Comparison of Fractionated Dose Versus Bolus Dose Injection in Spinal Anaesthesia for Patients Undergoing Elective Caesarean Section – A Randomised Double Blinded Study

Abstract

Background: Spinal anesthesia is widely used for infraumbilical surgeries due to its rapid onset and effective blockade. Levobupivacaine, a safer alternative to bupivacaine, provides reliable spinal anesthesia. However, the method of administration—bolus vs. fractionated—can significantly impact block quality and patient safety. This study investigates the clinical effects of fractionated versus bolus intrathecal dosing of levobupivacaine with buprenorphine in patients undergoing elective lower abdominal and lower limb surgeries.

Methods: A prospective, randomized, double-blinded trial was conducted with 50 ASA I–II patients divided into two groups: Group B (Bolus) received a single intrathecal injection, while Group F (Fractionated) received the same dose in two aliquots with a 90-second interval. Outcomes measured included onset and duration of sensory and motor block, duration of postoperative analgesia, hemodynamic stability, vasopressor requirement, and incidence of side effects.

Results: Both groups had comparable onset times for sensory and motor block. However, Group F showed significantly prolonged sensory and motor block durations and longer postoperative analgesia (349.46 vs. 285.15 min). Hemodynamic parameters were better maintained in the fractionated group, with reduced incidence of hypotension (12% vs. 36%) and lower vasopressor use. Nausea and vomiting were also less frequent in Group F.

Conclusion: Fractionated intrathecal administration of levobupivacaine with buprenorphine provides superior hemodynamic stability, longer-lasting analgesia, and fewer side effects compared to bolus dosing. This technique is recommended for safer and more effective spinal anesthesia, particularly in patients at risk of cardiovascular instability.