The effect of intravenous dexmedetomidine on the duration of brachial plexus block

ABSTRACT

BACKGROUND: Dexmedemomidine, a highly selective alpha-2 adrenoreceptor agonist has an analgesic and sedative effect without causing respiratory depression. In this study, we compared the duration of brachial plexus block (BPB), the time at which the patient first feels pain after performing BPB, the need for use of analgesics, and the occurrence rate of complications while continuous infusion with dexmedetomidine was used for sedation in patients undergoing BPB, to a control group, who were only infused with normal saline. METHODS: BPB was performed in 48 patients scheduled for upper limb surgery. Infraclavicular approach was provided with 40 ml of 1.5% mepivacaine and 200 microg of epinephrine using nerve stimulator. After verification of successful block, dexmedetomidine group received dexmedetomidine (loading dose 0.1 microg/kg/min for the first 10 minutes followed by a maintenance dose of 0.005 microg/kg/min as required to maintain bispectral index 60-80). In the control group, normal saline was infused at a rate of 10 ml/hr. The duration of BPB, the time at which the patient first feels pain after performing BPB, frequency of complication, and the use of analgesics of the both groups were checked. RESULTS: The motor and sensory block duration, and the time at which the patient first feels pain after BPB were longer in the dexmedetomidine group compared to the control group. And the need for analgesics were less in the dexmedetomidine group. CONCLUSIONS: Intravenous administration of dexmedetomidine prolongs the duration of BPB.