Nonlinear Dynamic and Chaotic Analysis of Fetal Heart Rate in Fetal Distress

Kim, Sa Jin; Shin, Jong Chul; Chung, Dae Young; Sim, Young Bo; Yi, Sang Hoon; Kim, Chang Yi; Kim, Soo Pyung

Abstract

OBJECTIVES
For estimating the antenatal fetal wellbeing to develop new analysis method of fetal heart rate(FHR) with electronic Fetal Heart Rate Monitoring(eFHRM) and computer.
METHODS
Heart rate signal is received from distressed fetus using eFHRM. It is necessary to carry out low pass filtering as a preprocess for the nonlinear method. Nonlinear parameters are calculated and classified to investigate the relations between these parameters and values of umbilical cord blood gas.
RESULTS
By dividing values of the umbilical cord blood gas into 5 fetuses of acidemic group and 17 fetuses of non-acidemic group after 22 neonates who presented fetal distress were born, the following results as compared with nonlinear chaotic analysis result were obtained. 1. Delay time through AMI for acidemic group was 16.80+/-3.11, and was higher than 15.41+/-2.27 for non-acidemic group, and is not significant in statistics. 2. Embedding Dimension calculated with FNN method was 5.60+/-2.07 for acidemic group, and 4.71+/-1.26 for non-acidemic group, and it was not significant statistically. 3. Correlation dimension for acidemic group was 1.41+/-0.20, and was higher than 1.10+/-0.38 for non-acidemic group, and is not significant in statistics. 4. Mean crossing value by isoangular return map was 28.80+/-11.34 for acidemic group, and 16.65+/-7.00 for non-acidemic group, and it was significant statistically(P=0.008). 5. In comparison of information entropy in 1-D ED, acidemic group was 6.32+/-0.38 and non-acidemic group was 6.20+/-0.28 and it was not significant statistically. Also, in comparison of value in 2-D ED, acidemic group was 10.20+/-0.34. It was higher than non-acidemic group of 9.51+/-0.43 significantly in statistics(P=0.004). But, in comparison of value in 2-D EP, acidemic group was 8.78+/-0.86 and non-acidemic group is of 9.22+/-0.74 and it wasn't significant statistically. And, 2-D ED(DI) value was 10.64+/-0.14 for acidemic group and 10.51+/-0.18 for non-acidemic group, and it wasn't significant statistically.
CONCLUSIONS
By the above result, nonliner dynamics and chaotic analysis of heart rate data with computer can serve as a new diagnosis method which may estimate the fetal wellbeing with real time. Through further studies for establishment of diagnosis standard and computer programming, real time diagnosis method shall be applied to clinical practice.