Abstract: Objective To investigate the median effective concentration(EC50) of target-controlled infusion(TCI) with sufentanil inhibits tracheal intubation response under McGrath video laryngoscope during anesthesia induction in elderly patients. Methods Twenty-nine patients, ASA physical status Ⅰ-Ⅱ, undergoing elective surgery under general anesthesia were included in this study. Patients were administered midazolam 0.02 mg/kg soon after coming into the operating room. Sufentanil was first administered 0.3 μg/L with a target effect-site concentration(Ce) by Bovill pharmacokinetic model TCI system. Propofol was administered by the March pharmacokinetic model TCI system at the same time. The Ce of propofol was administered from 1.5 mg/L to 2.5 mg/L in 2 steps. The interval between the two steps was 2 min. Rocuronium was administed 0.6 mg/kg when OAA/S≤2. The endotracheal catheter was performed by the same anesthetist under McGrath video laryngoscope after the balance of Ce and plasma concentration(Cp) of sufentanil. The next concentration of sufentanil was determined by using the modified Dixon's up-and-down sequential method. The ratio between adjacent concentrations was 1.2. The changes in cardiovascular response were recorded. Modified OAA/S sedation score were measured. Probability analysis was used for calculating EC50 and 95% confidence interval(CI). Results The EC50 of sufentanil TCI inhibiting tracheal intubation response under McGrath video laryngoscope in elderly patients was 0.194 μg/L, 95% CI was 0.174 μg/L-0.212 μg/L(P<0.01). The average amount of sufentanil during anesthesia induction was (0.211±0.039) μg/kg(P<0.01). Conclusions The Ce of sufentanil was 0.194 μg/L combined with propofol 2.5 mg/L TCI to inhibit tracheal intubation response under McGrath video laryngoscope in 50% elderly patients.
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