The Effect Of Adding Dexmedetomidine To Ropivacaine For Axillary Brachial Plexus Block

Objective: In this study, we aimed to explore the mechanism of action ofdexmedetomidine by investigate its effects as an adjuvant to ropivacaine onaxillary brachial plexus block.Methods:60American Society of Anesthesiologists’ I patients scheduledfor forearms or fingers surgeries were evaluated. Axillary brachial plexus blockwas performed with either29ml ropivacaine0.375%(Group C,n=20),29mlropivacaine0.375%plus0.5μg/Kg dexmedetomidine(Group BPD,n=20), or29ml ropivacaine0.375%plus systemic0.5μg/Kg dexmedetomidine (GroupIVD,n=20). Their vital signs, ramsay sedation score, duration of nerve block,vas score, use of analgesic and the relevant adverse reaction within48hoursafter the surgery were evaluated.Results: There were3cases with imperfect block and no general anesthesiacases in the three groups. The dose of0.5μg/Kg dexmedetomidine prolonged theduration of sensory and motor block when administered perineural andsystemically compared with ropivacaine alone.(P<0.05). Usage rate ofpostoperative analgesic was lower in group BPD (P<0.05). At T2and T3,thepatients of Group BPD and Group IVD had slower HR and higher ramsay sedation score than Group C (P<0.05). No block-related side-effects occurredduring the study period or at the follow-up examination.Conclusion:This study shows a profound prolongation of axillary brachialplexus block with perineurally administered dexmedetomidine as an adjuvant toropivacaine.It may works by the superposition effect of the local and thesystemic mechanisms.