Systemic granisetron can minimize hypotension and bradycardia during spinal anesthesia in patients undergoing elective lower-abdominal surgeries: a prospective, double-blind randomized controlled study

Abstract

Introduction Although it is considered safe, spinal anesthesia has many side effects, including hypotension, and bradycardia. Increased activity of chemoreceptors (Bezold–Jarisch reflex) may play a role in this. The release of serotonin has been suggested as a possible trigger for Bezold–Jarisch reflex. Granisetron, a selective 5-HT3 receptor antagonist, may play a role in preventing hypotension and bradycardia. Aim The aim of this study was to assess the effects of granisetron on hypotension, bradycardia, shivering, nausea, and vomiting after spinal anesthesia in patients undergoing elective lower-abdominal surgeries. Patients and methods This study was designed as a randomized, double-blind, placebo-controlled trial. Fifty-four American Society of Anesthesiologists I–III patients, ages 25–55 years, scheduled for elective lower-abdominal surgeries under spinal anesthesia were included in this prospective study and were divided into two equal groups. Group G received 1 mg intravenous granisetron diluted in 0.9% normal saline to a total volume of 5 ml, and group C received 5 ml normal saline 5 min before undergoing spinal anesthesia. The mean arterial blood pressure, the heart rate, nausea, vomiting, and shivering were assessed. Results The reduction in mean arterial blood pressure and heart rate was significantly lower in group G compared with group C. Regarding the incidence of complications, hypotension, bradycardia, nausea, and shivering were significantly lower in group G compared with group C. No significant difference was observed with regard to the incidence of vomiting. Conclusion In lower-abdominal surgery, intravenously 1 mg granisetron before subarachnoid block decreased the incidence of hypotension and bradycardia significantly, besides being effective for the prevention of nausea, vomiting, and shivering.