CN103705270B - Fetal Heart Monitoring Equipment - Google Patents

Abstract

The present invention provides a fetal heart rate monitoring device, which is characterized in that it includes a sensor node and a personal gateway, wherein the sensor node does not actively transmit ultrasonic waves to the fetus, but passively collects the sound or vibration of the abdomen surface of the pregnant woman to obtain The fetal heart rate signal is sent to the personal gateway in a wireless manner; the personal gateway is used to process the fetal heart rate signal sent by the sensor node to obtain the fetal heart rate. Through this device, pregnant women can wirelessly monitor the health status of the fetus at home for a long time. The passive fetal heart sound monitoring using sensors does not pose a health threat to the fetus, and is especially suitable for monitoring high-risk pregnant women.

Description

Fetal Heart Monitoring Equipment

technical field

The invention belongs to the field of electronic equipment and digital signal processing, in particular to a fetal heart rate monitoring device capable of long-term passive monitoring.

Background technique

During pregnancy, especially in the middle and late stages of pregnancy, various indicators of the fetus can be monitored to understand the health status of the fetus in the womb and detect fetal abnormalities early. The main purpose of monitoring the fetal heart rate is to obtain the real-time heart rate of the fetus. Whether the fetal heart rate is normal is an important indicator for judging whether the fetus is hypoxic in the mother's body. Therefore, fetal heart rate monitoring is an important item in pregnancy inspection.

At present, fetal heart rate monitoring mainly adopts Doppler ultrasonography. The principle of Doppler ultrasound monitoring is to use a probe capable of emitting ultrasound to transmit ultrasound to the position of the fetal heart. When the ultrasound meets the moving heart and is reflected, the frequency of the echo will change slightly due to the Doppler effect. , the heart rate of the fetus can be obtained by calculating the echo signal. Since Doppler ultrasound monitoring actively emits ultrasound for detection, it can effectively detect the weak heartbeat of the fetus, and the analysis accuracy of the fetal heart rate is high, so it is widely used in fetal heart rate monitoring.

However, ultrasound has certain thermal and acoustic effects on human tissues, which may be potentially harmful to the health of the fetus. Therefore, the time for ultrasound monitoring of the fetus should be controlled. If you want to monitor the fetal heart rate continuously for a long time to obtain the health information of the fetus in real time, using Doppler ultrasound is not an ideal choice. In addition, the current routine fetal heart rate monitoring in the hospital is about 20 minutes, and after the 30th week of pregnancy, it is necessary to go to the hospital every one to two weeks. For high-risk pregnant women, more frequent monitoring is required, and even hospitalization in advance is required, which brings great inconvenience to pregnant women and their families. Many pregnant women hope to know the health status of their fetuses at home at any time. At present, the common portable electronic fetal heart rate monitors all use Doppler ultrasound monitoring, and the ultrasound dose used by some of these devices has not been strictly tested and supervised, which may cause adverse effects on fetal health.

Before the Doppler ultrasound fetal heart monitor was popularized, traditional fetal sound auscultation equipment was often used for fetal heart monitoring, including wooden fetal heart receivers and medical stethoscopes. The passive detection method based on auscultation is safe and harmless to the fetus, but it has been gradually replaced by Doppler ultrasound equipment because it cannot amplify and record the sound signal. With the development of sensor technology, if the passive detection method of the sensor can be used, such as using an acoustic sensor to collect the sound signal of the mother's abdomen and using the signal processing method to calculate the fetal heart rate, the long-term uninterrupted monitoring of the fetus can be realized. Moreover, the safety is high and the cost is low.

Contents of the invention

(1) Technical problems to be solved

Aiming at the possible safety problems in the existing Doppler ultrasonic fetal heart sound monitoring, the present invention proposes a passive fetal heart rate monitoring device without using ultrasonic waves.

(2) Technical solutions

The present invention provides a fetal heart rate monitoring device, which includes a sensor node and a personal gateway, wherein the sensor node does not actively transmit ultrasonic waves to the fetus, but passively collects the sound or vibration of the pregnant woman's abdominal surface to obtain the fetal heart signal , and send it to the personal gateway in a wireless manner; the personal gateway is used to process the fetal heart rate signal sent by the sensor node to obtain the fetal heart rate.

