Ultrasonic doppler based remote fetal monitoring patch device

Abstract

The present application provides a kind of remote fetal monitoring patch device based on ultrasonic Doppler, synchronously acquires fetal heart rate, uterine muscle electricity, maternal heart rate and body temperature signal, effectively removes maternal interference using adaptive noise cancellation algorithm.Signal processing and feature extraction are completed locally in the patch, data compression ratio is ≥10:1, significantly reduces traffic cost and transmission delay, while protecting patient privacy.Using medical grade flexible material, wearing is comfortable and not binding;Disposable use avoids cross infection, paste firmly and no skin irritation.The whole process closed-loop management of "home collection-cloud analysis-doctor interpretation-real-time alarm" is realized, doctors can 24 hours online monitoring, abnormal response time <1 minute, significantly improve the perinatal safety of high-risk pregnant women.Pregnant women do not need professional training, 5 minutes can complete wearing and connection;The device is low in cost, suitable for large-scale popularization and application, which can effectively alleviate the problem of medical resource shortage.

Description

Technical Field

[0001] This invention relates to the field of monitoring equipment technology, and in particular to a remote fetal monitoring patch device based on ultrasound Doppler and its application. Background Technology

[0002] Fetal monitoring is a core means of ensuring maternal and infant safety during pregnancy. By continuously monitoring fetal heart rate (FHR), fetal movement, and uterine contractions (UC), abnormalities such as fetal hypoxia and distress can be detected early, allowing for timely intervention to reduce perinatal mortality and disability rates. According to the "China Maternal and Child Health Development Report 2025," there are approximately 10 million deliveries in my country each year, with high-risk pregnancies accounting for more than 25%. These include pregnancies with gestational diabetes mellitus (GDM), hypertensive disorders of pregnancy (HDCP), fetal growth restriction (FGR), and post-term pregnancy. These pregnant women require fetal monitoring 2-3 times per week or even daily.

[0003] Currently, the mainstream fetal monitoring technologies in clinical practice are divided into two categories: Hospital-based fetal heart rate monitoring: This method uses Doppler ultrasound technology. The pregnant woman must lie flat on the examination bed, and medical staff manually locate the fetal heartbeat. Each monitoring session lasts 20-40 minutes. This method has significant limitations: Time-consuming and laborious: Pregnant women need to frequently travel to and from the hospital, and a single monitoring session, including waiting in line, takes an average of 2-3 hours, resulting in a serious strain on medical resources; Intermittent monitoring: It can only capture the momentary state of the fetus and cannot detect intermittent abnormalities, with a false negative rate as high as 15%-20%; Poor experience: Pregnant women need to maintain a fixed posture for a long time, and multiple probes are wrapped around their abdomen, resulting in low comfort.

[0004] Home Doppler fetal heart monitor: This is a handheld device, requiring pregnant women to manually locate the fetal heartbeat daily, listening for 1-2 minutes at a time. This method has the following drawbacks: Relying on operational experience: Ordinary pregnant women have difficulty accurately locating the fetal heartbeat, especially when the gestational age is early or the fetal position is incorrect, with a success rate of less than 60%. Unable to monitor continuously: It can only obtain the instantaneous fetal heart rate and cannot record key indicators such as baseline fetal heart rate variability, acceleration, and deceleration, thus having limited clinical value; Without professional interpretation: Pregnant women who make their own judgments are prone to misinterpretation, leading to unnecessary panic or delays in treatment.

[0005] In recent years, a few wearable fetal monitoring devices have appeared on the market, but they still have the following fundamental technical defects: Excessive ultrasound power: Most devices have a spatial peak acoustic intensity (ISPTA) exceeding 100mW / cm², which does not meet the safety standards for fetal ultrasound and poses potential risks with long-term use. Severe signal interference: No maternal signal correction channel is set up, and interference from maternal heart rate, respiration, and movement is easily misinterpreted as fetal heart rate, with a false positive rate of over 30%. Short battery life: Reusable devices typically have a battery life of only 8-12 hours, which cannot meet the needs of 24-hour continuous monitoring; Large data transmission volume: The raw ultrasound signal is directly uploaded to the cloud, with a data volume of more than 100MB per hour, resulting in high traffic costs and large transmission latency. Non-disposable design: Reusable devices pose a risk of cross-infection, and the fit between the probe and the skin decreases with repeated use, affecting signal quality.

