Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Anaesthesia

BACKGROUND Neuroaxial block is regarded as the preferred anaesthetic technique for TURP operations. Limited duration remains one of its downsides which led to introduction of adjuvants to local anaesthetics (LA). Dexmedetomidine is a highly selective Ü2 agonist and its Ü2/Ü1 selectivity is 8 times higher than clonidine. AIM In this study, we investigated the effect of adding dexmedetomidine to intrathecal bupivacaine on onset and duration of sensory and motor block in addition to sedation and hemodynamic changes. Our aim was to find the least effective dose with minimal or no side effects. STUDY DESIGN Randomised controlled double blind study. METHODS Forty five patients were randomly assigned into three groups. A control group (n=15): patients received 3ml (15mg) of hyperbaric bupivacaine (0.5%) + 0.5 ml normal saline, Dex 1.5 group(n=15): patients received 3ml (15 mg) of hyperbaric bupivacaine (0.5%) + 1.5æg dexmedetomidine and Dex 3 group(n=15): patients received 3 ml (15mg) of hyperbaric bupivacaine + 3æg dexmedetomidine. Sensory block reaching time to T10, highest sensory block level, sensory regression to S1, motor block onset time to bromage 3, motor block duration , sedation level and hemodynamics were all recorded. RESULTS Sensory and motor block duration were increased significantly between the groups in a dose-dependent manner (p<0.001), time to T10 dermatome was significantly shorter in dex containing groups (p<0.001), highest level of sensory block was significantly higher in group dex3 and dex1.5 rather than control group (p=0.011), however there was no statistically significant difference regarding complete onset of motor block. There was a statistically significant increase in the sedation level in a dose dependant manner (p<0.001) in relation to the control group. There were no statistically significant differences regarding demographic data, hemodynamics and adverse effects between the groups.

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