Introduction
PONV, postoperative nausea and vomiting, Hypotension, hypotension
COMPLICATION
Hypotension is a common complication in patients under general anesthesiaEphedrine is an α- and β-adrenergic agonist that increases peripheral vascular resistance, cardiac output, and heart rate and thus maintains blood pressure. Prophylactic use of ephedrine at different doses (0.03–0.2 mg/kg) has been indicated to improve hypotension response after general anesthesia to varying degreesSerotonin 3 receptor antagonists are routinely used at the end of surgery for preventing postoperative nausea and vomiting (PONV) in patients at high risk for PONV during general anesthesia. They have been reported to reduce the incidence of hypotension and the need for vasopressin in obstetric and non-obstetric patients during intraspinal anesthesiaIn this study, we sought to determine the effective dose of prophylactic ephedrine for 50% of elderly patients who received a single intravenous dose of granisetron or placebo before induction in preventing hypotension after induction. This study will provide important reference for the effective dose of prophylactic ephedrine in preventing hypotension after general anesthesia induction and the optimal timing of granisetron administration in elderly patients at high risk for PONV.