MAC Bipsectral Index Below 50 for Chronic Opioid User

Study Overview
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Brief Summary
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The purpose of this study is to find difference in Minimum Alveolar Concentration(MAC) for maintaining Bispectral Index (BIS) below 50 between chronic opioid users and opioid naive patients.

Detailed Description
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Patients selection in elective surgery which need general anesthesia. MAC BIS50 data was collected in each patients (by blinded investigator) The data collection will be continued for enough sample size for using Dixon Up Down Method Analysis After Data collection, MAC BIS below 50 will be analyzed in both groups ( Chronic opioid users versus opioid naive patients)

Official Title
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The Effect of Chronic Opioid Use on Minimum Alveolar Concentration of Sevoflurane for Maintaining Bispectral(BIS) Index Below 50 ; Prospective, Blind Study

Conditions
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Anesthesia

Intervention / Treatment
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* Other: History for opioid use


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: The patients(ASA class I-III) who receive elective surgery signed in informed consent to participate in this trial voluntarily. Exclusion Criteria: History of Monoamine Oxidase (MAO) inhibitor use Chronic alcoholics Acute alcohol abuser Contraindication for inhalation agent use (Sevoflurane) BMI >30 History of medication use, which affect in the minimum concentration of sevoflurane;(barbiturates, chlorpromazine, diazepam, hydroxyzine, verapamil, marijuana) Craniotomy

Ages Eligible for Study
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Minimum Age: 41 Years
Maximum Age: 69 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: Treatment
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Chronic Opioid User<br>The patients (ASA class I-III) who receive elective surgery s aging between 41 and 69 and signed in informed consent to participate in this trial voluntarily. The Patients who use opioid medication daily and regularly immediately before the day of surgery for more than four weeks. The minimum criteria for opioid dose in the intervention goup is oral morphine 20mg per day: Morphine Equivalent Daily Dose(MEDD) | Other: History for opioid use<br> <br> |
| No Intervention: Opioid Naive patient<br>The patients (ASA class I-III) who receive elective surgery aging between 41 and 69 and signed in informed consent to participate in this trial voluntarily. The patients who do not use opioid medications immediately before the day of surgery for four weeks. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Minimum Alveolar Concentration below BIS 50 in Sevoflurane; percentage (eg: 1.2%) | Dixon's up down method is applied in this study. So pre-set concentration of sevoflurane will be used in each group. | 15 minutes after pre-set of the concentration of sevoflurane | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Minimum Alveolar Concentration