Dexmedetomidine Background Infusion Of Esmketamine Inhibits The 50% Effective Dose Of Body Movement In Patients Of Different Ages Undergoing Microendoscopic Discectomy

Objective:Under the quantitative background infusion of dexmedetomidine,calculate half the effective amount and 95%confidence intervals（confidence interval,CI）of esketamine to inhibit the dynamic response in patients of different ages;and compare the efficacy and safety of esketamine analgesia in patients of different ages to provide a reference for wider clinical application.methods:The study subjects selected 99 patients admitted from February 2022to October 2022.Combined with the statistical data of high incidence of lumbar disc herniation in China,33 patients in middle age group（group Z group,45-59 years old）,33 patients in aging group（L group,60-74 years old）,33 patients in elderly group（G group,75-90 years old）,gender,ASA grade I-Ⅱ,cardiac function grade I-Ⅱ,body mass index（BMI）18-26kg/㎡.In all three groups,dexmedetomidine was selected for background infusion,with a total load of 1 ug/kg for 15min,maintenance infusion of 0.3 ug/kg/h,and stopping at the suture.After the infusion started,when the modified vigilance/sedation score（MOAA/S score）reached 4 or less.The starting dose of the three groups was set to 0.3mg/kg according to the pre-experimental results,and the pump infusion time was 10min.In this test,the patient with physical reaction is selected as the qualitative index of esketamine analgesia,and the step test is conducted according to Dixon sequential method,and the dosage of esketamine in the next patient in each group of the test is determined by the physical reaction of the previous patient.If the physical reaction is set to be effective,the next patient reduces a gradient;otherwise,the dose is set as analgesia is ineffective,and the gradient is added in the next case with a dose gradient.The adjacent dose gradient ratio was 0.9.Each trial was conducted until the end of 8effective analgesic crossings.The ED₅₀and 95%CI were calculated according to the Dixon calculation formula.The data of effective cases in three experiments were extracted for comparative analysis and marked as Z-y,L-y and G-y groups.All patients were performed by the same anesthesiologist,and postoperative follow-up was performed by another anesthesiologist who was blinded to the content of the trial;local anesthesia,surgical procedures,and postoperative management were performed by the same group of surgeons.Results:96 patients undergoing elective percutaneous removal were finally included in this study.31 patients in group Z,including 15 patients with effective analgesia,33 patients in group L,including 18 patients with effective analgesia,and32 patients in group G,including 19 patients with effective analgesia.Half-effective amounts and 95%confidence intervals of esketamine inhibition during percutaneous foraminal mirror surgery were 0.31mg/kg（0.282mg/kg-0.335mg/kg）in group Z,0.25mg/kg（0.227mg/kg-0.267mg/kg）in group L,and 0.19mg/kg（0.176mg/kg-0.203mg/kg）in group G.The HR decrease of the three groups at T₁,T₂and T3 showed significant statistical difference（P<0.05）;the HR values at T₂and T3were slightly higher after esketamine infusion,with no significant statistical difference（P>0.05）;the MAP of the three groups showed little change at each time point with no significant statistical difference（P>0.05）.The RR values T1,T2 and T₅decreased with significant statistical differences（P<0.05）,but the three groups remained in 8 breaths;Pa O₂values T₁and T₂,with significant statistical differences（P<0.05）;there was no significant statistical difference in the Pa CO₂values of the three groups（P>0.05）.One patient in Group G in this study developed respiratory depression.The NRS scores of the three groups at different time points.The comparison results showed that the NRS scores of 2 hours in Z group were significantly higher than that of groups L and G,with significant statistical differences（P<0.05）.The recovery duration of the three group of patients in group G was significantly longer compared with group Z and group L,with significant statistical differences（P<0.05）.The statistical results of adverse reactions in the experiment showed that one patients in group Z complained of intraoperative hallucinations after being awake after surgery.There was no nausea and vomiting in the three groups.conclusion:The 50%effective dose and 95%confidence interval（ci）of ketamine in the treatment of percutaneous foraminal surgery were 0.31 mg/kg（0.282mg/kg-0.335 mg/kg）in group Z,0.25 mg/kg（0.227 mg/kg-0.267 mg/kg）in group L and 0.19 mg/kg（0.176 mg/kg-0.203 mg/kg）in group G.Clinical trials have shown that with close monitoring and effective mask delivery,background infusion of dexmedetomidine and intravenous anesthesia with ketamine can be safely used in middle-aged and elderly patients undergoing percutaneous lumbar discectomy with microendoscopic discectomy,but the incidence of respiratory depression in the elderly group was higher than that in other groups,monitoring should be strengthened to prevent its occurrence.