An observational study to compare the effect of intravenous dexmedetomidine versus intravenous magnesium sulphate pretreatment on characteristics of spinal anaesthesia

The study was conducted to assess & compare the effect of pretreatment with intravenous Dexmedetomidine and Magnesium sulphate on characteristics of SAB with hyperbaric bupivacaine. 80 ASA grade I and II patients (age: 18-60 years) scheduled for infraumblical surgery under spinal anesthesia were included & randomly divided into group-D (dexmedetomidine 1μ gm/kg) and group-M (magnesium sulfate 50 mg/kg). patients were given prefixed doses of either intravenous dexmedetomidine or Magnesium sulfate 15 mins before SAB. Incidence of hypotension, highest level & duration of sensory & motor blockage, duration of analgesia, vasopressor requirement and incidence of sedation, nausea & vomiting were compared. highest upper level of sensory block after SAB was higher in group-D (p value < 0.001) than group-M. onset of sensory & motor block was earlier & duration of sensory and motor block, time of rescue analgesia was longer in group-D (p value < 0.001). Depth of sedation was higher in group-D though oxygen saturation and respiratory rate was comparable in both groups. Postoperative VAS score (p value < 0.001) was lower in dexmedetomidine group. Study suggests that Intravenous dexmedetomidine at a dose of 1μg/kg is a better adjuvant to 0.5% hyperbaric bupivacaine than MgSo at a dose of 50 mg/kg in infra-umbilical surgeries, with complications of hypotension and bradycardia occurring at acceptable incidences.