Intrathecal Hyperbaric Bupivacaine Versus Hyperbaric Ropivacaine for Spinal Anaesthesia in Caesarean Section: A Randomized Controlled Trial From Northeast India

Background: Spinal anaesthesia (SA) is the preferred technique for elective caesarean section (CS), offering rapid onset, reliable surgical conditions, and avoidance of airway manipulation [1–4]. Hyperbaric bupivacaine remains standard but is associated with prolonged motor block and hypotension [3,6]. Ropivacaine, a pure S-enantiomer with lower cardiotoxicity and relative sensorymotor dissociation, may facilitate earlier mobilization with a comparable sensory profile [7–9]. Methods: In this single-blinded, randomized controlled trial conducted at Agartala Government Medical College & GBP Hospital, parturients (ASA I–II; 18–40 years; ≥37 to <42 weeks; height 145– 165 cm; weight 45–95 kg) scheduled for elective CS were allocated 1:1 to receive intrathecal hyperbaric bupivacaine 0.5% 12 mg (2.4 mL) or hyperbaric ropivacaine 0.75% 18 mg (2.4 mL). Randomization used variable blocks with sequentially numbered opaque sealed envelopes; participants were blinded. Primary outcomes were onset and duration of sensory block (to T6; regression to T10) and motor block (Bromage 3 onset; regression to 0). Secondary outcomes included duration of effective analgesia (to first rescue at VAS ≥ 4), intra-/postoperative haemodynamics (HR, SBP, DBP, MAP, SpO₂), and adverse effects. Statistical analysis employed t-tests and chisquare/Fisher's exact tests (p<0.05). Ethics approval Ref. No. F.4(6-13)/AGMC/…/2022/21,857 (09Jan-2023); CTRI/2024/05/067399. Results: Sixty-six parturients were analysed (33/group). Groups were comparable at baseline (age 26.6 ± 5.8 vs 28.0 ± 13.3 y; weight 68.9 ± 8.8 vs 68.0 ± 7.7 kg; height 151.4 ± 2.7 vs 147.6 ± 2.4 cm; all p>0.05). Ropivacaine produced faster onset of sensory block to T6 (4.18 ± 0.59 vs 6.05 ± 0.70 min; p = 0.001) and faster motor block onset (8.33 ± 1.33 vs 9.39 ± 0.87 min; p = 0.01). Regression was faster with ropivacaine for both sensory (to T10: 135.1 ± 7.5 vs 156.5 ± 10.0 min; p = 0.001) and motor block (149.3 ± 10.5 vs 176.1 ± 10.5 min; p = 0.025). Duration of effective analgesia was shorter with ropivacaine (136.3 ± 7.9 vs 158.6 ± 13.4 min; p = 0.003). Haemodynamics were similar between groups intra- and postoperatively without clinically meaningful differences. Intraoperative adverse events (nausea, vomiting, shivering, hypotension, bradycardia) were numerically fewer in the ropivacaine group; differences were not statistically significant. Conclusion: Intrathecal hyperbaric ropivacaine (18 mg) provided a comparable sensory block with significantly earlier onset and faster motor recovery than hyperbaric bupivacaine (12 mg) in elective CS, enabling earlier ambulation and potentially enhancing postoperative throughput—without compromising haemodynamic stability or safety.