Preferably, the personal gateway is further configured to be connected to a wide area network, and transmit the fetal heart rate to an external processing device.

Further, the sensing node includes: a sensor and a transceiver unit, wherein the sensor is used to collect the fetal heart signal, convert the fetal heart signal into an electrical signal, and send the electrical signal to The transceiving unit; the transceiving unit is configured to transmit the electrical signal received from the sensor to the personal gateway.

Preferably, the sensor node further includes a signal processing unit, and the sensor is further used to collect the fetal heart signal, convert the fetal heart signal into an electrical signal, and send the electrical signal to The signal processing unit; the signal processing unit is used to perform preliminary processing on the electrical signal, where the processing includes filtering, denoising, heart rate calculation, and sending the processed electrical signal to the transceiver unit; The transceiver unit is further configured to send the electrical signal received from the signal processing unit to the personal gateway.

Preferably, the signal processing unit is a single-chip microcomputer or DSP.

Preferably, the sensor is an acoustic sensor.

Preferably, the sensor is a piezoelectric sensor.

Preferably, the sensor further includes an analog-to-digital conversion unit for converting the fetal heart signal into a digital electrical signal.

Preferably, the transceiver unit is a Bluetooth module; the personal gateway is a smart phone.

(3) Beneficial effects

The monitoring equipment proposed by the invention adopts the passive detection method of the sensor, and has the characteristics of high safety, strong portability and the like. Using this device, pregnant women can carry out effective long-term passive monitoring of the fetus at home, and can transmit fetal heart rate data to external devices through the network, so that they can get remote assistance from doctors and provide a powerful guarantee for the healthy growth of the fetus. protection.

Description of drawings

Figure 1 is a diagram of a fetal heart rate monitoring device provided in an embodiment of the present invention;

Fig. 2 is a block diagram of the sensing nodes of the fetal heart rate monitoring device provided in the embodiment of the present invention;

Fig. 3 is the schematic diagram that the sensor node and the smart phone as the personal gateway transmit data and interconnect with the wide area network in the embodiment of the present invention;

Fig. 4 is a schematic diagram of transmitting data between the sensor node and the smart phone equipped with the circuit board of the first transceiver unit and interconnecting with the wide area network in the embodiment of the present invention;

Fig. 5 is a schematic diagram of sensor nodes and personal gateway devices transferring data and interconnecting with a wide area network in an embodiment of the present invention;

Fig. 6 is a flowchart of a method for obtaining fetal heart rate in an embodiment of the present invention;

Fig. 7 is a schematic diagram of a fetal heartbeat mode provided by an embodiment of the present invention;

Fig. 8 is an effect diagram of pattern matching on fetal heart signal provided by the embodiment of the present invention;

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

The invention provides a fetal heart rate monitoring system, which includes a sensor node and a personal gateway.

The structural block diagram of the sensor node for fetal heart sound monitoring is shown in Figure 2. The sensor node includes a sensor and a transceiver unit. Among them, the sensor is used to convert the fetal heart signal into an electrical signal, and any sensor capable of converting a sound signal or a vibration signal into an electrical signal and having sufficient sensitivity can be used to implement this solution.

Preferably, the present invention can use acoustic sensors, such as using high-sensitivity microphones. The high-sensitivity microphone is mainly composed of a tapered resonant cavity and an electret microphone. The center of the tapered resonant cavity is a cavity structure, which can effectively collect weak fetal heart sound signals. A high-sensitivity electret microphone is embedded in the center of the bottom end of the tapered cavity, which can convert sound signals into electrical signals for output.

Preferably, the present invention can also use a piezoelectric film sensor, and the piezoelectric sensor is closely attached to the skin on the abdomen surface of the pregnant woman. When the fetal heartbeat is transmitted to the abdomen surface of the pregnant woman, it will cause vibration, and the piezoelectric film can sense the vibration. The resulting pressure changes and converts the pressure signal into an electrical signal output.

