A Comparative Study of Intrathecal Dexmedetomidine and Midazolam as an Adjuvant to Bupivacaine for Total Abdominal Hysterectomy

BACKGROUNDDexmedetomidine, a highly selective α2 adrenergic agonist and Midazolam, a benzodiazepine derivative both modulate spinal analgesia by different mechanisms.We compared Dexmedetomidine and Midazolam as an adjuvant to hyperbaric Bupivacaine in subarachnoid blockade to evaluate the onset and duration of motor and sensory block, post-operative analgesia, hemodynamic changes and adverse effects. MATERIALS AND METHODSIn this randomized controlled trial, sixty female patients aged 18 -65 years of ASA grade 1 and 2, randomly allocated into two groups (30 in each group), posted for total abdominal hysterectomy, were studied.Group D received 12.5 mg of hyperbaric Bupivacaine plus Dexmedetomidine (10 µg) in 1 ml of normal saline.Group M received 12.5 mg hyperbaric Bupivacaine plus Midazolam (2.5 mg) in 1 ml of normal saline.The two groups were compared with respect to onset of sensory and motor block, regression time of sensory and motor block, rescue analgesia, hemodynamic data and adverse effects.Sample size was taken for convenience.Statistical Package for Social Science (SPSS 18.0 evaluation version) was used for the analysis to obtain the data and Microsoft Word, Excel have been used to generate graphs, tables, etc. Results on continuous measurement are presented on Mean ± SD and continuous data is analysed.Significance is assessed at 5% level of significance. RESULTSGroup D patients showed a significantly prolonged sensory and motor block than Group M patients.The sensory regression time to S1 was (324.67 ± 27.26 min) in Group D and (254.00 ± 20.44 min) in Group M. The time of motor block regression to reach Bromage 0 was (314.33 ± 23.44 min) in Group D and (212.33 ± 11.35 min) in Group M. Rescue analgesic time was significantly prolonged in Group D (419.33 ± 21.80 min) as compared to Group M (271.33 ± 30.14 min). CONCLUSIONDexmedetomidine (10 mcg) as an adjuvant to Bupivacaine in subarachnoid blockade is associated with longer sensory, motor block and longer duration of analgesia in comparison to Midazolam (2.5 mg) with a comparable incidence of side effects.