Comparison of intrathecal meperidine and lidocaine in endoscopic urological procedures

The purpose of this study was to determine if a small dose of intrathecal meperidine would achieve adequate spinal anaesthesia while minimizing complications and to compare its effectiveness with lidocaine. The spinal anaesthetic effects of five per cent lidocaine 0.5 mg.kg-1 in 7.5 percent glucose (n = 20) or five per cent meperidine 0.5 mg.kg-1 (n = 22) were evaluated in 42 ASA physical status II or III patients. Intrathecal injection of the anaesthetic agent was given with the patient in the sitting position in which he remained for ten minutes before being placed in the lithotomy position. The onset time for sensory blockade was seven minutes in the lidocaine group and ten minutes in the meperidine group. Final sensory levels were identical in both groups. Mean arterial blood pressure decreased significantly in the lidocaine group but not in the meperidine group. Motor block was absent in ten patients in the meperidine group but was present in all the patients in the lidocaine group. Duration of postoperative analgesia was 968 min in the meperidine group and 681 min in the lidocaine group (NS). Complications such as nausea, vomiting, itching, drowsiness and respiratory depression were similar in the two groups. It is concluded that low-dose meperidine, 0.5 mg.kg-1, is effective as a spinal anaesthetic agent and has few complications.