Effect of Prophylactic Ondansetron on the Incidence of Spinal Anesthesia-Induced Shivering and Hypotension in Elective Cesarean Sections:Double-Blind, Placebo-Controlled, Randomized Clinical Trial

Background: Spinal anesthesia is the preferred method of anesthesia for caesarean section; however, it is associated with dangerous adverse effects on both mother and fetus, this includes: spinal anesthesia induced shivering and hypotension. Previous studies suggest serotonin may have a role in hypotension, bradycardia, and shivering occurrence perioeratively. In this prospective double-blind randomized control trial study, we evaluated the efficacy of the ondansetron, a serotonin receptor antagonist, on the incidence of spinal anesthesia-induced shivering, hypotension, nausea, vomiting and other possible complications in elective caesarean sections. This study conducted in Palestine, West Bank, Nablus city in the caesarean section operation rooms, and post-anesthesia care unit at Rafidia governmental hospital. Eighty full-term elective caesarean section parturient (Age 18-50 years) with ASA 1 or 2 classification were recruited and randomly allocated into two groups: prophylactic IV ondansetron treatment group and placebo 0.9% saline control group. The primary outcomes were the incidence of spinal anesthesia-induced shivering and hypotension, while secondary outcomes were perioperative bradycardia, nausea, vomiting, headache, pain, pruritus, dizziness and respiratory depression and parturient satisfaction. Results: Incidence of intraoperative hypotension and dizziness in the ondansetron group was significantly lower than which occurred in the control group (22.5% vs. 62.5% respectively; P < 0.001), the incidences and intensity of intraoperative shivering in the ondansetron group was lower than the control group (12.5 % vs. 32.5 % respectively; P = 0.032), Intraoperative nausea intensity in the ondansetron group was lower than control group (P = 0.049). Postoperatively, the incidence of postoperative dizziness in the ondansetron group was lower than the control group (5% vs. 37.5 % respectively; P = 0.001), the incidence and intensity of postoperative shivering in the ondansetron group was lower than the control group (12.5% vs. 37.5 % respectively; P = 0.01). Incidence and intensity of postoperative nausea in the ondansetron group was lower than the control group (17.5% vs. 40 % respectively; P = 0.026), the incidence of postoperative vomiting in the ondansetron group was lower than the control group (25.5% vs. 2.5 % respectively; P = 0.014).Conclusion: Prophylactic 4 mg IV ondansetron can significantly attenuate the incidences of spinal anesthesia-induced shivering and hypotension, dizziness, nausea, and vomiting occurrence and increase parturient satisfaction scale for parturient who undergo caesarean section.