RESUMO
Objective To evaluate effects of dexmedetomidine on onset ,duration of supraclavicular brachial plexus block induced by levobupivacaine and postoperative analgesia with ultrasound guide .Methods Eighty patients undergoing elective surgeries of distal arm and forearm with class Ⅰ ~ Ⅱ ASA were enrolled ,and the patients were randomly divided into two groups ,one was control group (group C) patients with supraclavicular brachial plexus block by 30 ml of 5% levobupivacaine contained 1 ml normal saline ,the other was dexmedetomidine group patients (group D) with supraclavicular brachial plexus block by 30 ml of 5% levobupivacaine contained 100μg dexmedetomidine .The supraclavicular brachial plexus block was guided with ultrasound .Observation indicators include :sensory and motor onset blocks ,duration of sensory and motor blocks ,time to first rescue analgesia and hemodynamic parameters .Results The differences of sensory block onset between group C and D were not significant .Compared to group C ,motor block onset of group D was significantly shorter (P<0 .01) ,sensory block duration and motor block duration were longer (P<0.001) ,time to first rescue analgesia after the surgeries was longer (P<0 .001) .Mean arterial pressure and mean heart rate of group D were significantly lower than those of group C ,respectively (P<0 .02) .Conclusions Dexmedetomidine can significantly prolong the duration of block and postoperative analgesia of supracla-vicular brachial plexus block induced by levobupivacaine .