[0006] Therefore, developing a safe, comfortable, convenient, and accurate disposable remote fetal monitoring patch device to achieve continuous dynamic monitoring at home for 24 hours is of great clinical significance and social value for reducing perinatal risks for high-risk pregnant women, alleviating the burden on the medical system, and improving the medical experience for pregnant women. Summary of the Invention

[0007] To address the technical problems existing in the prior art, the present invention provides the following technical solution: On the one hand, a remote fetal monitoring patch device based on ultrasound Doppler is provided, comprising: The flexible substrate is made of medical-grade PDMS material; An adhesive layer, located on the lower surface of a flexible substrate, is used to adhere to the abdominal wall of a pregnant woman; The core sensing unit, integrated inside the flexible substrate, includes a miniature ultrasound Doppler module, a uterine electromyography sensor, a maternal heart rate sensor, and a body temperature sensor, used to simultaneously acquire fetal heart rate, fetal movement, uterine contractions, maternal heart rate, and body temperature signals. The edge computing and control unit is electrically connected to the core sensing unit and is used for preprocessing the acquired signals, multi-parameter fusion interference correction, feature extraction and data compression. The wireless communication unit, electrically connected to the edge computing and control unit, is used to upload encrypted compressed data to a mobile app and a cloud server. The power supply unit is used to supply power to the device.

[0008] Preferably, the miniature ultrasonic Doppler module is a 3MHz phased array probe, consisting of one transmitting unit and four receiving units, with an ultrasonic output spatial peak sound intensity ≤50mW / cm², a detection depth of 2-8cm, and automatic fetal heart rate tracking function.

[0009] Preferably, the edge computing and control unit uses an nRF52840 microcontroller, runs an adaptive noise cancellation algorithm, uses the maternal heart rate signal as a reference input, cancels maternal interference from the ultrasound signal, and the corrected fetal heart rate measurement accuracy is ±2 beats / min.

[0010] Preferably, the edge computing and control unit adopts a wavelet transform-based compression algorithm with a data compression ratio of ≥10:1, and the compressed data is encrypted using the AES-128 encryption algorithm.

[0011] Preferably, the wireless communication unit is a Bluetooth 5.0 low-power module that supports resume download functionality.

[0012] Preferably, the power supply unit is a CR2450 disposable lithium manganese button battery with a capacity of 600mAh.

[0013] Preferably, the device is elliptical in shape.

[0014] Preferably, the edge computing and control unit can detect abnormal fetal heart rate, fetal movement and uterine contractions in real time. When an abnormality occurs, an alarm is issued through the patch indicator light and mobile APP, and alarm information is sent to the cloud server simultaneously.

[0015] Preferably, the uterine electromyography sensor consists of two differential stainless steel electrodes symmetrically distributed on both sides of the ultrasound probe, used to collect uterine smooth muscle electromyography signals to reflect the intensity, frequency, and duration of uterine contractions.

[0016] On the other hand, the application of the aforementioned remote fetal monitoring patch device in the preparation of fetal monitoring devices is provided, which is suitable for continuous dynamic monitoring of fetal heart rate, fetal movement and uterine contractions at home for pregnant women with more than 28 weeks of pregnancy, and is especially suitable for high-risk pregnant women with gestational diabetes, gestational hypertension and other conditions.

[0017] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: 1. Safe and reliable low-power ultrasound technology: The peak sound intensity of the ultrasound output space is ≤50mW / cm², which is far below the international safety standard. There is no potential risk when using it continuously for 24 hours. It adopts phased array automatic fetal heart tracking technology, which does not require manual adjustment of position and the signal is stable and reliable.

[0018] 2. Multi-parameter fusion interference correction technology: Simultaneously collect fetal heart rate, uterine electromyography, maternal heart rate and body temperature signals, and use an adaptive noise cancellation algorithm to effectively remove maternal interference. The accuracy of fetal heart rate measurement is >98%, and the false positive rate is <5%.

