This randomized controlled,double blind study will done after approval by ethical committee of Ahvaz Jundishapoor University of Medical Sciences and taking the clinical randomized trial code from the IRCTcenter.52patients candidate for elective surgeries of upper limb addmitted in trauma center of Imamkhomeini hospital in Ahvaz will been studied.after obtaining the written informed consent from patients,they wil randomly allocated into 2 groups A&B.under standard monitoring and IV access patients will receive oxygen with face mask ,fluid and premedication with sedative drugs.the supraclavicular brachial plexus block will performed using ultrasonographic gauide with anesthesiologist.groupe A will receive solution of Lidocain plus magnesium sulfate and groupe B will receive Lidocain plus normal salin.the anesthesiology resident who didnot know about the pharmaceutical composition and patient groups,will assess the sensory and motor block,vital signs and postoperative pain,and will complete the questionnaire.
sensory block level will assess by pinprick testing dermatomes of sensory regions with using 3-point scale.the intensity of motor block will assess using the modified bromage scale.during surgery ECG,HR,NIBPand oxygen saturation will monitored and written every 15 minutes.postoperative pain wil assess using VAS score at 0,1,2,4,8,16&24 hours after surgeries.patients with VAS>3 will receive analgesic as meperidin 25 mg/IM.the side effects will assess during surgeries and 24 hours afterthem.