The effect of intravenous ondansetron on maternal haemodynamics during elective caesarean delivery under spinal anaesthesia: a double-blind, randomised, placebo-controlled trial.
BACKGROUND
Spinal anaesthesia for caesarean delivery is frequently associated with adverse effects such as maternal hypotension and bradycardia. Prophylactic administration of ondansetron has been reported to provide a protective effect. We studied the effect of different doses of ondansetron in obstetric patients.


METHODS
This prospective double-blind, randomised, placebo-controlled study included 128 healthy pregnant women scheduled for elective caesarean delivery under spinal anaesthesia. Women were randomly allocated into four groups (n=32) to receive either placebo or ondansetron 2, 4 or 8 mg intravenously before induction of spinal anaesthesia. Demographic, obstetric, intraoperative timing and anaesthetic variables were assessed at 16 time points. Anaesthetic variables assessed included blood pressure, heart rate, oxygen saturation, nausea, vomiting, electrocardiographic changes, skin flushing, discomfort or pruritus and vasopressor requirements.


RESULTS
There were no differences in the number of patients with hypotension in the placebo (43.8%) and ondansetron 2mg (53.1%), 4 mg (56.3%) and 8 mg (53.1%) groups (P=0.77), nor the percentage of time points with systolic hypotension (7.3% in the placebo group and 11.1%, 15.7% and 12.6% in the ondansetron 2, 4 and 8 mg groups, respectively, P=0.32). There were no differences between groups in ephedrine (P=0.11) or phenylephrine (P=0.89) requirements and the number of patients with adverse effects.


CONCLUSIONS
In our study, prophylactic ondansetron had little effect on the incidence of hypotension in healthy parturients undergoing spinal anaesthesia with bupivacaine and fentanyl for elective caesarean delivery.
['Ortiz-Gómez|J R|JR|', 'Palacio-Abizanda|F J|FJ|', 'Morillas-Ramirez|F|F|', 'Fornet-Ruiz|I|I|', 'Lorenzo-Jiménez|A|A|', 'Bermejo-Albares|M L|ML|']
D000328:Adult D000773:Anesthesia, Obstetrical D000775:Anesthesia, Spinal D000932:Antiemetics D001794:Blood Pressure D002585:Cesarean Section D004305:Dose-Response Relationship, Drug D004311:Double-Blind Method D017558:Elective Surgical Procedures D005260:Female D006439:Hemodynamics D006801:Humans D007275:Injections, Intravenous D017294:Ondansetron D011247:Pregnancy D011446:Prospective Studies
Ondansetron Caesarean delivery Spinal anaesthesia Hypotension