Adding low dose meperidine to spinal lidocaine prolongs postoperative analgesia

Purpose: To investigate the effects of the addition of low dose meperidine to spinal lidocaine on the sensory and motor blockade profile, and the qual ity and duration of postoperative analgesia. Methods: In a randomized double blind prospective dose finding study 40 pat ients undergoing transurethral prostatectomy with spinal anesthetic were al located to receive 75 mg lidocaine 5% intrathecally as the sole agent (grou p A), or co-administered with 0.15 mg.kg(-1) meperidine (group B) or 0.30 m g.kg(-1) meperidine (group C). Sensory and motor blockade profiles were doc umented. Postoperatively, the amount of analgesics required, time to first analgesic, Visual analogue scores and adverse events were recorded. Results: Sensory blocks at or above T-10 was maintained for 128, 156 and 14 5 minutes in groups A, B and C respectively There was no difference in the latency or duration of the motor block among the three groups. Patients in group C had tower visual analogue pain scores (VAPS) over time than did tho se in groups A and B (P < 0.05). Time to first analgesia was longer(429 +/- 197 minutes) in group C than in group A (254 +/- 157 minutes) (P < 0.05). Fewer patients in group C required parenteral opioid postoperatively than i n group A (P < 0.05). The incidence of bradycardia was higher in the groups receiving meperidine, No symptoms of transient radicular irritation (TRI) were reported in the groups receiving meperidine. Conclusion: The addition of 0.3 mg.kg(-1) of meperidine to spinal lidocaine prolongs postoperative analgesia without delaying discharge from post anes thetic care unit (Table II) and reduces the requirement for parenteral anal gesics (Table III).