JPH0331454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fetal monitoring device that continuously monitors the fetal heart rate from the middle to late stages of pregnancy without restricting the movements of expectant and nursing mothers.

(Prior Art) Fetal monitoring devices that continuously monitor fetal heart rate using ultrasound technology have been known. The monitoring device installs an ultrasound probe on the abdominal wall of the pregnant woman, obtains a Doppler shift signal based on the fetal arterial blood flow from the signal detected by the ultrasound probe, and records the fetal heart rate from this, It is configured for continuous monitoring.

With such a fetal monitoring device, it is easy to obtain signals related only to the fetal heartbeat.
NST (non-stress-test: continuous monitoring of fetal heart rate to assess fetal health),
Alternatively, home monitoring can be performed without restricting the behavior of expectant mothers at all.

(Problems to be solved by the invention) However, in conventional fetal monitoring devices, the ultrasound probe is installed on the abdominal wall of the pregnant woman.
There is a problem in that the coupling between the ultrasonic wave transmitting/receiving surface of the ultrasonic probe and the abdomen becomes unstable due to the movement of the abdomen when a pregnant woman walks, resulting in signal disturbance.

The present invention has been made in view of the above, and its purpose is to realize a fetal monitoring device that can continuously obtain undisturbed signals even when a pregnant woman moves, such as by walking. be.

(Means for Solving the Problems) The fetal monitoring device of the present invention that achieves the above object has the following features:
The ultrasonic probe has a flat cylindrical shape with a watertight structure.
It is configured to transmit and receive ultrasound beams in a direction approximately parallel to the short axis, and is installed deep inside the pregnant woman's vagina with the ultrasound transmission and reception surface facing the advanced part of the fetus to be examined, and detects the desired signal. It's becoming like that.

(Function) The cylindrical external ultrasound probe is stably installed at a predetermined location within the vagina. Moreover, the ultrasonic probe transmits and receives ultrasonic waves under conditions as if it were immersed in salt water. That is, the ultrasonic probe has a configuration suitable for installation in the vagina, and couples the ultrasonic wave transmitting/receiving surface with the fetus to be examined via a liquid. Therefore, signal detection is not affected by the walking of the pregnant and nursing mother (movement of the mother's body).

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 3 are configuration diagrams showing a fetal monitoring device according to an embodiment of the present invention, and FIG. 1 is an outline diagram of an ultrasound probe (telemeter capsule);
Figure 2 is a configuration diagram of the electric circuit housed in the ultrasonic probe, and Figure 3 is a configuration diagram of the electric circuit that relays the electric signal from the ultrasound probe to the main body of the device (not shown). be. In FIG. 1, an ultrasonic probe 1 has a flat cylindrical shape with a watertight structure, and includes two semicircular transducers 2 and 3 disposed on one flat surface of the tube, and a side wall of the tube. Each has an antenna 4 that can be pulled out. The transducers 2 and 3 transmit and receive ultrasonic beams in a direction substantially parallel to the short axis of the cylinder. The circuit housed in the ultrasonic probe 1 includes a transducer 2 as shown in FIG.
an oscillator 5 that ultrasonically drives the signal using a CW signal; a Doppler receiver 6 that obtains a Doppler shift signal from the signal received by the transducer 3;
It is composed of a telemeter transmitter 7 that frequency-modulates the frequency at ~10-odd MHz and sends it to the antenna 4, and a power supply section 8 that drives each circuit inside the cylinder. The Doppler receiving section 6 includes a circuit for obtaining a Doppler shift signal from a received signal, a Doppler filter (wall filter) for cutting out low frequencies, a detection circuit, a low-pass filter, etc. (all not shown). On the other hand, the relay circuit includes a bar antenna 9 that receives radio waves from the antenna 4, a high frequency amplifier 10 that amplifies the signal received by the bar antenna 9, and shapes the output of the high frequency amplifier 10, as shown in FIG. An AGC limiter 11, a mixer 13 that demodulates the signal from the AGC limiter 11 using the signal from the oscillator 12 as a reference signal, a bandpass filter 14 that extracts only the desired frequency from the demodulated signal, and an output of the bandpass filter 14. It is composed of a buffer amplifier (antenna driver amplifier) 16 that amplifies the signal and sends it to the antenna 15. In addition, the main body of the device (not shown) has an antenna 15.
It consists of an antenna that receives radio waves from the antenna, an amplifier that amplifies the signal received by the antenna, a recorder that records the amplified signal, etc. Note that transmission between the relay circuit and the main device is performed in the VHF band or UHF band.

