A Clinical Study to Evaluate the Effect of Intrathecal Atropine on Post Operative Nausea and Vomiting in Patients Receiving Intrathecal Morphine and Hyperbaric Bupivacaine for Spinal Anaesthesia: Prospective Randomized Trial

Background and Objective: Intrathecal morphine for lower abdominal surgeries provides excellent postoperative analgesia but is associated with significant Post Operative Nausea and Vomiting (PONV). This study was intended to evaluate the effect of intrathecal atropine on PONV in patients receiving intrathecal morphine and hyperbaric bupivacaine for spinal anaesthesia in lower abdominal surgery. Methods: 103 patients of ASA physical status I & II posted for elective lower abdominal surgery under spinal anaesthesia were enrolled. They were randomly allocated to two groups - Group A [n=51] - atropine, Group C [n=52] - control. Along with hyperbaric bupivacaine 3ml and morphine 200mcg, group A received atropine 100mcg and group C received normal saline, intrathecally. Postoperatively, PONV, haemodynamic parameters, sedation and postoperative pain was assessed over 24 hours. Other adverse effects, if any were also recorded. Results: The incidence of PONV was 68% in control group and 34% in atropine group (P value < 0.001). Severity of PONV was greater in group C (28% grade 2 PONV) compared to group A (8% grade 2 PONV)(p<0.001). Cumulative comsumption of metoclopramide [mean (SD), median (IQR)] during 24 hours in group C was 10.6 ± 8.42, 10 (0-20) mg and 5 ± 7.62, 0(0-10) mg in group A (p – 0.001). No significant differences in terms of subarachnoid block characteristics, hemodynamic variables, sedation scores and postoperative pain was observed. The incidence of other side effects was comparable in both groups. Conclusion: Intrathecal atropine added to morphine resulted in decrease in incidence and severity of PONV. There was also reduction in requirement of rescue anti emetics.