Abstract

Background and Aims: Spinal anesthesia (SA) is safe and effective technique for a range of surgical procedures. SA related triggering of Bezold Zarisch reflex demonstrated by hypotension, bradycardia and vasodilation is known to result from stimulation of 5-HT3 receptors in vagal nerve endings1,2,. Prophylactic administration of ondansetrona a 5-HT3 receptor blocker may reduce the side effects. The aim of the present study is to verify the hypothesis that blockage of type 3 serotonin receptors by intra venous ondansetron administration would reduce hypotension and bradycardia induced by SA. Method: The study was conducted on 140 patients undergoing SA . There were two sets of population, obstetric and non obstetric. Each set of population had their own control group. After taking the patient to the operation theatre, venous access was established, and basic monitors were connected . Base line blood pressure and heart rate were noted before the SA.. Then in sitting position, SA was performed . After spinal, Heart rate(HR), systolic(SBP), diastolic (DBP) and mean arterial pressure (MAP), and oxygen saturation (Sp02) were recorded at time of spinal drug administration and at 2 min intervals upto 18 min. Adverse effect such as nausea and vomiting, were monitored. Drop in systolic blood pressure to less than or equal to 90 mm of Hg was treated with iv ephedrine 6 mg and HR fall to less than 50 beats per minute with iv 0.2 mg glycopyrrolate . Amount of ephedrine and glycopyrrolate consumed were also noted. The comparison of normally distributed continuous variables between the groups was performed using Student's t-test. Nominal categorical data between the groups were compared using Chi- squared test or Fisher's exact test as appropriate. P< 0.05 was considered statistically significant..

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