Comparison of the Effects of Dexmedetomidine and Propofol on the Cardiovascular Autonomic Nervous System During Spinal Anesthesia

Study Overview
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Brief Summary
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Spinal anesthesia induces bradycardia and hypotnesion, because itself decreases parasympathetic activity and increases sympathetic activity. These imbalance of autonomic nervous system can be measured by heart rate variability. Propofol and dexmedetomidine, which are used for sedation during spinal anesthesia, also affect autonomic nervous system, but the exact effects are not well known. The purpose of this study is measuring the effects of propofol or dexmedetomidine on autonomic nervous system in spinal anesthesia.

Detailed Description
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Spinal anesthesia induces bradycardia and hypotnesion, because itself decreases parasympathetic activity and increases sympathetic activity. These imbalance of autonomic nervous system can be measured by heart rate variability. Propofol and dexmedetomidine, which are used for sedation during spinal anesthesia, also affect autonomic nervous system but the exact effects are not well known. Moreoever, the effect of spinal anesthesia combined with sedation agent on autonomic nervous system has not been evaluated. The purpose of this study is measuring the effects of propofol or dexmedetomidine on autonomic nervous system in spinal anesthesia. The current study is prospective randomized pilot study. Patients are assigned to propofol group and dexmedetomidine group. Using electrocardiaogram analysis, the change of autonomic nervous system will be measured from preoperative to end of surgery.

Official Title
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Comparison of the Effects of Dexmedetomidine and Propofol on the Cardiovascular Autonomic Nervous System During Spinal Anesthesia: Pilot Study

Conditions
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Spinal Anesthesia, Autonomic Nervous System

Intervention / Treatment
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* Drug: Propofol
* Drug: Dexmedetomidin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age 20 60 years old Scheduled lower extremity surgery under spinal anesthesia Exclusion Criteria: Arryhthmia Uncooperative patients Diabetes On medication: beta blocker, psychiatric medicine Thyroid function abnormality

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 60 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: Propofol group: propofol infusion as sedation drug Dexmedetomidine group: dexmedetomidine infusion as sedation drug
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Propofol group<br>Using propofol as a sedation drug Infusion rate control Effect site concentration 0.3 1.0 mg/ml using target concentration infusion Bispectral index 60 80 | Drug: Propofol<br>* Propofol as a sedation drug<br>* Other names: FRESofol MCT inj 1% 500mg/50ml, Fresenium Kabi;|
| Active Comparator: Dexmedetomidine group<br>Using dexmedetomidine as a sedation drug First 10 minutes 1.0 mcg/kg loading After 10 minutes 0.3-1.0 mcg/kg/hr maintenance Bispectral index 60 80 | Drug: Dexmedetomidin<br>* Dexmedetomidine as a sedation drug<br>* Other names: Medex inj, 200mcg/2ml, ILSUNG;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serial heart rate variability | Serial change of frequency domain results from EKG RR interval Baseline: before entering the operating room T0: Preinduction T1: 10 minutes after spinal anesthesia T2: 10 minutes after starting sedation T3: 20 minutes after starting sedationi Frequency domain results Total power (ms2) Low frequency (ms2) High frequency (ms2) LF/HF ratio | 40 minutes (before entering the operating room   20 minutes after starting sedation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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spinal anesthesia, autonomic nervous system, dexmedetomidine, propofol