Bispectral Index(BIS) on Depth of Sedation With Dexmedetomidine, Propofol and Midazolam During Spinal Anesthesia

Study Overview
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Brief Summary
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This study is to investigate on the objective relevance between bispectral index (BIS) and Observer's assessment of alertness/sedation (OAA/S) scale in patients sedated with Midazolam, propofol and dexmedetomidine during spinal anesthesia. Also, we will evaluate the reflection of actual sedation levels on BIS monitoring.

Detailed Description
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Sedation is an important element of regional anesthesia during surgery, which allows to finish surgery smoothly by reducing patients' anxiety and fear who undergo regional and local anesthesia. If adequate sedation is not maintained during regional anesthesia, surgery may be disturbed by patient's movement. This can cause the patient to be physically and mentally stressed with discomfort. Commonly used measurement to determine the adequate sedation level relies on subjective physician's assessment such as scoring for response to talk, shake and pain. This measurement is unreliable and not continuous. Recently, BIS is used to guide sedation during spinal anesthesia as an objective monitoring method in many studies. but previous studies result contrasting in the correlation between BIS and sedation levels with lack in evaluation between sedative drugs. In this study, the investigators will investigate the usefullness of BIS monitoring during regional anesthesia with sedation and evaluate the suitability of correlation BIS and OAA/S between drugs (midazolam, propofol and dexmedetomidine). The anesthetic and sedation protocol will be standardized.

Official Title
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Usefulness of Bispectal Index (BIS) on Depth of Sedation With Dexmedetomidine, Propofol and Midazolam During Spinal Anesthesia : a Prospective Randomized Study

Conditions
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Sedation, Anesthesia, Spinal

Intervention / Treatment
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* Drug: Dexmedetomidine
* Drug: Propofol
* Drug: Midazolam


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who scheduled for knee arthroscopic surgery under spinal anesthesia Exclusion Criteria: Patients with a history of hepatic, renal, cardiovascular disease, and those who have allergy to study drugs (dexmedetomidine, propofol, midazolam). Hemodynamically unstable patients. Patients who is noncommunicative.

Ages Eligible for Study
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Minimum Age: 18 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: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: This study compares to the same intervention (monitor BIS scores and OAA/S scores timely) between all of three sedative drugs.
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dexmedetomidine<br>Dexmedetomidine : initial loading 0.5- 1 mng/kg for 10 minutes and maintenance 0.2-0.7mng/kg/hr Check BIS (bispectral index) score and OAA/S (Observer assessment of alertness/sedation score) by time | Drug: Dexmedetomidine<br>* initial loading dose (0.5   1㎍/kg for 10 minutes) and maintenance infusion (0.2-0.7㎍/kg/hr)<br>|
| Active Comparator: Propofol<br>Propofol : 0.75-3 mg/kr/hr continous infusion Check BIS (bispectral index) score and OAA/S (Observer assessment of alertness/sedation score) by time | Drug: Propofol<br>* continuous infusion (0.75-3mg/kg/hr)<br>|
| Active Comparator: Midazolam<br>Midazolam : initial loading 0.5- 1 mng/kg for 10 minutes and maintenance 0.2-0.7mng/kg/hr Check BIS (bispectral index) score and OAA/S (Observer assessment of alertness/sedation score) by time | Drug: Midazolam<br>* 0.05mg/kg bolus injection and if not OAA/S ≤ 3 within 5 minutes, add 0.01mg/kg at intervals of 1 2 minutes<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| correlation between BIS and OAA/S (observer's assessment of alertness/sedation) score | Statistically significant (p<0.05) correlations between BIS (range of 0-100) and OAA/S scale (range of 1-5) in dexmedetomidine, propofol and midazolam. | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The amount of rescue analgesics (fentanyl in mg) and rescue hypnotic (propofol in mg) | The amount of rescue hypnotics due to insufficient sedation (total additional volume of propofol in mg) and rescue analgesics (total additional volume of fentanyl in mng) due to insufficient pain control | 1 day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bispectral index monitor