RESUMO
Objective:To evaluate the effect of dexmedetomidine on the blood concentrations of ropivacaine during sciatic nerve block in rabbits.Methods:Twelve New Zealand rabbits of both sexes, weighing 2-3 kg, were randomly divided into ropivacaine group (R group) and ropivacaine mixed with dexmedetomidine group (RD group). The right femoral vein was cannulated for blood sampling in both groups, 0.375% ropivacaine 3 ml was injected around the left sciatic nerve in group R, and 0.375% ropivacaine 3 ml containing 1.5 μg/kg dexmedetomidine was injected instead in group RD.Blood samples from the right femoral vein were collected before nerve block (T 0) and at 15, 30, 45, 60, 120 and 180 min after nerve block (T 1-6) for determination of plasma concentrations of ropivacaine using high-performance liquid chromatography after centrifugation, and concentration-time curves were plotted. Results:Compared with group R, the blood concentrations of ropivacaine were significantly decreased at T 1-3 ( P<0.05), no significant change was found in the blood concentrations of ropivacaine at T 4-6 ( P>0.05), the peak blood concentration of ropivacaine was significantly decreased ( P<0.01), and no significant change was found in the time to peak blood concentrations of ropivacaine or area under the concentration-time curves in group RD ( P>0.05). Conclusions:Dexmedetomidine can decrease the blood concentrations of ropivacaine during sciatic nerve block in rabbits.