A dose-response study of intravenous regional anesthesia with meperidine

Intravenous regional anesthesia (IVRA) with meperidine in doses greater tha n or equal to 100 mg provides effective postoperative analgesia. However, t his technique is associated with excessive opioid-related side effects, whi ch limit its clinical usefulness. The minimal dose of meperidine that is ef fective for NRA has yet to be established. We added 0, 10, 20, 30, 40, or 5 0 mg of meperidine to 0.5% lidocaine IVRA for either carpal tunnel or tenol ysis surgery. Pain and sedation scores and the incidence of side effects we re assessed in the postanesthesia care unit. The duration of analgesia, def ined as the time to first request for pain medications, and use of acetamin ophen/codeine (T3) tablets were measured. The duration of analgesia increas ed, in a dose-dependent manner, in the groups that received 0, 10, 20, and 30 mg of meperidine. There was no significant difference in the duration of analgesia for patients receiving greater than or equal to 30 mg of meperid ine. T3 use was similar in the groups that received 0, 10, and 20 mg of mep eridine and in the groups that received 30, 40, and 50 mg. T3 use was signi ficantly lower in the larger dose groups. The incidence of sedation and of all other side effects was significantly higher in the groups that received 30-50 mg of meperidine compared with those that received smaller doses. We conclude that doses of meperidine large enough to produce the most effecti ve postoperative analgesia with IVRA lidocaine causes a significant inciden ce of side effects, thus limiting its clinical usefulness. Implications: Me peridine may be a useful addition to 0.5% Lidocaine for IV regional anesthe sia. We showed that 30 mg is the optimal dose of meperidine with respect to postoperative analgesia. However, this dose caused a significant incidence of sedation, dizziness, and postoperative nausea and vomiting.