Effects of Ondansetron Timing During Spinal Anesthesia for Urologic Surgery
Trial statusNot yet recruiting
Trial phasePhase 4
Trial typeInterventional
Biological sexMale
Age65+
SponsorIstanbul University
About this trial
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.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Male sex.
Age 65 years or older.
ASA physical status I-III.
Scheduled for elective transurethral resection of the prostate (TUR-P) or transurethral resection of bladder tumor (TUR-BT) under spinal anesthesia.
Disqualifiers
Known hypersensitivity or contraindication to ondansetron.
Corrected QT interval (QTc) >480 ms.
Significant cardiac conduction abnormality.
Concomitant use of medications known to prolong the QT interval.
Trial design
Design model
Parallel
Treatments tested in this trial
Ondansetron 8 mg
DrugOndansetron 8 mg will be administered intravenously according to the assigned study arm. In the early ondansetron arm, the drug will be administered approximately 10 minutes before completion of the intrathecal injection. In the late ondansetron arm, the drug will be administered approximately 5 minutes after completion of the intrathecal injection.
0.9 % sodium chloride
DrugPlacebo will be administered intravenously in the same volume and appearance as the active study drug according to the blinded study protocol.
Treatment groups
99 Participants
are divided into 3 treatment groupsGroup A: Early OndansetronExperimental treatment 2 interventions
Group B: Late OndansetronActive comparator 2 interventions
Group C: PlaceboPlacebo comparator 1 intervention
Trial outcomes
Primary outcomes
1
Bilateral Frontal Regional Cerebral Oxygen Saturation (rSO₂)
Regional cerebral oxygen saturation (rSO₂, %) will be measured bilaterally over the frontal cortex using near-infrared spectroscopy. Left and right rSO₂ values will be recorded at each prespecified assessment time point.
Time frame
Before spinal anesthesia (baseline) and at 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 minutes after spinal anesthesiaSecondary outcomes
1
Incidence of Hypotension
Hypotension will be defined as a mean arterial pressure (MAP) below 65 mmHg and/or a reduction in systolic blood pressure of at least 30% from baseline.
Time frame
During the first 60 minutes after spinal anesthesia2
Time to First Hypotensive Episode
Time from completion of spinal anesthesia to the first episode meeting the predefined criteria for hypotension.
Time frame
During the first 60 minutes after spinal anesthesia3
Requirement for Ephedrine
Proportion of participants requiring intravenous ephedrine for treatment of hypotension.
Time frame
During the first 60 minutes after spinal anesthesia4
Total Ephedrine Dose
Total cumulative dose of intravenous ephedrine administered for treatment of hypotension, measured in milligrams.
Time frame
During the first 60 minutes after spinal anesthesiaSponsors and contacts
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Source ClinicalTrials.gov
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