COMPARATIVE STUDY BETWEEN CLONIDINE, KETAMINE, AND XYLOCAINE IN INTRAVENOUS REGIONAL ANESTHESIA

Abstract

Biers block in the upper limb used for minor elective hand surgery since 1908 xylocaine is the local anaesthetic of choice in this technique by it's binding and thus inactivating the Na channel in the axons of the peripheral nerve and prevent propagation of action potential yet xylocaine has no or very short postoperative analgesia. From this point clonidine and ketamine was tried to be used as mixture with xylocaine to potential its sensory and motor block together with satisfactory postoperative period of pain free. Clonidine is an a2 agonist having the following effect: *Cardiovascular system: They inhibit norepinephrine release from peipheral postjunctional nerve endings. Also, a2 agonists exert an important hypotensive action by affecting central vasomotor control. *Respiratory system: Clonidine exerts a minor respiratory depressant effect, which is clinically insignificant. *Endocrine system: They enhance release of growth hormone, inhibit the release of ACTH and insulin, and decrease levels of circulating norepinephrine. *Renal system: They induce diuresis. *Gastrointestinal system: they reduce salivary creations and decrease vagally mediated gastric and small bowel motility. *Hematologic system: they produce aggregation of human platelets. *Local analgesic effect: through it's action on the peripheral nerve by inhibiting voltage dependent calcium channels and inhibiting nociceptive neurotransmitter release.