Fistula monitoring apparatus

Abstract

A fistula monitoring apparatus, comprising: a housing (100), wherein a first accommodation space is formed inside the housing; a monitoring module (200), which is arranged at one end of the housing (100), and is used for measuring the blood flow velocity in a fistula and generating corresponding monitoring data; and a central control module (105), which is arranged in the first accommodation space, receives the monitoring data, and outputs the monitoring data or result information generated on the basis of the monitoring data. The monitoring module (200) and the central control module (105) are compactly arranged in the accommodation space in the housing (100), such that compared with larger wearable internal-fistula detection apparatuses, the overall volume of the fistula monitoring apparatus is effectively reduced, and the compact size makes the fistula monitoring apparatus more portable; and an intuitive and low-cost auxiliary monitoring means is provided for fistula state evaluation.

Description

A fistula listening device Technical Field

[0001] This invention relates to the field of medical auxiliary equipment technology, and in particular to a fistula monitoring device. Background Technology

[0002] Hemodialysis is a renal replacement therapy used to treat patients with chronic renal failure. Before hemodialysis, vascular access needs to be established. Arteriovenous fistulas (AVFs) have become a commonly used vascular access option due to their advantages such as good long-term dialysis efficacy, high patient survival rates, low infection rates, and low thrombosis rates.

[0003] However, fistulas are prone to failure, requiring the creation of new arteriovenous fistulas in other locations, i.e., repeat fistula reconstruction. This surgery is expensive, placing a significant financial burden on patients. Furthermore, the primary sites for fistula creation are the extremities, where vascular resources are limited. As available vessels gradually become unusable, patients are forced to choose other, riskier vascular access routes. Therefore, daily maintenance and monitoring of the fistula are crucial; otherwise, the probability of fistula failure increases. Once a fistula fails, the longer it remains unresponsive, the greater the physical burden on the patient.

[0004] However, existing fistula detection devices are usually wearable, which are bulky, complex to operate, inconvenient to carry and use in daily life, and not conducive to the continuous monitoring and management of fistulas. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention proposes a fistula monitoring device.

[0006] The technical solution adopted in this invention is a fistula monitoring device, comprising:

[0007] The shell, whose interior forms a first accommodating space;

[0008] A monitoring module is disposed at one end of the housing. The monitoring module is used to detect the blood flow velocity of the fistula and generate corresponding monitoring data.

[0009] A central control module is placed within the first accommodating space. The central control module receives the monitoring data and outputs the monitoring data or outputs result information generated based on the monitoring data.

[0010] Preferably, the listening module includes one or more of an ultrasonic component, a laser component, or a magnetic resonance component integrated on or detachably connected to the housing.

[0011] Preferably, the monitoring module includes an ultrasonic component, which includes an ultrasonic circuit and an ultrasonic probe. The ultrasonic circuit is signal-connected to the central control module and the ultrasonic probe, respectively, and the ultrasonic probe emits ultrasonic waves and receives reflected waves.

[0012] Preferably, the ultrasonic probe includes a probe housing, an ultrasonic transmitting end for emitting ultrasonic waves, and an ultrasonic receiving end for receiving reflected waves. One end of the housing has a first opening communicating with the first accommodating space. The ultrasonic probe is at least partially accommodated in the first opening. The ultrasonic transmitting end and the ultrasonic receiving end are both disposed on the side of the probe housing near the first accommodating space. The end face of the probe housing facing away from the first accommodating space is neither parallel nor perpendicular to the plane where the ultrasonic transmitting end is located. The end face of the probe housing facing away from the first accommodating space is parallel to the plane where the ultrasonic receiving end is located.

[0013] Preferably, the ultrasonic probe has an ultrasonic frequency range of 2-10MHz, and / or the ultrasonic probe supports dual-mode switching between pulse wave and continuous wave, and / or the ultrasonic probe has a beamwidth ≤2mm.

[0014] Preferably, the monitoring module includes a laser component, which includes a laser emitter and a photodetector that are respectively connected to the central control module via signals. The laser emitter is used to emit laser light, and the photodetector is used to receive scattered light.

[0015] Preferably, the wavelength of the laser emitter is selected from 633nm or 780-850nm, and the output power is 1-5mW; and / or

[0016] The laser emitter has a spectral linewidth ≤ 1 nm and a divergence angle ≤ 1 mrad; and / or

[0017] The laser emitter operates at a voltage of 3.3-5V and has a static current of ≤10mA.

[0018] Preferably, the photodetector is a photodiode with a responsivity ≥ 0.8 A / W and a dark current ≤ 1 nA; or the photodetector is a photomultiplier tube with an amplification factor ≥ 10⁶, a response speed ≥ 100 MHz, and a rise time ≤ 3 ns.

[0019] Preferably, it also includes an auscultation module, which is connected to or integrated into the housing, and is used to collect auscultation signals from the fistula and generate corresponding auscultation data.

[0020] Preferably, the auscultation module includes a stethoscope head, a stethoscope circuit, a transmission cable, and a connector connected in sequence. The auscultation module is plugged into the housing through the connector and is connected to the central control module through the connector. The stethoscope head includes a first cover, a first outer shell, and a first diaphragm. The first outer shell is made of metal, and the first diaphragm is disposed at the end of the first outer shell through the first cover and is used to receive the vibration signal of the fistula.

[0021] Preferably, the connector is a waterproof plug; and / or the first diaphragm is made of polyethersulfone or silicone rubber with a thickness between 0.05-0.2 mm and a vibration response frequency between 20-2000 Hz; and / or the surface of the first housing is provided with an anti-slip texture.

[0022] Preferably, the auscultation module includes a second housing, a second cover, a second diaphragm, and a microphone assembly. The second housing and the second cover form a second accommodating space. The second diaphragm is disposed at the end of the second housing through the second cover and is used to receive vibration signals from the fistula. The microphone assembly is located within the second accommodating space and is used to receive vibration signals transmitted by the second diaphragm. When the auscultation module is separated from the housing, the microphone assembly is connected to the central control module via a wireless communication signal. The surface of the second housing is provided with contacts. When the auscultation module is connected to the housing, the microphone assembly is electrically connected to the central control module through the contacts.

[0023] Preferably, the sound receiving assembly includes a stethoscope cavity, a guide tube, and a sound receiving element. The stethoscope cavity has openings at both ends. One end of the stethoscope cavity is covered with the second diaphragm, and the other end of the stethoscope cavity is connected to one end of the guide tube. The sound receiving element extends into the other end of the guide tube.

[0024] Preferably, the stethoscope module further includes a circuit board, the microphone is disposed on one side of the circuit board, and when the microphone extends into one end of the guide tube, the circuit board seals that end of the guide tube.

[0025] Preferably, the stethoscope cavity is made of plastic, and the inner wall of the stethoscope cavity is covered with an embedded layer, which is made of metal.

[0026] Preferably, the fistula monitoring device further includes a speaker, which is installed within the second accommodating space and electrically connected to the circuit board. A horn hole is provided at the end of the second housing away from the second diaphragm, and the speaker is positioned directly opposite the horn hole; and / or

[0027] The speaker is installed in the first accommodating space and electrically connected to the central control module. The housing is provided with a speaker hole, and the speaker is positioned directly opposite the speaker hole.

[0028] Preferably, the fistula listening device further includes an electrothermal module disposed within the first accommodating space, the electrothermal module being capable of heating at least one side of the housing.

[0029] Preferably, the fistula monitoring device further includes an angle sensor, which is used to detect and correct the angle between the direction of sound wave or laser emission and the direction of blood flow.

