Comparison of Equivalent Doses of Intrathecal Hyperbaric Levo-bupivacaine and Hyperbaric Bupivacaine for Caesarean Section: A Prospective Randomised Double-Blind Study

Abstract

Introduction: Subarachnoid Block (SAB) with Hyperbaric Bupivacaine (HB) is the most common anaesthetic technique for Lower Segment Caesarean Section (LSCS). Levo-bupivacaine, an enantiomer of racemic bupivacaine, has been developed to provide anaesthesia with the same effectiveness but with better haemodynamic stability. Aim: To compare the effectiveness of hyperbaric levo-bupivacaine to HB in achieving sensory and motor blocks in Caesarean Section(CS) using equivalent doses. Materials and Methods: Eighty parturients aged 18-38 years with no co-morbidities were randomly divided into two groups receiving equivalent doses of HB and hyperbaric levo-bupivacaine for SAB. The effectiveness of the two drugs was compared in terms of the time taken to achieve sensory and motor blocks, as well as the time for block regression for two segments for sensory block and the return of motor block assessed by the ability to flex the ankle joint. Adverse events such as a fall in Systolic Blood Pressure (SBP) and the dose of vasopressor were noted for the two groups. Results: The time taken to attain a T6 dermatomal block level was 2.43±1.00 and 2.80±1.51 (p-value 0.08) for the bupivacaine and levo-bupivacaine groups, respectively. Complete motor block of the lower limb was achieved in 4.85±1.67 and 5.15±1.82 (p-value 0.53). However, the time to 2-segment regression for sensory block was significantly faster in the levo-bupivacaine group than in the bupivacaine group (125.9±28.56 minutes and 109.13±28.84 minutes, respectively, p-value 0.009). Regression from motor block was also found to be highly statistically significant (158.38±34.92 minutes for bupivacaine and 138.75±25.71 minutes for the levo-bupivacaine group, p-value 0.006). Spinal-induced hypotension was comparable in both groups, but the bupivacaine group needed a much higher repetition of dose of vasopressor than the levo-bupivacaine group. Conclusion: Levo-bupivacaine is comparable to its racemic isomer bupivacaine in achieving anaesthesia when administered Intrathecally (IT) for CS. However, with equivalent doses, the duration of action is significantly shorter with hyperbaric levo-bupivacaine. Dose adjustment might be required with hyperbaric levo-bupivacaine based on the duration of the surgery. Haemodynamic stability is also similar with both drugs.

Keywords

• caesarean delivery
• intrathecal anaesthesia
• sensory block