The Effect of Ondansetron on Spinal Anesthesia in Caesarean Section

Study Overview
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Brief Summary
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The purpose of this study is to compare the administration of two different doses of ondansetron to placebo to prevent hypotension and bradycardia following spinal anaesthesia. Apart from haemodynamic parameters (blood pressure and heart rate),characters of the spinal blockage (time of onset and regression) will be recorded too.

Detailed Description
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The day before surgery the procedure will be explained to the patient and the written consent will be obtained. In the operating room, intraoperative monitoring will include electrocardiography (ECG), noninvasive blood pressure, oxygen saturation by pulse oximetry (SpO2) and heart rate (HR). Two peripheral intravenous catheters wil be placed for fluid replacement and administration of drugs. Participants will be randomly assigned to one of the following groups: Group A: Women will receive 4 milligrams (mg) of ondansetron diluted in 100 milliliters (ml) of normal saline 0.9 percent 10 minutes before spinal anaesthesia Group B:Women will receive 8 mg of ondansetron diluted in 100ml of normal saline 0.9 percent 10 minutes before spinal anaesthesia Group C:Women will receive 100ml of normal saline 0.9 percent 10 minutes before spinal anaesthesia Subsequently, after receiving 500ml of colloid solution, spinal anesthesia will be performed at level L3-L4 or L4-L5 in the vertebral space with 1.6ml of 0.75 percent ropivacaine and 15mcg of fentanyl, using a 27-gauge pencil point spinal needle with patients in a left lateral position. After subarachnoid infusion, participants will be placed supine with left uterine displacement and anesthetic and motor blockage will be evaluated every one minute until anesthetic blockage reaches the level of T4 neurotome and the motor block becomes complete (Bromage grade 3). This time will be called Time to max effect (Tmax). Hypotension, defined as systolic blood pressure below 100 millimeters of Mercury (mmHg), will be treated using 5mg ephedrine if the heart rate is less than 100 beats per minute or with 20mcg of phenylephrine if the heart rate is greater than 100 beats per minute. Bradycardia, defined as a fall in heart rate below 60 beats per minute will be treated with atropine (0.6mg). Immediately after the delivery of the neonate, all women will receive a solution of oxytocin (20 units) intravenously. Half an hour before the end of the procedure they will receive an additional 1g of paracetamol and 75mg of diclofenac.

Official Title
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The Effect of Ondansetron on Spinal Anesthesia in Caesarean Section

Conditions
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Hypotension

Intervention / Treatment
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* Drug: Ondansetron 4mg
* Drug: Ondansetron 8mg
* Drug: 100ml normal saline 0.9 percent


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Physical status according to American Society of Anesthesiologists (ASA) I-II Singleton pregnant women in full term pregnancy Patients scheduled for cesarean section Height 158cm-170cm Exclusion Criteria: patient's own refusal contraindications to spinal anesthesia (coagulation disorders, inflammation at the puncture site, allergy to local anesthetics) ondansetron allergy body mass index> 33kg / m^2 height <158cm, or> 170cm hypertensive disorders of pregnancy cardiovascular disease receiving selective serotonin reuptake inhibitors (SSRI's) or treatment for migraine placenta previa.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group A<br>Intravenous administration of ondansetron 4mg diluted in 100ml of normal saline 0.9 percent within 10 minutes prior to spinal anesthesia. | Drug: Ondansetron 4mg<br>* Intravenous administration of ondansetron 4mg diluted in 100ml of normal saline 0.9 percent within 10 minutes prior to spinal anesthesia.<br>* Other names: Onda;|
| Active Comparator: Group B<br>Intravenous administration of ondansetron 8mg diluted in 100ml of normal saline 0.9 percent within 10 minutes prior to spinal anesthesia. | Drug: Ondansetron 8mg<br>* Intravenous administration of ondansetron 8mg diluted in 100ml of normal saline 0.9 percent within 10 minutes prior to spinal anesthesia.<br>* Other names: Onda;|
| Placebo Comparator: Group C<br>Intravenous administration of 100ml of normal saline 0.9 percent within 10 minutes prior to spinal anesthesia. | Drug: 100ml normal saline 0.9 percent<br>* Intravenous administration of 100ml of normal saline 0.9 percent within 10 minutes prior to spinal anesthesia.<br>* Other names: N/S 0.9 percent;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from Baseline Systolic Blood Pressure during cesarean section | every one minute after spinal anaesthesia and every five minutes after the delivery of the neonate until the end of the surgery | 60 minutes | 
| Change from Baseline Heart Rate | every one minute after spinal anaesthesia and every five minutes after the delivery of the neonate until the end of the surgery | 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensory blockade | Time for onset of sensory block at T4 | 20 minutes | 
| Motor blockade | Time to Bromage 2 and to Bromage 3 | 20 minutes | 
| Sensory regression | Time to two segment regression | 120 minutes | 
| Motor block regression | Time to Bromage 1 and Bromage 0 | 120 minutes | 
| Time to maximum effect (Tmax) | Time when the motor blockade is complete and sensory blockade is in at the level of T4 dermatome | 20 minutes | 
| Time to minimum effect (Tmin) | Time to two segment regression of the sensory block (T6) and for motor block regression to Bromage1 and Bromage 0 | 120 minutes | 
| Nausea | Scale for nausea (0:no nausea 10:worst possible nausea) | 0 hours, 2 hours, 4 hours, 8 hours, 24 hours postoperatively | 
| Vomiting | Number of vomits | 0 hours, 2 hours, 4 hours, 8 hours, 24 hours postoperatively | 
| Shivering | Yes:shiver No:no shiver | 0 hours, 2 hours, 4 hours, 8 hours, 24 hours postoperatively | 
| Total ephedrine consumption | Total ephedrine consumption intraoperatively | 60 minutes | 
| Total phenylephrine consumption | Total phenylephrine consumption intraoperatively | 60 minutes | 
| Total atropine consumption | Total atropine consumption intraoperatively | 60 minutes | 
| Neonate Apgar score | Apgar score in the 1st and 5th minute after delivery of the neonate | 5 minutes | 
| Umbilical cord ph | Umbilical cord ph after delivery | 15 minutes | 
| Need for administration of antiemetic agent | Need for administration of antiemetic agent intraoperatively | 90 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ondansetron