[0030] The present invention also discloses a fistula monitoring device, comprising:

[0031] The shell, whose interior forms a first accommodating space;

[0032] A monitoring module is disposed at one end of the housing. The monitoring module is used to detect the blood flow velocity of the fistula and generate corresponding monitoring data. The monitoring module includes one or more of the following: an ultrasound component, a laser component, or a magnetic resonance component integrated on or detachably connected to the housing.

[0033] Auscultation module, which is connected to or integrated into the housing, is used to collect auscultation signals from the fistula and generate corresponding auscultation data;

[0034] A central control module is placed within the first accommodating space. The central control module receives the monitoring data and auscultation data, and outputs the monitoring data or outputs result information generated based on the monitoring data.

[0035] Preferably, the auscultation module includes a second housing, a second cover, a second diaphragm, and a microphone assembly. The second housing and the second cover form a second accommodating space. The second diaphragm is disposed at the end of the second housing through the second cover and is used to receive vibration signals from the fistula. The microphone assembly is located within the second accommodating space and is used to receive vibration signals transmitted by the second diaphragm. When the auscultation module is separated from the housing, the microphone assembly is connected to the central control module via a wireless communication signal. The surface of the second housing is provided with contacts. When the auscultation module is connected to the housing, the microphone assembly is electrically connected to the central control module through the contacts.

[0036] The sound receiving assembly includes a stethoscope cavity, a guide tube, and a sound receiving element. The stethoscope cavity has openings at both ends. One end of the stethoscope cavity is covered with the second diaphragm, and the other end of the stethoscope cavity is connected to one end of the guide tube. The sound receiving element extends into the other end of the guide tube, and the guide tube is made of a soft sound-insulating material.

[0037] The stethoscope module also includes a circuit board, and the microphone is disposed on one side of the circuit board. When the microphone extends into one end of the guide tube, the circuit board seals that end of the guide tube.

[0038] The stethoscope cavity is made of plastic, and the inner wall of the stethoscope cavity is covered with an inner layer, which is formed by stamping or stretching a metal sheet.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The fistula monitoring device of this invention, through its reasonable internal structural layout, such as compactly placing the monitoring module and the central control module within the housing, effectively reduces the overall size compared to larger wearable fistula detection devices. Its compact shape makes it easier to carry, whether for medical staff moving between different wards or departments, or for patients to carry in their daily lives for fistula detection at any time, without causing too much burden. It facilitates rapid detection in various scenarios, making fistula detection a relatively easy and natural daily activity. This encourages patients to actively participate in the self-monitoring and management of their fistulas, ensuring continuous attention to the health status of the fistula. Medical staff can also track changes in the fistula's status more frequently, promptly identify potential problems, and provide more comprehensive and timely data support for the scientific management of fistulas.

[0041] 2. Wearable devices often involve complex functions and structures, leading to cumbersome operation and requiring professional training to master their use. In contrast, the fistula monitoring device of this invention features clearly defined components with logical connections. The ultrasound module, controlled by the central control module, enables the ultrasound head to transmit and receive ultrasound waves. Furthermore, the output process of the central control module is relatively intuitive, allowing users (whether medical personnel or patients with simple guidance) to easily understand and operate the device. This eliminates the need for extensive learning of complex procedures, enabling fistula detection and significantly improving efficiency.

[0042] 3. Existing wearable devices may not be convenient or efficient enough in terms of data storage, transmission, and analysis feedback. In this invention, the central control module can transmit monitored audio to a data center for storage and analysis via a mobile smart device. The analysis results can also be fed back to the user via a mobile smart device, such as a mobile app. This makes long-term archiving and review of fistula detection data, as well as timely adjustments to fistula management strategies based on analysis results (such as adjusting treatment plans and scheduling follow-up appointments), much more convenient, facilitating more refined and scientific continuous management of fistulas.

[0043] 4. The auscultation module provides an intuitive and cost-effective auxiliary monitoring method for fistula status assessment. It digitizes and data-drivens the doctor's experience-based auscultation process, enabling the objective recording and analysis of vascular sounds, an important clinical sign, to be corroborated with quantitative blood flow parameters. This enriches the information dimensions of fistula health assessment, while its modular design increases the device's functional flexibility and ease of use. Attached Figure Description

[0044] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0045] Figure 1 is a schematic diagram of the fistula monitoring device in one embodiment;

[0046] Figure 2 is an exploded view of a fistula listening device in one embodiment;

[0047] Figure 3 is a schematic diagram of the structure of the ultrasonic module in one embodiment;

[0048] Figure 4 shows the application scenarios of the ultrasonic module;

[0049] Figure 5 is a schematic diagram of the fistula monitoring device in one embodiment;

[0050] Figure 6 is a schematic diagram of the structure of the auscultation module in one embodiment;

[0051] Figure 7 is a schematic diagram of the fistula monitoring device in one embodiment;

[0052] Figure 8 is an exploded view of the auscultation module in one embodiment;

[0053] Figure 9 is a cross-sectional view of the auscultation module;

[0054] Figure 10 is an exploded view of a portion of the fistula listening device in one embodiment;

[0055] Figure 11 is a schematic diagram of the structure of the ultrasonic module in one embodiment;

[0056] Figure 12 is a schematic diagram of the data interaction architecture of a fistula monitoring device in one embodiment;

[0057] Figure 13 is a schematic diagram of the data interaction architecture of the fistula monitoring device in one embodiment.

[0058] 100. Housing; 101. Lower housing; 102. Upper housing; 103. Screen cover; 104. First button; 105. Central control module; 106. First battery; 107. Battery casing; 108. Heating element; 109. Speaker; 110. Second button; 111. Metal plate;

[0059] 200. Monitoring module; 201. Probe housing; 202. Ultrasonic transmitter; 203. Ultrasonic receiver; 204. Ultrasonic circuit;

[0060] 300. Stethoscope module; 301. First cover; 302. First outer shell; 303. First diaphragm; 304. Third outer shell; 305. Stethoscope circuit; 306. Transmission cable; 307. Connector;

[0061] 321. Second outer shell; 322. Speaker; 323. Second battery; 324. Circuit board; 325. Guide tube; 326. Stethoscope cavity; 327. Inner layer; 328. Second diaphragm; 329. Second cover; 330. Ear. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0063] In one embodiment, a fistula monitoring device is provided. This device is primarily used for non-invasive and convenient hemodynamic monitoring of arteriovenous fistulas (AVFs) in hemodialysis patients, aiming to detect abnormal signs such as fistula stenosis and thrombosis through routine monitoring, thereby assisting in fistula health management.

[0064] Please refer to Figures 1, 2 and 7. The fistula monitoring device in this embodiment mainly includes a housing 100, a monitoring module 200 and a central control module 105.

[0065] The housing 100 serves as the main structural component and external protective part of the entire device, forming a closed or semi-closed first accommodating space inside. The housing 100 is typically made of engineering plastics (such as ABS, PC), metal, or composite materials with a certain strength and rigidity. Its shape is designed as a cuboid, cylinder, or other ergonomic form for easy gripping by medical personnel and to fit snugly against the patient's fistula area. One end of the housing 100 has an operating area that can accommodate buttons, interfaces, and other components.

