Razi Journal of Medical Sciences

    Background: Different additives�have been used to prolong sensory and motor blockade of the regional anesthetics. The aim of this study was the evaluation of sensory and motor blockade as well as the side effects of adding clonidine 75 mcg to a loading dose of bupivacaine %0.5 in supraclavicular brachial plexus blockade with catheter insertion for upper extremity procedures.

Methods: In this prospective, randomized, double-blind, controlled study sixty patients aged 20 – 60 years (ASA physical status I or II), candidated for upper extremity orthopedic surgry under supraclavicular brachial plexus blockade, were allocated in two groups (30 in each group). The supraclavicular blockade was performed by peripheral nerve stimulator, and after desirable muscular responses, anesthetic solutions were injected. Control group (B) received 25 ml of 0.5% bupivacaine, and the study group (BC) received 25 ml of 0.5% bupivacaine containing 75 mcg clonidine. After that, supraclavicular catheter for additional injections was indwelt. For additional intraoperative analgesia, 0.5% bupivacaine (5 ml) through catheter and  sufentanil and midazolam (Intavenously-IV) was administered. Onset of  complete sensory and motor blockade, intraoperative drug administered (bupivacaine, sufentanil and midazolam), complications, duration of postoperative analgesia and motor blockade, time for first postoperative analgesic request, and demographic data were recorded. For normal distribution of the quantitative data t-test  and otherwise Mann-Whitney's U test was used. For qualitative variables, Chi² test was performed. Statistical analysis was carried out by SPSS V.12.  

Results: There were no significant differences in the demographic and clinical data between groups (in regard  to age, gender, weight, anesthesia and surgical durations). Onset of complete sensory and motor blocks were more rapid in BC than B group (p<0.01). Also there were no siginificant differences in the number of bupivacaine administrations through supraclavicular catheter, and IV sufentanil and midazolam between the two groups. Duration of postoperative analgesia and motor blockade in BC group was more prolonged than B group (p<0.0001). Complications did not show significant difference between the two groups. Time for first postoperative analgesic request was significantly greater in the BC group than B group (p<0.0001).   

Conclusion: Addition of 75 mcg clonidine to 0.5% bupivacaine for supraclavicular blockade potentiates sensory and motor blockade, and prolongs the time for first postoperative analgesic request without having more side effects, and may be an appropriate alternative adjuvants for adding to bupivacaine.