[0019] 3. Edge computing and efficient data compression: Signal processing and feature extraction are completed locally on the patch, with a data compression ratio of ≥10:1 and a single-hour data upload volume of ≤10MB, which greatly reduces traffic costs and transmission latency, while protecting patient privacy.

[0020] 4. Disposable, flexible, and comfortable design: Made of medical-grade flexible material, with a thickness of ≤2mm and a weight of ≤10g, it is comfortable to wear without any restriction; disposable use avoids cross-infection, and the adhesive is firm and does not irritate the skin.

[0021] 5. Ultra-long battery life and low power consumption design: It adopts a disposable lithium manganese battery and a time-sharing working mechanism, with a continuous working time of ≥30 hours, meeting the needs of 24-hour continuous monitoring.

[0022] 6. Full-process remote monitoring system: It realizes closed-loop management of the entire process of "home data collection - cloud analysis - doctor interpretation - real-time alarm". Doctors can monitor online 24 hours a day, and the abnormal response time is less than 1 minute, which significantly improves the perinatal safety of high-risk pregnant women.

[0023] 7. Easy to operate and popularize: Pregnant women do not need professional training and can complete the wearing and connection in 5 minutes; the equipment cost is low and it is suitable for large-scale promotion and application, which can effectively alleviate the problem of medical resource shortage. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is an example of the application effect of a flexible substrate provided by an embodiment of the present invention; Figure 2 This is a schematic diagram of the control system circuit of this equipment; Figure 3 This is a block diagram of the control system for the core sensing unit of this invention; Figure 4 This is a schematic diagram of the application control logic of a device provided in an embodiment of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0027] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0028] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning.

[0029] In this embodiment of the invention, sometimes a subscript such as W1 may be mistakenly written as a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0030] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0031] I. Project Proposal for the Development of Remote Fetal Monitoring Patch This design addresses the shortcomings of existing clinical fetal monitoring technologies, such as "hospital fetal heart rate monitors" and "home Doppler fetal heart rate monitors," by innovatively integrating miniature ultrasound Doppler technology, multi-parameter sensor fusion technology, edge computing technology, and low-power wireless communication technology into a disposable flexible patch, thus developing a remote fetal monitoring patch device based on ultrasound Doppler.

[0032] 1. Necessity of project approval: Urgent clinical need: Every year, about 2.5 million high-risk pregnant women in China require frequent fetal monitoring, but existing medical resources cannot meet the need for continuous monitoring, and about 30% of fetal distress in utero is not detected in time.

[0033] Significant technological gaps exist: Currently, there are no disposable fetal monitoring patches on the market that simultaneously possess multi-channel signal correction, edge computing compression, and 24-hour battery life.

[0034] The economic benefits are considerable: the estimated cost of this equipment is about 80-100 yuan per piece, and the selling price is 200-300 yuan per piece. Based on an annual sales volume of 1 million pieces, it can achieve an annual sales revenue of 200-300 million yuan.

[0035] Significant social benefits: It can increase the coverage rate of fetal monitoring for high-risk pregnant women from the current 40% to over 90%, reduce perinatal deaths and disabilities by approximately 50,000 cases annually, and save more than 2 billion yuan in medical expenses.

[0036] 2. Development Goals: A disposable flexible patch integrating a miniature ultrasonic Doppler probe, a multi-parameter sensing module, an edge computing module, and a Bluetooth communication module has been developed, with a thickness of ≤2mm and a weight of ≤10g. It enables simultaneous acquisition of fetal heart rate, fetal movement, uterine electromyography, maternal heart rate, and body temperature. The fetal heart rate measurement range is 90-210 beats / min, with an accuracy of ±2 beats / min. Data compression is achieved using edge computing technology, with a compression ratio of ≥10:1 and a single-hour upload data volume of ≤10MB. The peak acoustic intensity of the ultrasound output space is ≤50mW / cm², which meets international fetal ultrasound safety standards. A single-use battery provides ≥30 hours of continuous operation, meeting the needs of 24-hour continuous monitoring. The equipment has obtained the national medical device registration certificate, enabling industrial-scale production.

