Investigation of Cerebral Motor Activity Modulations Following Median Nerve Stimulation During General Anaesthesia

Study Overview
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Brief Summary
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Accidental Awareness during General Anesthesia (AAGA) occurs in 1-2% of high-risk practice patients and is a cause of severe psychological trauma, termed post-traumatic stress disorder (PTSD). Actually, no monitoring techniques can accurately predict or detect an AAGA. Since the first reflex for a patient during an AAGA is to move, a brain-computer interface (BCI) based on the detection of an intention of movement would be conceivable to alert the anesthetist. The investigators previously showed that median nerve stimulation (MNS) could be the keystone of a BCI specialized in the detection of movement intention. Indeed, based on these previous results, the investigators can envisage a routine system where the patient would be stimulated at the median nerve position, while a BCI device would analyze the event-related desynchronization (ERD) and event-related synchronization (ERS) modulations in the motor cortex to check whether the patient is intending to move or not. According to the investigator's knowledge, no published studies have investigated the detection of EEG patterns in relation to peripheral nerve stimulation over the sensorimotor cortex during general anesthesia. The main objective of this study is to describe the changes in terms of ERD and ERS modulations, in the EEG signal over the motor cortex, during general anesthesia with propofol, while a median nerve stimulation is performed. STIM-MOTANA is an interventional and prospective study conducted in patients scheduled for surgery under general anesthesia, involving EEG measurements and median nerve stimulation. In this study, 30 patients will undergo surgery under total intravenous anesthesia using a propofol target-controlled infusion pump. The rest of the anesthetic protocol will be at the discretion of the anesthesiologist in charge. Changes in ERD and ERS during median nerve stimulation according to the various propofol concentrations will be continuously monitored by an EEG amplifier. Pre- and post-injection comparisons of propofol will be performed by paired series tests. After surgery, patients will have a gradual decrease of propofol at different effect-site concentrations (from 4.0 μg/ml to 2.0 μg/ml, in increments of 0.5 μg/ml).

Official Title
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Study of Modulations of Motor Brain Activity Following Stimulation of the Median Nerve During General Anesthesia

Conditions
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Accidental Awareness During General Anesthesia

Intervention / Treatment
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* Drug: Propofol
* Device: Median nerve stimulation
* Device: EEG measurements


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients >18 years and <81 years Right-handed Programmed for surgery with the use of an intravenous anesthesia with a propofol concentration objective Exclusion Criteria: Allergy to propofol, soy or peanuts BMI<20 or >30 Pregnant or breastfeeding women Adult unable to give consent Medical or surgical history that may interfere with median nerve stimulation or the obtention of the EEG signal (for example: diabetes, polyneuropathy, central neurodegenerative disease, epilepsy, brain surgery) History of right median nerve injury Amputation of the upper right limb Impossibility of affixing an EEG helmet Addiction

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 81 Years

Sexes Eligible for Study
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Male

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Median nerve stimulation<br> | Drug: Propofol<br>* STIM-MOTANA is an interventional and prospective study conducted in patients scheduled for surgery under general anesthesia, involving EEG measurements and median nerve stimulation. In this study, 30 patients will undergo surgery under total intravenous anesthesia using a propofol target-controlled infusion pump. The rest of the anesthetic protocol will be at the discretion of the anesthesiologist in charge. After surgery, patients will have a gradual decrease of propofol at different effect-site concentrations (from 4.0 μg/ml to 2.0 μg/ml, in increments of 0.5 μg/ml).<br>Device: Median nerve stimulation<br>* The right-hand median nerve will be stimulated in the same way as for measurement with a conduction velocity or for an evoked potential. Two stimulation electrodes will be placed on the right-hand wrist according to the standards.The stimulation is transcutaneous and painless using the specific Micromed device Sd Ltm Stim Energy (Micromed, Mˆacon, France). The stimulus intensity will range between 3 and 14 mA. The stimulation duration will be 100 ms with a frequency of 0.1 Hz.<br>Device: EEG measurements<br>* Changes in ERD and ERS patterns during median nerve stimulation according to the various propofol concentrations will be continuously monitored by an EEG amplifier. EEG signals will be acquired using the OpenViBE platform with a Biosemi Active Two 64-channel EEG system, arranged in the Biosemi's ABC system covering the entire scalp at 2048 Hz. Among all recorded sites, some of the electrodes will be localized around the primary motor cortex, the motor cortex, the somatosensory cortex, and the occipital cortex.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Amplitude of the ERD (event-related desynchronization)/ERS (event- related synchronization) | The main evaluation outcome will be the amplitude of the ERD (event-related desynchronization)/ERS (event- related synchronization) after median nerve stimulation, within 4 s of the stimulation, at various propofol concentrations. This amplitude will be calculated using a baseline taken before each stimulation. The amplitudes of the ERD and ERS will be extracted. The ERDs and ERSs will be displayed from the time each stimulation is performed until 4 s after the stimulation is completed. | From the time each stimulation is performed until 4 seconds after the stimulation is completed. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Detection of ERD patterns via new machine-learning algorithms (percent of correct detection) | Verify the detection of ERD patterns via new machine-learning algorithms at different propofol concentrations. ERD patterns will be analysed manually, as well as automated by a machine-learning algorythm. Endpoint will be the percentage (%) of correctly identified ERD pattern by the algorythm. | From the time each stimulation is performed until 4 seconds after the stimulation is completed. | 
| Modulation of ERD patterns by anesthetics drugs. Percentage of variation in amplitude. | Another secondary criteria will to describe how the ERD generated by an MNS would be modulated by anesthetics drugs. Amplitude of ERD patterns will be recorded (microV) and the effect of anesthetic drugs on this amplitude will be described as percentage change. | From the time each stimulation is performed until 4 seconds after the stimulation is completed. | 
| Detection of ERS patterns via new machine-learning algorithms (percentage of correct detection) | Verify the detection of ERS patterns via new machine-learning algorithms at different propofol concentrations. ERS patterns will be analysed manually, as well as automated by a machine-learning algorythm. Endpoint will be the percentage (%) of correctly identified ERS pattern by the algorythm. | From the time each stimulation is performed until 4 seconds after the stimulation is completed. | 
| Modulation of ERS patterns by anesthetics drugs via new machine-learning algorithms (percentage change in amplitude) | Another secondary criteria will to describe how the ERS generated by an MNS would be modulated by anesthetics drugs. Amplitude of ERS patterns will be recorded (microV) and the effect of anesthetic drugs on this amplitude will be described as percentage change. | From the time each stimulation is performed until 4 seconds after the stimulation is completed. |