Effect of Single-Dose Intravenous Dexamethasone and Ondansetron on Hemodynamic Stability and PONV in Lower-Limb Surgery under Spinal Anesthesia

Abstract

Background: Spinal anesthetic has improved perioperative care for lower-limb procedures. However, sympathetic blocking can induce considerable hemodynamic instability. While fluid preloading and vasopressors are established preventive interventions, dexamethasone and ondansetron, employed as antiemetics, have lately been studied for their cardiovascular-stabilizing effects. This study compares the effects of preoperative intravenous dexamethasone (8 mg) and ondansetron (8 mg) on hemodynamic stability and postoperative nausea and vomiting during spinal anesthesia. Methods: 192 ASA I-II patients undergoing elective lower-limb orthopedic surgery under spinal anesthesia at Alkafeel Hospital in Karbala from 2nd September, 2022, to 3rd November, 2024, were assigned to four groups: dexamethasone (Group D), ondansetron (Group O), combination (Group B), and control (Group C). MAP, HR, and SpO₂ incidences of nausea and vomiting were measured at 5, 10, 15, 30, and 60 minutes after spinal block. Results: MAP and HR did not differ significantly between groups (p = 0.326 and 0.458, respectively). At 5 minutes, Group B had greater MAP (p = 0.001) and HR (p = 0.030) than Group C. No significant differences in SpO₂ levels were seen (p > 0.05). The incidence of nausea was lowest in Group B (2.1%), compared to Group C (14.6%) (p = 0.009). Vomiting occurred in all groups, with zero incidences in Group B. Conclusion: Combining dexamethasone and ondansetron before lower-limb surgery under spinal anesthesia improved cardiovascular stability and reduced nausea