Background: Intravenous dexmedetomidine is used as adjuvant during general anesthesia due to its sedative and analgesic effects. The present study was aimed to evaluate the effects of intravenous dexmedetomidine on sensory and motor block characteristics, hemodynamic parameters and sedation during subarachnoid block.
Materials and methods: In this double-blind randomized placebo control study, 60 patients of American Society of Anesthesiologist I and II were randomized into two groups by computer generated table. Patients of Group D administered intravenous dexmedetomidine 0.5 μg/kg and patients of Group C received similar volume of normal saline, administered after 20 min of subarachnoid block with 0.5% hyperbaric bupivacaine. The cephalic level of sensory block, total duration of sensory analgesia and motor block were recorded. Sedation scores using Ramsey Sedation Score (RSS) and hemodynamic changes were also assessed.
Results: Demographic profile, duration of surgery and cephalic level of sensory block were comparable. The time for two segments regression was 142.35 ± 30.7 min in Group D, longer than Group C (98.54 ± 23.2 min). Duration of sensory blockade was 259.7 ± 46.8 min in the Group D versus 216.4 ± 31.4 min in Group C (P < 0.001). The mean duration of motor blockade showed no statistically significant difference between groups. There was clinically significant decrease in heart rate and blood pressure in patients of Group D. The RSS was higher (arousable sedation) in patients of Group D. No respiratory depression was observed.
Conclusion: Intravenous dexmedetomidine in dosage of 0.5 μg/kg, administered after 20 min of subarachnoid block prolonged the duration of sensory and motor blockade with arousable sedation.
Keywords: Bupivacaine; dexmedetomidine; intravenous; subarachnoid block.