No abstract

SummaryPeribulbar anaesthesia with 1% ropivacaine and 0.75% bupivacaine, both with hyaluronidase, was assessed in a prospective, randomised, double-blind study of 100 patients undergoing cataract surgery. Pharmacokinetic data were obtained from 22 subjects. Akinesia of the globe developed slightly more rapidly in the ropivacaine group, but this difference was only statistically significant at 2 min after injection of the local anaesthetic. Lid akinesia was significantly more complete in the ropivacaine group. There were no differences between the groups with respect to peri-operative analgesia or duration of akinesia. The dose-adjusted maximum concentration of ropivacaine was approximately twice that of bupivacaine with significantly higher values of the area under the concentration-time curves. No drug-related adverse effects were observed. We conclude that there are no clinically significant differences in the quality of the sensory and motor block between 1% ropivacaine and 0.75% bupivacaine when used for peribulbar anaesthesia.

We describe two instances of central nervous system (CNS) toxicity in the same patient following repeated brachial plexus blocks induced by high doses of ropivacaine (6 mg x kg(-1) and 4.5 mg x kg(-1), respectively). Although very high total and free plasma concentrations of ropivacaine were found up to 98 min after induction of the blocks, no signs of cardiovascular toxicity apart from hypertension and sinus tachycardia were observed. The measured plasma concentrations are the highest so far reported in the literature. We conclude that this case demonstrates the high cardiovascular safety level of ropivacaine. These high doses, however, resulted in severe toxic CNS symptoms. Therefore, it is stressed that the dose in relation to the weight of the patient must be calculated when administering a large volume of local anesthetic.

Absorption and tissue distribution of ropivacaine is slower than for bupivacaine following caudal administration in children.

The use of MCPB was associated statistically insignificantly with less retinal microemboli compared to CCPB. MCPB was complicated by excess bleeding and need for transfusion. The feasibility of MCPB techniques in valve surgery requires further studies.