[0037] 3. Scope of Application This device is suitable for fetal monitoring during pregnancy in medical institutions at all levels and in home settings, specifically including: 1) Target audience: All pregnant women who are more than 28 weeks pregnant, especially high-risk pregnant women: gestational diabetes, gestational hypertension, fetal growth restriction, post-term pregnancy, abnormal amniotic fluid, multiple pregnancy, etc. Pregnant women with a history of adverse pregnancy outcomes; Pregnant women who feel abnormal fetal movement.

[0038] 2) Applicable Scenarios: Home-based routine monitoring; Community health service centers provide primary care; Continuous monitoring of pregnant women during transport; Bedside monitoring in hospital wards.

[0039] 3) Contraindications: Pregnancy less than 28 weeks; Those with broken, infected, or allergic skin on their abdomen; For those allergic to medical silicone or pressure-sensitive adhesive.

[0040] II. Equipment Design Specifications This device adopts an integrated flexible design, with an overall elliptical patch structure, measuring 120mm in length, 80mm in width, and 1.8mm in thickness, weighing 8.5g. It consists of five parts: a flexible substrate and adhesive layer, a core sensing unit, an edge computing and control unit, a wireless communication unit, and a power supply unit. All electronic components are integrated onto the flexible PCB board using surface mount technology (SMT), ensuring the device's flexibility and wearing comfort.

[0041] The patch module is integrated into an elliptical flexible substrate and an adhesive layer 100.

[0042] The flexible substrate and adhesive layer 100 serve as a carrier, and their shape and usage diagram are shown in Figure 1. Their structural composition is as follows: Substrate material: 0.1mm thick medical-grade polydimethylsiloxane (PDMS) film, which has good biocompatibility, flexibility and breathability; Adhesive layer: Medical-grade acrylic pressure-sensitive adhesive, 0.05mm thick, with an adhesion strength ≥1N / cm, can maintain firm adhesion for 72 hours without residue; Release paper: Made of silicone paper, remove before use.

[0043] Technical parameters: Biocompatibility: Complies with GB / T 16886.1-2011 standard, with no cytotoxicity or skin irritation; Waterproof rating: IPX4, protects against everyday sweat and splashes; Breathability: Water vapor transmission rate ≥2000g / (m²·24h) to avoid skin stuffiness caused by prolonged wear.

[0044] The surface-mount module includes a core sensing unit, an edge computing and control unit, a wireless communication unit, and a power supply unit. Its control system design is as follows: Figure 2 As shown.

[0045] Control System Description (I) Core Sensing Unit like Figure 3 As shown, the core sensing unit consists of a miniature ultrasound Doppler module, a uterine electromyography sensor, a maternal heart rate sensor, and a body temperature sensor, enabling simultaneous acquisition of multiple parameters and interference correction.

[0046] 1. The miniature ultrasonic Doppler module uses a custom-designed 3MHz piezoelectric miniature ultrasonic Doppler probe, consisting of a phased array of one transmitting unit and four receiving units. Technical parameters: Spatial peak acoustic intensity (ISPTA) of ultrasound output: ≤50mW / cm², far below the fetal ultrasound safety limit (100mW / cm²) stipulated by the International Electrotechnical Commission (IEC). Detection depth: 2-8cm, covering the uterine depth of pregnant women over 28 weeks of gestation; Sampling frequency: 1kHz; Power consumption: ≤2mW.

[0047] This module is based on the Doppler effect. The transmitting unit emits low-power ultrasound waves of 3MHz into the uterus. When the ultrasound waves encounter the moving fetal heart, a frequency shift signal is generated.

[0048] in, For Doppler frequency shift, The transmission frequency is 3MHz, and v is the velocity of the fetal heart wall. θ is the angle between the sound beam and the direction of blood flow, and c is the speed of ultrasound propagation in human tissue (1540 m / s).

[0049] Automatic fetal heart rate tracking technology: Four receiving units are arranged in a cross shape. By comparing the signal strength of different receiving units, the optimal detection direction for the fetal heart rate is automatically identified. When the signal strength is below the threshold, the phased array automatically adjusts the sound beam angle (±15°) to achieve automatic tracking of the fetal heart rate without requiring the pregnant woman to manually adjust the position.

