Abstract

EFFECTS OF PROPHYLACTIC ONDANSETRON ON SPINAL ANAESTHESIA INDUCED HYPOTENSION AND BRADYCARDIA: A PROSPECTIVE, RANDOMIZED, DOUBLE-BLIND STUDY.

Dr. Amir Nazir and Dr. Feroz Ahmad Dar*

ABSTRACT

Background: The Bezold-Jarisch reflex is the likely cause of hypotension and bradycardia associated with spinal anaesthesia. The aim of this study was to investigate the effect of ondansetron (5-HT3 receptor antagonist) on spinal induced hypotension and bradycardia in caesarean section. Methods: Total hundred parturient patients undergoing caesarean section participated in the study with 50 patients in the group O which received intravenous ondansetron 1μg/kg diluted in 10ml NaCl Solution and 50 patients in group NS which received 10ml 0.9% NaCl solution five minutes before spinal anaesthesia. The heart rate, arterial blood pressure, shivering, nausea, vomiting and any other adverse effects were recorded after spinal anaesthesia. Results: Hypotension was seen only 7 patients (14%) in group O as compared to 23 patients (46%) in group NS (p <0.001).Three patients (6%) in group O and nine patients (18%) in group NS suffered from bradycardia (p= 0.0307). Significant number of cases experienced nausea and vomiting in group NS as compared to group O (40% vs 10% and 30% vs 8%, respectively). Compared with the group O, the maximum decline of SBP, DBP, and MAP was seen in group NS after 3min onwards up to 45 min after spinal anaesthesia. After that the haemodynamics changes were insignificant among the two groups. Moreover, there was significant increase in the use of ephedrine in groups NS and O (10.25±2.5mg vs 7.5±1.25mg, p<0.0001). Conclusion: Prophylactic intravenous 0.1mg/kg ondansetron reduces the spinal-induced hypotension, bradycardia and the need for rescue vasopressor.

Keywords: Bezold Jarisch Reflex, Ondansetron, Hypotension, Bradycardia.