Peribulbar anesthesia by ropivacaine plus lidocaine versus bupivacaine plus lidocaine for opthalmic surgery

ABSTRACT

The most recently introduced local anesthetic, ropivacaine, possesses properties similar to those of bupivacaine, but is less neuro- and cardiotoxic. Ropivacaine has not yet been compared with the commonly used anesthetic mixtures for ophthalmologic surgery. The aim of this study was to compare the effects of ropivacaine and bupivacaine, each combined with lidocaine, during peribulbar anesthesia for vitroretinal surgeries. 60 patients were enrolled in this study. The patients were divided into 2 groups, 30 patients each. Bupivacaine group was given a mixture of 50% bupivacaine 0.5% and 50% lidocaine 2%, and Ropivacaine group, 50% ropivacaine 0. 75% and 50% lidocaine 2%. All blocks were done after sedation with 2-4 mg nalbuphine, 1-2 mg midazolam, and 30-50 mg propofol. Peribulbar block was performed by the Bloomberg's modification of the Davis and Mandel technique. Sensory and motor blocks were assessed every 3 minutes for 15 minutes after injection. Resolution of the motor block was evaluated 1, 3, 6 and 24 h after the end of surgery. At the same times, the following variables were assessed degree of pain, occurrence of nausea and vomiting, headache, and any untoward event; analgesic medication administration; and acceptance of the anesthetic technique. Patient characteristics and duration of surgery were similar in the two groups. The onset time of sensory and motor blocks were similar in the two groups with no significant difference. Incomplete kinesis occurred in 6 patients in bupivacaine group and 10 patients in ropivacaine group, but was statistically insignificant. Also, the resolution of motor block occurred in 27 patients in ropivacaine group within 6 hours from the time of injection, while only 18 patients in bupivacaine group has resolution of motor block within the 6 hour period. The number of patients who required postoperative pain medication was significantly higher in bupivacaine group [10 vs. 4 patients]. Also, the number of patients with no pain was always significantly higher in ropivacaine group at 1, 3, 6, and 24 hours postoperatively. Acceptance of anesthesia technique was good in all patients. We concluded from this study that a 11 mixture of 0.75% ropivacaine and 2% lidocaine peribulbar anesthesia provided a short and predictable onset time of surgical anesthesia similar to that provided by a 11 mixture of 0.5% bupivacaine and 2% lidocaine, with better control of postoperative pain relief, less requirement of postoperative analgesia, faster resolution of motor block, and more patients acceptance of anesthesia technique