Clinical Research Directory

Effects of Ondansetron Timing During Spinal Anesthesia for Urologic Surgery

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.

Dexamethasone Versus Ondansetron for Preventing Post-Spinal Hypotension in Preeclampsia

This study compares the efficacy and safety of intravenous dexamethasone versus intravenous ondansetron in preventing low blood pressure (hypotension) following spinal anesthesia in pregnant women with preeclampsia undergoing scheduled cesarean delivery. Spinal anesthesia is the preferred anesthetic method for cesarean delivery, but it frequently causes a sudden drop in maternal blood pressure. In patients with preeclampsia, post-spinal hypotension can compromise blood flow to the placenta and vital organs. While traditional vasopressor medications are used to restore blood pressure, non-adrenergic prophylactic agents such as dexamethasone and ondansetron may help maintain hemodynamic stability through different physiological pathways. Participants will be randomly assigned to receive either intravenous dexamethasone (8 mg) or intravenous ondansetron (4 mg) 15 minutes prior to the initiation of spinal anesthesia. Blood pressure, heart rate, vasopressor requirements, optic nerve sheath diameter, and maternal and neonatal outcomes will be monitored throughout the surgery and during the immediate postoperative period.

Investigation of the Role of Internal Jugular Vein Collapsibility Index in Predicting Spinal Anesthesia-Induced Hypotension in Preeclamptic Parturients

This prospective, single-center observational study aims to evaluate the predictive value of the internal jugular vein collapsibility index (IJVCI) for spinal anesthesia-associated hypotension in preeclamptic parturients (gestational age ≥28 weeks) undergoing cesarean delivery classified as Lucas category 3-4. Preoperative IJVCI will be measured using ultrasonography before spinal anesthesia during spontaneous and deep respiration. The incidence of hypotension within the first 20 minutes after spinal anesthesia will be recorded. The diagnostic performance of IJVCI in predicting hypotension will be analyzed.