When using the fetal heart rate monitoring device of the present invention, since the fetus will move to a certain extent in the uterus, the position where the fetal heartbeat is the strongest in the abdomen of the mother is not fixed, and the pregnant woman can obtain the best monitoring by adjusting the position of the sensor Effect.

Preferably, the sensor further includes an analog-to-digital conversion unit for converting the fetal heart signal output by the sensor into a digital electrical signal, which facilitates the processing of the fetal heart sound signal by the signal processing circuit at the back end.

The transceiver unit is used to transmit the collected data to the personal gateway so that the user can save the data for further medical analysis and processing. Preferably, the transceiving unit wirelessly transmits the collected data to the personal gateway.

Preferably, in addition to the sensor and the transceiver unit, the sensor node can further be provided with a signal processing unit for processing the fetal heart rate signal and extracting the fetal heart rate. The signal processing unit can use a single-chip microcomputer or DSP to perform preliminary processing on the fetal heart sound signal. The processing here can include filtering, denoising, heart rate calculation, etc., but not limited to the above aspects, and then transmit it to the personal gateway through the transceiver unit, wherein , DSP is a digital signal processor. It is also possible to directly transmit the unprocessed fetal heart sound signal to the personal gateway, and the personal gateway processes the fetal heart signal to extract the fetal heart rate.

There are many ways to realize the data transmission between the transceiver unit of the sensor node and the personal gateway, and three examples are provided here:

The first scheme is shown in Figure 3. The transceiver unit of the sensor node adopts a Bluetooth module, and the smart phone is used as a personal gateway, and the two communicate wirelessly through the Bluetooth protocol. Through wireless communication with the smart phone, the sensor node can send the fetal heart rate data and the real-time heart rate of the fetus to the smart phone and save them. Pregnant women and family members can see the real-time heart rate curve of the fetus on the smart phone. At the same time, pregnant women can pass the fetal heart rate data saved on the mobile phone to the doctor or to the terminal equipment of the hospital through the network. The doctor can judge whether the fetus is abnormal according to the change curve of the fetal heart rate data.

The second scheme is shown in Figure 4. In this scheme, the wireless transceiver unit of the sensor node adopts a wireless transceiver module, and the first transceiver unit circuit board is installed on the back of the smart phone as a personal gateway. The first transceiver unit circuit board includes a wireless transceiver module. unit, MCU and USB connector, wherein the MCU is a single chip microcomputer; the smart phone is connected to the first transceiver unit circuit board through a USB connector. Wireless communication is performed between the wireless transceiver module and the smart phone, and the data is further transmitted to an external processing device by the smart phone through the network, which is the same as the first solution.

The third scheme is shown in Figure 5. The wireless transceiver unit of the sensor node adopts a wireless transceiver module, and the personal gateway adopts a device including a wireless transceiver unit, a storage unit, an MCU, a power consumption management module, and a general interface for interacting with a wide area network. Both sensor nodes and personal gateways communicate wirelessly. The personal gateway transmits the fetal heart rate data to the external processing equipment through the wide area network. Through this solution, users no longer need to use smart phones for data transmission, which expands the applicability of the fetal heart rate monitoring device.

The device can obtain the fetal heart rate by the following method for obtaining the fetal heart rate, but the signal processing method for obtaining the fetal heart rate is not limited thereto. As shown in FIG. 6 , it is a flow chart of a method for obtaining the fetal heart rate.

S1. Analyzing the frequency domain characteristics of the fetal heart signal.

S2. Suppressing noise that is not within the effective frequency band of the fetal heart signal. The effective frequency band of the fetal heart signal is between 20 and 130 Hz, and the signal-to-noise ratio can be improved by suppressing noise.

S3. Calculate the energy of the signal within a predetermined time window. For the original heart sound signal, the heart sound of each beat lasts for a period of time, which is manifested in the time domain as a waveform that oscillates repeatedly near zero. Generally, there are multiple peaks and troughs, making it difficult to determine the exact position of the heart sound beat. The instantaneous energy, which calculates the energy of the signal within a predetermined time window, helps to determine the exact location of the heart sound beat. In this step, the average value of the square of the signal within a predetermined time window is used to represent the instantaneous energy of the signal.

