The effect of ondansetron administration 20 minutes prior to spinal anaesthesia on haemodynamic status in patients undergoing elective caesarean section: A comparison between two different doses

Abstract

Background and Aims: Spinal anaesthesia is currently the most common method used for managing patients undergoing elective caesarean sections. Recent meta-analyses have been supporting the use of 5-HT3 antagonists, like ondansetron, to attenuate hypotension induced by spinal block. Various doses of ondansetron were given intravenously five minutes before spinal block. However, a consensus on definitive dose and timing for maximal benefit is yet to be agreed upon. Methods: Our prospective randomised clinical trial investigated a new approach by administrating intravenous ondansetron 20 minutes before spinal anaesthesia. This work investigated ondansetron effect on both haemodynamic changes and vasopressors use by dividing patients into three groups. The first group O4 (n = 51) received 4 mg ondansetron, the second group O6 (n = 51) received 6 mg ondansetron, and the control group C (n = 50) received normal saline. We recorded systolic blood pressure (SBP), diastolic blood pressure (DBP) and the mean blood pressure (MBP) at different time intervals. Results: There was no significant difference in blood pressure measurements among the study groups ( P > 0.05). The consumption of ephedrine in the control group is higher than both of the ondansetron groups ( P > 0.001), with a mean dose of 27.2 ± 20.5 mg of ephedrine for group C, compared to 17.8 ± 14.9 and 14.7 ± 11.3 in O4 and O6 groups, respectively. Episodes of hypotension and number of patients with hypotension were not significantly different among the studied groups ( P = 0.07; P = 0.96, respectively). Conclusions: Prophylactic 4 and 6 mg ondansetron given 20 minutes before spinal anaesthesia in caesarean section does not reduce the incidence of hypotension.

Effect of Prophylactic Intravenous Ondansetron on Hemodynamic Parameters in Elective Cesarean Section under Spinal Anesthesia

“…These findings are consistent with those made by Sahoo et al (7) who had 4 mg of ondansetron, given 5 minutes prior to spinal anesthesia for a caesarean section delivery, Trabelsi et al (2) In comparison to the control group, they found that patients who took ondansetron (5 mg) had higher SBP, DBP, and MAP. Also, Samarah et al (9) researchers tested a novel strategy by giving intravenous ondansetron 20 minutes before to spinal anesthesia, and they found no discernible change in blood pressure readings across the trial groups (P>0.05). This discrepancy with the current study may be due to the difference in the type of surgery and population in the first study and the timing difference in the second as mentioned before.…”

“…Furthermore, Samarah et al (9) discovered that ondansetron prevented hypotension in caesareansurgery patients who were pregnant, but the impact was not superior to that of vasoconstrictors.…”

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

“…This study sheds light on the available evidence on this topic to this date. Prior studies have explored the use of ondansetron on the risk of incident hypotension and bradycardia and reported that this medication does not provide clinical benefit [10][11][12][13] . Meta-analysis performed by Chengmao Zhou et al 14 with 21 randomized controlled trials found no statistically difference in hypotensive events between groups.…”

“…Previous studies tried to demonstrate that administration of ondansetron, a potent and highly selective 5-HT3 receptor antagonist, minutes before spinal anesthesia could attenuate hypotension and bradycardia. While a few studies showed that ondansetron administration might be beneficial [7][8][9] , most have shown evidence of little or no protection [10][11][12][13][14] . Small sample sizes, differences in the administration of co-interventions (e.g., pre-loading/co-loading fluids) and heterogeneity in the definitions of hypotension might be some of the causes for this discrepancy.…”