The Effect of Local Anesthetic and Clonidine on the Cutaneous Silent Period During Spinal Anesthesia

Study Overview
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Brief Summary
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The cutaneous silent period is a non-invasive technique that gives insight into the function of thin A delta fibers and as such can be a complement to conventional electrophysiological methods used to study the peripheral nerves. Clonidine is a selective partial agonist of the alpha-2 receptors which, added intrathecally to levobupivacaine, enhances the effect of a local anesthetic, prolongs sensory and motor block during local anesthesia and extends the length of post-operative analgesia. It is believed that clonidine achieves this effect by activating the postsynaptic alpha-2 receptors in the gelatine substance of the spinal cord and blocking the conduction of A-delta and C fibers. The aim of the study is to examine functional changes of Aδ - fibers during the application of spinal anesthesia by measuring the cutaneous slinet period and compare the effect of intrathecal administration of a combination of local anesthetic and clonidine in the quiet skin period in relation to the application of local anesthetic only.

Official Title
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The Effect of Local Anesthetic and Clonidine on the Cutaneous Silent Period During and After Spinal Anesthesia

Conditions
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Inguinal Hernia, Spinal Anesthesia

Intervention / Treatment
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* Drug: levobupivacaine
* Drug: clonidine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA one and two status BMI 18,5 to 24 Exclusion Criteria: Coagulation disorders Polyneuropathy Diabetes mellitus Alcoholism Systemic inflammatory and malignant diseases Stroke

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 0.5% levobupivacaine with 0.015% clonidine<br>0.5% levobupivacaine 15 mg with 0.015% clonidine 50 mcg and 40% glucose 0.5 ml will be preformed as subarachnoid block | Drug: levobupivacaine<br>* Comparing: 0.5% levobupivacaine 15 milligrams (mg) , 0.015% clonidine 50 micrograms (mcg) and 40% glucose 0.5 milliliters (ml) with 0.5 levobupivacaine 15 mg , 0.9% saline 0.33 ml and 40% glucose 0.5 ml<br>* Other names: chirocaine;Drug: clonidine<br>* Comparing: 0.5% levobupivacaine 15 mg , 0.015% clonidine 50 mcg and 40% glucose 0.5 ml with 0.5 levobupivacaine 15 mg , 0.9% saline 0.33 ml and 40% glucose 0.5 ml<br>* Other names: catapressan;|
| Active Comparator: 0.5% levobupivacaine with 0.9% saline<br>0.5% levobupivacaine 15 mg with 0.33 ml of 0.9% saline and 40% glucose 0.5 ml will be preformed as subarachnoid block | Drug: levobupivacaine<br>* Comparing: 0.5% levobupivacaine 15 milligrams (mg) , 0.015% clonidine 50 micrograms (mcg) and 40% glucose 0.5 milliliters (ml) with 0.5 levobupivacaine 15 mg , 0.9% saline 0.33 ml and 40% glucose 0.5 ml<br>* Other names: chirocaine;Drug: clonidine<br>* Comparing: 0.5% levobupivacaine 15 mg , 0.015% clonidine 50 mcg and 40% glucose 0.5 ml with 0.5 levobupivacaine 15 mg , 0.9% saline 0.33 ml and 40% glucose 0.5 ml<br>* Other names: catapressan;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 4 Item Duration of Latency and duration of the cutaneous silent period | Duration of latency and duration of the cutaneous silent (msec) period before subarahnoid block, after regression of motor block, sixth hour of intrathecal administration, 24 hours after intrathecal administration | 24 hours perioperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Duration of motor block | The duration of motor block and its regression will be monitored by Bromage scale:0- Bromage patient can perform movements in the hip, knee and foot. Bromage 1-patient can not perform movements in the hip, but can flexes the knee and move the foot, Bromage 2- patient can not perform movements in the hip and knee, but can move a foot. Bromage 3- patient can not perform movements in the hip, knee nor move the foot. The time of intrathecal levobupivacaine solution or levobupivacaine and clonidine solution is considered to be time zero. | 24 hours perioperative | 
| Duration of sensory block | The time needed for the regression of sensory block in two dermatome will be measured; the time (min) required for a regression in the S1 dermatome, the time required to restore motor functions in Bromage 0 and the duration of analgesia(min). | 24 hours perioperative | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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levobupivacaine, nerve fibers, clonidine