The Study On The New Methods For Detection And Analysis Of Electronic Fetal Heart Rate Monitoring

Fetal surveillance is an important measure to keep pregnant woman and her foetus healthy. Electronic fetal heart rate monitoring is commonly used to assess fetal well-being as a clinical measure. Fetal monitor detects the fetal heart rate signal, uterine contraction signal and marks the fetal movement. And at the same time fetal monitor transfers these data information to a central workstation. The central workstation is responsible for saving, analyzing and managing the check records of patients. And it is more difficult to detect and analyze fetal heart rate accurately, which is the content in this paper.In this paper we analyze several techniques of FHR detection and confirm the method we used: echo signal is detected with the principle of ultrasonic Doppler; it is filtered for envelope, and then the fetal heart rate signal is extracted from the filtered signal with special algorithm of digital signal processing. After analyzing the autocorrelation function, we find the amount of calculation is so large that it can only be realized with high-speed processor and the cost of the instrument is higher. In this paper we use average magnitude difference function to extract the fetal heart rate signal. The advantage of this algorithm is that the amount of calculation is so little that it can be realized with popular single-chip system and the cost of it is lower. The algorithm proved to be adaptive in the clinical tests and be able to fulfill the requirements of actual monitoring.The traditional method to analyze the cardiotocography is artificial analysis. The accuracy and consistency of this method is not good. And the work intensity of doctors is high. In the paper we develop an analysis system of electronic fetal heart rate monitoring including basic analysis system and advanced analysis system based on PC. And it can avoid the subjective error of artificial analysis effectively and get objective indices with good consistency. The accuracy of analysis is improved a lot. The basic analysis system is based on scoring analysis which is widely used in the clinical monitoring. It can analyze the basic parameters and score automatically. 1000clinical tests have proved that the scoring system has good consistency with artificial scoring by clinicians. Short-term variation in the basic analysis system proved to be a new and good index to help the clinicians predict the acidosis and hypoxia of the foetus. Advanced analysis system is developed from a new point of view. It is based on international authoritative criteria for fetal surveillance. We build an expert system to analyze the CTG with the consideration of actual clinical situation. 500 clinical tests have proved that the analysis result of expert system has better consistency with fetal clinical status. Advanced analysis system also tries to introduce the analytical method in frequency domain. It provides the power spectrum analysis function for fetal heart rate variation to help the clinicians obtain more useful information related to fetal health from the fetal heart rate signal.