A Comparative Study Of Intrathecal Hyperbaric Bupivacaine 0.5% With Clonidine Versus Plain Hyperbaric Bupivacaine 0.5% In Adults Undergoing Lower Abdominal Surgery

Abstract

Background: Spinal anesthesia remains the gold standard neuraxial technique for lower abdominal surgical procedures due to its rapid onset and reliable blockade. While hyperbaric bupivacaine 0.5% provides effective surgical anesthesia, its limited duration of action (typically 90-120 minutes) often necessitates adjuvant medications to extend postoperative analgesia. Clonidine, a selective α₂-adrenergic agonist, demonstrates synergistic effects when combined with local anesthetics by prolonging sensory blockade through dorsal horn receptor modulation. Current evidence suggests clonidine's dual mechanism of action - both presynaptic inhibition of nociceptive neurotransmitters and postsynaptic hyperpolarization - may enhance bupivacaine's pharmacodynamics without significant hemodynamic compromise. This study aims to quantitatively compare the anesthetic profiles of clonidine-supplemented versus plain hyperbaric bupivacaine in lower abdominal procedures.

Methodology: This prospective randomized controlled trial will enroll 50 ASA physical status I-II patients (18-65 years) undergoing elective lower abdominal surgery under spinal anesthesia. Participants will be randomly allocated to: Group A (n=25): 3.0 mL hyperbaric bupivacaine 0.5% + 30 μg preservative-free clonidine;Group B (n=25): 3.0 mL plain hyperbaric bupivacaine 0.5%

Results: Preliminary findings demonstrate clonidine's significant advantages: 28% faster sensory onset (2.6±0.3 vs 3.6±0.4 minutes; p<0.01). 42% prolonged sensory duration (293.6±25.3 vs 208.4±24.6 minutes; p<0.001). Enhanced motor blockade duration (254.8±39.4 vs 154.4±28.0 minutes; p<0.001). Hemodynamic parameters remained stable across groups (p>0.05), with comparable complication rates.

Conclusion: The addition of 30μg clonidine to hyperbaric bupivacaine 0.5% significantly improves both the quality and duration of spinal anesthesia for lower abdominal procedures. This adjuvant combination offers: Accelerated neural blockade onset. Prolonged postoperative analgesia. Maintained hemodynamic stability. These benefits support clonidine's role as an effective neuraxial adjuvant, particularly for procedures requiring extended pain management.