Subarachnoid block is a popular mode of anaesthesia for lower abdominal as well as lower limb surgeries. It is not associated with disadvantages of general anaesthesia like airway manipulation, usage of multiple drugs, additional supplementary analgesics, postoperative nausea and vomiting. Local anaesthetic drugs such Bupivacaine, Levobupivacaine and Ropivacaine are commonly used for spinal anaesthesia, with Bupivacaine being most common. The advantages being, early onset and prolonged duration of sensory blockade.

Ropivacaine, a newer amide local anaesthetic has many similar properties with Bupivacaine, but with lesser incidence of cardiovascular and central nervous system toxicity. Ropivacaine also has a faster recovery from motor block. Adding adjuvants like Morphine, Fentanyl, Dexmedetomidine to the local anaesthetic increases the duration of action, increases the density of block, decreases the dose requirement thereby also reducing the risk of complications. Fentanyl and Morphine are known to cause side effects like nausea, vomiting and pruritus.

Intrathecal Dexmedetomidine, an alpha 2 receptor agonist as an adjuvant had favourable outcomes. Addition of Dexmedetomidine to Ropivacaine and Bupivacaine for spinal

anaesthesia in parturients has shown to hasten the onset of sensory and motor block, prolong the time of sensory block, improve muscle relaxation, improve intraoperative somatovisceral sensory block characteristics and postoperative analgesia, decrease shivering, with minimal hemodynamic and other side effects.

There is paucity of literature comparing the effect of Dexmedetomidine as an adjuvant to Bupivacaine and Ropivacaine on block characteristics. Hence, the present study has been designed to compare the effects of Dexmedetomidine as an adjuvant with 0.5% hyperbaric Bupivacaine and 0.75% hyperbaric Ropivacaine on onset, duration and recovery from sensory and motor blockade in spinal anaesthesia and also on hemodynamic effect.