According to the principle of ultrasound Doppler and the change of fetal cardiac current, the fetal heart rate recorder and the uterine contraction recorder are the main structures, which can describe the fetal heart movement pattern. The fetal monitor device provides continuous monitoring, visualization, and recording of fetal heart rate, as well as prenatal testing and monitoring of uterine function. This device should only be used by trained medical personnel in the hospital, clinic, office and patient's home.
Ⅰ. Use of tocotransducer monitor
The fetal monitor device is a noninvasive prenatal monitoring system that displays maternal abdominal contractions and fetal heart rate through waveforms and charts and records the data on a ribbon chart recorder. This data can be used to assess the health status of the fetus before delivery (stress response test). This device is restricted to use by trained health care personnel in hospitals, clinics, consulting rooms, and patients' homes.
A tocotransducer monitor is basically an instrument consisting of a doppler heart rate detector and a group of pressure detectors. It is placed in the abdomen of a pregnant woman or woman to monitor and continuously record the frequency and intensity of uterine contractions, and also to monitor changes in the fetal heart rate. It can continuously detect the fetal heart and uterine contractions minute by minute, and depict these two data, showing two recording curves. From the correlation between these two curves, health care providers can determine whether the fetus is in good condition (whether there is hypoxia), whether the umbilical cord is compressed, and whether the placenta is poor or aging (if there is, the fetus may be hypoxic).
Ⅱ. Characteristics of tocotransducer monitor
Monitoring data can be recorded continuously or intermittently on a ribbon chart recorder as required by the operator. Information recorded by the tocotransducer monitor includes chart trend data and monitor hardware and software status information, time and date, patient number, operational Settings changes, and patient and clinician event markers.
Ⅲ. Doppler effect of tocotransducer monitor
The wavelength of the radiation varies due to the relative motion of the light source and the observer. In front of a moving wave source, the wave is compressed so that the wavelength becomes shorter and the frequency becomes higher. Behind a moving wave source, the opposite effect occurs. The wavelength gets longer and the frequency gets lower. The higher the velocity of the wave source, the greater the effect. Based on the degree of red and blue shift of the light wave, the speed of the wave source in the direction of observation can be calculated. The displacement of the spectral line shows the speed of movement in the direction of observation. Unless the source is traveling very close to the speed of light, the magnitude of the Doppler shift is generally small. Doppler effect exists in all fluctuation phenomena.