A comparative study of intrathecal clonidine and dexmedetomidine on characteristics of bupivacaine spinal block for lower limb surgeries.

INTRODUCTION: Intrathecal clonidine or dexmedetomidine has improved the quality of spinal anesthesia, this clinical study was undertaken to assess the behavior of intrathecal clonidine as an adjuvant to bupivacaine in augmenting sensory block in patients undergoing lower limb surgeries.

MATERIALS AND METHODS: We studied 150 patients, between 18 and 60 years of age, patients were randomly divided into three groups of 50 each Group B: 0.5% bupivacaine 15 mg + 0.5 ml normal saline Group C: 0.5% bupivacaine 15 mg + 50 μg clonidine Group D: 0.5% bupivacaine 15 mg + 5 μg dexmedetomidine. Onset and duration of sensory block and motor block, the highest level of sensory blockade, duration of analgesia, and side-effects were assessed.

RESULTS: The onset of motor block was faster in Group C and Group D as compared to Group B, The time to reach Bromage scale 3 was fastest in Group C followed by Group D P < 0.001. The duration of sensory, motor blockade and duration of analgesia was longer in Groups C and D as compared to Group B, longest in Group D followed by C and B. The time to regression time to S1 dermatome was. It was longest in Group D followed by Group C and then Group B. Intergroup comparison B to C, B to D and C to D was significant. Duration of analgesia was significantly prolonged in Group C and Group D (P < 0.001) with a mean duration of 309.6 ± 50.99 min in Group C and 336.8 ± 55.38 min in Group D as compared to 204.8 ± 16.81 min in Group B. Intergroup comparison B to C, B to D and Group C to D was significant. Duration was longest in Group D followed by Group C and then Group B.

CONCLUSION: Supplementation of bupivacaine spinal block with a low dose of intrathecal dexmedetomidine (5 μg) or clonidine (50 μg) produces a significantly shorter onset of motor and sensory block and a significantly longer sensory and motor block than bupivacaine alone.