Ephedrine Versus Ondansetron During Cesarean Delivery

Ephedrine Versus Ondansetron in the Prevention of Hypotension During Cesarean Delivery: a Randomized, Double Blind, Placebo-controlled Trial

More than 30% of the patients receiving spinal anesthesia develop hypotension. Hypotension developed during cesarean section (C/S) under spinal anesthesia may jeopardize uteroplacental circulation leading to fetal compromise and even fetal death. The effect of prophylactic ondansetron on blood pressure after spinal anesthesia has not been compared in a clinical trial with that of a vasoconstrictor. The investigators will compare ephedrine and ondansetron for the prevention of maternal hypotension after spinal anesthesia for elective cesarean delivery.

Some vasopressive drugs including ephedrine and phenylephrine have been widely used to prevent maternal hypotension. Although ephedrine has mixed a-adrenoceptor activity , it maintains arterial pressure mainly by increases in cardiac output and heart rate as a result of its predominant activity on β1-adrenoceptors. It has been demonstrated that ondansetron preloading with crystalloid infusion reduces maternal hypotension in parturient women undergoing cesarean delivery. Ondansetron has been widely used in the clinic to prevent nausea and vomiting caused by cancer chemotherapy, radiation therapy, and surgery. Ondansetron has been proven as a well-tolerated drug, but the most common side effects of ondansetron include headache, constipation, diarrhea, asthenia, and somnolence.

According to patients' randomized groups, study medication was given over 1 min, 5 min before spinal anesthesia Patients were randomly assigned into 1 of 4 groups, using computer generated sequence and opaque envelopes, according to the prophylactic intravenous drug dose used: Group E: were administered intravenous ephedrine 10 mg diluted in 10 mL 0.9% saline over 1 minute; Group OL: were administered intravenous ondansetron 4 mg diluted in 10 mL 0.9% saline over 1 minute; Group OH: were administered intravenous ondansetron 8 mg diluted in 10 mL 0.9% saline over 1 minute; Group P: was a control group who received 0.9% saline 10 mL over 1 minute as a placebo.

This is a double-blind study at the level of patients, careproviders, and outcome assessors. Anesthesiologists, surgeons, and operating personnel did not know which study treatment was used. Syringes were identical in terms of volume, color, viscosity, and odor.

Monitoring with pulse oximetry, noninvasive blood pressure measurement and electrocardiogram was established on arrival to the operating room Group E: were administered intravenous ephedrine 10 mg diluted in 10 mL 0.9% saline over 1 minute; Then under aseptic precautions, spinal anesthesia was administered.

Monitoring with pulse oximetry, noninvasive blood pressure measurement and electrocardiogram was established on arrival to the operating room Group OL: were administered intravenous ondansetron 4 mg diluted in 10 mL 0.9% saline over 1 minute; Then under aseptic precautions, spinal anesthesia was administered.

Monitoring with pulse oximetry, noninvasive blood pressure measurement and electrocardiogram was established on arrival to the operating room Group OH: were administered intravenous ondansetron 8 mg diluted in 10 mL 0.9% saline over 1 minute; Then under aseptic precautions, spinal anesthesia was administered.

Monitoring with pulse oximetry, noninvasive blood pressure measurement and electrocardiogram was established on arrival to the operating room Group P: was a control group who received 0.9% saline 10 mL over 1 minute as a placebo. Then under aseptic precautions, spinal anesthesia was administered.

Mean arterial blood pressure was recorded every 2 minute for 10 minutes then every 5 minutes until delivery. Time of intrathecal injection was considered as 0 min.

Inclusion Criteria: age >18, <40 years; American Society of Anesthesiologists physical status I or II; term pregnancy singleton pregnancy; elective cesarean delivery under spinal anesthesia Exclusion Criteria: Patients with a history of diabetes mellitus other than gestational diabetes, hypertension, body mass index >40 kg/m2, complicated pregnancy, allergy to study drugs, long QT syndrome, Contraindication to spinal anesthesia Patients who required general anesthesia were withdrawn from the study.

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request