In the above configuration, as shown in FIG. 4 (a midsagittal cross-sectional view of the pelvis of a woman near term of pregnancy), the ultrasound probe 1 is positioned deep within the vagina 18 of a pregnant woman 17 with an ultrasound transmitting and receiving wave surface. (The vibrators 2 and 3) are placed toward the advanced part of the fetus 19 to be examined (in the case of a normal fetus, this refers to the head). Further, the relay circuit (the circuit shown in FIG. 3) is carried by the expectant and nursing mother, and the main body of the device is installed in or near the area of movement of the expectant and nursing mother. Vibrator 2
The CW ultrasound transmitted from the fetus 19 is irradiated to the advanced part (head) of the fetus 19 to be examined, and the ultrasound containing blood flow components of the basilar artery or carotid artery is received by the transducer 3 and subjected to Doppler reception. Part 6 is given. The output of the Doppler receiver 6 becomes a pulsatile Doppler shift signal whose low frequency is sufficiently cut out by the Doppler filter (components due to body movement are removed). The above-mentioned pulsatile Doppler shift signal is frequency-modulated by the telemeter transmitter 7 and transmitted from the antenna 4. Inside the mother body (antenna 4)
Radio waves are received by the bar antenna 9, demodulated and amplified within the relay circuit, and then sent out from the antenna 15. Radio waves from the antenna 15 are received by the antenna of the main body of the device and are continuously recorded. This allows the fetal heart rate of the pregnant woman to be continuously monitored.

In the above embodiment, the ultrasonic probe 1 has a configuration in which the antenna 4 is pulled out of the tube, but the following configuration is also possible. If the frequency modulation band is from several MHz to ten-odd MHz as in the above embodiment, a sufficient degree of coupling can be achieved with inductive coupling, so tuning must be done inside the cylinder of the ultrasound probe and inside the case of the relay circuit. An air-core coil, bar antenna, or loop antenna may be incorporated.
Further, the pregnant woman can also carry a tape recorder instead of the relay circuit and record desired signals using a method of recording signals from the ultrasound probe 1, a so-called stored telemetry method. Furthermore, the ultrasound probe 1 is placed at various positions 2 in the cervix 20 and the uterus.
1, 22, or 23 (see FIG. 3 for each), it is possible to obtain a desired ultrasonic signal by directing the ultrasonic wave transmitting/receiving surface in a predetermined direction. When the ultrasound probe 1 is installed at each position in the uterus, the ultrasound probe is installed between the amniotic membrane and the uterine wall.

(Effects of the Invention) As explained above, according to the fetal monitoring device of the present invention, the ultrasound probe has a configuration suitable for being installed deep inside the vagina of a pregnant woman, and the ultrasound probe transmits ultrasound waves through liquid. Since coupling is achieved between the transmitting/receiving wave surface and the fetus under test, signal detection is not affected by the walking of the pregnant and nursing mother (movement of the mother's body), making it possible to continuously monitor the undisturbed fetal heart rate. can.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the external shape of an ultrasonic probe according to an embodiment of the present invention, and FIG. 2 is a configuration diagram showing an electric circuit housed within the ultrasound probe according to an embodiment of the present invention. , FIG. 3 is a block diagram showing a signal relay circuit according to an embodiment of the present invention, and FIG. 4 is an explanatory diagram of an installed state of an ultrasonic probe according to an embodiment of the present invention. 1... Ultrasonic probe, 2 and 3... Vibrator, 4
and 15... antenna, 5 and 12... oscillator,
6... Doppler receiving section, 7... Telemeter transmitting section,
8...Power supply section, 9...Bar antenna, 10...High frequency amplifier, 11...AGC limiter, 13...
Mixer, 14... Bandpass filter, 16...
Batsuhuaamp, 17...Maternal body, 18...Vagina, 1
9...fetus, 20...cervix.

Claims (1)

[Scope of Claims] 1. A fetal monitoring device that continuously monitors the fetal heart rate by obtaining a Doppler signal based on the arterial blood flow of the fetus from an ultrasound probe installed in a pregnant woman, comprising: has a flat cylindrical outer shape with a watertight structure, and is configured to transmit and receive ultrasound beams in a direction approximately parallel to the short axis, and transmits and receives ultrasound to the advanced part of the fetus to be examined deep inside the pregnant woman's vagina. A fetal monitoring device characterized in that it is installed with the wavefront facing the target and detects a desired signal. 2. The fetal monitoring device according to claim 1, wherein the ultrasound probe constitutes a wireless transmission system with the main body of the monitoring device. 3. The fetal monitoring device according to claim 2, wherein the ultrasound probe is equipped with a wireless transmission means. 4. The fetal monitoring device according to claim 2, wherein the wireless transmission system includes a wireless relay means carried by the pregnant and nursing mother.