Stduy On The Age-Dependent EEG Characteristics Under The Propofol And Sevoflurane Combined Anesthesia

Because of the development of children’s brain is not completely,the changes of nerve oscillations caused by anesthetic drugs are different from those of adults,so the algorithm and monitoring instruments of anesthesia depth for adults cannot be applied to the monitoring of general anesthesia in children directly.How to analyze the EEG signals of patients of different ages during general anesthesia,as so as to describe the influence of anesthetic drugs on the changes of neural activity in the brain at different developmental stages quantitatively,has great value to study the effective and stable anesthesia depth algorithm.Based on the clinical data,this paper used the EEG in patients of different ages under the combined anesthesia of propofol-sevoflurane to study age dependence.Firstly,this paper introduced the acquisition and pretreatment of EEG signals in patients of different ages,and divides the pre-processed data into 6 groups according to age.This study based on power spectrum and spectrum analysis of the different age groups found that,the EEG signals energy of infants is low,and after the age to 10 months,the slow oscillations and alpha oscillations is appeared,the slow oscillation of electrical energy in the 0 and 1 year old age group is the largest,alpha frequency electrical energy in3 to 6 years old age group is the largest,and the total energy of 0.1-45 Hz frequency in infancy to 3 to 6 years of age,and decrease with the growth of the age,then decreases with increasing age.This finding reflected the pruning and thinning of synapses,suggesting that the characteristics of the EEG spectrum can reflect the degree of brain development.Secondly,this paper analyzes EEG signals based on phase amplitude coupling and wavelet double congruence.For amplitude phase coupling,this paper statistics the proportion of different coupling model of different age groups and the different age groups of modulation index under different anesthesia statistical analysis found that,in less than 1year old age group had no obvious coupling mode,but the proportion of the coupling mode in 3 to 6 years old age group significantly increased,at the same time for more than one year old age group the anesthesia maintenance phase modulation index were significantly higher than those of conscious period.For wavelet double consistency,thispaper introduces the calculation process of double consistency index based on wavelet double consistency matrix,and makes statistics on the double consistency index of different age groups,and found that the values of the Diag_Rlow,Diag_Rhigh,Diag_sum,SI,Max_Eigen and Diag_En indexes increased as the age to 1-3 years and then decreased.The above findings prove that the phase amplitude coupling and wavelet double consistency are age-dependent and can reflect the changes of the level and intensity of synaptic density during brain development.Finally,the age dependence of anesthesia depth is analyzed from the angle of nonlinear entropy in this paper.Four nonlinear entropy algorithms was adopted in this study,to analyze the size of the entropy and changes along with the age growth process in the condition of anesthesia keeping of the different age groups,and entropy and age were analyzed by multiple linear regression analysis then found that,in more than 1 year old age groups the values of the Tsallis permutation entropy and Renyi permutation entropy increased as the age to 3-6 years and then decreased.The values of the sample entropy and Renyi wavelet entropy increased with age from 0 years to 3-6 years and then decreased.All of the above four entropy algorithms have age dependence,but the values of the sample entropy and Renyi wavelet entropy have higher significance with the linear regression model of age,which is more suitable for the estimation of anesthesia depth of patients of different ages compared with the other two entropy algorithms.In a word,the frequency spectrum,phase amplitude coupling,double consistency,and nonlinear entropy algorithms all have age dependence,and the change trend of different indicators with age under anesthesia is same as the development trajectory of brain,which can effectively describe the characteristics of anesthesia EEG under different ages.