[0066] The monitoring module 200 is the core detection unit of the device, located at one end of the housing 100, facing the fistula being tested. Specifically, at least a portion of the detection components of the monitoring module 200 (such as the contact surface of the probe) are exposed outside the housing 100 to allow contact with the patient's skin at the fistula site. The monitoring module 200 is configured as a non-invasive detection unit to contact or be adjacent to the fistula skin surface, sensing hemodynamically related physical signals (such as sound wave reflection, light scattering, or Doppler shift) in real time, and converting the acquired physical signals into monitoring data in the form of electrical signals. The monitoring module 200 can integrate sensing elements and front-end signal conditioning circuitry to ensure high-fidelity acquisition of the original signal. During detection, the monitoring module 200 emits detection energy signals (such as ultrasound, laser, etc.) towards the target blood vessel area and receives signals reflected or scattered back by flowing blood. By analyzing the returned signals (e.g., calculating the Doppler shift), the monitoring module 200 can generate monitoring data corresponding to the current blood flow velocity in real time. The monitored data can be the original frequency-shifted electrical signal or a digitized flow rate value obtained through preliminary analog-to-digital conversion or calculation.

[0067] Referring to Figure 2, the central control module 105, serving as the control and data processing hub of the device, is housed within the first accommodating space inside the housing 100. The central control module 105 establishes a signal connection with the monitoring module 200, including wired or wireless connections, to receive monitoring data collected and transmitted in real time by the monitoring module 200. The central control module 105 includes at least a processor, a storage unit, and an output interface for receiving monitoring data from the monitoring module 200 and performing data processing, analysis, or forwarding operations. Based on preset algorithms or clinical rules, the central control module 105 can directly output the raw monitoring data or generate result information based on that data, such as blood flow velocity values, spectrograms, and abnormal indications, which can then be presented to the user through a display screen, audio broadcast, or wireless transmission.

[0068] The central control module 105 primarily functions in the following ways: First, processing the received monitoring data, such as filtering and noise reduction, signal enhancement, and numerical calculations; second, generating more clinically relevant results based on the processed monitoring data according to preset programs or algorithms, such as determining whether blood flow velocity is within the normal range, generating flow velocity-time curves, or providing status indicators such as "unobstructed" or "abnormal"; third, controlling the entire workflow of the device, such as responding to power-on and detection commands. Furthermore, the central control module 105 also integrates an output function, enabling it to output the aforementioned monitoring data or results generated based on the monitoring data to the user or external systems in some form. This output can be direct and local, or indirect and remote. For example, the central control module 105 can intuitively display blood flow velocity values ​​or waveforms by driving the display screen integrated on the housing 100; it can also play characteristic sounds or voice prompts representing blood flow status through the built-in speaker 109; in addition, the central control module 105 can also send data to external mobile smart devices (such as smartphones, tablets) or remote data centers through integrated or wired communication interfaces, such as USB, Bluetooth, Wi-Fi modules, for further analysis, storage or remote diagnosis.

[0069] The fistula monitoring device provided in this embodiment integrates the monitoring module 200 for detecting blood flow velocity and the central control module 105 for processing and outputting data into a single housing 100, achieving integration and miniaturization of the detection device. Its advantages are as follows: First, its compact structure and significantly smaller size compared to traditional desktop or large wearable detection devices make it convenient for medical personnel to carry for bedside examinations and for patients to perform daily self-monitoring in the home environment. Second, the operation process is simplified; users only need to place the device probe at the fistula location and start the detection; data acquisition, processing, and output are all automatically completed internally, lowering the barrier to entry. Finally, thanks to the data output capability of the central control module 105, the detection results can be easily viewed locally or transmitted and managed remotely, providing an efficient technical means for establishing long-term, continuous fistula health records and timely professional intervention, thereby helping to improve the long-term patency rate of arteriovenous fistulas and reduce the risks of dialysis treatment.

[0070] In one embodiment, referring to Figures 12 and 13, the central control module 105 can also transmit the monitored sound signal to a data center via a wired or wireless network connection through a mobile smart device. The data center is responsible for storing and analyzing the received sound data. The data center can store this sound data for a long time and in a large capacity, making it convenient to retrieve and view it at any time. At the same time, professional data analysis algorithms and software are used to deeply mine the characteristics and patterns of the sound data, such as analyzing the correlation between sound frequency, intensity, duration, and other elements and the specific condition of the fistula, aiming to extract valuable diagnostic information. The results obtained after analysis are transmitted back to the user via the network. The data transfer can be accomplished using mobile smart devices such as mobile phones. The mobile phone acts as an intermediary bridge, transmitting data from the server corresponding to the fistula monitoring device to the server. Finally, the server sends the analysis results back to the relevant application (app) on the mobile phone, allowing the user to conveniently view detailed and intuitive analysis conclusions, know the detection status, and corresponding diagnostic prompts through the mobile app.

[0071] In one embodiment, the listening module 200 includes one or more of an ultrasound component, a laser component, or a magnetic resonance component integrated into or detachably connected to the housing 100.

[0072] Specifically, the monitoring module 200, as a blood flow sensing unit, can be configured with different types of physical sensing modules according to clinical needs. The ultrasound component, based on the Doppler principle, emits ultrasound waves and receives reflected echoes caused by blood flow to obtain blood flow velocity information. The laser component, based on the laser Doppler effect, emits coherent laser light and detects the frequency shift of scattered light within tissue to achieve non-contact measurement of microcirculatory blood flow. The magnetic resonance component receives or interacts with phase-contrast magnetic resonance blood flow data from an external magnetic resonance imaging system to provide high-precision reference values. These components can be individually integrated into one end of the housing 100 or arbitrarily combined to adapt to clinical scenarios with different depths, flow velocity ranges, or monitoring accuracies.

[0073] The connection methods between the components and the housing 100 include, but are not limited to, mechanical snap-fit, threaded interface, magnetic structure, or electrical contact plug-in. These methods support both fixed, integrated designs to enhance structural stability and detachable, modular configurations for easy replacement, calibration, or sterilization. When a detachable connection is used, the monitoring module 200 and the central control module 105 can transmit signals via electrical contact terminals or near-field wireless communication, ensuring data integrity and operational flexibility.

[0074] By employing a combination of one or more of the aforementioned monitoring components, the fistula monitoring device of this embodiment can achieve multimodal blood flow monitoring on a single device platform, taking into account the detection needs of superficial and deep blood vessels, as well as high flow velocity and low perfusion states. This significantly improves the applicability, robustness, and clinical diagnostic value of the device, while also providing a hardware foundation for subsequent multi-source data fusion analysis.

[0075] In one embodiment, the monitoring module 200 includes an ultrasound component. The ultrasound circuit establishes signal connections with the central control module 105 and the ultrasound probe, respectively, to drive the ultrasound probe to emit ultrasound waves and process the reflected echo signals received by the ultrasound probe to generate monitoring data characterizing the blood flow status.

[0076] This embodiment utilizes an ultrasound component to instantly capture dynamic changes in blood flow velocity and rapidly provide numerical feedback, effectively supporting immediate bedside assessment and decision-making. Its operation is extremely convenient, requiring no complex pre-treatment; the probe can be directly placed against the body surface for measurement, with low requirements for the testing environment. Furthermore, its equipment and testing costs are low, making it suitable for large-scale screening and repeated patient measurements. In addition, ultrasound does not cause ionizing radiation damage to human tissues, possessing high safety, and can be used for long-term safety monitoring of special populations such as pregnant women and children.

[0077] Further, referring to Figure 3, the ultrasound probe includes a probe housing 201, an ultrasound transmitter 202, and an ultrasound receiver 203. The ultrasound transmitter 202 is configured to convert electrical signals into ultrasound waves and radiate them towards the fistula region; the ultrasound receiver 203 is configured to receive reflected ultrasound waves modulated by blood flow and convert them into electrical signals, which are then output to the ultrasound circuit 204 (see Figure 11). One end of the housing 100 has a first opening communicating with an internal first accommodating space, and the ultrasound probe is at least partially embedded within this first opening so that the detection surface faces the external measured area.

