Effects of Epidural Local Anesthetics on Propofol Induction

Study Overview
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Brief Summary
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The investigators designed a prospective, randomized, placebo-controlled study to determine whether thoracic epidural anesthesia(TEA) with different local anesthetics has different influences on the propofol dose during induction.

Official Title
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Effects of Thoracic Epidural Anesthesia With Different Local Anesthetics on Propofol Induction

Conditions
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General Anesthesia, Propofol Target-controlled Infusion, Thoracic Epidural Anesthesia

Intervention / Treatment
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* Drug: Lidocaine
* Drug: Bupivacaine
* Drug: Ropivacaine
* Drug: Normal Saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Surgery for thoracotomies, BMI: 18-25 Kg/m2, American Society of Anesthesiologists(ASA) classification I or II. Exclusion Criteria: liver or kidney disease, alcohol dependence, take sedative recently, contraindications for epidural anesthesia.

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 65 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Normal saline<br>General anesthesia combined with thoracic epidural 0.9% normal saline 8ml | Drug: Normal Saline<br>* General anesthesia combined with thoracic epidural 0.9% normal saline<br>|
| Experimental: Lidocaine<br>General anesthesia combined with thoracic epidural 1% lidocaine 8ml | Drug: Lidocaine<br>* General anesthesia combined with thoracic epidural 1% lidocaine<br>|
| Experimental: Bupivacaine<br>General anesthesia combined with thoracic epidural 0.25% bupivacaine 8ml | Drug: Bupivacaine<br>* General anesthesia combined with thoracic epidural 0.25% bupivacaine<br>|
| Experimental: Ropivacaine<br>General anesthesia combined with thoracic epidural 0.3% ropivacaine 8ml | Drug: Ropivacaine<br>* General anesthesia combined with thoracic epidural 0.3% ropivacaine<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Propofol Effect-site Concentration | The effect-site concentration of propofol when loss of consciousness during propofol target-controlled infusing(TCI) induction of anesthesia. | Before starting anesthesia to finishing endotracheal intubation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean Arterial Pressure | The mean arterial pressure of each patient was recorded at five different time points | Before starting anesthesia to finishing endotracheal intubation | 
| Heart Rate | The heart rate of each patient was recorded at five different time points | Before starting anesthesia to finishing endotracheal intubation | 
| Bispectral Index Score | The bispectral index(BIS) score of each patient was recorded at two different time points. BIS values varies from 0 to 100(0, no cerebral activity; 40 to 60, general anesthesia; 60 to 85, sedated; 85 to 100, awake). | Before starting anesthesia to finishing endotracheal intubation |