Comparative Efficacy of Intrathecal Bupivacaine Alone and Combination of Bupivacaine with Clonidine in Spinal Anaesthesia.

INTRODUCTION: Clonidine is an α2 agonist agent that has been used as an adjuvant to local anaesthetics in regional anaesthesia.

AIM: This study compared two combinations of bupivacaine and clonidine with bupivacaine alone for surgeries below the level of umbilicus in spinal anaesthesia.

MATERIALS AND METHODS: We conducted a randomized double blind study on 90 patients of ASA I and ASA II aged 20-60 years, 30 in each group, undergoing surgery below the level of umbilicus in spinal anaesthesia. For intrathecal block, Group 1 received bupivacaine hydrochloride 12.5mg (2.5ml) in 8% dextrose (0.5% sensorcaine heavy) + 1ml (150μg) of preservative free clonidine. Group 2 received bupivacaine hydrochloride 12.5mg (2.5ml) in dextrose (0.5% sensorcaine heavy) + 0.5ml (75μg) of preservative free clonidine + 0.5ml of normal saline to make the volumes of all the groups same. Group 3 received bupivacaine hydrochloride 2.5ml in 8% dextrose (0.5% sensorcaine heavy) + 1ml of normal saline to make the volumes of all the groups same. Heart rate, NIBP, oxygen saturation and respiratory rate were monitored. The onset and duration of sensory block, the highest dermatomal level of sensory block, motor block, time to complete motor block recovery and duration of spinal anaesthesia were recorded.

STATISTICAL ANALYSIS: The data of the study was recorded in the record chart and results were evaluated using statistical tests (ANOVA test, post-hoc turkey hsd test, paired t-test and chi-square test).

RESULTS: Demographic data, the incidence and duration of bradycardia were comparable amongst the groups. The duration of sensory and motor block were greatest in group 1, followed by group 2 and group 3 (p <0.01). Decrease in the systolic blood pressure of group 2 and group 3 was noted as compared to group 1. No significant sedation or respiratory depression was observed in any group.

CONCLUSION: Addition of clonidine to bupivacaine intrathecally is although a reliable method to prolong spinal anaesthesia but close monitoring for hypotension is desirable.