[0078] Both the ultrasonic transmitter 202 and the ultrasonic receiver 203 are arranged on the side of the probe housing 201 near the first accommodating space, facilitating electrical connection with the ultrasonic circuit 204 housed within the housing 100. Further, referring to Figure 4, the outer surface (i.e., the probe surface in contact with the skin) formed at the end of the probe housing 201 away from the first accommodating space is inclined in a non-parallel and non-perpendicular manner to the plane containing the ultrasonic transmitter 202, thereby optimizing the incident angle of the ultrasonic beam and reducing strong interface reflection interference caused by perpendicular incident light. Simultaneously, the probe surface is parallel to the plane containing the ultrasonic receiver 203, ensuring that the received sound field is aligned with the normal of the probe surface, thus improving the capture efficiency and signal-to-noise ratio of the echo signal.

[0079] Through the above structural layout, this embodiment achieves reasonable separation and directional optimization of the transmitting and receiving acoustic paths without increasing the probe volume, effectively suppressing near-field clutter interference, enhancing sensitivity to low-velocity blood flow signals, and improving the accuracy and stability of fistula blood flow monitoring.

[0080] In one embodiment, the ultrasonic probe has an ultrasonic frequency range of 2-10MHz, and / or the ultrasonic probe supports dual-mode switching between pulse and continuous waves, and / or the ultrasonic probe has a beamwidth ≤2mm.

[0081] In one embodiment, the ultrasound probe operates at frequencies ranging from 2 MHz to 10 MHz. Specifically, the selection of the ultrasound frequency range balances penetration depth and spatial resolution: a lower frequency of 2–5 MHz is used to enhance tissue penetration when monitoring deep fistula vessels; while a higher frequency of 5–10 MHz is selected to obtain better axial and lateral resolution when assessing superficial arteriovenous fistulas. This wideband design allows a single probe to be adapted to different anatomical locations and patient body types, improving the versatility of the device.

[0082] Furthermore, the ultrasound probe supports a dual-mode switching mechanism for pulsed wave (PW) and continuous wave (CW). In pulsed wave mode, the system achieves precise velocity measurement of blood flow at specific depths through time gating, suitable for assessing focal stenosis or complex shunts. In continuous wave mode, the system can detect high-speed blood flow without distance limitations, effectively avoiding spectral aliasing, and is suitable for monitoring peak flow velocity in high-flow fistulas. The two modes can be selected by the user or automatically switched by the central control module according to clinical needs, enhancing dynamic monitoring capabilities.

[0083] Furthermore, the ultrasound probe is acoustically focused, ensuring its effective beam width is controlled within 2mm. This narrow beam significantly improves lateral resolution and reduces signal interference from adjacent tissues, thereby enabling more accurate localization of fistula vessels and separation of their blood flow signals. This is particularly beneficial for monitoring small-diameter or tortuous vessels.

[0084] The synergistic effect of these technical features significantly improves the adaptability, accuracy, and reliability of ultrasound monitoring without increasing equipment complexity, providing a high-quality Doppler signal basis for fistula functional assessment.

[0085] In practical use, medical coupling gel is first applied to the fistula site to reduce air gaps and enhance ultrasound transmission efficiency. Then, the ultrasound probe is placed over the fistula surface, maintaining stable contact. The probe emits ultrasound waves of a specific frequency (frequency...). When sound waves pass through flowing blood, a Doppler shift (f) occurs due to the movement of red blood cells. dThis is the difference between the received signal frequency and the transmitted signal frequency. According to the formula:

[0086]

[0087] Where: v is the blood flow velocity (unit: m / s); f d The frequency of the received sound wave is the difference between the received frequency and the transmitted frequency, i.e., the Doppler shift; c is the speed of sound in the medium, which is about 1540 m / s in human blood. θ is the frequency of the sound wave emitted by the ultrasound probe; θ is the angle between the direction of ultrasound emission and the direction of blood flow, and cosθ is used to correct the effect of the angle on the frequency shift.

[0088] The angle θ can be detected and dynamically calibrated in real time by the device's built-in gyroscope or tilt sensor, ensuring accurate flow velocity calculation even under different probe placement orientations. Known parameters c, and real-time f d With θ, the system can instantly calculate the current blood flow velocity v.

[0089] To further improve measurement accuracy, considering factors such as individual differences, tissue characteristics, and instrument drift, a calibration mechanism driven by clinical big data can be introduced. Specifically, by collecting a large amount of blood flow data under standard conditions (such as those validated by PC-MRI), an error model is established, and a calibration quantity V is generated. t The final calibrated blood flow velocity V0 is calculated using the following formula: V0 = v + V t V t The calibration values ​​are derived from analysis of a large clinical database and are statistically significant and representative.

[0090] The calibration process can be preset before leaving the factory or automatically updated during use based on the user group, thereby effectively reducing system errors and improving the clinical reliability of measurement results.

[0091] Through the above technical solution, this embodiment achieves high-precision, real-time, and portable monitoring of fistula blood flow velocity, which is suitable for scenarios such as arteriovenous fistula function assessment, stenosis early warning, and postoperative follow-up, and has the advantages of miniaturization, low cost, and high adaptability.

[0092] In one embodiment, the monitoring module includes a laser assembly, which comprises two core components: a laser emitter and a photodetector. Both are connected to a central control module housed within the first accommodating space of the housing via signal wires and are integrated at one end of the housing to form an integrated detection terminal. During operation, the laser emitter, driven by an excitation signal from the central control module, emits a laser beam towards the fistula area. This laser penetrates the skin and superficial soft tissue, acting on the blood flow within the fistula. Red blood cells in the blood scatter the laser beam, forming scattered light carrying blood flow velocity information. The photodetector receives this scattered light and converts it into monitoring data in the form of electrical signals, which is then synchronously transmitted to the central control module. The central control module then performs data reception and subsequent output processing.

[0093] The technical effects of this embodiment are specifically manifested in the following aspects: First, the laser component, relying on the detection logic of laser Doppler, has high spatiotemporal resolution and can detect blood flow velocity in fistula vessels with a diameter of micrometers. The temporal resolution can reach the millisecond level, effectively capturing the instantaneous flow velocity fluctuations of fistula blood flow and improving the precision of monitoring data. Second, it is suitable for microcirculation fistula scenarios in areas such as skin. For areas that are difficult to effectively cover by traditional monitoring technologies, it can achieve accurate blood flow velocity detection, expanding the applicability of the device. Third, the detection end of the laser component supports non-invasive patch-type or minimally invasive fiber optic probe-type layouts, which can adapt to the fistula detection needs of different local tissues, enhance the flexibility of the device's scenario adaptation, and the detection process does not require an additional coupling medium, simplifying the operation process.

[0094] In one embodiment, the laser emitter uses a wavelength of 633nm or 780-850nm, where 633nm is suitable for superficial skin microcirculation detection and 780-850nm is suitable for deep tissue penetration, optimizing the absorption and scattering characteristics of biological tissues to the laser. The output power is set to 1-5mW, with power fluctuations controlled within ±5% to ensure the stability of blood flow signal acquisition. The spectral linewidth is ≤1nm to suppress frequency noise, and the divergence angle is ≤1mrad to achieve high-precision beam focusing. The operating voltage is 3.3-5V, and the quiescent current is ≤10mA to meet the requirements of low-power portable devices. The peak response wavelength of the photodetector deviates from the laser emitter wavelength by ≤±10nm to ensure spectral matching of the received optical signal. When a photodiode is used, its responsivity is ≥0.8A / W and dark current is ≤1nA, providing high sensitivity and signal capture capability in ultra-low noise environments. When a photomultiplier tube is used, its amplification factor is ≥10. 6With a response speed ≥100MHz and a rise time ≤3ns, it achieves high-gain amplification and millisecond-level dynamic response of weak scattered light signals. The synergistic effect of these parameters significantly improves the signal-to-noise ratio (≥30dB), temporal resolution (≤1ms), and spatial resolution (≤10μm) of laser Doppler blood flow monitoring, meeting the requirements for accurate quantification of dynamic changes in microcirculatory blood flow and providing a highly reliable data foundation for the functional assessment of fistula microvessels.

