Sparing Effects of Sufentanil on Epidural Ropivacaine in Elderly Patients Undergoing Transurethral Resection of Prostate Surgery

PURPOSE: This study examined the sparing effect of sufentanil on the median effective concentration (EC(50)) of epidural ropivacaine in elderly patients undergoing elective transurethral resection of prostate (TURP). MATERIALS AND METHODS: This was a prospective randomized double-blind dose-response study. Fifty eight elderly patients with American Society of Anesthesiologists physical status I-II who were scheduled for TURP surgery under epidural anesthesia were randomly allocated to a group receiving 15 mL of ropivacaine (group R) or a group receiving ropivacaine plus 5 µg of sufentanil (group RS). The concentration of ropivacaine was determined by a Dixon's up-and-down sequential allocation. The first participant received 0.3% of ropivacaine in both groups and subsequent concentrations were determined by the response of the previous patient in the same group. The EC(50) of epidural ropivacaine was analyzed using the Dixon and Massey method. RESULTS: The EC(50) of ropivacaine during TURP surgery was 0.186% (95% confidence interval, 0.173-0.200%) in group R, and 0.136% (95% confidence interval, 0.127-0.144%) in group RS (p<0.01). No differences in Bromage scale of motor block examination and the onset time of sensory block were observed. CONCLUSION: Administration of 5 µg of epidural sufentanil caused a 37% reduction in the EC(50) of epidural ropivacaine in elderly patients who underwent TURP surgery. Thus, sufentanil addition during surgery of TURP can decrease the dose of ropivacaine anesthesia required.