The Effect of Different Doses of Ondansetron in Prevention of Hypotension and Shivering in Patients Undergoing Lower Limb Surgery under Spinal Anesthesia

Abstract Background: Spinal anesthesia is a safe and very effective technique for lower limb surgical mannoveurs but it is asso-ciated with many side effects as hypotension and shivering which are distressing to the patients. Benefits of spinal an-esthesia for lower limb surgery include reduced mortality, deep vein thrombosis (DVT), transfusion requirements and pulmonary complications. Several studies suggested that ondansetron, used for prophylaxis and treatment of nausea and vomiting. Aim of Study: The aim of this work is to assess the efficacy of administration of different doses of intravenous ondansetron on attenuation of spinal induced hypotension as primary outcome of the present study and shivering as secondary outcome during lower limb surgery. Patients and Methods: Patients were randomly allocated into three equal groups, Group (C) received normal saline as control group, Group (OL) received 4mg ondansetron i.v, Group (OH) received 8mg ondansetron i.v. slowly. Patients were assessed for haemodynamic changes, motor block, incidence of any complication and the use of pethidine and ephedrine. Results: In comparison of mean blood pressure of groups OL and OH to the control group. MBP of control group was significantly lower than group OL immediately after induction and also at 5, 10, 15 and 20 minutes intraoperative MBP of control group was significantly lower than group OH imme-diately after induction and also at 10, 15, 20 and 30 minutes intraoperative. There was significant difference regarding MBP between group OL and group OH at 30 and 60 minutes (MBP of group OH was significantly higher. p-value 0.02 and 0.043 respectively). Dose of administered pethidine and ephedrine was statistically lower in groups OH than group OL than control group. Conclusion: Administration of two different doses of intravenous ondansetron, 4mg and 8mg, efficiently attenuates spinal induced hypotension and shivering compared to the control saline group. Incidence of hypotension and shivering was less observed in ondansetron 8mg group than ondansetron 4mg group.