A Randomised Controlled Trial to Evaluate the Effect of Ondansetron to Attenuate Hypotension and Bradycardia during Spinal Anaesthesia in Caesarean Section

Abstract

Background and Aim: Spinal anaesthesia has been an easy, rapid and safe anesthesia given to the parturients for cesarean section with advantages such as less maternal mortality, use of fewer drugs, direct maternal and paternal experience of childbirth and decreased blood loss while providing excellent postoperative pain control. Hypotension and bradycardia are the most common side effects of spinal anesthesia. This study was undertaken to assess the efficacy of prophylactic dose of ondansetron in reducing the incidence of hypotension, bradycardia apart from nausea and vomiting in patients receiving spinal anaesthesia for elective caesarean section.

Material and Methods: After obtaining approval from institutional ethical committee

[SVIEC/ON/MEDI/RP/AUG/24/4], 80 parturients of ASA II posted for elective caesarean section under spinal anaesthesia were enrolled and divided into 2 groups. Group (A) (40 patients): Inj. Ondansetron 4mg diluted in 10 ml normal saline given intravenously over 1 min, 5 min before spinal anaesthesia. Group (B) (40 patients): Injection 10 ml of normal saline given intravenously over 1 min, 5 min before spinal anaesthesia. The primary aim was to study the effect of ondansetron in decreasing incidences of bradycardia and hypotension during caesarean section. The secondary aim was to evaluate requirement of amount of ephedrine and atropine following hypotension and bradycardia caused by spinal anaesthesia. Heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure and oxygen saturation (SpO2) were recorded.

Results: Incidence of fall in systolic blood pressure in group A was 22.50 % and in Group B was 52.50% (p value of 0.006). However, there was no significant difference in diastolic blood pressure, mean arterial pressure and heart rate. Mean ephedrine consumption in group A was less than group B which was statistically significant. (p value of 0.007). Incidence of nausea and vomitting in group A was less than group B which was statistically significant with p value of 0.029.

Conclusion: Prophylactic administration of ondansetron, a 5HT-3 receptor antagonist produces a significant reduction in the incidence of hypotension in caesarean sections. It also reduces the number of patients who requires ephedrine and its overall dose for the treatment of hypotension. Ondansetron significantly reduces the incidence of nausea and vomiting.