Introduction: The effects of ropivacaine and bupivacaine in interscalene block have been studied, but we usually combine lidocaine with ropivacaine or bupivacaine to fasten the onset. However, the effects of these combinations are not studied. Purpose: To compare the effects of two different concentrations of the combination of ropivacaine or bupivacaine with lidocaine. Materials and Methods: One hundred adult patients scheduled for repair of fracture of the upper extremity under interscalene block were randomly allocated into one of the groups receiving the combination of 15 mL of ropivacaine 0.375% (Ropivacaine 0.375 group), ropivacaine 0.75 % (Ropivacaine 0.75 group), bupivacaine 0.25 % (Bupivacaine 0.25 group), or bupivacaine 0.5 % (Bupivacaine 0.5 group) with lidocaine 1.0 % 15 mL. The onset and duration of motor and sensory blocks were compared among the 4 groups by Kruskal Wallis test followed by Mann-Whitney U test. Results: Three patients in the Ropivacaine 0.375 group did not show any motor blocks. Ropivacaine groups had significantly slower onset of motor block and longer duration of motor and sensory blocks than Bupivacaine groups. Bupivacaine 0.5 group had significantly longer duration of both blocks than Bupivacaine 0.25 group, while Ropivacaine 0.375 and 0.75 groups had the similar duration of both blocks. Conclusions: In interscalene block combined with lidocaine, ropivacaine had slower onset of motor block and longer duration of both blocks than bupivacaine. Only bupivacaine showed the different duration of the blocks between two concentrations.
Key words: interscalene brachial plexus block, ropivacaine, bupivacaine, sensory block, motor block
|
