Although spinal bupivacaine may have too long duration to be useful in the ambulatory setting, recent animal data suggest that lidocaine added to spinal bupivacaine may reduce the duration of bupivacaine spinal anesthesia. We explored whether lidocaine added to spinal bupivacaine could shorten the duration of bupivacaine spinal anesthesia in humans similarly to what has been reported in animals. Ninety patients presenting for transurethral resection of bladder tumor or prostate were assigned to one of three groups by double blind randomization to receive intrathecal 1.5 mL of hyperbaric 0.5% bupivacaine, plus 0.6 mL of one of three solutions: saline (Group I, n = 30, control), 1% lidocaine (Group II, n = 30), and 2% lidocaine (Group III, n = 30). Peak sensory block level, time to peak sensory block, times to two-segment, L1, and S2 regressions from peak sensory block, motor blocks at peak sensory block, L1, and S2 regressions, and postanesthesia care unit stay time (PACU time) were measured. Times to peak sensory block were similar in all three groups. Times to two-segment, L1, and S2 regressions from peak sensory block, and PACU time were significantly reduced in Group II compared to Group I. Times to L1, S2 regressions, and PACU times in Group III were significantly prolonged. We conclude that lidocaine (6 mg) mixed to spinal bupivacaine (7.5 mg) can shorten the duration of bupivacaine spinal anesthesia, therefore provide more rapid recovery from the spinal anesthesia compared to the same dose of bupivacaine (7.5 mg) alone.
Lee, Bai, Lee, Kim, Shin, Lee, , , (2008). The duration of intrathecal bupivacaine mixed with lidocaine. Anesthesia and analgesia, 2008 Sep;107(3):824-7. https://www.ncbi.nlm.nih.gov/pubmed/18713891