Effect of intravenous ondansetron on spinal anesthesia-induced hypotension and bradycardia: A randomized controlled double-blinded study

Abstract

Background: Spinal anesthesia is a safe anesthetic technique commonly practiced. However, it is associated with hypotension (33%), bradycardia (13%), and shivering which are induced by hypovolemia, sympathetic blockade, and Bezold–Jarisch reflex through intracardiac serotonin (5HT3) receptors and vagus nerve. Aim: To study the effect of intravenous (i.v.) ondansetron on hypotension and bradycardia induced by spinal anesthesia. Setting and Design: This was a randomized controlled double-blinded study done in a tertiary care teaching hospital. Methods: Of 140 patients, 70 in Group A received 2 mL of i.v. ondansetron 4 mg and 70 in the Group B received 2 mL of i.v. normal saline. 3 mL of 0.5% hyperbaric bupivacaine was injected intrathecally. Measurements of blood pressure and heart rate (HR) were taken every 3 min for 30 min after spinal anesthesia was performed. Mean arterial pressure (MAP) drop more than 20% was considered as incidence of hypotension and ephedrine 6 mg i.v. was given. HR drop >20% was regarded as bradycardia and atropine 0.5 mg i.v. was given. Statistical Tests: Quantitative data were analyzed using ANOVA test and qualitative data were analyzed using Chi-square test. Results: Both groups are comparable in demographic data. Four (5.7%) patients in Group B and no patients in Group A had incidence of bradycardia and atropine requirement ( P = 0.120). There was no statistically significant difference in systolic blood pressure, diastolic blood pressure, and MAP. 19 (27%) patients in Group A and 33 (47.1%) in Group B required ephedrine with P = 0.029. 12 (17.1%) in Group B and no patients in Group A had shivering with P = 0.0001. Conclusion: Our study indicates that prophylactic use of ondansetron before spinal anesthesia significantly reduces the requirement of ephedrine and shivering.

Effect of ondansetron on spinal anesthesia-induced hypotension in non-obstetric surgeries: a randomised, double-blind and placebo-controlled trial

“…Accordingly, a more recent double-blind, randomized, placebo-controlled study with patients between 20 and 60 years old, totaling 140 patients, reported that participants receiving ondansetron prior to neuraxial block had similar blood pressure and heart rate compared to placebo. 27 Our study also found no effect on hypotension and bradycardia in young non-obstetric patients receiving ondansetron. It is likely that, despite the sympathetic block, the adequate venous return of these patients, due to an effective venoconstriction, will be able to maintain the preload, making the Bezold Jarish reflex less relevant in this patient population.…”

Effect of Intravenous Ondansetron for Prevention of Spinal Anaesthesia Induced Hypotension during Caesarean Section

“…Our study also demonstrated beneficial effects of ondansetron for prevention of shivering with incidence of 43.07% in saline group and 23.07% in ondansteron group. Studies done by Tatikonda et al 16 and Marashi et al 14 also demonstrated similar benefit. Both of these studies were done in ceseraen section using 15 mg of bupivacaine which was higher than the dose used in our study (11 mg).…”

“…Ondansetron, a 5-HT3 antagonist has been found to be effective in attenuation of spinal induced hypotension in various studies done in both obstetric and non-obstetric population. 11,[14][15][16] We have used intravenous ondansetron 4 mg 5 minutes before spinal anaesthesia for elective caesarean section in our study as a measure to prevent hypotension and found it to be effective.…”

Intravenous Palonosetron for Attenuation of Hypotensive Response and Bradycardia during Spinal Anaesthesia

“…However the dose of palonosetron used in their study was much smaller as compared to our study which could be the probable reason for the difference in the results. Similarly, in a study by Choudhary J et al on comparison of i.v palonosetron and iv granisetron concluded that premedication in form of granisetron 1 mg and Palonosetron 0.075 mg before spinal anesthesia does not attenuate the hemodynamic changes in patients undergoing abdominal hysterectomy [15] .…”