[0050] 2. Uterine electromyography sensor The uterine electromyography (EMG) sensor collects the bioelectrical signals (EHG) generated during uterine smooth muscle contractions, reflecting the intensity, frequency, and duration of these contractions. The signal frequency range is 0.05-3 Hz, and the amplitude is 10-1000 μV.

[0051] Hardware selection: Two differential electrodes are used, made of medical-grade stainless steel, with a size of 2mm×2mm, symmetrically distributed on both sides of the ultrasound probe.

[0052] Technical parameters: Input impedance: ≥100MΩ; Common-mode rejection ratio: ≥80dB; Sampling frequency: 100Hz.

[0053] 3. Maternal heart rate sensor The maternal heart rate sensor detects changes in the absorption of green light by the blood to obtain the maternal heart rate signal, which is then used to correct maternal interference in the ultrasound signal.

[0054] Hardware selection: A photoplethysmography (PPG) sensor is used, integrating a green LED (520nm) and a photodiode.

[0055] Technical parameters: Heart rate measurement range: 40-180 beats / minute; Accuracy: ±2 times / min; Sampling frequency: 100Hz.

[0056] 4. Body temperature sensor The body temperature sensor can use an NTC thermistor (operating range: measurement range: 32-42℃; accuracy: ±0.1℃; sampling frequency: 1Hz), in a 0603 package.

[0057] NTC thermistors calculate body surface temperature by measuring changes in the thermistor's resistance. They are used to monitor changes in a pregnant woman's body temperature and to correct for the influence of temperature on ultrasound sensors. This is a standard technology and will not be elaborated upon here.

[0058] (ii) Edge computing and control unit The edge computing and control unit, acting as the device's microcontroller (using a low-power microcontroller such as Nordic's nRF52840, integrating an ARM Cortex-M4F core (64MHz), 1MB Flash and 256KB RAM, and also integrating a Bluetooth 5.0 communication module), is responsible for signal acquisition, processing, and computation. Its core operating program is as follows: a. Control the synchronous acquisition of data by each sensing unit; b. Perform preprocessing, feature extraction, and data compression on the original signal; an example is shown below: Signal preprocessing methods can be adopted as follows: Ultrasonic signal: Noise was removed by bandpass filtering (100-1000Hz), and the envelope signal was extracted by Hilbert transform; Uterine electromyography signals: wavelet transform was used to remove power frequency interference and motion artifacts; PPG signal: Baseline drift is removed using a moving average filter.

[0059] The following are some of the feature extraction methods: Key clinical indicators such as fetal heart rate baseline, accelerations, decelerations, and variability are extracted from the corrected ultrasound signal; the intensity, frequency, and duration of uterine contractions are extracted from the uterine electromyography signal; and fetal movement is automatically identified by analyzing the instantaneous changes in fetal heart rate and the synchronicity of uterine electromyography.

[0060] Data compression employs a lossy compression algorithm based on wavelet transform to compress the original signal, achieving a compression ratio of ≥10:1 while preserving all key clinical features. The compressed data is then encrypted using the AES-128 encryption algorithm to ensure data security.

[0061] c. Run a multi-parameter fusion algorithm to correct for maternal interference and extract accurate fetal heart rate and fetal movement signals. While general parameter fusion uses a weighted fusion mechanism, this equipment employs a multi-parameter fusion interference correction mechanism to eliminate maternal noise. Specifically: An adaptive noise cancellation (ANC) algorithm is used, with the maternal heart rate signal as a reference input, to cancel out interference from the maternal heartbeat and respiration in the ultrasound signal.

[0062] Where d(n) is the original ultrasound signal, and x(n) is the maternal heart rate reference signal. Here are the adaptive filter coefficients, and e(n) is the corrected fetal heart rate signal.

[0063] d. Managing wireless communication and power consumption; e. Local anomaly alarm.

[0064] The table below illustrates the communication data format for the control inputs and outputs of a microcontroller: .

