Clinical outcomes of ondansetron administration with elective cesarean section

Background: Intraoperative vital sign variability such as hypotension and bradycardia continue to remain a concern for patients undergoing cesarean delivery under spinal anesthesia. Recent literature has suggested that administering a 5-hydroxytryptamine3 antagonist such as ondansetron prior to spinal anesthesia for cesarean delivery can mitigate intraoperative vital sign variability and reduce vasopressor utilization.

Purpose and objectives: The purpose of this project was to examine the optimal perioperative timing of ondansetron administration and associated maternal clinical outcomes with elective cesarean delivery. The main objectives were to determine if intraoperative hemodynamic variables and vasopressor administration significantly differed regarding ondansetron timing.

Method: A retrospective medical record review was conducted from 68 patients with cesarean delivery under spinal anesthesia to compare the timing of ondansetron administration (pre-spinal versus post-spinal) with intraoperative vital sign variability and vasopressor utilization.

Results: There were no significant differences between pre-spinal and post-spinal ondansetron groups regarding systolic blood pressure (p=0.11), diastolic blood pressure (p=0.56), mean arterial pressure (p=0.75), or heart rate (p=0.75). Also, there were no significant differences regarding intraoperative phenylephrine (p=0.86) and ephedrine (p=0.08) administration.

Implications: Although statistical significance was not found, the systolic blood pressure was consistently higher and less vasopressor medication was administered in the pre-spinal ondansetron group. Results such as these, in combination with recently published literature should be taken into consideration to guide obstetric anesthesia practitioners regarding optimal perioperative timing of ondansetron until a practice standard is set forth.