Campbell K, MacNeill I, Patrick J
J Biomed Eng. 1980 Apr;2(2):108-12. doi: 10.1016/0141-5425(80)90061-8.
Thirty-one healthy human fetuses were each observed with a real-time scanner continuously for 24 h. The percentage of time spent breathing was computed for each 5 min observation period during the 24 h which produced a time series of 288 observations for each fetus. Box-Jenkins modelling techniques and analysis of frequency spectrum distribution were used to quantify mathematically the human fetal breathing data. The data was described mathematically by a first-order auto-regression z(t)=0.7 z(t-1) + epsilon(t) which confirmed and quantified the episodic nature of foetal breathing activity. Evaluation of the spectral distribution of the fetal breathing movements identified a significant band of pseudo-periodic components with repeat periods ranging from 100 to 500 min (P less than 0.001). Results of this study indicated that the occurrence of fetal breathing movements were non-random and that Box-Jenkins modelling results and spectral power distribution may be useful in identification and description of any fetal breathing patterns which differ from normal patterns.
31名健康人类胎儿均通过实时扫描仪连续观察24小时。计算24小时内每个5分钟观察期的呼吸时间百分比，从而为每个胎儿生成一个包含288次观察结果的时间序列。采用Box-Jenkins建模技术和频谱分布分析对人类胎儿呼吸数据进行数学量化。该数据通过一阶自回归z(t)=0.7z(t - 1)+ε(t)进行数学描述，这证实并量化了胎儿呼吸活动的间歇性。对胎儿呼吸运动的频谱分布评估确定了一个显著的伪周期性成分带，其重复周期范围为100至500分钟（P<0.001）。本研究结果表明，胎儿呼吸运动的发生并非随机，Box-Jenkins建模结果和频谱功率分布可能有助于识别和描述任何与正常模式不同的胎儿呼吸模式。
