A clinical comparison of equal concentration and volume of ropivacaine and bupivacaine for interscalene brachial plexus anesthesia and analgesia in shoulder surgery.

BACKGROUND AND OBJECTIVES: The aim of this study was to compare the same volume and concentration of bupivacaine and ropivacaine for interscalene brachial plexus block anesthesia and postoperative analgesia in shoulder surgery.

METHODS: Forty-four patients scheduled for elective shoulder surgery were prospectively randomized to receive in a double-blind fashion 30 mL of either 0.5% bupivacaine or ropivacaine for interscalene block. The block was prolonged after surgery by using a patient-controlled interscalene analgesia with 0.15% of either bupivacaine or ropivacaine. The mean onset times of surgical blocks were determined after interscalene block. Pain relief was regularly assessed by using a visual analog scale, side effects were noted, and the patients were asked to rate their satisfaction at the end of the study.

RESULTS: Two patients with bupivacaine and 1 with ropivacaine failed to achieve surgical block and were excluded. The mean onset times of surgical blocks were 18 +/- 12 minutes with ropivacaine and 21 +/- 13 minutes with bupivacaine. The pain scores, total volume infused of local anesthetics, incremental dose requested and received, total rescue analgesic, and side effects were similar between the groups. Postoperative pain control was similarly effective and patient satisfaction was high in both groups.

CONCLUSIONS: This study shows that the same volume and concentration of bupivacaine and ropivacaine (30 mL of 0.5%) for interscalene brachial plexus block anesthesia produce similar surgical block. When prolonging the block with a patient-controlled interscalene analgesia infusion, 0.15% bupivacaine or ropivacaine provide adequate pain relief, similar side effects, and high patient satisfaction after shoulder surgery.