Effectiveness of Granisetron in Prevention of Hypotension Following Spinal Anaesthesia in Patients Undergoing Elective Caesarean Section

Background and aim: Spinal anesthesia is the most common type of anesthesia administered for caesarean section and it is frequently associated with hypotension. When post-spinal hypotension is accompanied with bradycardia, the condition may become more complicated. Numerous pharmacological agents have therefore been tried for prevention of hypotension and 5HT3 antagonists are the latest in the armamentarium. However, studies have shown conflicting evidence regardings the effectiveness of 5HT3 inhibitors (ondansetron and granisetron) in preventing spinal hypotension. We have tried to address this controversy and also wanted to explore the adverse effects of granisetron on the foetus, if any. Materials and methods: Two hundred patients were included in the study and divided into two groups of 100 patients each. Group S patients received 5ml of 0.9% normal saline while Group G patients received IV granisetron 1mg (diluted to 5ml) 10 minutes prior to administration of spinal anesthesia. Analysis of variance (ANOVA) test was used for comparing the data, Student t-test was applied to compare the difference between the two means and Chi-Square test was used to test significance of difference of proportions. Results: The incidence of hypotension in Group S was 69%, whereas it was 37% in Group G (p<0.001), hence patients of Group S required a significantly higher (p=0.001) amount of mephentermine. Haemodynamic parameters were well maintained throughout the study period in patients of Group G. The neonatal outcome was assessed by Apgar score at 0 minutes, one minute, and five minutes after delivery, and it was comparable between the two study groups. Conclusion: Intravenous granisetron 1mg if administered before administering spinal anesthesia can effectively attenuate hypotension in parturients without any adverse effects on the mother and the neonate.