Abstract: ObjectiveTo compare effects of sufentanil and dexamethasone on the action of ropivacaine. Methods90 patients were randomly allocated into three groups with 30 cases each in a double-blinded method. Guided by a nerve stimulator, lumbar plexus combined sciatic nerve block was performed with 1%ropivacaine 20mL plus normal saline(NS) 30ml in group I,1%ropivacaine 20mL plus sufentanil 20 g(2mL) and normal saline(NS) 28mL in group II, or 1%ropivacaine 20mL plus dexamethasone 10mg and normal saline(NS) 28mL in group III, so as to observe the each target. ResultsThe durations of sensory and motor blockade in group I were lumbar plexus(7.9±3.6, 5.9±3.4)h and sciatic nerve(8.2±3.5,6.6±3.2)h, respectively ,which were significantly shorter than(15.1±2.4, 10.2±3.5)h and(16.3±2.7, 11.7±3.8)h in group II and(23.6±4.2, 14.7±5.6)h and(23.3±2.4, 14.1±5.1)h in group III(P <0.01). The durations of sensory and motor blockade in group II were significantly shorter than group III(P <0.01). The postoperative sufentanil consumption and PCA button press times in group I were more than that of group II and group III(P <0.05) at 48h after operation. ConclusionSufentanil 0.4 g ·mL-1 and 0.2mg ·mL-1 dexamethasone significantly prolonged the action of ropivacaine in lumbar plexus combined sciatic nerve block and dexamethasone prolonged the action of ropivacaine more than that of sufentanil.

Key words: ropivacaine, sufentanil, dexamethasone, nerve block