A comparison of the dose of anesthetic agents and the effective interval from the block procedure to skin incision for ultrasound-guided supraclavicular brachial plexus block in upper extremity surgery

Objective: The aim of this study was to review and evaluate the selection and dose of anesthetic agents and the interval from the block procedure to skin incision for supraclavicular brachial plexus block in upper extremity surgery. Methods: We reviewed our cases that underwent upper extremity surgery using only ultrasound-guided supraclavicular brachial plexus block in our hospital between 2011 and 2016. Adverse events during surgery were evaluated. Receiver operating characteristic (ROC) curves were constructed to investigate the relationship between the time from the end of the block procedure to skin incision and the use of local anesthesia on the surgical site. Results: There were 255 patients who were divided into three groups according to the anesthetic agents used: group 1, 1% lidocaine (L) 10 ml þ 0.75% ropivacaine (R) 20 ml (n = 62); group 2, L 20 ml þ R 10 ml (n = 93); and group 3, L 10 ml þ R 15 ml (n = 100). The rate of use of local anesthesia on the surgical site was significantly higher in group 3 than in the other two groups. There were no significant differences in the other evaluated items among the three groups. ROC curve analysis indicated that 24 min from the end of the block procedure to skin incision might reduce the use of local anesthesia. Conclusion: The total volume of anesthetic agents had an important influence on the rate of the addition of local anesthesia for surgical pain; however, the combined dose of agents did not influence the evaluation items. For effective analgesia, 24 min should elapse from the end of the block procedure to skin incision.