Intravenous regional anesthesia using lidocaine and clonidine

Background: Clonidine has been added to local anesthetic regimens for vario us peripheral nerve blocks, resulting in prolonged anesthesia and analgesia . The authors postulated that using clonidine as a component of intravenous regional anesthesia (IVRA) would enhance postoperative analgesia. Methods: Forty-five patients undergoing ambulatory hand surgery received NR A with Lidocaine, 0.5%, and were assigned randomly and blindly to three gro ups. The control group received intravenous saline, the intravenous clonidi ne group received 1 mu g/kg clonidine intravenously, and the IVRA clonidine group received 1 mu g/kg clonidine as part of the IVRA solution. After the ir operations, the patients' pain and sedation scores and analgesic use wer e recorded. Results: Patients in the IVRA clonidine group had a significantly longer pe riod of subjective comfort when they required no analgesics (median [range] ) for 460 min (215-1,440 min), compared with 115 min (14-390 min) for the c ontrol group and 125 min (17-295 min) for the intravenous clonidine group ( P < 0.0001). The patients who received NRA with clonidine reported signific antly lower pain scores 1 and 2 h after tourniquet deflation compared with the other groups, and they required no fentanyl in the postanesthesia care unit. They also required fewer analgesic tablets (325 mg acetaminophen with 30 mg codeine) in the first 24 h (2 +/- 1, mean +/- SD) compared with the other two groups, 5 +/- 1 tablets (control) and 4 +/- 2 tablets (intravenou s clonidine) (P < 0.0001). No significant postoperative sedation, hypotensi on, or bradycardia developed in any of the patients. Conclusion: The addition of 1 mu g/kg clonidine to lidocaine, 0.5%, for IVR A in patients undergoing ambulatory hand surgery improves postoperative ana lgesia without causing significant side effects during the first postoperat ive day.