[0095] During fistula monitoring, the patient is placed in an environment free from strong light interference. The detection end of the laser component is directly placed over the fistula site, eliminating the need for auxiliary consumables such as coupling agents or drag-reducing agents, simplifying the operation. Based on the laser Doppler principle, the laser emitter emits laser light into the fistula area. Red blood cells in the bloodstream scatter the incident laser light, and the photodetector receives this scattered light and converts it into monitoring data in the form of electrical signals, which is synchronously transmitted to the central control module. The central control module uses the Doppler frequency shift f in the monitoring data... d Combining the angle θ between the incident laser and the direction of blood flow, and the laser wavelength λ in human soft tissue (obtained by converting the laser vacuum wavelength λ0 to the refractive index n of human soft tissue), the formula is used to...

[0096]

[0097] Calculate blood flow velocity v, f d Cosθ is the Doppler frequency shift (Hz), the frequency difference between the scattered light and the incident light, and is the signal directly detected by the device; v is the blood flow velocity (m / s), i.e., the velocity of the red blood cells being measured; θ is the angle between the incident laser and the direction of blood flow. The smaller the angle, the larger the cosθ value, the stronger the frequency shift signal, and the higher the measurement accuracy; λ is the wavelength (m) of the laser in the measurement medium (human soft tissue), and the conversion relationship is... (λ0 is the wavelength of the laser in vacuum, and n is the refractive index of human soft tissue, with a conventional value of n≈1.33).

[0098] To accurately measure the value of v, the calibration value V1 generated from clinical big data is called. After optimizing the measurement accuracy using the calibration formula V0=v+V1, the corresponding monitoring data or result information is output.

[0099] The miniaturized design of this laser component adapter allows for targeted detection of superficial vascular fistulas; the elimination of auxiliary consumables simplifies the operation process and lowers the barrier to entry; the low-cost hardware architecture is well-suited to the cost requirements of primary healthcare and home monitoring scenarios; and by adjusting the probe angle to reduce the θ value, the frequency shift signal can be enhanced, and combined with clinical big data calibration, the measurement accuracy of fistula blood flow velocity is effectively improved.

[0100] In one embodiment, the monitoring module includes a magnetic resonance component based on magnetic resonance phase-contrast imaging technology. This component, serving as a dedicated detection unit working in conjunction with an external magnetic resonance imaging device, comprises a gradient coil and a radio frequency (RF) coil, both of which establish signal connections with the central control module within the device. During operation, the device is placed within the main magnetic field of the magnetic resonance imaging equipment. The gradient coil applies a precisely controllable gradient magnetic field, such as a three-dimensional gradient magnetic field, in a specific direction to encode the phase of hydrogen protons in flowing blood. Simultaneously, the RF coil emits excitation pulses and receives resonance signals returned by hydrogen protons from the blood flow region; these signals already contain phase change information caused by blood flow motion. The RF coil converts the received analog resonance signal into an electrical signal, which is then transmitted to the central control module for acquisition and preliminary processing. The central control module can further transmit this phase information to the host of the magnetic resonance system or to an external server via a communication unit. Utilizing the proportional relationship between phase difference and flow velocity, a precise two-dimensional or three-dimensional blood flow velocity distribution map is ultimately calculated.

[0101] The advantages of this embodiment are that it is not limited by depth; for the detection of flow velocity in deep blood vessels (such as intracranial vessels and major blood vessels of the heart), there is no need to consider tissue penetration issues. It achieves non-invasive, absolute quantitative measurement of blood flow velocity in fistulas and adjacent deep vessels, and is not limited by acoustic or optical penetration depth. It can provide high spatial resolution anatomical and functional information, providing crucial imaging and hemodynamic data for preoperative assessment and accurate postoperative follow-up in complex cases. It offers wide-range, precise quantification, allowing simultaneous measurement of flow velocity in vessels at multiple sites with high quantitative accuracy, supporting the calculation of derived parameters such as blood flow rate and blood flow shear force. It is free of ionizing radiation, avoiding radiation damage while achieving precise quantification, making it suitable for long-term follow-up flow velocity monitoring studies.

[0102] In one embodiment, specific performance characteristics of the gradient coil in the magnetic resonance imaging (MRI) assembly are defined. The gradient coil is configured such that its gradient intensity is adjustable over a wide range from 0.1 mT / m to 50 mT / m, thereby adapting to the precise phase encoding requirements of different scenarios, from slow venous blood flow to high arterial blood flow. Its gradient switching speed is not less than 100 T / (m·s), and the switching time is controlled within 1 millisecond. This effectively reduces signal distortion caused by blood flow motion during gradient magnetic field switching, ensuring the temporal resolution and accuracy of dynamic flow velocity measurement. Furthermore, within the target vessel measurement area, the uniformity deviation of the gradient magnetic field generated by the gradient coil does not exceed ±1%, ensuring the consistency of phase encoding across the entire measurement cross-section and providing a foundation for obtaining accurate and reliable quantitative blood flow velocity data.

[0103] Furthermore, the performance of the radiofrequency coil is specified. Its spatial resolution reaches at least 0.5mm × 0.5mm × 1mm, enabling clear imaging of the fistula and its surrounding small vascular structures, providing precise anatomical localization for flow velocity measurement. Simultaneously, the radiofrequency power deposition of the radiofrequency coil is strictly limited to below 4W / kg (the average value for the entire human body), complying with international safety standards and ensuring patient safety during prolonged or repeated measurements, avoiding the risk of tissue overheating.

[0104] Furthermore, the magnetic resonance assembly also includes a main magnetic field generating unit for producing a stable static magnetic field. The main magnetic field strength of this unit is suppressed to within ±10 Ω per hour during time fluctuations. -6 The magnetic field uniformity deviation within the target measurement area is controlled within ±5 ppm. This high level of temporal stability and spatial uniformity is key to ensuring the baseline stability of hydrogen proton phase difference measurement, avoiding the introduction of additional noise and systematic errors, and ultimately enabling blood flow velocity calculation based on the phase contrast principle to have extremely high repeatability and quantitative accuracy.

[0105] Using phase contrast imaging (PC-MRI), a three-dimensional gradient magnetic field is applied, causing hydrogen protons in the bloodstream to shift in phase due to their motion, while protons in stationary tissues do not change in phase. The phase difference is proportional to the blood flow velocity. It is applicable to blood vessels in all parts of the body (arteries, veins, deep vessels, including microvessels), is non-invasive, has high spatial resolution, and can simultaneously measure vascular cross-section, flow velocity, and blood flow, making it suitable for precision medical imaging and vascular function assessment scenarios.

