Evaluation of bupivacaine-clonidine combination for unilateral spinal anesthesia in lower limb below-knee orthopedic surgery

Background and Objectives: The purposes of this study were to evaluate the onset, quality and duration of sensory and motor blockade between hyperbaric bupivacaine and clonidine combination with bupivacaine alone when administered intrathecally for unilateral spinal anesthesia in below-knee orthopedic surgery, efficacy of clonidine for post-operative analgesia and side-effects of clonidine, if any. Methods: Sixty ASA I and ASA II patients scheduled for elective surgery with time duration up to 90 min were studied. Patients were randomised in two equal groups by the lottery method. Group A (control group) was given Inj. bupivacaine (hyperbaric) 0.5% - 12.5 mg (2.5 ml) + 0.5 ml of normal saline intrathecally. Group B (clonidine group) was given Inj. bupivacaine (hyperbaric) 0.5% - 12.5 mg (2.5 ml) + 50 mcg clonidine in 0.5 ml volume intrathecally. Results: The mean peak sensory block was earlier in Group B (4.7 +/- 1.23 min) as compared with Group A (6.27 +/- 1.51 min). The mean peak motor block was earlier in Group B (6.17 +/- 1.20 min) as compared with Group A (8.63 +/- 1.71 min). The two-segment regression of sensory block was longer in Group B (106.23 +/- 9.17 min) as compared with Group A (104.43 +/- 17.75 min), which is clinically significant. Requirement of rescue analgesia was considerably prolonged in Group B (450.33 +/- 95.10 min) as compared with Group A (220 +/- 36.36 min), which was also clinically highly significant. Conclusion: Intrathecal clonidine potentiates bupivacaine induced spinal sensory block and, motor block and reduces the analgesic requirement in the early post-operative period in unilateral spinal anesthesia for lower limb below knee surgery.