Li Xiaotian, Zheng Daan, Zhou Shufeng, Tang Dakan, Wang Caiyan, Wu Guoqiang
Dept. of Maternal and Fetal Medicine, Obstetrics and Gynecology Hospital, Fudan University, 419 Fangxie Road, Shanghai, China.
Acta Obstet Gynecol Scand. 2005 Sep;84(9):837-43. doi: 10.1111/j.0001-6349.2005.00773.x.
The aim of this study is to investigate the relationship between approximate entropy (ApEn) of fetal heart rate (FHR) with umbilical blood gas parameters and the power spectrum of FHR variability in Chinese and to test whether ApEn of FHR variability could be used as a predictor of fetal distress in women at term pregnancy.
Sixty-seven pregnant women with singleton, term fetus were recruited for the recording of FHR variability and the data were used for the estimate of ApEn. Blood gases after birth were measured through umbilical artery.
In all 67 neonates, there was some amount of interinfant variability in the ApEn values with a mean of 1.139 +/- 0.169. The ApEn values were significantly (P < 0.05) correlated with pO(2), SO(2), pCO(2), pH, HCO(3), or base excess (BE). The 15 fetuses with low ApEn (ApEn <1.0) had higher risk of metabolic acidosis (BE less than -12 mmol/l) than those with high ApEn (ApEn > or =1) (likelihood ratio = 12.301, P < 0.001). The powers of FHR variability in all frequency ranges (0-0.256 Hz) were lower in the low-ApEn group than those in the high-ApEn group.
The ApEn of FHR variability significantly decreased during fetal asphyxia, including hypoxia, hypercapnia, and both respiratory and metabolic acidosis; low ApEn was linked to decreased power spectrum density in all frequency domains. The ApEn values may be used as a predictor of fetal distress in women at term pregnancy.
本研究旨在探讨中国人群中胎儿心率（FHR）的近似熵（ApEn）与脐血气参数及FHR变异性功率谱之间的关系，并测试FHR变异性的ApEn是否可作为足月妊娠妇女胎儿窘迫的预测指标。
招募67名单胎足月妊娠孕妇记录FHR变异性，并将数据用于ApEn估计。出生后通过脐动脉测量血气。
在所有67例新生儿中，ApEn值存在一定的个体间差异，平均值为1.139±0.169。ApEn值与pO₂、SO₂、pCO₂、pH、HCO₃或碱剩余（BE）显著相关（P<0.05）。ApEn低（ApEn<1.0）的15例胎儿发生代谢性酸中毒（BE小于-12 mmol/l）的风险高于ApEn高（ApEn≥1）的胎儿（似然比=12.301，P<0.001）。低ApEn组在所有频率范围（0-0.256 Hz）的FHR变异性功率均低于高ApEn组。
胎儿窒息期间，包括缺氧、高碳酸血症以及呼吸性和代谢性酸中毒，FHR变异性的ApEn显著降低；低ApEn与所有频率域的功率谱密度降低有关。ApEn值可作为足月妊娠妇女胎儿窘迫的预测指标。