[0106] The blood flow velocity formula (phase difference-velocity correlation formula) is as follows:

[0107]

[0108] Where ν is the blood flow velocity (m / s), which is the target measurement value; It is the phase difference (rad) between moving protons and stationary tissue protons, which is directly detected and decoded by MRI equipment; It is the velocity coding gradient direction coefficient (dimensionless), which is used when encoding along the blood flow direction. =1, directional deviation will reduce measurement accuracy; It is the gyromagnetic ratio of hydrogen protons (a fixed constant), with values ​​ranging from... ≈42.58MHz / T; G is the flow rate coding gradient intensity (T / m), which can be adjusted according to blood flow velocity (high-speed blood flow requires a high gradient, and low-speed blood flow requires a low gradient); It is the application time (s) of the flow velocity encoding gradient. The application time needs to be adapted to the blood flow cycle to avoid signal ambiguity.

[0109] In one embodiment, the fistula monitoring device further includes an auscultation module 300. This auscultation module 300, as an independent physiological signal acquisition unit, can be physically connected to the housing 100 or directly integrated into the interior or surface of the housing 100. Its core function is to acquire vascular sounds at the fistula site through mechanical contact, i.e., the vibration and sound signals generated when blood flows through specific structures such as fistula stenosis, bends, or anastomoses, and convert this physical vibration into corresponding electrical signals, thereby generating monitoring data on the auscultatory characteristics of the fistula. The auscultation module 300 establishes a signal connection with the central control module 105 inside the housing 100 via wired or wireless means, transmitting the acquired monitoring data to the central control module 105 in real time for processing, analysis, or fusion analysis with blood flow velocity data from the monitoring module. The advantage of this solution is that it provides an intuitive and low-cost auxiliary monitoring method for fistula status assessment. It digitizes and digitizes the "auscultation" process that doctors rely on experience, enabling the objective recording and analysis of vascular sounds, an important clinical sign, to be corroborated with quantitative blood flow parameters. This enriches the information dimensions of fistula health assessment, while its modular design increases the device's functional flexibility and ease of use.

[0110] In one embodiment, referring to Figures 5 and 6, the stethoscope module 300 is configured as a wired external module that can be used independently of the housing 100. It includes a stethoscope head, a stethoscope circuit 305, a transmission cable 306, and an electrical connector 307 located at the end of the transmission cable 306, connected in sequence. The stethoscope module 300 is mechanically and electrically connected to a pre-set corresponding port on the housing 100 via the connector 307 in a pluggable manner, thereby establishing a stable wired signal connection with the central control module 105 inside the housing 100 through the connector 307. The stethoscope circuit 305 is housed within a third housing 304, which protects the stethoscope circuit 305.

[0111] The stethoscope head, serving as a signal acquisition terminal, comprises a first housing 302, a first diaphragm 303, and a first cover 301 for fixing the diaphragm. The first housing 302 is made of metal, providing not only the necessary structural strength and durability, but also leveraging the inherent acoustic properties of metal to more efficiently conduct and retain the subtle mechanical waves generated by vascular vibrations. The first diaphragm 303, made of a flexible acoustic-sensitive material, is tensioned and sealed at the end opening of the first housing 302 via the first cover 301. In use, the first diaphragm 303 is placed on the skin surface of the patient's fistula site, directly sensing and receiving mechanical vibration signals excited by changes in subcutaneous hemodynamics. These vibration signals are converted into mechanical vibrations by the diaphragm and transmitted through the first housing 302 to the internal stethoscope circuitry 305. The stethoscope circuit 305 typically includes a preamplifier and a filter, which are used to convert weak mechanical vibration signals into electrical signals and perform preliminary conditioning. The signals are then transmitted via a transmission cable 306 and a connector 307 to the central control module 105 inside the housing 100 for further processing and analysis.

[0112] The beneficial effect of this embodiment is that it provides a wired auscultation solution with a reliable structure and stable signal transmission. The metal-cased auscultator head ensures the sensitivity of signal acquisition and the feel of traditional auscultation, while the pluggable modular design allows the auscultation function to be activated as needed, enhancing the flexibility of the device and facilitating independent maintenance or replacement of each component.

[0113] In one embodiment, the components of the auscultation module 300 are further optimized and defined to improve its clinical usability, environmental adaptability, and signal acquisition performance.

[0114] The length of the transmission cable 306 is set between 50 cm and 150 cm. This length range is optimized to provide sufficient operational freedom, allowing medical staff to operate flexibly around the patient at the bedside, while effectively avoiding tangling, signal attenuation, or inconvenience caused by excessive cable length, thus achieving a balance between operational convenience and signal transmission stability.

[0115] The connector 307 is configured as a waterproof plug. This design enhances the physical protection of the connection interface between the stethoscope module 300 and the main housing 100, enabling it to withstand liquid splashes or humid environments that may be encountered in daily use. It effectively prevents poor contact, short circuits, or corrosion caused by liquid intrusion, thereby improving the reliability and durability of the entire device in complex medical environments.

[0116] The stethoscope diaphragm is preferably made of polyethersulfone or silicone rubber. Both materials offer good biocompatibility, flexibility, and long-term stability. The diaphragm thickness is precisely controlled between 0.05 mm and 0.2 mm, allowing its vibration response frequency to cover a range of 20 Hz to 2000 Hz. This combined design ensures the diaphragm's high sensitivity to weak vascular vibration signals from the human skin surface, while accurately transmitting typical frequency components encompassing clinically important vascular sounds (such as murmurs and thrills), achieving high-fidelity acquisition of auscultation signals.

[0117] The surface of the first housing 302 is textured with an anti-slip pattern. This design significantly increases the coefficient of friction when the operator holds the stethoscope head, preventing accidental slippage upon contact with skin coupling gel or sweat, thus improving operational stability and safety. Simultaneously, the wall thickness of the first housing 302 is limited to between 1.5 mm and 3 mm. This thickness range ensures sufficient structural strength to protect the internal space and maintain the stability of the acoustic cavity while also meeting the overall lightweight requirements of the component, resulting in a better grip on the stethoscope head and reducing operator hand fatigue.

[0118] In another embodiment, referring to Figures 7 and 8, an integrated auscultation module 300 with a dual connection mode is provided. The module mainly includes a second housing 321, a second cover 329, a second diaphragm 328, and a sound-receiving assembly. The second housing 321 and the second cover 329 cooperate to form a substantially enclosed second accommodating space. The second diaphragm 328 is fixed and tensioned at one end of the second housing 321 via the second cover 329, and its function is to directly contact the patient's skin to receive mechanical vibration signals generated at the fistula site.

[0119] The microphone assembly, as a complete signal conversion unit, is housed within the second accommodating space. It receives the vibration signals captured and transmitted by the second diaphragm 328 and converts them into corresponding electrical signals. A key feature of this embodiment is its flexible connection method: when the stethoscope module 300 is used as an independent component physically separated from the housing 100, its integrated wireless communication module (part of the microphone assembly) activates, enabling the microphone assembly to establish a signal connection with the central control module 105 inside the housing 100 via wireless communication protocols such as Bluetooth and Wi-Fi, achieving wireless data transmission. Furthermore, exposed electrical contacts are provided on the surface (e.g., bottom or side) of the second housing 321. When the user physically connects the stethoscope module 300 to the housing 100 via a specific slot or base, these contacts can precisely contact the corresponding connector inside the housing 100, allowing the microphone assembly to establish a stable and high-speed electrical connection with the central control module 105 via this wired contact connection method. This also allows for charging of the second battery 323 within the stethoscope module 300.

[0120] The beneficial effect of this solution is that it provides a stethoscope module 300 that can flexibly switch between "wireless standalone use" and "wired integrated use" modes. The wireless mode offers great operational freedom and convenience, making it particularly suitable for flexible bedside examinations; while the wired contact connection mode provides more stable signal transmission and synchronous charging capabilities, and may enable tighter functional integration with the main unit. This dual-mode design significantly enhances the adaptability and user-friendliness of the entire fistula listening device.

