Ondansetron Attenuates Hypotension Due To Subarachnoid Block-A Randomised Double Blind, Placebo-Controlled Study
Background: A decrease in arterial blood pressure is one of the known complications of subarachnoid block (SAB) and represents a major cause of concern in some patients. Improvements in surgical and anaesthetic techniques have not helped to curb the incidence of hypotension. Therefore search is going on for various modalities to decrease the incidence. Aim: To test the hypothesis that ondansetron attenuates the arterial hypotension and bradycardia produced due to subarachnoid block. Methods: A randomised double blind, placebo-controlled study was performed on 60 patients. They were divided into two groups. Group O patients received 8 mg ondansetron in 10 ml of isotonic NaCl intravenously before SAB. Group P patients had received isotonic NaCl solution 10 ml intravenously without any added medication before SAB. The systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP) and heart rate (HR) were recorded every 5 minutes for first 20 minutes and every 10 Minutes up to 40 minutes. After the subarachnoid block in both groups and subjected to statistical analysis. The Statistical analysis was performed by STATA 11.1 (College Station TX USA). Students paired t-test was used to assess the significance difference between the pre and post comparisons of heart rate and blood pressures. Continuous variables were expressed as mean and standard deviation; Categorical variables were expressed as frequency and percentage. P<0.05 considered as statistically significance. Results: It was noted that the systolic and diastolic and mean arterial blood pressure fall was less in ondasetron group while comparing to the placebo group. The ondansetron group and the placebo group patients did not have significant effect on heart rate induced by SAB. Conclusion: The attenuation of fall in blood pressure during subarachnoid block can be achieved with ondansetron given intravenously before SAB.