Local anesthetic agents for vitreoretinal surgery: no advantage to mixing solutions.

Abstract

To compare the efficacy of lidocaine, bupivacaine, and a mixture of both in patients undergoing peribulbar anesthesia for vitreoretinal surgery. Cross-sectional study. Ninety patients. Patients who underwent vitreoretinal surgery were randomized into 3 groups based on the peribulbar injection they received: lidocaine, bupivacaine, or a combination of lidocaine and bupivacaine. Time of onset of analgesia, akinesia, and intraoperative pain, if any, was noted. The efficacy of the block was graded from 0 to 5 depending on the adequacy of anesthesia and akinesia and the need for local supplementation. Mean times of onset (± standard deviation) of sensory blockade for the lidocaine, bupivacaine, and combination groups were 2.14±0.18, 2.19±0.13, and 2.17±0.11 minutes, respectively (P = 0.103). Mean times of onset (± standard deviation) of motor blockade for the lidocaine, bupivacaine, and combination groups were 3.04±1.81, 4.04±2.68, and 3.38±2.48 minutes, respectively (P = 0.255). Mean time of onset of intraoperative pain for the bupivacaine group, 149.33±46.33 minutes, was prolonged significantly compared with that of the combination group, 115.83±34.49 minutes, and that of the lidocaine group, 94.17±49.86 minutes (P < 0.001). Adequate anesthesia and akinesia (grade 5) were achieved in 56.7% of the patients in the bupivacaine group compared with 23.3% in the lidocaine group and 30% in the combination group (P = 0.049). In peribulbar anesthesia, 0.5% bupivacaine solution provides better quality of anesthesia than does combination 2% lidocaine and 0.5% bupivacaine in patients undergoing vitreoretinal surgery.