新生儿心动周期信号混沌特征分析及参考值测定

摘要:

目的 对正常新生儿心动周期信号混沌特征分析及参考值测定。方法 用重庆医科大学生物医学工程研究室研制的儿童心动周期信号混沌特征分析系统，ＩＩ导联，采样频率３００ Ｈｚ，获得５１２ 心动周期组成的心动周期信号（ＨＰＳ） 。计算ＨＰＳ的混沌特征参数：相对分散度（ＨＲＤ）、李氏指数（ＨＬＥ） 、分维数（ＨＦＤ） 和混沌度（ＨＣＣ）。分析ＨＰＳ的功率谱和动态谱。计算ＨＰＳ的功率谱参数９ 项。结果 正常新生儿ＨＰＳ 的混沌特征参数为：ＨＲＤ６ ．３３ ±１ ．８７ ；ＨＬＥ３．１７ ±０．７１ ；ＨＦＤ１．８３ ±０．０４；ＨＣＣ１９．９９±１２ ．４０ 。正常新生儿ＨＰＳ的功率谱特征参数为：超低频带功率（ＰＶＶ） ６２６．８９ ±４９６．４２ ＭＳ２ ； 低频带功率（ＰＶＬ）：２５１ ．３５ ±１７０．３１ ＭＳ２ ；高频带功率（ＰＶＨ） １４８．９７±１２８．５７ ＭＳ２ ；超低频带相对功率（ＰＲＶ） ５７ ．５４ ％ ±１５ ．６８％ ；低频带相对功率（ＰＲＬ） ２６．６８％ ±１０．１５％ ；高频带相对功率（ＰＲＨ） １５ ．１５ ％ ±７ ．３７ ％ ；超低频带与高频带功率比（ＲＶＨ） ５ ．５３ ±４．４８；低频带与高频带功率比（ＲＬＨ） １．９９±０．

Abstract:

Objective To analyze chaotic characteristics of heart period signals (HPS) in normal neonates. Methods 512 HPS from 73 normal neonates were collected to analyze their chaotic characteristics using a computerized system. Results Four parameters of chaotic characteristics were calculated: HPS relative dispersion (6.33±1.87), HPS lyapunov exponent (3.17±0.71), HPS fractal dimension (1.83±0.04), and heart cycle chaosness (19.99±12.40). The power value and power rate of HPS in very low (626.89±496.42 MS 2 and 57.54%±15.68%), low (251.35±170.31 MS 2 and 26.68%±10.15%), and high frequency bands (148.97±128.57 MS 2 and 15.15%±7.37%) were analyzed respectively, with a total frequency band power of 1062.17±696.60 MS 2. The power value ratios of very low/high (5.53±4.48) and low/high frequency bands (1.99±0.93) were also calculated. Conclusions Comparing the data with those of adults, we found lower chaotic characteristics of HPS in neonates with a higher power rate in the very low frequency band. The results suggest that the complexity of the heart state and the controlling ability of the autonomic nervous system to the heart are lower and that the interaction component is predominant comparatively in normal neonates.