Effect of ondansetron in maternal hypotension during cesarean delivery: an observational study

Abstract

Background: Spinal anesthesia is the most common anesthetic technique for cesarean delivery. Thus, hypotension is associated with a reduction in uteroplacental flow which may induce fetal morbidity. Activation of the Bezold Jarisch reflex (mediated by 5HT3 receptors) can worsen hypotension and decrease cardiac output. We studied the effect of ondansetron administration before spinal anesthesia on the trajectory of blood pressure during cesarean delivery. Methods: We conducted a retrospective chart review of all cesarean deliveries that occurred between April 1st 2020 and April 1st 2021 and included 85 pregnant women (43 with ondansetron and 42 in the control group). Data were obtained from the electronic medical record database of the British Hospital of Buenos Aires. Socio- demographic, obstetric, anesthetic and perioperative characteristics of patients were assessed. Results: There were no significant differences in the trajectories of the change from baseline of mean arterial blood pressure between ondansetron and control group (0.14% (95% CI: 0.06 to 0.21) per minute). This also applied to heart rate (-0.10% per minute (95% CI: -0.19 to 0.01). The need of any infusion (phenylephrine or atropine) comparing ondansetron to the reference group was 1.12 (95% CI: 0.68, 1.85). There were eight events of shivering (16.3%) in the ondansetron exposed group and four events of shivering (8.5%) in the reference group. APGAR values showed no clinical difference between groups. Conclusions: In this single-center cohort study, we did not observe an effect of routine administration of ondansetron before spinal anesthesia in cesarean section on improving arterial blood pressure or heart rate throughout the procedure.