Association of opioid dependence with the clinical performance of intrathecal ropivacaine during spinal anesthesia: A prospective cohort study

Abstract

Background: Opioid dependence may be associated with altered pain processing and may influence the efficacy of local anesthetics during spinal anesthesia. Objectives: This study evaluated the association of opioid dependence with sensory and motor block characteristics and early postoperative analgesic outcomes following intrathecal ropivacaine anesthesia. Methods: In this prospective cohort study, 60 patients undergoing surgery under spinal anesthesia were enrolled, including 30 opioid-dependent patients and 30 non-dependent controls. Opioid dependence was characterized by a history of regular use of heroin-containing opioid preparations, with recent exposure confirmed by blood-based screening. All participants received intrathecal 0.5% ropivacaine (8 - 10 mg) with fentanyl 25 μg. Sensory block onset and duration, time to maximum sensory block, motor block characteristics, recovery-room pain scores, rescue analgesia, hemodynamic parameters, adverse events, and patient satisfaction were assessed. Results: Ultimately, 28 patients in each group were analyzed. No statistically significant differences in baseline demographic characteristics were observed between the groups. Opioid-dependent patients had shorter sensory and motor block durations (P = 0.003 and P = 0.001, respectively), longer sensory block onset time (P = 0.001), and longer time to maximum sensory block (P = 0.002). Motor block onset and time to maximum motor block did not differ significantly between the groups. Recovery-room pain scores were higher at several assessment time points in the opioid-dependent group, and 11/28 (39.3%) patients in this group required morphine, compared with 4/28 (14.3%) controls (P = 0.035). No significant differences were observed in overall patient satisfaction or adverse events. Hemodynamic measurements did not differ significantly at most time points; however, systolic blood pressure was higher at 25 minutes and heart rate was lower at 12 minutes after spinal anesthesia in the opioid-dependent group (both P = 0.039). Conclusions: Opioid dependence was associated with shorter sensory and motor block durations, a longer sensory block onset time, and greater analgesic requirements in the early recovery room after spinal anesthesia with intrathecal ropivacaine. These findings suggest that opioid-dependent patients may benefit from individualized perioperative anesthetic and analgesic strategies to optimize pain management and potentially improve clinical outcomes.