Comparative Study of Intrathecal 0.5% Isobaric Versus 0.5% Hyperbaric Bupivacaine in Same Volume and Dose to Assess the Quality of Spinal Anaesthesia and Haemodynamic Changes Occurring During Cesarean Section

Aim: To compare the efficacy of 0.5% hyperbaric bupivacaine with isobaric bupivacaine and observe haemodynamic changes occurring in patients undergoing lower segment cesarean section. Methods: A prospective randomized double blind study in 60 patients of ASA 1 and ASA II undergoing lower segment cesarean section was designed to compare the efficacy of hyperbaric with isobaric bupivacaine. The patients were randomly divided into two groups. Group I received 0.5% hyperbaric bupivacaine 2.5ml (12.5mg) and Group II received isobaric 0.5% bupivacaine 2.5ml (12.5mg) intrathecally. Sensory block was assessed by pinprick and modified bromage scale was used to assess motor block. Results: Significant difference was found between the two groups at 3min regarding the sensory block. T6 level reached in 10(37%) patients in group I and 17(77%) patients in group II. However no significant difference was found between the two groups at 5min regarding the sensory and motor block. The rapid onset of sensory block with 0.5% isobaric bupivacaine in group II produced more decrease in systolic and mean blood pressure when compared with 0.5% hyperbaric bupivacaine in group I at 5min but after 45min it was not statistically significant. Ephedrine was given to 7 patients in group I and 11 patients in group II to treat hypotension. Conclusion: The results of our study suggest that 0.5% isobaricbaric bupivacaine was more predictable for sensory block level when compared with 0.5% hyperbaric bupivacaine in cesarean section under spinal anaesthesia. Although the rapid onset of sensory block with isobaric bupivacaine produced more hypotension when compared with its hyperbaric form but it was not statistically significant.