About seventy to eighty percent of patients experience hypotension during caesarean section conducted under spinal anaesthesia. Bezold Jarisch Reflex is hypothesized to be one of the main factors contributing to this cycle of deleterious hypotension and bradycardia. Studies suggests that ondansetron (5-HT3 receptor antagonist) can antagonize this cycle of events from the receptor level and can prevent it.
To study the efficacy of prophylactic intravenous ondansetron in preventing hypotension due to spinal anaesthesia and to compare the hemodynamic parameters among two study groups undergoing planned elective caesarean section.
It was a prospective comparative study and out of sixty subjects undergoing elective caesarean section, thirty were those received intravenous ondansetron 4 mg intravenously 5 to 10 minutes prior to spinal anaesthesia and thirty were those who did not receive any ondansetron prior to the spinal anaesthesia. Incidence of hypotension, use of vasopressor, systolic and diastolic blood pressure, mean arterial pressure and heart rate were measured at baseline, every 2 - minute for first 20 minutes followed by every 5-minute till the end of the procedure.
We observed that there was significant statistical difference in the number of hypotensive incidents between the Saline and the Ondansetron group, The number of hypotensive episodes was significantly less (p-value: 0.00096) and the number of cases which received vasopressor were also correspondingly less in the Ondansetron group (p-value: 0.00096).
We observed that intravenous Ondansetron at a dose of 4mg given 5 to 10 minutes prior to spinal anaesthesia significantly reduced the incidence of episodes of hypotension due to spinal anaesthesia in obstetric patients who underwent elective caesarean delivery.