[0065] (iii) Wireless communication unit This device implements wireless transmission; therefore, the wireless communication unit uses a Bluetooth 5.0 module integrated within the nRF52840, supporting BLE Low Power mode. It employs a custom GATT service protocol, with a data transmission rate of 1kbps and a transmission distance ≤10m.

[0066] Bluetooth transmission function: Establish a Bluetooth connection with the pregnant woman's smartphone; Upload the encrypted compressed data to the mobile app; It receives control commands from a mobile app and feedback from doctors.

[0067] Resume interrupted transmission mechanism: When the Bluetooth connection is interrupted, the data is automatically stored in the local Flash (maximum storage capacity 8MB, can store 24 hours of compressed data), and the transmission will automatically resume after the connection is restored to ensure that the data is not lost.

[0068] (iv) Power supply unit To reduce the size and weight of the device, this power unit uses a 3V disposable lithium manganese button battery (CR2450) with a capacity of 600mAh, which is integrated inside the patch and cannot be replaced.

[0069] The power supply provides 3V DC power to other modules.

[0070] The power supply unit adopts a low-power design: A time-sharing working mechanism is adopted: the ultrasound module collects data once every 100ms, with each data acquisition lasting 1ms; other sensors operate according to their respective sampling frequencies. When idle, it automatically enters low-power mode with a current ≤1μA; The transmit power is dynamically adjusted based on the Bluetooth signal strength to reduce power consumption while ensuring communication quality.

[0071] Battery life: Continuous working time ≥ 30 hours, meeting the needs of 24-hour continuous monitoring.

[0072] Power Management: The microcontroller monitors the battery voltage in real time. When the voltage drops below 2.2V, it issues a low battery alarm via a mobile app.

[0073] III. Application Control Logic like Figure 4 As shown, the application control logic of this device adopts a finite state machine design, including five states: standby state, active state, monitoring state, abnormal alarm state, and termination state. The state transition process is as follows: 1. Standby mode After leaving the factory, the device is in standby mode with all modules powered off. Only the button circuit is activated in low-power mode with a current ≤0.1μA and a battery life ≥2 years.

[0074] 2. Activated status After pressing and holding the activation button for 3 seconds, the device enters the activation state, and the system begins initialization: The microcontroller starts up and completes its hardware self-test; Each sensor module is powered on and calibrated; The Bluetooth module initiates a broadcast, waiting for the phone to connect; The blue indicator light flashes once per second.

[0075] If the phone is not connected within 30 seconds, the device will automatically return to standby mode.

[0076] 3. Monitoring Status After a successful Bluetooth connection, the device enters monitoring mode, and the blue indicator light remains constantly on. Each sensor module collects data synchronously at a set frequency; Edge computing units perform data preprocessing, interference correction, feature extraction, and compression and encryption. The encrypted data is uploaded to the mobile app via Bluetooth, and then uploaded to the cloud server by the app. The cloud server analyzes the data in real time and generates monitoring reports for doctors to interpret remotely. The device automatically assesses signal quality every hour. If the signal quality is below the threshold, the device will prompt the pregnant woman to adjust the position of the patch via the app.

[0077] 4. Abnormal alarm status When the edge computing unit or cloud server detects the following abnormal conditions, the device enters an abnormal alarm state: Abnormal fetal heart rate: baseline <110 bpm or >160 bpm, lasting for more than 10 minutes; Abnormal fetal heart rate variability: variability <5 beats / min, lasting for more than 40 minutes; Abnormal deceleration: Late deceleration, severe variable deceleration, or prolonged deceleration occurs; Abnormal fetal movement: Fetal movement <10 times in 2 hours; Abnormal uterine contractions: Contraction frequency > 5 times / 10 minutes, lasting more than 30 minutes.

[0078] Alarm methods: The red indicator light on the patch flashes once per second; The mobile app emits sound and vibration alarms, and displays the type of abnormality and handling suggestions; The cloud server synchronously sends alarm information to the doctor's workstation, reminding the doctor to intervene in a timely manner.

[0079] 5. Ending state When the battery is depleted or the pregnant woman manually ends the monitoring, the device enters the shutdown state, all modules are powered off, and the indicator lights go out. Used patches should be disposed of as medical waste.

