Synchronous Effect of Anesthetics on fMRI, EEG and Clinical Responses

Study Overview
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Brief Summary
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Background: The mechanisms of action of intravenous anesthetics are unclear and the current monitors have limitations. This signifies difficulties when assessing the correct dosage due to the considerable inter-individual variability of the patients, particularly in the elderly or seriously ill. It is necessary to customize the administration of anesthetics as underdosage can lead to the patient awareness during aggressive procedures, and over-dosage can cause serious complications and even augment mortality. Objective: To design a new monitoring system of the levels of consciousness and analgesia in anesthetized subjects which is more accurate than those currently employed. It will be based on the synchronic changes of functional magnetic resonance (fMR) and electroencephalograph (EEG) readings, and clinical responses. Methodology: Thirty healthy volunteers will be given propofol and remifentanil in different combinations, and painful stimuli will be also applied. The principal variable will be fMR images obtained by echo-planar imaging sequences. Real time will be correlated with cortical connectivity maps, EEG parameters (qCON, qNOX), clinical responses, and concentrations of anesthetics measured by pharmacokinetic and pharmacodynamic models (TCI).

Detailed Description
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Main goal: Develop a system for monitoring the effect of anesthetics on consciousness and pain, based on synchronous changes in functional neuroimaging, EEG and clinical responses. Secondary objectives: Analyze the changes produced in the cortical connectivity map during the induction of anesthesia to understand the process of advancement. Know more accurately the neuronal circuits involved in propofol-induced sleep. Study if the application of a known painful stimulus modifies in any way (clinical, EEG or by RMf) the LOC that has just been reached. Establish propofol dosing guidelines adjusted to each patient, studying if they reach the LOC at sedative or hypnotic doses. Establish remifentanil dosing guidelines, adjusted to each patient, studying the concentration of remifentanil to which the pain response in neuroimaging is inhibited (activation deactivation neuronal in fMRI). Validate existing mathematical models in relation to plasma and brain concentrations of propofol and remifentanil. Validate the value of clinical signs to predict whether a patient feels the painful stimulus received.

Official Title
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Synchronous Effect of Anesthetics on fMRI, EEG and Clinical Responses. Development of a More Precise System for Monitoring Anesthetic Effect.

Conditions
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Sedative Overdose

Intervention / Treatment
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* Drug: Propofol
* Drug: Remifentanil


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adult volunteers (ASA 1 physical state) who agree to participate voluntarily in the study, previous information about it by the Principal Investigators (IP). Exclusion Criteria: Psychological, psychiatric or neurological disorders. Consumption of drugs. Alterations cutaneous or anatomical cranial. Idiomatic or communication barrier. Allergy to propofol, remifentanil or to some of its excipients. Body mass index (BMI) <18 or> 30 kg / m2. Pregnancy. Airway or ventilation criteria hard. Absence of accompanying adult at the end of the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 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: Basic Science
Intervention Model: Sequential Assignment
Interventional Model Description: Volunteers receiving propofol and then remifentanil.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Volunteers receiving propofol and remifentanil<br>Volunteers receive propofol to the loss of consciousness. Then they receive remifentanil during 12 min (pain stimuli in their finger also) | Drug: Propofol<br>* sedation<br>* Other names: remifentanil;Drug: Remifentanil<br>* remifentanil<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time and dose of propofol at loss of consciousness(LOC) | Volunteers stop tightening pneumatic pear. We register time and dose of propofol when the volunteer stops tightening pneumatic pear. | 10-15 min | 
| Register EEG and neuroimage during remifentanil administration. | After LOC, volunteers receive increasing doses of remifentanil and painful stimuli in the nail bed. If apnea, stop infusion remifentanil Volunteers receive increasing doses of remifentanil and painful stimuli in the nail bed. If apnea, stop infusion remifentanil. We registered time, dose, saturation and breathing frequency in every volunteer. | 10-15 min | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Propofol, remifentanil, hypnosis, EEG, fMRI,