Effects of Ondansetron Timing During Spinal Anesthesia for Urologic Surgery

Summary

This study will evaluate whether the timing of intravenous ondansetron administration affects cerebral oxygenation and hemodynamic stability in older adults undergoing endoscopic urologic surgery under spinal anesthesia. Participants aged 65 years or older will be randomly assigned to one of three groups: ondansetron administered before spinal anesthesia, ondansetron administered after spinal anesthesia, or placebo. Ondansetron will be administered intravenously at a dose of 8 mg. Cerebral oxygenation will be assessed using bilateral frontal near-infrared spectroscopy (NIRS). Regional cerebral oxygen saturation (rSO₂) will be recorded before spinal anesthesia and at 5-minute intervals during the first 60 minutes after spinal anesthesia. The study will also evaluate blood pressure, heart rate, vasopressor requirements, bradycardia, postoperative nausea and vomiting, post-spinal headache, and postoperative delirium. The aim is to determine whether the timing of ondansetron administration influences cerebral oxygenation and hemodynamic stability after spinal anesthesia.

Timeline

Start

2026-09-30

Primary completion

2027-01-02

Completion

2027-01-22

Publications

• Background Nishikawa K, Hagiwara R, Nakamura K, Ishizeki J, Kubo K, Saito S, Goto F. The effects of the extent of spinal block on the BIS score and regional cerebral oxygen saturation in elderly patients: A prospective, randomized, and double-blinded study. J Clin Monit Comput. 2007 Apr;21(2):109-14. doi: 10.1007/s10877-006-9063-7. Epub 2007 Jan 10.
• Background Tatikonda CM, Rajappa GC, Rath P, Abbas M, Madhapura VS, Gopal NV. Effect of Intravenous Ondansetron on Spinal Anesthesia-Induced Hypotension and Bradycardia: A Randomized Controlled Double-Blinded Study. Anesth Essays Res. 2019 Apr-Jun;13(2):340-346. doi: 10.4103/aer.AER_22_19.
• Background Mendonca FT, Crepaldi Junior LC, Gersanti RC, de Araujo KC. Effect of ondansetron on spinal anesthesia-induced hypotension in non-obstetric surgeries: a randomised, double-blind and placebo-controlled trial. Braz J Anesthesiol. 2021 May-Jun;71(3):233-240. doi: 10.1016/j.bjane.2020.12.028. Epub 2021 Mar 22.
• Background Kusku A, Demir G, Cukurova Z, Eren G, Hergunsel O. Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy. Braz J Anesthesiol. 2014 Jul-Aug;64(4):241-6. doi: 10.1016/j.bjane.2013.06.012. Epub 2013 Oct 18.

Drugs

Indications

No indication recorded.