[0080] IV. Equipment Packaging Method Each tablet is individually aseptically packaged and contains: One remote fetal monitoring patch; One alcohol swab; One instruction manual.

[0081] V. Instructions for Using the Monitoring Patch 1. Preparation: Pregnant women should wash their hands thoroughly and clean their abdominal skin with alcohol wipes, waiting for the alcohol to completely evaporate. Remove the release paper from the patch and avoid touching the adhesive layer.

[0082] 2. Patch application: Locate the fundus of the uterus (at 28 weeks of gestation, the fundus is located 3 fingerbreadths above the navel), and place the center of the patch 2-3 cm below the fundus of the uterus and 2 cm to the left or right of the midline of the abdomen; Gently press the edge of the patch with your finger to ensure it adheres firmly without bubbles or wrinkles.

[0083] 3. Device activation and connection: Press and hold the activation button on the side of the patch for 3 seconds. The blue indicator light will flash 3 times, indicating that the device has been successfully activated. Open the mobile app, scan the QR code on the patch packaging, and the device pairing and connection will be completed automatically; The app displays "Device connection successful, monitoring started," indicating that deployment is complete.

[0084] VI. Precautions for use This equipment is for single use only and must not be reused. It should be disposed of as medical waste after use. Before wearing, clean your abdominal skin to remove oil and sweat, and ensure that the patch fits snugly against your skin. The patch should be applied 2-3 cm below the fundus of the uterus, on both sides of the midline of the abdomen, avoiding scars and the placental attachment site; Avoid strenuous exercise, bathing, and swimming while wearing the patch to prevent it from falling off or getting wet. If allergic reactions such as itchy skin or redness occur, the patch should be removed immediately. The device is for auxiliary monitoring only and cannot replace the diagnosis of a professional doctor. If any abnormalities are found, seek medical attention promptly. Do not use in environments with strong electromagnetic radiation, as this may affect signal quality; The equipment should be stored in a cool, dry place, away from direct sunlight and high temperatures. Example 1

[0085] I. Application Scenarios This example was applied to a remote fetal monitoring center in the obstetrics and gynecology department of a tertiary hospital. The patient was a 32-year-old woman, 34 weeks pregnant, diagnosed with gestational hypertension (severe preeclampsia), requiring daily fetal monitoring. The patient had a history of cesarean section, and this pregnancy was a singleton pregnancy in cephalic presentation.

[0086] II. Equipment Implementation 1. In-hospital training and equipment distribution: The doctor explained the usage and precautions of the equipment to the patient in detail; Patients should practice wearing the device for the first time under the guidance of a doctor to master the correct wearing position and connection method; One device will be distributed to the patient, and the patient will be instructed to download and register the mobile app and complete the binding of their personal information.

[0087] 2. Home monitoring process: The patient put on the device at home at 8:00 a.m. the following day and completed the activation and connection process according to the instructions. The device begins continuous monitoring, and the patient can continue their daily activities without needing to maintain a fixed posture. During the monitoring period, the APP displays the fetal heart rate curve, uterine contraction curve, and fetal movement count in real time; The cloud server synchronizes the data to the hospital's remote monitoring center, where dedicated doctors provide online interpretation 24 hours a day.

[0088] 3. Exception handling: Monitoring until 22:15 that day showed that the cloud server detected frequent late decelerations in the fetal heart rate, with the baseline fetal heart rate dropping to 105 beats / min and the variation range being <3 beats / min; The system immediately triggered a Level 3 alarm: the red indicator light on the patch flashed, the patient's mobile app emitted a strong vibration and sound alarm, and at the same time sent an emergency alarm message to the doctor's workstation; The on-duty doctor received the alarm within 1 minute, checked the real-time monitoring curve, determined that the fetus was at risk of intrauterine distress, and immediately contacted the patient by phone to instruct them to go to the hospital emergency room immediately. The patient arrived at the hospital at 23:00 and underwent an emergency cesarean section, delivering a male infant weighing 2300g. The Apgar score was 7 at 1 minute and 9 at 5 minutes. Both mother and baby were safe after the operation.

