A Phase 4 interventional study of Ondansetron and 0.9% Normal Saline placebo in Spinal Anaesthesia Induced Hypotension, sponsored by Assiut University. Not yet recruiting at 1 site in Egypt. Open to participants aged 65 Years and older. Per ClinicalTrials.gov, last updated 2026-11-04.
Sponsored by Assiut University · Phase 4, Interventional, and Prevention
This study aims to compare prophylactic intravenous ondansetron 4 mg versus placebo regarding the incidence of spinal anaesthesia-induced hypotension, defined as mean arterial pressure (MAP) fall >20% from baseline or systolic blood pressure (SBP) \<90 mmHg/fall >20% from baseline, in elderly patients undergoing fracture hip surgery. The hypothesis is that a significant difference exists.
Spinal anesthesia is widely used for fracture hip surgery because it provides effective surgical anesthesia while avoiding many physiological effects associated with general anesthesia. However, spinal anesthesia-induced hypotension (SIH), defined as a mean arterial pressure (MAP) decrease >20% from baseline or systolic blood pressure (SBP) \<90 mmHg or a >20% decrease from baseline, is one of its most common complications. It primarily results from sympathetic blockade, causing vasodilation, reduced venous return, decreased cardiac output, and subsequent arterial hypotension. This may be particularly significant in elderly patients because of reduced cardiovascular, arterial, and autonomic reserve, together with a higher prevalence of cardiovascular disease and polypharmacy.
A sudden reduction in left-ventricular preload may activate cardiac mechanoreceptors and trigger the Bezold-Jarisch reflex (BJR). Serotonin-sensitive 5-HT3 receptors located on intracardiac vagal nerve endings may enhance vagal activity, contributing to bradycardia defined as heart rate (HR) \< 50 beat per minute (bpm) and hypotension.
Ondansetron, a selective 5-HT3 receptor antagonist widely used as an antiemetic, has been investigated to attenuate the BJR and reduce SIH. Several randomized trials and meta-analyses have reported that prophylactic intravenous ondansetron, commonly given at 4-8 mg shortly before spinal injection, reduces post-spinal hypotension, bradycardia, and rescue vasopressor requirements, including in elderly surgical patients. An exploratory analysis suggested a greater preventive effect in patients aged ≥65 years.
However, the elderly subgroup was small and a 8 mg dose was used, leaving uncertainty regarding the optimal dose.
Spinal anesthesia technique The conduct of spinal anesthesia will be standardized across the two groups. On arrival to the operating room, standard ASA monitors including a pulse oximetry, electrocardiography and non-invasive blood pressure will be applied and the patients will be continuously monitored.
Baseline hemodynamics will be recorded at one, three, and five minutes before the studied drug administration, and the average will be taken as a baseline.
After an intravenous (IV) access is secured, all patients will receive an intraoperative infusion of 5-10 ml/kg Ringer's lactate or Normal saline solution per hour.
With the parturient in a sitting position, spinal anaesthesia will be conducted using the midline or paramedian approach after proper antiseptic cleaning and draping in the lumbar vertebral interspace of L3-L4 or a level below using a 25 or 22-gauge Quincke needle. After confirming free flow of cerebrospinal fluid, a 3 mL of hyperbaric bupivacaine 0.5% will be injected intrathecal in both Groups the same dose, Then all patients will be then made to lie supine.
Block-level will be tested every five minutes using a frozen plastic ampule of sterile water along the midclavicular line to check the response to cold, and the highest sensory level obtained will be registered.
Motor level will be assessed every five minutes using the Modified Bromage Scale, where Grade 0 indicates full movement of the hip, knee, and ankle; Grade 1 indicates inability to raise the extended leg while retaining the ability to flex the knee and move the ankle; Grade 2 indicates inability to flex the knee while retaining ankle movement; and Grade 3 indicates complete motor block with inability to move the hip, knee, or ankle. The highest Modified Bromage grade obtained will be recorded.
Surgeons will be allowed to proceed with surgery after attaining a block level of at least up to T10.
