO2 < 200 mmHg, noradrenaline > 0,3 µg/kg/min, dobutamine > 10 µg/kg/min Neuromuscular disease or recent use of neuromuscular blocking agents (2h30) with a TOF ratio below 4/4 95%. Refusal of study participation or to pursue the study by the patient, no consent Pregnancy or breastfeeding Absence of coverage by the French statutory healthcare insurance system

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
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Each patient, serving as their own control, receives both types of phrenic nerve stimulation : magnetic stimulation and electric stimulation. The order is randomized. For avoid a carry-over effect (diaphragm potentiation), a wash-out period of 15 minutes will be respected between the two type of stimulation.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Magnetic stimulation and electric stimulation<br>The patient receive first the magnetic stimulation with MagStim 200 tool. Then 15 min after he will receive the electric stimulation with the SonoStim tool : ultrasonography phrenic nerve tracking and targeted electric stimulation with a nerve stimulator usually used for neuromuscular transmission monitoring (TOFScan, Drager) | Procedure: Magnetic stimulation<br>* Cervical bilateral phrenic nerve stimulation with the MagStim 200 tool.<br>Procedure: Electric stimulation<br>* Cervical bilateral phrenic nerve stimulation after ultrasonography nerve tracking and targeted electric stimulation with a nerve stimulator usually used for neuromuscular transmission monitoring (TOFScan, Drager)<br>|
| Experimental: Electric stimulation and magnetic stimulation<br>The patient receive first electric stimulation with the SonoStim tool : ultrasonography phrenic nerve tracking and targeted electric stimulation with a nerve stimulator usually used for neuromuscular transmission monitoring (TOFScan, Drager). Then 15 min after he will receive the magnetic stimulation with MagStim 200 tool | Procedure: Magnetic stimulation<br>* Cervical bilateral phrenic nerve stimulation with the MagStim 200 tool.<br>Procedure: Electric stimulation<br>* Cervical bilateral phrenic nerve stimulation after ultrasonography nerve tracking and targeted electric stimulation with a nerve stimulator usually used for neuromuscular transmission monitoring (TOFScan, Drager)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tracheal pressure (Ptrach) during diaphragm pacing | Negative pressure in the occluded breathing circuit, assessed with a manometer located just after the endotracheal tube, during diaphragm stimulation | During electric of magnetic phrenic nerve stimulation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Behavioral Pain Scale (BPS) after stimulation | The BPS is a scale of pain for critical care patients, from 3 (no or minimal pain) to 12 points (maximum pain). | Immediately after phrenic nerve stimulation | 
| Distance in millimeter between anatomical and ultrasound phrenic nerve location | Distance between classical anatomical landmarks of the phrenic nerve location (underneath the posterior border of the sternocleidomastoid muscle, at the level of the cricoid cartilage), and the phrenic nerve location with ultrasound | During ultrasonography phrenic nerve tracking | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Intensive Care Unit, Invasive Mechanical Ventilation, Diaphragm weakness assessment, Rehabilitation