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A Comparison of Intrathecal Plain Solutions Containing Ropivacaine 20 or 15 mg Versus Bupivacaine 10 mg

2004; Lippincott Williams & Wilkins; Volume: 99; Issue: 3 Linguagem: Inglês

10.1213/01.ane.0000129976.26455.32

1526-7598

Helena Kallio, Eljas-Veli T. Snäll, Markku P. Kero, Per H. Rosenberg,

Intraoperative Neuromonitoring and Anesthetic Effects

In Brief Ropivacaine, which blocks sensory nerve fibers more readily than motor fibers, is considered to be less potent than bupivacaine. Our hypothesis was that, when used in spinal anesthesia for day surgery, ropi-vacaine 15 and 20 mg would provide faster motor recovery than bupivacaine 10 mg. This prospective, randomized, double-blinded study included 90 ambulatory lower-extremity surgery patients who received 2 mL of ropivacaine 1%, ropivacaine 0.75%, or bupivacaine 0.5%. Motor block was tested with the Bromage scale, and sensory block was tested with pinprick. Ropivacaine 15 mg provided faster recovery of motor block (150 min) than did bupivacaine 10 mg (210 min; P = 0.005), but the median duration of sensory block at T10 (140 min) did not differ significantly from that with bupivacaine 10 mg (140 min). The median duration of sensory block at T10 was significantly longer with ropivacaine 20 mg (170 min) than with bupivacaine 10 mg (140 min; P =0.005), but the median recovery from motor block (210 min) did not differ significantly. We conclude that the duration of sensory block of ropivacaine was two thirds and the duration of motor block was half when compared with bupivacaine, with calculations based on the duration-per-milligram of the local anesthetic. IMPLICATIONS: In spinal anesthesia, ropivacaine provided two thirds of the duration in sensory block and half of the duration in motor block compared with bupivacaine. Both 20 and 15 mg of ropivacaine are suitable for lower-extremity surgery of 1 h in duration. The latter dose is preferable in day-case surgery because of rapid motor recovery.