[0121] In one embodiment, the auscultation module 300 further includes a status sensor. The status sensor is integrated on the second housing 321 or circuit board 324 of the auscultation module 300 and is signal-connected to a control unit on the circuit board inside the auscultation module 300 or directly to the central control module inside the housing 100.

[0122] The status sensor is configured to perform dual status sensing functions: firstly, to sense the physical connection between the auscultation module 300 and the housing 100, i.e., to determine whether the two are in an integrated state of mechanical docking and electrical connection; secondly, to sense whether the auscultation module 300 itself is in a state of readiness for auscultation work, in contact with the surface of the human body being tested. The status sensor may include, but is not limited to: connector contact sensors for detecting the continuity of electrical connections, Hall effect sensors or microswitches for detecting physical engagement, and capacitive proximity sensors, pressure sensors, or infrared sensors for detecting human body contact.

[0123] The control logic of the stethoscope module 300 is configured to respond to the sensing signal of the status sensor. Specifically, when the status sensor detects that the stethoscope module 300 is in contact with the human body surface (i.e., in a stethoscope state), the control unit or central control module will automatically generate or send an activation signal, waking the stethoscope module 300 from a low-power standby state and activating its core functional modules such as the sound receiving component and signal conditioning circuit, thereby entering the formal working state and beginning to collect stethoscope signals. Conversely, when contact is detected to have ceased, the stethoscope module can automatically or after a delay return to the standby state.

[0124] The beneficial effects of this embodiment are that by introducing intelligent state perception and automatic control mechanisms, the user experience and energy efficiency management of the device are significantly improved. Automatic human contact detection enables intelligent operation of "pick up and use, put down and stop," avoiding the tediousness of manual switching and effectively preventing energy waste caused by forgetting to turn it off. Simultaneously, combined with the perception of the connection status with the host, the system can more intelligently manage data paths and power modes (e.g., prioritizing wired communication and charging when connected, and enabling wireless communication and the internal battery when used independently), thereby optimizing the overall system's workflow, reliability, and battery life.

[0125] Preferably, the outer sides of the second housing 321 are integrally formed or fixedly connected with symmetrically distributed protrusions, which can be configured as ear-shaped structures 330 for easy gripping and positioning. The status sensor, such as a capacitive sensor for detecting human contact or a Hall sensor for detecting docking with the housing 100, is disposed within the internal cavity of the ear-shaped structure 330. This arrangement brings the sensor closer to the typical contact area of ​​the user's fingers when gripping the device or the alignment point when docking with the host, thereby improving the sensitivity and accuracy of status sensing.

[0126] Furthermore, electrical contacts (e.g., charging springs) for charging and / or wired signal transmission provided on the second housing 321 are also preferably arranged on the end face of the ear portion 330. This end face serves as the primary docking guide and contact plane when the stethoscope module 300 mates with the corresponding base or slot on the housing 100.

[0127] The beneficial effects of this solution lie in its efficient use of space and physical integration of functions by centrally arranging key functional components (status sensors and electrical contacts) within a specially designed ear structure. This ear structure not only enhances the grip and operational stability, but its end face also serves as a reliable electrical interface plane, ensuring connection stability and signal integrity during engagement. Simultaneously, the built-in status sensor design allows for more direct and accurate detection of user grip or engagement status, providing reliable and timely status input for the stethoscope module's intelligent wake-up, mode switching, and power management, thus optimizing the overall smoothness and energy efficiency of human-computer interaction.

[0128] In a further embodiment, the specific structure of the sound-receiving component inside the stethoscope module 300 has been optimized. Referring to Figure 9, the sound-receiving component mainly includes a stethoscope cavity 326, a guide tube 325, and a sound-receiving element. The stethoscope cavity 326 is a cavity structure with a specific shape and openings at both ends. One opening is covered and sealed by the second diaphragm 328, allowing the vibrations captured by the second diaphragm 328 to form acoustic resonance within the stethoscope cavity 326; the other opening is connected to one end of the guide tube 325. The guide tube 325 serves as an acoustic channel, with the other end into which the sound-receiving element extends. This structure establishes a complete and controlled acoustic signal transmission path from the second diaphragm 328, through the stethoscope cavity 326, the guide tube 325, to the sound-receiving element, aiming to efficiently and faithfully guide and concentrate mechanical vibrations to the electroacoustic conversion element. The guide tube 325 can be made of a soft sound-insulating material.

[0129] Furthermore, the stethoscope module 300 also includes a circuit board 324, on which the microphone or similar receiver is mounted. When assembled, the circuit board 324 with the receiver is positioned so that the sensing portion of the receiver precisely extends into the end opening of the guide tube 325. Simultaneously, the circuit board 324 itself (or in conjunction with a sealing ring) tightly seals the end opening of the guide tube 325, thus forming a essentially sealed acoustic cavity together with the stethoscope cavity 326 and the guide tube 325. This design not only secures the receiver but, more importantly, effectively isolates external ambient noise from intruding from the rear end of the guide tube 325, ensuring the purity of the acquired sound signal.

[0130] Furthermore, the main body of the stethoscope cavity 326 is made of plastic to achieve lightweight and cost control. To improve its acoustic performance, an embedded layer 327, made of metal, is firmly coated on the inner wall of the plastic stethoscope cavity 326. This composite structure allows the stethoscope cavity 326 to combine the molding and processing convenience of plastic with the excellent acoustic properties of metal (such as higher acoustic impedance and better resonance characteristics), enabling it to more effectively conduct and maintain the specific frequency of vascular sounds introduced by the diaphragm, suppress unnecessary intracavitary acoustic energy loss and distortion, thereby ultimately improving the overall sensitivity and signal-to-noise ratio of the auscultation signal.

[0131] The guide tube 325 can be made of a soft sound-insulating material (such as silicone, rubber, or foamed polymer). This design allows the guide tube 325 to effectively conduct sound waves while absorbing and damping mechanical vibration interference transmitted from the outside to the tube wall using its soft properties, and blocking the intrusion of ambient air noise with its sound-insulating properties, thereby providing good passive noise reduction and acoustic isolation for auscultation signals at the physical channel level.

[0132] Furthermore, the inner layer 327 covering the inner wall of the stethoscope cavity 326 can be pre-formed into a specific shape using a metal sheet through plastic forming processes such as stamping or stretching, and then embedded or adhered to the inner surface of the plastic stethoscope cavity 326. Using stamping or stretching processes allows for the efficient and precise manufacture of metal lining components with matching shapes and uniform thickness at a lower cost, ensuring a tight and stable bond between the inner layer 327 and the plastic cavity, and facilitating the implementation of complex cavity surface designs, thereby optimizing acoustic resonance characteristics.

[0133] In one embodiment, the fistula monitoring device also integrates a sound output function. Specifically, a speaker 322 is directly mounted inside the second accommodating space of the auscultation module 300. The speaker 322 is electrically connected to a circuit board 324 disposed in the second accommodating space and is controlled by an audio drive circuit on the circuit board 324. A dedicated horn hole is provided on the second housing 321 at the end away from the second diaphragm 328. The sound-producing unit of the speaker 322 is oriented so that its front is precisely aligned with and adjacent to the horn hole. This configuration allows the auscultation module 300 to function as an independent audio playback unit when operating independently, directly playing the acquired vascular sounds or prompts from the central control module 105, providing the user with immediate and clear auditory feedback.

