Efficacy of different doses of dexmedetomidine mixed with ropivacaine for brachial plexus block / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the efficacy of different doses of dexmedetomidine mixed with ropivacaine for brachial plexus block.Methods One hundred and twenty ASA physical status Ⅰ or Ⅱ patients of both sexes,aged 20-60 yr,weighing 40-70 kg,scheduled for upper extremity surgery under brachial plexus block,were randomly divided into 6 groups (n =20 each)ropivacaine group (group R) and different doses of dexmedetomidine groups (groups RD1-5).Brachial plexus block was performed using the interscalene approach.In group R,interscalene brachial plexus block was performed using 0.5 ％ ropivacaine 25 ml (single injection).In groups RD1.5,interscalene brachial plexus block was induced with a mixture (25 ml) of dexmedetomidine 0.25,0.50,0.75,1.00,1.25μg/kg and 0.5 ％ ropivacaine,respectively.The onset time and duration of sensory and motor block were recorded.The adverse effects such as adverse cardiovascular events,excessive sedation,and pneumothorax were also recorded.Results Compared with group R,the onset time was significantly shortened,and the duration of block was prolonged (P ＜ 0.05).Compared with groups RD1 and RD2,the onset time was significantly shortened,and the duration of block was prolonged in groups RD3 5 (P ＜ 0.05).There was no significant difference in the parameters mentioned above between groups RD1 and RD2 or among groups RD3,RD4 and RD5 (P ＞ 0.05).Some patients developed bradycardia,hypotension or excessive sedation in groups RD4 and RD5,while no adverse effects were observed in the other groups.Conclusion Dexmedetomidine 0.75 μg/kg mixed with 0.5 ％ ropivacaine 25 ml can be safely and effectively used for brachial plexus block in patients.