Sensory, motor, and sympathetic block during epidural analgesia with 0.5% and 0.75% ropivacaine with and without epinephrine.

ABSTRACT

BACKGROUND AND OBJECTIVES: Ropivacaine is a new long-acting local anesthetic, with vasoconstrictive properties. The purpose of this randomized, double-blind study was to evaluate sensory, motor, and sympathetic block following epidural anesthesia, and the influence of the addition of epinephrine. METHODS: Forty-eight male patients, scheduled for transurethral surgery, received 20 mL of 0.5% or 0.75% ropivacaine with or without addition of epinephrine (5 micrograms/mL) epidurally. Sensory block was assessed by pinprick, motor block by a modified Bromage scale, and sympathetic block by skin resistance level, skin resistance response, skin temperature, and skin blood flow (laser Doppler flowmetry). RESULTS: Onset time for analgesia was short (Th10 blocked after median 5.3-6.7 minutes), and maximum segmental level was median Th 2-3 (range, Th5-C4). A tendency toward a dose-response relationship (duration of sensory block) was noted for the 0.75% solutions (median, 258-264 minutes at Th10) compared to the 0.5% solutions (median, 228-234 minutes at Th10). Only about half of the patients exhibited a complete motor block of the lower extremities with a longer duration with the 0.75% solutions. The majority of patients had a marked or complete sympathetic block in the lower limbs. Short-lasting, mild hypotension, responding well to ephedrine intravenously, was noted in 40%-70% of the patients. No serious adverse reactions were observed. CONCLUSIONS: Ropivacaine given epidurally provided adequate sensory anesthesia and motor block for transurethral surgery. Addition of epinephrine did not provide any significant prolongation of the sensory or motor block, nor any influence upon the sympathetic block.