EFFECT OF PROPHYLACTIC ADMINISTRATION OF ONDANSETRON ON SPINAL INDUCED HYPOTENSION IN PATIENTS UNDERGOING LOWER SEGMENT CESAREAN SECTION (LSCS)

Abstract

Background: Spinal anesthesia is widely applied to lower part cesarean section but is often burdened with maternal hypotension that is mostly brought about by sympathetic blockage and low vascular tone. Ondansetron Prophylaxis ondansetron has also been examined as a possible method of preventing hypotension caused by the spine by the means of adjusting serotonin-mediated cardiovascular reflexes. Aim: To assess the effect of prophylactic ondansetron on the incidence of spinal anesthesia-induced hypotension and related maternal and neonatal outcomes among women undergoing elective lower-segment cesarean section. Methods: It was a prospective randomized clinical trial carried out in the Department of Anesthesiology, Hameed Latif Hospital, Lahore. 102 women that fit the eligibility criteria were recruited by means of non-probability convenience sampling and were randomized into placebo and ondansetron groups, 51 participants each. Ondansetron or placebo was given intravenously 5 minutes prior to spinal anesthesia. At 1, 3 and 5 minutes after spinal anesthesia and then at 3-minute interval, maternal hemodynamic parameters were observed. Data were examined with SPSS and p-value of less than 0.05 was termed as statistically significant. Results: Baseline demographic and obstetric characteristics were comparable between groups, including age (28.3 ± 2.5 vs. 28.1 ± 2.4 years; p = 0.684) and gestational age (39.5 ± 0.8 vs. 39.6 ± 0.7 weeks; p = 0.527). Hypotension occurred significantly less frequently in the ondansetron group than in the placebo group (19.6% vs. 45.1%; p = 0.008). Vasoconstrictor requirement was also lower with ondansetron (7.8% vs. 25.5%; p = 0.018), while the lowest MAP was significantly higher (72.7 ± 4.6 vs. 68.9 ± 5.8 mmHg; p < 0.001). Supine hypotensive syndrome occurred in 3.9% versus 19.6% (p = 0.025), and nausea and vomiting occurred in 5.9% versus 23.5% (p = 0.014) in the ondansetron and placebo groups, respectively. Umbilical artery pH was significantly higher in the ondansetron group (7.32 ± 0.03 vs. 7.28 ± 0.04; p < 0.001), whereas Apgar scores did not differ significantly between groups. Conclusion: Ondansetron prophylaxis contributed to a significant reduction in incidence of spinal-induced hypotension and vasopressor-demand as well as an increase in maternal hemodynamic stability in elective LSCS. These results justify the use of ondansetron as a potentially useful prophylaxis due to obstetric spinal anesthesia, but the effectiveness of ondansetron needs to be proved in larger multicenter studies.