A Comparison of the Analgesic Effects of Oral Clonidine as Premedication with that of Adding Clonidine to Lidocaine Solution in Bier's Block for Upper Extremity Surgery

Clonidine has been found to decrease the tourniquet pain and enhance analgesia, when added to lidocaine in Intravenous Regional Anesthesia (IVRA) for upper extremity surgery. Our study evaluates the efficacy of oral clonidine as premedication before IVRA with that of lidocaine for upper extremity surgery and compares it to that of clonidine added as adjunct to lidocaine solution for IVRA.Patients and Materials: We conducted a prospective randomized double-blinded study on 60 patients undergoing upper extremity surgery under IVRA. Patients were randomized to receive plain lidocaine, 200 mg in 41 ml for IVRA(group IVRA), lidocaine 200 mg in 40 ml plus clonidine 2 µg/kg in 1 ml (group IVRA–C), or plain lidocaine, 200 mg in 41 ml for IVRA plus oral clonidine 2mg as premedication 1.5 hrs before surgery (group IVRA-OC). Patients in the first two groups received a placebo as premedication. Times of proximal tourniquet deflation and distal tourniquet inflation(T1), time of first intraoperative request for analgesics(T2), time of first postoperative request for analgesics(T3), and the total analgesic consumption were recorded. SPSS V. 13 was used for statistical analysis. Quantitative data are shown as mean+/- SD and qualitative data are presented with frequency. Chi square and ANOVA tests were used for data analysis. p<0.05 was considered as significant. In this study 60 patients were divided in to three groups of 20 each. The groups were IVRA, IVRA-C and IVRA–OC. There were no significant differences among the three groups in regard to the demographic characteristics and the duration of surgery. Time duration of proximal cuff deflation and distal cuff inflation was 49.5 +/_ 10.5 minutes in group IVRA–C, which was almost twice that of the other two groups (p= 0.0001). Time for first intraoperative request for analgesics was significantly different (longer) in group IVRA–C as compared to group IVRA p= 0.01). Time for first postoperative request for analgesics and the total analgesic consumption were significantly longer and lower, respectively in group IVRA-OC (p = 0.0001). The addition of clonidine to lidocaine for IVRA, delays the onset of tourniquet pain and decreases analgesic consumption for tourniquet pain relief intraoperatively. Oral clonidine, on the other hand, is mostly effective in postoperative pain relief.