Efficacy of prophylactic intravenous administration of ondansetron for prevention of spinal anesthesia induced hypotension in elderly patients

Objective: Hypotension is the commonest side effect associated with spinal anesthesia. Multiple modalities have been tested to find adequate preventive measure. Main objective of this study is to find out the effectiveness of prophylactic administration of inj. ondansetron for prevention of spinal anesthesia induced hypotension in elderly patients. Study design: Double blind, randomized controlled trial. Place and duration of study: This study was conducted in our anesthesiology department from 01 July 2014 to 31 December 2014. Methodology: 100 patients were selected for the study using non-probability sampling technique, and divided into two groups of 50 each using random numbers table. Each patient was preloaded with ringer's lactate solution in a dose of 10 ml/kg. Patients of Group A received 8 mg of ondansetron IV five minutes prior to administration of spinal anesthesia; whereas patients of Group B were injected normal saline IV. Data were collected and analyzed using IBM SPSS version 20. Chi square test was used to compare hypotension between two groups. A p-value < 0.05 was taken as significant. Results: Mean age of Group A was 64.16 +/- 8.47 years, whereas that of Group B was 62.58 +/- 8.99 (p value= 0.39). Mean weight of Group A was 72.64 +/- 5.82 kg, whereas that of Group B was 70.66 +/- 5.96 kg (p - value= 0.295). Hypotension was present in 23 (46%) patients in Group A, where as it was present in 34 (68%) patients in Group B (p value= 0.026). Bradycardia was recorded in 3(06%) vs. 11(22%) patients in Group A and B respectively (p=0.021). Conclusion: We conclude that intravenous administration of 8 mg of ondansetron, 5 minutes prior to subarachnoid block, is effective in decreasing frequency of hypotension and bradycardia in elderly patients.