| Background: Burst Suppression(BS)is an EEG pattern characterized by alternating high-amplitude EEG activity(burst)and relatively low-amplitude EEG activity(suppression).The emergence of explosive inhibition usually means that the cerebral cortex function of the patient is inhibited or even damaged,and its essence reflects that the normal metabolic activity of the brain is affected.Many studies have shown that explosive suppression is related to a series of adverse reactions after surgery.Therefore,exploring the related risk factors that cause explosive suppression during surgery to avoid its occurrence is beneficial to the postoperative recovery and brain health of elderly patients.of.At present,research on outbreak suppression at home and abroad is mainly focused on the impact of a specific anesthetic or specific pathological conditions such as hypoxia and hypothermia on outbreak suppression.There are few factors that cause outbreak suppression in general elderly patients during elective surgery.the study.In view of the different anesthetic drugs and related physiological indicators in the anesthesia induction period and the maintenance period,it is necessary to explore the risk factors that cause the outbreak suppression during the anesthesia induction period and the maintenance period.Objective: This study is a single-center prospective cohort study,which aims to explore the risk factors that cause Burst Suppression in the induction and maintenance phases of anesthesia in elderly patients.Methods: According to the exclusion and inclusion criteria of the experiment,select the period from January 2019 to December 2020,aged 65 years or older in XX hospital,ASAI-III level is planned to undergo elective non-cardiac surgery under general anesthesia(including general surgery,orthopedics,thoracic surgery,204 elderly patients were admitted to the general ward after urology and gynecology).All patients were induced by intravenous rapid induction,and intraoperative anesthesia was maintained with propofol-remifentanil intravenous anesthesia.Use Masimo’s Sedline EEG monitor to monitor the patient’s brain in real-time four-channel EEG.When the Suppression Ratio(SR)on the EEG is greater than 0 and the Density Spectral Array(DSA)has a unique blue black vertical line at the base,it proves that there is explosive suppression.Collect the basic condition data of patients before surgery,including gender,age,body mass index(BMI),past history of cardiovascular and cerebrovascular diseases,history of mental illness,history of oral medication,preoperative MMSE score,ASA score,and internal environmental indicators.Observe and record the occurrence of burst suppression during the operation,and hemodynamic indicators for anesthesia,including mean arterial pressure,systolic blood pressure,diastolic blood pressure,end-breathing carbon dioxide,and body temperature.In view of the different medications in the induction and maintenance phases of anesthesia and the changes in related physiological indicators,the risk factors that cause BS during the induction and maintenance phases are discussed separately.Patients were divided into four groups according to whether they had burst suppression during the induction and maintenance phases of anesthesia: the induction burst suppression group(IB),the induction non-burst suppression group(IN),and the maintenance burst suppression group(MB)And the maintenance period non-burst suppression group(MN).Multivariate Logistics regression and backward conditional method were used to explore the respective risk factors of explosive inhibition in the induction period and explosive inhibition in the maintenance period.Result: 1.There are a total of 122 patients in the induction period non-burst suppression group(IN),and a total of 82 patients in the induction period burst suppression group(IB).Compared with the IN group,patients in the IB group had higher preoperative diastolic blood pressure,more people with preoperative hypertension,and cerebrovascular disease,while fewer patients with preoperative Hb content decreased,and preoperative MMSE scores were lower.There are differences Statistically significant(P<0.05).There were differences between the IB group and the IN group in three aspects: the amount of propofol during the induction phase,the partial pressure of carbon dioxide at the end of the induction phase,and the degree of blood pressure drop during the induction phase compared with the preoperative blood pressure,and the differences were statistically significant(P<0.001).Compared with the IN group,the IB group had a smaller amount of midazolam during induction,a smaller intraoperative MAP,and a higher diastolic blood pressure during the induction period.The differences were statistically significant(P<0.05).2.There were 116 patients in the maintenance-phase non-burst suppression group(MN group),and 88 patients in the maintenance-phase burst suppression group(MB group).Compared with the MN group,patients in the MB group were older,had a higher preoperative MMSE score,decreased preoperative albumin and increased preoperative fasting blood glucose,and the difference was statistically significant(P<0.05).There was a statistically significant difference between the MB and MN maintenance phase end-respiratory carbon dioxide partial pressure classification data(P<0.001).Compared with the MN group,the intraoperative MAP value,systolic blood pressure and diastolic blood pressure of the MB group decreased,and the difference was statistically significant(P<0.001).3.Multivariate logistic regression in the induction period showed: preoperative Mini-Mental State Examination(MMSE)high score,history of hypertension,increase in mean arterial pressure(MAP)during induction,propofol The use of(≥ 1.5 mg/kg)and end-respiratory carbon dioxide partial pressure(> 30 mm Hg)are protective factors;the amount of midazolam during the induction period and the diastolic blood pressure during the induction period are risk factors for explosive suppression.4.Multivariate logistic regression in the maintenance phase showed that the increase in MAP during the operation was a protective factor for explosive suppression;the degree of intraoperative blood pressure drop greater than 20% and the end-respiratory carbon dioxide partial pressure less than 30 mm Hg were risk factors for explosive suppression.Conclusion: The risk factors that cause explosive suppression in the induction and maintenance phases of elderly patients are not the same.1.High preoperative MMSE score,history of hypertension,increased MAP during induction,use of propofol(≥ 1.5mg/kg),and partial pressure of end-respiratory carbon dioxide(> 30 mm Hg)are protective factors for BS during induction;The dosage of midazolam and the diastolic blood pressure during the induction period are risk factors for BS during the induction period.2.Intraoperative increase in MAP is a protective factor for BS in the maintenance phase;intraoperative blood pressure drop greater than 20% and end-respiratory carbon dioxide partial pressure less than 30 mm Hg are risk factors for BS in the maintenance phase.3.Reducing the amount of sedative drugs during the induction period of anesthesia can reduce the occurrence of BS during the induction period.Whether in the induction or maintenance period of anesthesia,maintaining the patient’s hemodynamic stability,avoiding low blood pressure,maintaining a high level of MAP,avoiding low end-breathing carbon dioxide partial pressure,and maintaining homeostasis are all helpful to avoid the occurrence of BS. |
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