ABSTRACT
Currently only few local anaesthetics are used for intrathecal administration, like bupivacaine, lignocaine, ropivacaine and tetracaine. Opioid analogues have been used as additive in spinal anaesthesia to improve the onset of action, to prolong the duration of block and to improve the quality of intraoperative and postoperative analgesia. Fentanyl is a partial agonist on μ-opioid receptors and Dexmedetomidine is a α2-agonist. Intrathecal dexmedetomidine when combined with spinal bupivacaine prolongs the sensory block by depressing the release of C-fibers transmitters and by hyperpolarization of post-synaptic dorsal horn neurons.1 We compared the effects of adding Dexmedetomidine and Fentanyl as an adjuvant to intrathecal hyperbaric bupivacaine for vaginal hysterectomy.METHODSA total of 100 patients of age 35 to 65 yrs. of body mass index (BMI) within normal range (18.5 to 24.9 Kg/m2) posted for vaginal hysterectomy were divided into two equal groups (Group 1 and 2) in a prospective, randomized, double-blind fashion. In Group 1 (n=50), (2.5 ml) Hyperbaric Bupivacaine + (0.5 ml) Dexmedetomidine (5 mcg) and in Group 2 (n=50) (2.5 ml) Hyperbaric Bupivacaine + (0.5 ml) Fentanyl (25 mcg) were used. Total volume injected intrathecally was 3.0 ml. We observed the effect on onset of sensory and motor blockade, maximum level of sensory and motor blockade, haemodynamic effects during intraoperative period (for 120 min), effect on overall duration and quality of analgesia during postoperative period using VAS score and any side effects.RESULTSWe observed that mean time to achieve sensory block and motor block/ Bromage-3 was shorter in dexmedetomidine group. There was no statistically significant difference for the onset of sensory and motor block in dexmedetomidine and fentanyl group (p value > 0.05). The sensory and motor block were more prolonged in dexmedetomidine group than fentanyl group showing significant difference among the two groups (p value<0.001). Overall duration of analgesia was significantly longer in dexmedetomidine group than fentanyl group showing significant difference among the two groups (p value <0.001).CONCLUSIONSIn our opinion adding Dexmedetomidine 5 mcg to Bupivacaine 12.5 mg not only provides rapid onset, profound analgesia with good relaxation for surgery but also prolongs the duration of sensory and motor blockade. The overall effect and duration are superior to addition of 25 mcg of Fentanyl.