THE RECOVERY PROFILE OF HYPERBARIC SPINAL-ANESTHESIA WITH LIDOCAINE, TETRACAINE, AND BUPIVACAINE

Background and Objectives. Surgical procedures previously considered t oo lengthy for the ambulatory surgery setting are now being performed during spinal anesthesia. The complete recovery profile of tetracaine and bupivacaine are now of interest but are not available in the liter ature. This study was conducted to compare times to ambulation, voidin g, and complete block resolution, as well as the incidence of back and radicular pain, after spinal anesthesia with lidocaine, bupivacaine, and tetracaine. Methods. Twelve adult volunteers underwent spinal anes thesia on three separate occasions with three local anesthetics (lidoc aine 100 mg, bupivacaine 15 mg, and tetracaine 15 mg in hyperbaric sol utions) in random order and in a double-blind fashion. A 24-gauge Spro tte spinal needle was placed at the L2-3 interspace. The level of anal gesia to pinprick was determined moving cephalad in the midclavicular line until a dermatome was reached at which the prick felt as sharp as over an unblocked dermatome. One dermatome caudad to this point was r ecorded every 5 minutes as the level of analgesia. We also recorded th e times to voiding, unassisted ambulation, and complete resolution of sacral anesthesia. Results. There was no difference between tetracaine and bupivacaine in time taken for two-and four-segment regression of the analgesia level. However, times to ambulation and complete resolut ion of the block were significantly shorter with bupivacaine then with tetracaine. With lidocaine, times to four-segment regression, ambulat ion, voiding, and complete regression of the block were significantly shorter than with bupivacaine and tetracaine. Time to two-segment regr ession did not differ among local anesthetics. Back and radicular pain symptoms were reported by three subjects after lidocaine subarachnoid block but not after tetracaine or bupivacaine. Conclusion. Among indi vidual subjects, lidocaine exhibited the shortest recovery profile. Ho wever, the recovery profiles of the three anesthetics were very variab le between subjects. Time to meeting discharge criteria after bupivaca ine or tetracaine was faster in a few subjects than that after lidocai ne in other subjects. For ambulatory anesthesia, times to two-and four -segment regression do not accurately predict time to readiness for di scharge after spinal anesthesia.