哮喘儿童心动周期信号混沌特征和功率谱分析

目的 研究哮喘儿童心动周期信号(HPS)的混沌特征和功率谱特征，探讨其混沌特征、谱特征在哮喘发作与缓解时的差别，分析其自主神经系统功能的变化。方法：采用儿童心动周期信号混沌特征分析系统，计算47例哮喘儿童和103例正常儿童HPS的混沌特征参数和谱特征参数。同时分析其中18例哮喘儿童发作期和缓解期上述指标的变化，并分析HPS的功率谱和动态谱。结果：47例哮喘儿童HPS的混沌特征参数中，相对分散度为 4.50±2.06，李氏指数为 3.17±1.26，混沌度为 26.34±13.78，均低于正常儿童［(7.29±1.62)，(5.09±0.99)，(51.08±17.32)］(P＜0.01或0.05＝；其HPS的谱特征参数［超低频带功率(PVV)为(320.61±372.28)ms2，低频带功率为(221.00±243.86)ms2，高频带功率为(224.38±327.51)ms2，超低频带相对功率为(42.84±18.47)%，高频带相对功率为(26.58±17.63)%，超低频带与高频带功率比为2.72±2.74，低频带与高频带功率比为1.79±1.58，总功率］为(827.44±933.22)ms2)与正常儿童比较，差异亦有显著性(P＜0.01或0.05＝。18例哮喘儿童缓解期上述各指标与发作期比较均有不同程度恢复，差异有显著性(P＜0.01或0.05＝。结论：哮喘儿童心脏状态的复杂性降低，自主神经系统对心脏的调控能力也相应降低，且以交感成分相对占优势。哮喘儿童发作期的自主神经功能紊乱可能是暂时的和可逆的。

Chaotic Characteristics and Power Spectrum Characteristics of Heart Period Signals in Children with Asthma

Objective To study the chaotic characteristics and power spectrum characteristics of heart period signals (HPS) in children with asthma. Methods The parameters of the chaotic characteristics and the power spectrum characteristics of HPS were detected using a computerized system for analyzing chaotic characteristics of HPS in 47 children with asthma and 103 normal children. These parameters were tested in the remission phase in 18 of the 47 asthmatic children to analyze their changes. Results Of the parameters of the chaotic characteristics, relative dispersion of heart period (HRD), lyapunov exponent of heart period (HLE) and heart cycle chaosness (HCC) ( 4.50 ± 2.06 , 3.17 ± 1.26 and 26.34 ± 13.78 , respectively) in the children with asthma were all lower than those in the normal children ( 7.29 ± 1.62 , 5.09 ± 0.99 and 51.08 ± 17.32 , respectively)(P< 0.01 or 0.05 ). Of the parameters of the power spectrum, the power value in very low frequency band (PVV), power value in low frequency band (PVL), power value in high frequency band (PVH), power rate in very low frequency band (PRV), power rate in low frequency band (PRL), power rate in high frequency band (PRH), ratio of power in very low frequency band to that in high frequency band (RVH), ratio of power in low frequency band to that in high frequency band RLH and total frequency band power (TFP)( 320.61 ± 372.28 ) ms 2, ( 221.00 ± 243.86 )ms 2, ( 224.38 ± 327.51 )ms 2, ( 42.84 ± 18.47 )%, ( 26.58 ± 17.63 )%, ( 2.72 ± 2.74 ), ( 1.79 ± 1.58 ), and ( 827.44 ± 933.22 ) ms 2, respectively] differed from those in the normal children (P< 0.01 or 0.05 ). These abnormal parameters of asthmatic children got recovery with different degrees in the remission phase. Conclusions The complexity of the heart state is reduced in children with asthma, and the control ability of the autonomic nervous system for the heart is also depressed. The functional disorder of autonomic nerves of asthmatic children in the attack phase might be temporary and reversible.