European Journal of Molecular & Clinical Medicine

Ropivacaine reversibly interferes with the entry of sodium into the nerve cell membranes, leading to decreased membrane permeability to sodium and raises the threshold for electrical excitability. It blocks the generation and the conduction of nerve impulses, presumably by increasing the threshold for electrical excitation in the nerve, by slowing the propagation of the nerve impulse, and by reducing the rate of rise of the action potential. Randomization was done using a random number table generated from computer software and divided into 2 groups of 40 each. Group B: 2.5 ml of 0.5% hyperbaric bupivacaine with 25 μg fentanyl, Group R: 2.5 ml of 0.75% isobaric ropivacaine with 25 μg fentanyl. The difference in the fall of heart rate from baseline in both the groups was clinically comparable. Only two (5% in group B) had an episode of bradycardia between 6-9 min after the sub-arachnoid block which resolved after a single dose of 0.6 mg of atropine in both the cases.