[0089] 4. Monitoring data statistics: The monitoring lasted 14 hours and 15 minutes, collecting 14.2 hours of valid data, with a data completeness rate of 99.7%. A total of 32 fetal movements and 18 uterine contractions were recorded. The baseline fetal heart rate was 135 beats / min, with an average variation of 12 beats / min. The abnormal event occurred 14 hours and 15 minutes after the start of monitoring, and the time from the occurrence of the abnormality to the doctor's alarm response was less than 60 seconds.

[0090] III. Comparison of Technical Effects Compared with traditional in-hospital fetal heart rate monitoring, the technical advantages of this embodiment are as follows:

[0091] In comparison, the portable abdominal patch device of this application is superior to traditional monitoring methods in terms of efficiency and accuracy of detection, and has positive application value for clinical pregnancy and childbirth monitoring.

[0092] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A remote fetal monitoring patch device based on Doppler ultrasound, characterized in that, include: The flexible substrate is made of medical-grade PDMS material; An adhesive layer, located on the lower surface of a flexible substrate, is used to adhere to the abdominal wall of a pregnant woman; The core sensing unit, integrated inside the flexible substrate, includes a miniature ultrasound Doppler module, a uterine electromyography sensor, a maternal heart rate sensor, and a body temperature sensor, used to simultaneously acquire fetal heart rate, fetal movement, uterine contractions, maternal heart rate, and body temperature signals. The edge computing and control unit is electrically connected to the core sensing unit and is used for preprocessing the acquired signals, multi-parameter fusion interference correction, feature extraction and data compression. The wireless communication unit, electrically connected to the edge computing and control unit, is used to upload encrypted compressed data to a mobile app and a cloud server. The power supply unit is used to supply power to the device.

2. The remote fetal monitoring patch device according to claim 1, characterized in that, The miniature ultrasonic Doppler module is a 3MHz phased array probe, consisting of one transmitting unit and four receiving units, with a spatial peak acoustic intensity of ≤50mW / cm². 2 It has a detection depth of 2-8cm and features automatic fetal heart rate tracking.

3. The remote fetal monitoring patch device according to claim 1, characterized in that, The edge computing and control unit uses an nRF52840 microcontroller and runs an adaptive noise cancellation algorithm. It uses the maternal heart rate signal as a reference input to cancel maternal interference from the ultrasound signal, and the corrected fetal heart rate measurement accuracy is ±2 beats / min.

4. The remote fetal monitoring patch device according to claim 1, characterized in that, The edge computing and control unit adopts a wavelet transform-based compression algorithm with a data compression ratio of ≥10:1, and the compressed data is encrypted using the AES-128 encryption algorithm.

5. The remote fetal monitoring patch device according to claim 1, characterized in that, The wireless communication unit is a Bluetooth 5.0 low-power module, which supports breakpoint resume function.

6. The remote fetal monitoring patch device according to claim 1, characterized in that, The power supply unit is a CR2450 disposable lithium manganese button battery with a capacity of 600mAh.

7. The remote fetal monitoring patch device according to claim 1, characterized in that, The flexible substrate of the device has an elliptical shape that adapts to the abdominal curve.

8. The remote fetal monitoring patch device according to claim 1, characterized in that, The edge computing and control unit can detect abnormal fetal heart rate, fetal movement and uterine contractions in real time. When an abnormality occurs, an alarm is issued through the patch indicator light and mobile APP, and alarm information is sent to the cloud server at the same time.

9. The remote fetal monitoring patch device according to claim 1, characterized in that, The uterine electromyography sensor consists of two differential stainless steel electrodes symmetrically distributed on both sides of the ultrasound probe. It is used to collect uterine smooth muscle electromotive force signals, reflecting the intensity, frequency, and duration of uterine contractions.

10. The application of the remote fetal monitoring patch device according to claim 1 in the manufacture of fetal monitoring devices, characterized in that, It is suitable for home-based continuous dynamic monitoring of fetal heart rate, fetal movement and uterine contractions in pregnant women over 28 weeks of gestation, and is especially suitable for high-risk pregnant women such as those with gestational diabetes and gestational hypertension.

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