Spinal anaesthesia for caesarean section: plain vs hyperbaric bupivacaine

Objective: To compare the clinical characteristics of sensory and motor block as well as haemodynamic stability using plain and hyperbaric bupivacaine in spinal anaesthesia for caesarean section.Methods: Two equal groups were formed from a total of 60 patients who were enrolled in this prospective randomised double-blinded study that was done at tertiary care hospital in Karach, during 2005 to 2006. Equal volume of plain and hyperbaric bupivacaine 10 mg with 25 mcg of fentanyl was used for spinal anaesthesia in the two groups that were formed on the basis of random allocation. Characteristics of sensory and motor block, episodes of hypotension and bradycardia as well as use of ephedrine and atropine were recorded by blinded investigator.Results: There was no difference in the onset of block, time to achieve maximum level of block and haemodynamic parameters between the two groups. However, plain bupivacaine took more time for two dermatomes sensory level regression below T4, and resulted in prolonged block duration. No statistically significant difference was found for episodes of hypotension, bradycardia and use of ephedrine and atropine.CONCLUSIONS: In obstetric population, both plain and hyperbaric bupivacaine 10 mg, with fentanyl produced adequate anaesthesia for caesarean section without any differences in the time of onset, extent of the block and haemodynamic parameters. However, sensory level regression was delayed in the plain group which may have caused prolonged duration of block