| In recent years,with the expectation of improving prognosis of spinal surgery and improve the accuracy of patients increasing,intraoperative neurophysiological monitoring has become a trend in[1-4].Among them,intraoperative neurophysiological monitoring in the sense of evoked potential(SEP)and motor evoked potential(MEP)become essential for lumbar spine surgery,they can not only greatly improve the prognosis of the patients,but also timely let surgeons comprehensive understanding and judging the integrity of neural function of patients under narcosis state,to stop the dangerous operation,to reduce the nerve injury possibly,to reduce iatrogenic injury,and to ensure the integrity of the spinal cord function [5-6].However,most of anesthesia drugs will have different effects on neural electrophysiological monitoring,and often present a dose-dependent manner,thus the accuracy and the monitoring results are always influenced [7-10].Remifentanil and sevoflurane is currently used in the department of neurosurgery surgery as the anesthesia drug [11,12].The purpose of this study is to discover the effects of different doses of remifentanil combined with sevoflurane on intraoperative monitoring of intraoperative nerve electrophysiology.1.Comparison of the effects of different doses of remifentanil on somatosensory evoked potentials and motor evoked potentials monitoring during lumbar surgery.(1)Objective: To monitor the latency and amplitude of SEP and MEP in different dose of remifentanil before the surgeries.(2)Methods: The research was performed in 30 patients who were accord with ASA grade Ι~Ⅲ undergoing lumbar surgery with SEPand MEP monitoring.These 30 patients were randomly divided into 3 groups(10 cases in each group)recorded as group 0.2R,group 0.4R and group 0.6R.Patients were asked to be fasting and water deprivation more than 12 h.The patients were all opened two venous accesses routinely,monitoring automated non-invasive blood pressure(NIBP),oxygen saturation(SPO2),electrocardiogram(ECG)and entropy index.At the same time,gave them oxygen mask and inhalation 100% concentration of oxygen,then 1% tetracaine throat spray.2% lidocaine was used in local anesthesia of radial artery puncture catheter and the ART was monitored continuously after the Allen test is negative.Each group anesthesia was induced with midazolam 0.15mg/kg and remifentanil 2μg/kg.Inducing fiberoptic tracheal intubation when the entropy index reaching 35-40,then using anesthesia machine to control the breath,100% concentration of oxygen inhalation,tidal volume 8-10ml/kg,respiratory frequency 12 times /min,suction call ratio of 1:2,PETCO2 was maintained in the 30-35 mm Hg.Then placed the monitoring electrode electrophysiological recording electrode(using needle electrode,electrode paste electrode by surface stimulation.SEP CZ’ recording leads is negative,FZ is positive,the ground on the shoulder.Was observed with the differentiation degree of the P40 latency,amplitude of P40-N55 and waveform stimulating electrode in the medial malleolus posterior tibial nerve,stimulation intensity 20-40 mA and stimulation frequency 2.1-4.7Hz,superposition times for 100 times.MEP C1 and C2 in monitoring the stimulating electrode placement,mutual stimulation of positive and negative.Records/reference electrode in the abductor hallucis record,voltage stimulation with 5 on that frequency 500 Hz,stimulation voltage100-200 V and stimulus duration of 0.1-0.5ms).Stimulating immediately after intubation,recording curve and related value as basic value.The maintenance amount of remifentanil was different,group 0.2R 0.2μg/kg·min,group 0.4R 0.4μg/kg·min,group 0.6R 0.6μg/kg·min.ART,HR and entropy index were recorded when 5 min,10 min,15 min after remifentanil started pumping.And at the same time we observe the changes of SEP and MEP latency and amplitude.(3)Results: The latency and amplitude of SEP and MEP in group 0.2R,group 0.4R and group 0.6R were not affected.(4)Conclusion:Remifentanil 0.2-0.6μg/kg·min constant speed pump injection has no significant effect on SEP and MEP monitoring during the operation.The remifentanil in operation of conventional dose of constant speed pump was 0.2μg/kg·min.But in need of intraoperative neurophysiological monitoring in spinal surgery,in order to avoid the use of muscle relaxants,and meet the requirements of braking of patients,the doses of ease pain and sedation medication were increased to maintain the appropriate depth of anesthesia.Experimental study of remifentanil 0.2-0.6μg/kg·min dose groups can meet the needs of lumbar spine surgery without electrophysiological monitoring impact and can be safely use for electrophysiological monitoring of lumbar spine surgery.2.The effects of different doses of remifentanil combined with sevoflurane on the evoked potentials and motor evoked potentials monitoring during lumbar surgery.(1)Objective: To investigate different doses of remifentanil combined with inhalation of sevoflurane anesthesia effect on neurophysiological monitoring,in order to provide a basis for intraoperative anesthesia regimen and dosage as well as surgical treatment,and to explore the related mechanisms.(2)Methods: According to the selection criteria of study1,30 patients were randomly divided into 3 groups(n=10),that is,group0.2R+S,group 0.4R+S and group 0.6R+S.Induction and monitoring of anesthesia were similar to study1.After recording the basic values,sevoflurane maintained at 0.5MAC was inhaled immediately,followed by a constant speed pump into the remifentanil whose concentration was different.Group 0.2R+S was 0.2μg/kg·min,group 0.4R+S was 0.4μg/kg·min and group 0.6R+S was 0.6μg/kg·min.Record the patient’s ART,HR and entropy index at 5min,10 min,15min after pumping started,and at the same time observe the changes of latency,amplitude and waveform of SEP and MEP at different stimulation time points.After recording,routine maintaining of anesthesia was conducted.(3)Conclusion: Sevoflurane maintained at 0.5MAC combined with 0.2μg/kg·min of remifentanil was more suitable for SEP and MEP monitoring.When the dosage of sevoflurane was stable at 0.5MAC and the concentration of remifentanil was greater than 0.4 μg/kg·min,the safety of monitoring during operation would be decreased. |
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