Evaluation of intrathecal neostigmine in different doses added to bupivacaine for postoperative analgesia

Objectives: 1. To evaluate the efficacy and safety of intrathecal neostigmine with bupivacaine in two different doses for postoperative analgesia.2. To assess the effect of intrathecal neostigmine on the characteristics of bupivacaine spinal anesthesia. Study Design & Setting: Prospective Double Blind, Hospital based Study. Materials & Methods: Ninety patients aged 20-40 years of ASA I-II, undergoing lower abdominal and lower limb surgeries under spinal anaesthesia participated in the study were divided into 3 groups as Group A (n=30) received 2.5ml intrathecal bupivacaine 0.5% (Control group) Group B (n=30) received 50µg intrathecal neostigmine + 2.5 ml bupivacaine 0.5% Group C (n=30) received 150µg intrathecal neostigmine + 2.5 ml bupivacaine 0.5%. Standardized anaesthetic technique was carried out. Level of sensory block by pin prick method and motor block was assessed by Bromage scale. Time from start of anaesthesia to Bromage grade II, Time of 2 segment regression and motor recovery was checked and recorded every 15 minutes after completion of surgery. Patients with Visual Analogne Scale Score (VAS) above 4 received rescue analgesia. Side effects were noted and data statistically evaluated. Results: Total duration of motor block was significantly prolonged in groups B & C compared to A. VAS scores at 1, 2, 3, 4, 6, 8, 10, 12 and 24 hours was significantly higher in the control group. The mean duration of analgesia was significantly prolonged in group B (340±8.6) and group C (700±8.65) than group A (263.30±7.57) p value< 0.05 4 patients in the 50 mcg neostigmine group and 5 in the 150mcg neostigmine group developed nausea.7 patients in 50mcg and 11 in 150mcg groups developed vomiting. Conclusion: Intrathecal neostigmine results in effective analgesia postoperatively. Further it prolongs sensory and motor block induced by bupivacaine spinal anaesthesia and at the same time cause no haemodynamic or ventilatory depression in the intraoperative and postoperative period