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.
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