Data collection
Hemodynamic parameters including heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and oxygen saturation (SpO2) will be recorded at the following time points:
The incidence of postoperative nausea and vomiting (PONV) episodes will be assessed in the first 24 h (at 2, 4, 6, 8, 12, 24 hours after surgery).
Patients who will develop shivering will be warmed with heated blankets.
Assiut University is the lead sponsor of 5,068 studies on the registry; 2,179 are open to participants now.
Of its 14 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
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Exclusion Criteria:
Ondansetron 4 mg diluted in 10 mL 0.9% normal saline over 60-90 seconds prior to spinal injection
Drug: Ondansetron
IV bolus of 10 mL 0.9% normal saline over 60-90 seconds prior to spinal injection
Drug: 0.9% Normal Saline placebo
4 mg diluted in 10 mL 0.9% normal saline.
10 mL IV 0.9% normal saline
Effect of prophylactic intravenous ondansetron versus Placebo on the incidence of spinal anaesthesia-induced hypotension
Compare the effect of prophylactic intravenous ondansetron 4 mg versus Placebo on the incidence of spinal anaesthesia-induced hypotension, defined as MAP fall \> 20% from baseline, or systolic blood pressure \< 90 mmHg / fall \> 20% from baseline, in elderly patients undergoing fracture hip surgery under spinal anaesthesia.
Time frame: From induction of spinal anaesthesia until completion of surgery.
The incidence of severe hypotension
Severe hypotension, defined as systolic blood pressure (SBP) dropping to \<60% of baseline
Time frame: From induction of spinal anaesthesia until completion of surgery.
The number of episodes of intraoperative hypotension.
The percentage of people who experience hypotension, defined as MAP fall \> 20% from baseline, or systolic blood pressure \< 90 mmHg / fall \> 20% from baseline, intraoperatively
Time frame: From induction of spinal anaesthesia until completion of surgery.
The incidence of bradycardia
The Percentage of people who experience Bradycardia, defined as heart rate (HR) \<50 bpm, intraoperatively
Time frame: From induction of spinal anaesthesia until completion of surgery.
The total rescue vasopressor (ephedrine) and atropine requirements between groups
Total dose of intraoperative ephedrine or atropine if hypotension or bradycardia occurs
Time frame: From induction of spinal anaesthesia until completion of surgery.
The incidence of postoperative nausea and vomiting (PONV)
PONV was evaluated using the PONV grading scale in the post-anesthesia care unit (PACU) at 2, 4, 6, 8, 12, and 24 hours PONV will be assessed using a four-grade scale: Grade 0 indicates no PONV; Grade I indicates nausea without vomiting; Grade II indicates nausea with vomiting occurring fewer than three times per day; and Grade III indicates vomiting occurring three or more times per day.
Time frame: Up to 24 hours postoperatively
The incidence of intraoperative and postoperative shivering between groups
Assess the presence of shivering intraoperatively and postoperatively
Time frame: From induction of spinal anaesthesia up to 24 hours postoperatively
Sensory block characteristics (onset and duration) between groups.
Block-level will be tested every five minutes using a frozen plastic ampule of sterile water along the midclavicular line to check the response to cold, and the highest sensory level obtained will be recorded Surgeons will be allowed to proceed with surgery after attaining a block level of at least T10.
Time frame: From induction of spinal anaesthesia until completion of surgery.
Motor block characteristics (onset, Modified Bromage score, and duration) between groups.
Motor level will be assessed every five minutes using the Modified Bromage Scale, where Grade 0 indicates full movement of the hip, knee, and ankle; Grade 1 indicates inability to raise the extended leg while retaining the ability to flex the knee and move the ankle; Grade 2 indicates inability to flex the knee while retaining ankle movement; and Grade 3 indicates complete motor block with inability to move the hip, knee, or ankle. The highest Modified Bromage grade obtained will be recorded. Surgeons will be allowed to proceed with surgery after attaining a block level of at least T10.
Time frame: From induction of spinal anaesthesia until completion of surgery.
Plan to share: Undecided
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Ondansetron