Hypnotic and Anti-nociceptive Components of Magnesium

Study Overview
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Brief Summary
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The aim of our study is to evaluate the effect of magnesium on the hypnotic effect of propofol.

Detailed Description
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The aim of our study is to evaluate the effect of magnesium on the hypnotic effect of propofol. To achieve this, the investigators will analyse the effect of magnesium on the brain concentrations of propofol required to achieve a State Entropy value between 50-60, which corresponds to the recommended depth of anaesthesia. Our study will also evaluate the intraoperative anti- nociceptive effect of magnesium using pupillometry and its two indices, PPI and PRD

Official Title
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Study of the Hypnotic and Anti-nociceptive Components of Magnesium Using Electroencephalogram Spectral Entropy and Pupillometry During Total Intravenous General Anaesthesia

Conditions
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Anesthesia

Intervention / Treatment
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* Drug: Magnesium sulfate IV
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult > 18 years Patients of both sexes Any patient scheduled for thyroidectomy at the University Hospital of Liege Exclusion Criteria: Heart failure with left ventricular ejection fraction < 35 Renal insufficiency (clearance < 40 mL/min) Neuromuscular diseases Atrioventricular block Pregnancy

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Double blinded prospective randomized controlled trial
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Magnesium sulfate IV<br>10 patients scheduled for thyroidectomy | Drug: Magnesium sulfate IV<br>* Infusion of magnesium sulphate 50 mg/kg (eq. 0.5ml/kg of magnesium sulphate 100mg/ml)<br>|
| Placebo Comparator: Placebo<br>10 patients scheduled for thyroidectomy | Drug: Placebo<br>* Infusion of NaCl (sodium chloride) 0.9% (placebo eq. 0.5ml/kg of NaCl 0.9%)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Propofol target concentration | The target concentration of Propofol TCI (target-control infusion) to achieve a state entropy value between 50-60 | through study completion, an average of 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Morphine consumption | Morphine consumption titrated in the recovery room and morphine equivalents claimed during the first 24 hours postoperatively | through study completion, an average of 3 months | 
| PPI Measure | PPI (pupillary pain index) by pupillometry with AlgiScan® monitoring, before endotracheal intubation and with a State Entropy of 50-60, then every 5 min between endotracheal intubation and surgical incision | through study completion, an average of 3 months | 
| PRD Measure | PRD (pupillary reflex dilatation) during laryngoscopy maintained for 30 sec, surgical incision and 10min after surgical incision | through study completion, an average of 3 months |