Clinical Evaluation of Supraclavicular Block with a Mixture of Local Anesthetics ; Comparison of the Effect on Onset and Duration

Kim, Byung Gee; Lee, Il Ok; Kim, Nan Suk; Choi, Young Suk

Abstract

In the case of brachial plexus block, mixtures of local anesthetics can combine better features of both components, rapid onset and long duration. Combining effects may influence the onset and duration of neural blockade. Our study was undertaken in order to compare the onset time (time of injection to time of loss of pain on pin prick) and duration of analgesia (time of return of sense of pain on pin prick minus time required for onset of analgesia) of a lidocaine and bupivacaine mixture with 5 minutes interval injection of lidocaine and bupivacaine. The patients admitted to our hospital for hand or forearm operations were divided into three groups. In Group 1, 9 patients were injected with 0.5% bupivacaine 150 mg only, in Group 2, 11 patients were injected with a mixture of 29: lidocaine 200 mg and 0.5% bupivacaine 100 mg, in Group 3, 10 patients were injected with 2% lidocaine 200 mg and 5 minutes later, 0.5% bupivacaine 100 mg was injected through the same needle. Group 3 had the shortest onset time (7.2+/-0.2 minutes) with moderately long duration (9.4+/-2.4hours). Group 2 had a moderately rapid onset time (9.4+/-2.3 mintes) with the shortest duration (8.6+/-1.6 hours). Group 1 had the slowest onset time (14.8+/-4.3 minutes) with the longest duration (11.3+/-2. 4 hours). The time for analgesia to reach the C7 dermatome was the slowest in group 1 and Group 2, but in Group 3, there was no difference in the time needed to achieve analgesia in all dermatomes.