S4. Determine the peak of the instantaneous energy signal. The peak of the instantaneous energy signal is the moment when the intensity of the fetal heart sound is the highest, which is used as the position of the heartbeat.

S5. Obtain the initial heart rate through pattern matching, and determine the approximate heart rate range of the fetus. The fetal heartbeat generally follows a fixed pattern, as shown in FIG. 7 , that is, a heartbeat cycle is mainly composed of two heartbeats, which are the first heart sound and the second heart sound respectively. Generally, the interval from the first heart sound to the second heart sound is smaller than the interval from the second heart sound to the first heart sound in the next heartbeat cycle. Through the method of parameter scanning, determine the best heartbeat mode of the current heartbeat signal, and then process the heartbeat signal containing noise according to the best heartbeat pattern, identify the heartbeat signal conforming to the best heartbeat pattern, and screen out noise interference, its implementation The effect is shown in Figure 8. Then the average heart rate of the fetus is calculated according to the result of the pattern matching.

S6. Based on the average heart rate and the heartbeat pattern acquired in the previous step, perform pattern matching on the subsequent fetal heart rate signal. Based on the average heart rate and heartbeat pattern acquired in the previous step, pattern matching can be continued on the fetal heartbeat signals in the subsequent 4 heartbeat cycles. Since the heart rate changes very little within 4 heartbeat cycles, the average heart rate and heartbeat pattern obtained in the previous step can be directly used. After the matching is completed, the average heart rate and heartbeat pattern are updated based on the data of the current 4 heartbeat cycles, and then used for pattern matching in the next 4 heartbeat cycles.

S7. Calculate the real-time heart rate of the fetus. The method for calculating the fetal real-time heart rate is to obtain the distance between the normal matching peaks separated by one heartbeat cycle, so as to obtain the time length of the heartbeat cycle. The number of heartbeat cycles in one minute is the real-time heart rate.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (2)

1. a fetal rhythm monitoring equipment, is characterized in that, comprises sensing node and Personal gateway, wherein,

Described sensing node, does not initiatively launch ultrasound wave to fetus, but gathers the sound on her abdominal surface passively or vibrate to obtain fetal heart rate signal, and wirelessly sends to described Personal gateway;

Described sensing node comprises: sensor, Transmit-Receive Unit and signal processing unit, wherein,

Described sensor, for gathering described fetal heart rate signal, and is converted into the signal of telecommunication by described fetal heart rate signal, and the described signal of telecommunication is sent to described signal processing unit; Described signal processing unit, for carrying out preliminary treatment to the described signal of telecommunication, process here comprises filtering, denoising, heart rate calculating, and the signal of telecommunication after process is sent to described Transmit-Receive Unit;

Described Transmit-Receive Unit, is further used for the signal of telecommunication received from described signal processing unit to be sent to described Personal gateway;

Described sensor adopts acoustic sensor; Described acoustic sensor is made up of taper resonator cavity and electret microphone, described taper resonator cavity center is cavity structure, gather fetal heart sound signal, embed an electret microphone at the bottom center place of described taper resonator cavity, acoustical signal is converted into the signal of telecommunication and exports by described electret microphone;

Described signal processing unit is single-chip microcomputer or DSP;

Described Transmit-Receive Unit is bluetooth module;

Described Personal gateway, processes for the fetal heart rate signal sent described sensing node, obtains Fetal Heart Rate;

Described Personal gateway adopts and comprises wireless transmit/receive units, memory element, MCU, power managed module and carry out the equipment of mutual general-purpose interface with wide area network; Described Personal gateway is connected with wide area network by described general-purpose interface, sends described Fetal Heart Rate to external processing apparatus;

Or described Personal gateway adopts the first Transmit-Receive Unit circuit, described first Transmit-Receive Unit circuit comprises wireless transmit/receive units, MCU and USB joint, and smart mobile phone is connected by USB joint with the first described Transmit-Receive Unit circuit board;

Or described Personal gateway is smart mobile phone.

2. fetal rhythm monitoring equipment as claimed in claim 1, it is characterized in that, described sensor comprises AD conversion unit further, for described fetal heart rate signal is converted into digital electric signal.