Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 0 0 2026 01 28 1379 1379 Ali Zaidan Department of Intensive Care Unit, University Hospital of Farhat Hached, Faculty of Medicine of Sousse, University of Sousse, Sousse, Tunisia. Imed Chouchene Department of Intensive Care Unit, University Hospital of Farhat Hached, Faculty of Medicine of Sousse, University of Sousse, Sousse, Tunisia. 2025 08 16 2025 09 13 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. https://aacc.tums.ac.ir/index.php/aacc/article/view/1379