The median effective dose of remimazolam for inhibiting tracheal intubation response in patients undergoing thyroid surgery:recurrent laryngeal nerve monitoring combined with 2×ED95 cisatracurium

LIU Haorong; ZHANG Xiaotong; HE Qixia; CHEN Cuiping; ZHU Yanwen; ZHUANG Hongling; CHEN Yong; LU Zhiqi; LU Yan

doi:10.20227/j.cnki.2096-3610.2025.05.011

Abstract：Objective To determine the median effective dose(ED50)of remimazolam for suppressing tracheal intubation-induced responses during thyroid surgery under recurrent laryngeal nerve monitoring,when combined with cisatracurium at twice its 95%effective dose(2×ED95).Methods In this prospective study,56 ASA Ⅰ-Ⅱ patients scheduled for elective thyroidectomy with intraoperative nerve monitoring between July 2023 and February 2024 were enrolled.The remimazolam dose was determined using a biased-coin up-and-down sequential method,starting at 0.3 mg/kg.After achieving a BIS≤60 and a Modified Observer's Assessment of Alertness/Sedation(MOAA/S)score≤1,patients received cisatracurium 0.1 mg/kg(2×ED95)and sufentanil 0.4 μg/kg.Intubation was performed 5 minutes later using video laryngoscopy.The remimazolam dose for subsequent patients was adjusted based on the cardiovascular response observed during intubation.Probit regression was used to calculate ED50,ED95,and 95%CI.Hemodynamic variables including systolic blood pressure(SBP),diastolic blood pressure(DBP),mean arterial pressure(MAP),bispectral index(BIS),blood oxygen saturation of pulse(SpO2)were recorded at four time points:T0(baseline),T1(pre-intubation),T2(30 seconds post-cuff inflation),and T3(3 minutes post-intubation).Intubation conditions,time to nerve monitoring,and perioperative adverse events were also assessed.Based on the occurrence of an intubation response,subjects were divided into positive and negative groups,and the remimazolam dosage and BIS differences at T1 were compared between the two groups.Results The ED50 of remimazolam for suppressing tracheal intubation-induced hemodynamic responses was 0.287 mg/kg(95%CI:0.249-0.296 mg/kg),and the ED95 was 0.310 mg/kg(95%CI:0.304-0.422 mg/kg).MAP significantly decreased from T1 to T3 compared with T0,HR was reduced at T1 and T3,and SpO₂ increased across the same intervals(all P<0.05).No statistically significant difference in remimazolam doses was observed between the two groups(P>0.05),and BIS values were all<60 before intubation(indicating adequate sedation).Postoperative adverse events included 2 cases of nausea and vomiting,1 case of sore throat,and 1 case of hypotension.No instances of intraoperative awareness or intubation failure were observed.Conclusion During thyroid surgery with recurrent laryngeal nerve monitoring,the ED50 of remimazolam for suppressing tracheal intubation-induced hemodynamic responses was determined to be 0.287 mg/kg when combined with cisatracurium at 2×ED95.