A prospective, randomized, double-blinded comparison of ropivacaine 0.5%, 0.75%, and 1% ropivacaine for peribulbar block

Study Objective: To evaluate the efficacy of three different concentrations of ropivacaine (0.5%, 0.75%, and 1%) together with a single concentration of hyaluronidase administered for peribulbar block. Design: Prospective, randomized, double-blind study. Setting: Anesthesia department of a university teaching hospital. Patients: 68 ASA physical status I, II, and III patients undergoing elective cataract surgery. Interventions: Patients were randomly allocated to receive peribulbar block with 65 mL of either 0.5% (Group Ropi-5; n = 22), 0.75% (Group Ropi-7.5; n = 22), or 1% ropivacaine (Group Ropi-10, n = 24). In all patients, 0.5 mL of hyaluronidase was added to the local anesthetic solution. Measurements and Main Results: A larger proportion of patients in Groups Ropi-7.5 (82%) and Ropi-10 (83%) showed complete motor block 15 minutes after injection compared with Group Ropi-5 (55%; p = 0.05, and p = 0.03, respectively). Hypotension (reduction of systolic blood pressure by 30% or more from baseline) was observed in two Group Ropi-5 patients (9%), and two Group Ropi-7.5 patients (9%; p = 0.31), whereas bradycardia (reduction in heart rate less than or equal to 50 bpm) was observed in one Group Ropi-5 patient (4%), and three Group Ropi-10 patients (12%; p = 0.18). Seven hours after surgery, a smaller proportion of Group Ropi-10 patients (64%) showed complete recovery of sensory function as compared with both Group Ropi-5 (94%) and Group Ropi-7.5 (90%; p = 0.03 and p = 0.03, respectively). Complete recovery of motor function 1 hour after surgery was more frequent in Group Ropi-5 (37%) than in Group Ropi-7.5 (5%) or Group Ropi-10 (9%; p = 0.05 and p = 0.05, respectively); however, no other differences in recovery of motor function were observed at any other observation times, with complete recovery in all patients 7 hours after surgery. Conclusions: While confirming that ropivacaine is a good option for peribulbar anesthesia, this study demonstrated that the use of 0.75% or 1% concentrations are Preferred in that they produce quick and deep sensory and motor block of the operated eye. If recovery of normal motor function is important after surgery, the 0.75% concentration probably represents the best compromise. (C) 2004 by Elsevier Inc.