The ED50 of Remazolam Toluenesulfonate Combined with a Subthreshold Dose of Esketamine for Inhibiting Cardiovascular Response to Tracheal Intubation in Elderly Patients

Abstract

Objective: To explore the half-effective dose (ED50) of remazolam toluenesulfonate combined with subthreshold amounts of esketamine for inhibiting cardiovascular response to tracheal intubation in elderly patients. Method: We included 42 patients, aged 65–75, who required general anesthesia and single-lumen endotracheal intubation for elective surgery. The first patient was administered remazolam toluenesulfonate at a dose of 0.20 mg/kg. Once the patient lost consciousness, their alertness/sedation score (OAA/S score) was ≤ 1, and their BIS score was ≤ 60, and a subthreshold dose (0.3 mg/kg) of esketamine was given. The subsequent doses were adjusted using a sequential approach based on the cardiovascular response to tracheal intubation observed in the previous patient. The dose was modified in increments or decrements of 0.01 mg/kg. The ED50 and 95% CI of remazolam toluenesulfonate were calculated using the Dixon and Massey sequential distribution test method. Result: The inhibition of endotracheal intubation response was positively correlated with the dose of remazolam toluenesulfonate, and the depth of sedation could not be achieved when the amount was ≤ 0.22 mg/kg. The ED50 of remazolam toluenesulfonate combined with a subthreshold dose of esketamine in inhibiting cardiovascular response to tracheal intubation in elderly patients was 0.30 (0.28, 0.33) mg/kg. There was no statistically significant difference in blood pressure between the induction of anesthesia and before the operation. Conclusion: When compounded with 0.3 mg/kg esketamine, the ED50 of Remazolam toluenesulfonate in inhibiting cardiovascular response to endotracheal intubation in elderly patients was 0.30 mg/kg (95 % CI0.28–0.33 mg/kg).