The effects of an epidural infusion of ropivacaine versus saline on sensory block after spinal anesthesia.

Abstract

Several investigators have described the effect of bolus injections on sensory block during combined spinal epidural anesthesia. This study investigates the effects of the immediate epidural infusion of 0.2% ropivacaine versus 0.9% saline on spinal anesthesia. Forty-four patients undergoing partial hip replacement were randomly assigned to 2 groups, receiving epidural infusion of 0.2% ropivacaine 10 mL/h (group R, n = 22) or 0.9% NaCl 10 mL/h (group S, n = 22), immediately after spinal anesthesia with 7.5 mg 0.5% hyperbaric bupivacaine. Postoperative analgesia was provided in both groups using a ropivacaine patient-controlled epidural analgesia technique. Sensory block, motor block, postoperative pain scores, ropivacaine consumption, and patient satisfaction were recorded. There was no difference between the 2 groups in the characteristics of the sensory block. The duration of motor block was prolonged in group R (312 +/- 95 minutes vs 198 +/- 78 minutes; P < .001). Postoperative pain scores and 24-hour ropivacaine consumption were similar among groups. Demand/delivery ratio was 1.6 in group R and 3.5 in group S (P = .048). A significantly higher number of patients in group R described their satisfaction as excellent (20 patients vs 6 patients; P < .001). Epidural infusion of ropivacaine 0.2% initiated immediately after spinal anesthesia prolonged the regression of motor block but not the regression of sensory block when compared with saline infusion.