Effects of Ondansetron on Hemodynamic Changes After Spinal Anesthesia in Geriatric Urologic Surgery

Effects of Ondansetron on Hemodynamic Changes Induced by Spinal Anesthesia in Geriatric Urologic Surgery Patients

Spinal anesthesia is frequently used in urologic surgery in geriatric patients; however, it may cause significant hemodynamic changes such as hypotension and bradycardia. These changes can be more pronounced in elderly patients due to age-related physiological alterations. Ondansetron, a 5-HT3 receptor antagonist commonly used for the prevention of postoperative nausea and vomiting, has been suggested to attenuate spinal anesthesia-induced hemodynamic instability by modulating vagal reflexes.

This prospective observational study aimed to evaluate the effects of ondansetron on hemodynamic changes following spinal anesthesia in geriatric patients undergoing urologic surgery. Hemodynamic parameters were recorded during the intraoperative period, and the incidence of hypotension, bradycardia, and vasopressor requirements were assessed.

Study Overview

• Status: Completed
• Conditions: Bradycardia; Hypotension; Hypotension During Surgery; Spinal Anesthesia Induced Hemodynamic Change

Detailed Description

This study was designed as a prospective observational study conducted in geriatric patients undergoing urologic surgery under spinal anesthesia. Patient enrollment and data collection were performed prospectively between December 18, 2024, and April 18, 2025. The study protocol was approved by the TABED Ethics Committee (Approval No: 1-24-840, December 18, 2024).

Ondansetron was administered according to routine clinical practice. Hemodynamic parameters, including mean arterial pressure and heart rate, were recorded at predefined time points following spinal anesthesia. The incidence of spinal anesthesia-induced hypotension, bradycardia, and the need for vasopressor support were evaluated.

Although patient enrollment and data collection were conducted prospectively, the study was registered retrospectively at ClinicalTrials.gov due to delayed trial registration.

• Study Type: Observational
• Enrollment (Actual): 140

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Ankara
    • Ankara, Ankara, Turkey (Türkiye)
      • Ankara Bilkent City Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of geriatric patients aged 65 years and older undergoing elective urologic surgery under spinal anesthesia. Patients were managed according to routine clinical practice, with or without prophylactic ondansetron administration. Perioperative hemodynamic parameters, including blood pressure and heart rate, were prospectively recorded during the intraoperative period.

Description

Inclusion Criteria:

• Patients aged 65 years and older Patients scheduled for elective urologic surgery under spinal anesthesia American Society of Anesthesiologists (ASA) physical status I-III Patients who received routine perioperative management, with or without ondansetron administration Patients who provided written informed consent

Exclusion Criteria:

• Refusal or contraindication to spinal anesthesia Known hypersensitivity or contraindication to ondansetron Preexisting severe cardiac conduction abnormalities (e.g., high-grade atrioventricular block, sick sinus syndrome) Baseline bradycardia (heart rate < 50 beats per minute) Chronic use of medications significantly affecting heart rate or blood pressure (e.g., beta-blockers, calcium channel blockers, antiarrhythmic drugs) Emergency surgery Incomplete perioperative hemodynamic data

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Ondansetron Group; Geriatric patients undergoing urologic surgery under spinal anesthesia who received intravenous ondansetron as part of routine clinical practice prior to spinal block. Patients were observed without investigator-directed intervention.
Control Group; Geriatric patients undergoing urologic surgery under spinal anesthesia who did not receive ondansetron prior to spinal block and were managed according to routine clinical practice.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Spinal Anesthesia-Induced Hypotension	The occurrence of spinal anesthesia-induced hypotension, defined as a decrease in mean arterial pressure of 20% or more from baseline during the intraoperative period.	rom induction of spinal anesthesia until the end of surgery
Incidence of Spinal Anesthesia-Induced Bradycardia	The occurrence of spinal anesthesia-induced bradycardia, defined as a decrease in heart rate of 20% or more from baseline during the intraoperative period.	From induction of spinal anesthesia until the end of surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ephedrine Requirement	The need for intraoperative ephedrine administration to treat hypotension following spinal anesthesia.	From induction of spinal anesthesia until the end of surgery
Atropine Requirement	The need for intraoperative atropine administration to treat bradycardia following spinal anesthesia.	From induction of spinal anesthesia until the end of surgery

Collaborators and Investigators

• Sponsor: Ankara City Hospital Bilkent
• Investigators: Principal Investigator: Zeynep Nur Akçaboy, MD, Department of Anesthesiology, Ankara City Hospital

Study record dates

Study Major Dates

• Study Start (Actual): December 18, 2024
• Primary Completion (Actual): April 18, 2025
• Study Completion (Actual): April 18, 2025

Study Registration Dates

• First Submitted: April 20, 2026
• First Submitted That Met QC Criteria: April 20, 2026
• First Posted (Actual): April 24, 2026

Study Record Updates

• Last Update Posted (Actual): April 24, 2026
• Last Update Submitted That Met QC Criteria: April 20, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: spinal anesthesia; ondansetron; geriatric patients; hemodynamic instability; urologic surgery
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Hypotension; Bradycardia
• Other Study ID Numbers: TABED1-24-840

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No