Comparison of low doses of intrathecal bupivacaine in combined spinal epidural anaesthesia with epidural volume extension for caesarean delivery

AIMS AND OBJECTIVES: This study aims to compare relative efficacy of three different doses of intrathecal bupivacaine in combined spinal epidural anaesthesia (CSEA) for caesarean delivery. MATERIALS AND METHODS: In a double blinded manner, 204 cases were randomized into three groups: I, II, and III to receive a dose of 4, 5.5, and 7 mg of hyperbaric bupivacaine with a fixed dose of 25 μg fentanyl intrathecally, and Dextran 40 w/v 10 mL given for epidural volume extension (EVE), in CSEA. Our primary outcome was the number of effective doses. The block characteristics and side effects were also monitored. RESULTS: Out of 198 patients completing the study, 53, 63, and 65 in group I, II and III had effective doses. Mean P(i) (probability of an effective dose) in group I, II, and III, was 0.81, 0.95, and 0.97, respectively. The P(b) (superiority of one group over the other) of group II and III was higher than group I. The maximal sensory block height in group II and III (T(2)) was higher than group I (T(3)), with a shorter time required to achieve the same. Group I and II exhibited lesser motor blockade, lesser hypotension with early recovery as compared to group III. No significant adverse effects were observed between the groups. CONCLUSION: The intermediate dose of bupivacaine (5.5 mg) provided safe and effective anaesthesia for caesarean delivery with an additional advantage of lesser episodes of hypotension and partial motor blockade in CSEA.