الفهرس 
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Abstract
Surgical anesthesia of the upper limb, from the elbow to the hand, may be readily achieved by injection of local anesthetic around the brachial plexus. This regional anesthesia technique avoids the need for general anesthetic and its accompanying risks (postoperative nausea and vomiting, postoperative drowsiness, etc). Control of postoperative pain is also excellent as the sensory block typically persists for several hours following the injection.
Peripheral nerve blocks are almost always performed as blind procedures. The use of ultrasound appears to permit accurate deposition of the local anesthetic perineurally, and has the potential to improve the success and decrease the complications of supraclavicular brachial plexus block α2-adrenergic (α2-AR) receptor agonists have been successfully used in several clinical settings in view of diverse actions which include sedation, analgesia, anxiolysis, perioperative sympatholysis, cardiovascular stabilizing effects, reduced anesthetic requirements, and preservation of respiratory function.
Dexmedetomidine, is a selective α2-adrenoceptor agonist that is used as an adjuvant mixed with local anesthetics during regional anesthesia addition of opioids to local anesthetics has gained popularity. Opioids have multiple central neuraxial and peripheral mechanisms of analgesic action
Fentanyl is a mu opioid receptor agonist that has been used as adjuvant to local anesthetics to improve efficacy of peripheral nerve block
This study was carried out on patients scheduled for elective orthopedic upper limb surgeries.
The patients were divided into three groups, 30 patients each, according to the local anesthetic mixture used:
• C group (control group): 20 ml bupivacaine 0.5% + 1 ml normal saline 0.9%
• D group (dexmedetomidine group): 20 ml bupivacaine 0.5% + 75ug dexmedetomidine in 1 ml
• F group (fentanyl group): 20 ml bupivacaine 0.5% + 50ug fentanyl in 1 ml
The total volume of the local anesthetic mixture was equal (21 ml) for all patients.
A comparison was made between the three groups as regards motor and sensory block, onset, duration and quality of postoperative analgesia, hemodynamic and respiratory variables as well as side effects during forearm or hand surgery under ultrasound guided supraclavicular block.
Demographic data (age, sex, BMI) and operational data (duration of surgery) were statistically comparable among the three groups.
The present study revealed that supraclavicular brachial plexus block with 20ml 0.5% bupivacaine supplemented with 75μg dexmedetomidine significantly affect block characteristics evident by shortened onset time of both sensory and motor block compared
with the same block supplemented by 50μg fentanyl and 0.5% bupivacaine in patients undergoing upper limb surgery. Also addition of dexmedetomidine significantly prolongs the duration of sensory and motor block and reduced the total postoperative analgesic consumption.
No patients in the study demonstrated any signs or symptoms of local anesthetic drug toxicity.
There were no serious postoperative complications in the three groups.
Ultrasound guided supraclavicular block appears to be associated with a high success rate, short onset time and low complication rate.