The effect of fentanyl pretreatment on propofol sedation during spinal anesthesia

Abstract

Background: To test whether propofol with fentanyl pretreatment produces better sedative efficacy than that of propofol alone in patients under spinal anesthesia. Methods: Fifty-four patients undergoing lower leg orthopedic surgery were sedated randomly with propofol-normal saline (PN, n = 27) or propofol-fentanyl (PF, n = 27). In both groups, sedation was maintained with an initial loading dose of propofol 0.4 mg/kg, and subsequent infusion at a rate of 50 μg/kg/min. Prior to propofol administration, normal saline 0.02 ml/kg or fentanyl 1 μg/kg was given intravenously to Group PN and Group PF, respectively. We measured bispectral index (BIS) and the Observer’s Assessment of Alertness/ Sedation (OAA/S) scale scores to investigate sedative efficacy, prior to and at 5 minute intervals for 1 hour after propofol infusion. Results: BIS and OAA/S scores were decreased in both groups over time after starting propofol infusion (P ＜ 0.0001). Comparison between the PF group and the PN group at each time point did not demonstrate statistically significant differences, and group effect was also not found to be statistically significant for BIS and OAA/S [BIS, P = 0.4644 (group effect), P = 0.7817 (time*group interaction)], [OAA/S scale, P = 0.4373 (group effect), P = 0.125 (time*group interaction)]. Conclusions: Judging from the BIS and OAA/S scores, propofol with fentanyl pretreatment did not produce an additional sedative effect compared to propofol alone in spinal anesthesia.