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

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

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.

0.5% levobupivacaine 15 mg with 0.015% clonidine 50 mcg and 40% glucose 0.5 ml will be preformed as subarachnoid block

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

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

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

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

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.

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).

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

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