[0134] In other embodiments, the sound output function is integrated into the main body of the device. Specifically, the speaker 109 is installed in a first accommodating space inside the housing 100 and is directly electrically connected to the central control module 105, which serves as the control core, and is uniformly driven and controlled by the central control module 105. A speaker hole is also provided at a corresponding position (e.g., side or end face) on the housing 100. The speaker 109 is oriented so that its sound-emitting surface faces the speaker hole on the housing 100. This integrated design unifies the sound output function within the main housing 100. Regardless of the detection module used by the device (ultrasound, laser, or auscultation), all audio prompts, alarms, or vascular sound playback are output through the same speaker 109, achieving structural compactness and unified control, and ensuring optimal sound propagation path, effectively improving volume and sound quality.

[0135] In one embodiment, the housing 100 includes an upper housing 102 and a lower housing 101 that can be snapped together. Both the upper housing 102 and the lower housing 101 can be approximately rectangular, with regular and simple shapes, facilitating processing, manufacturing, and assembly. The first opening is formed at the connection between the upper housing 102 and the lower housing 101. This structure is relatively stable and easy to process, ensuring the accuracy and quality of the opening. It also provides a suitable position for the installation of the ultrasonic probe, allowing the ultrasonic probe to be accurately embedded in the opening and effectively contact the external environment to achieve the functions of ultrasonic wave transmission and reflected wave reception.

[0136] In one embodiment, the upper shell 102 has a second opening, and the lower shell 101 has a speaker hole. The central control module 105 includes a central control circuit, a display screen and a speaker 109 respectively connected to the central control circuit, and an ultrasonic circuit connected to the central control circuit. The central control circuit interacts with an external mobile device via a wireless communication interface. The display screen is embedded in the second opening, and the central control circuit and speaker 109 are placed in a first accommodating space, with the speaker 109 positioned directly opposite the speaker hole.

[0137] The second opening in the upper shell 102 provides a mounting position for the display screen. The display screen is fixed in the second opening by embedding, allowing it to intuitively display information to the user. The display screen is connected to the central control circuit and can receive various data output by the central control circuit, such as ultrasound test results, parameter setting information, equipment status, etc., and present them to the user in a visual way, making it convenient for the user to understand the working status of the equipment and the detection status of the fistula.

[0138] The speaker hole on the lower housing 101 corresponds to the speaker 109 placed in the first accommodating space. The speaker 109 is connected to the central control circuit and is used to convert the audio signal processed by the central control circuit into sound output. For example, during ultrasonic testing, the speaker 109 may emit a specific prompt tone to inform the user of the start, end, or abnormal situation of the test; or during data interaction, when receiving instructions or feedback information from an external mobile device, the speaker 109 will emit a corresponding sound to remind the user.

[0139] The central control circuit, as the core of the central control module 105, not only connects to the display screen and speaker 109, but also establishes a signal connection with the ultrasound circuit. It can receive ultrasound detection data transmitted by the ultrasound circuit and perform further processing, analysis, and integration. Simultaneously, the central control circuit has a wireless communication interface, enabling data interaction with external mobile devices (such as smartphones and tablets) to achieve data transmission and sharing. For example, ultrasound detection data can be sent to mobile devices for more detailed analysis, storage, or remote diagnosis. It can also receive control commands from mobile devices to remotely adjust the operating mode and parameters of the fistula monitoring device.

[0140] In one embodiment, the second opening is further covered by a screen cover 103. The screen cover 103 is located on the side of the display screen away from the first accommodating space, that is, on the outermost layer of the device, and is in direct contact with the external environment. The screen cover 103 can effectively prevent external dust, moisture, and some possible physical impacts from damaging the display screen. The screen cover 103 is made of transparent material, allowing users to clearly see various information displayed on the display screen, such as ultrasonic test results, equipment parameters, and operation prompts.

[0141] In one embodiment, the fistula listening device further includes an electrothermal module integrated therein. The electrothermal module is disposed entirely within a first accommodating space inside the housing 100, and its core function is to actively generate heat and transfer the heat to at least one outer surface of the housing 100, thereby controlling the heating of that surface.

[0142] Furthermore, to optimize heat conduction and distribution efficiency, referring to Figure 10, the portion of the housing 100 corresponding to the heating area of ​​the electric heating module is specifically designed to include a metal plate 111, such as an aluminum plate with good thermal conductivity. This metal plate 111 constitutes at least a portion of the inner wall or the entire structure of this side of the housing 100, maintaining close thermal contact with the internal electric heating module.

[0143] The heating module may include heating elements (such as resistance wires, thermistors, etc.), temperature control devices, and insulation materials. The heating elements are responsible for generating heat, the temperature control devices are used to precisely control the heating temperature to prevent excessively high or low temperatures from adversely affecting the equipment and users, and the insulation materials help concentrate heat in the required area, reduce heat loss and thermal interference to other components, and ensure that heat is efficiently applied to the inner surface of the housing 100.

[0144] During dialysis treatment, the patient's fistula arm is usually exposed, making it prone to cold and discomfort. The built-in heating module of the fistula monitoring device directly warms the patient's arm, effectively alleviating discomfort caused by cold. This allows the patient to be more relaxed and comfortable during long treatment sessions, helping to improve patient tolerance and cooperation. A properly warm environment promotes local blood circulation in the patient's arm, which plays a positive role in maintaining the normal function of the fistula. Good blood circulation helps reduce the risk of thrombosis, ensuring the smooth progress of dialysis treatment, and also contributes to the long-term stability and health of the fistula, reducing the incidence of complications caused by poor blood circulation.

[0145] In one embodiment, the electrothermal module includes a heating element 108 and a temperature control circuit. The temperature control circuit is signal-connected to the central control circuit and connected to the heating element 108 via a wire. The temperature control circuit provides electrical energy to the heating element 108, which converts the electrical energy into heat energy and releases it. The heating element 108 abuts against the lower shell 101, allowing the heat generated by the heating element 108 to be efficiently conducted to the lower shell 101 and further transferred to external objects (such as the patient's arm) in contact with the lower shell 101, thereby achieving the function of heating the local environment. On the one hand, the temperature control circuit establishes a signal connection with the central control circuit, enabling it to receive instructions and feedback information from the central control circuit and achieve coordinated operation with the entire device control system; on the other hand, it is connected to the heating element 108 via a wire, providing electrical energy to the heating element 108 and precisely controlling the heating power and temperature changes of the heating element 108.

[0146] When the fistula monitoring device activates its heating function, the central control circuit sends a signal to the temperature control circuit, which then supplies power to the heating element 108, causing it to convert electrical energy into heat. During the heating process, the temperature control circuit continuously monitors the temperature of the heating element 108 and dynamically adjusts the electrical energy supplied to it through a feedback adjustment mechanism. This ensures that the temperature of the heating element 108 remains within a preset safe and suitable range, preventing excessively high or low temperatures from harming the patient or affecting the heating effect.

[0147] The built-in electrothermal module actively heats a specific side of the housing 100, providing warmth to the patient's localized area when that side comes into contact with the patient's arm skin. This significantly improves patient comfort, especially during hemodialysis and other procedures involving limb exposure, alleviating discomfort from cold. Furthermore, the gentle heat helps promote superficial blood circulation at the contact site, potentially playing a positive role in maintaining local blood flow in the fistula area. The use of a metal plate 111 (such as an aluminum plate), due to its high thermal conductivity, enables rapid heat response and uniform heat diffusion, preventing localized overheating and enhancing safety and user comfort.

[0148] In one embodiment, the fistula monitoring device further includes an angle sensor for detecting and correcting the angle between the direction of sound wave or laser emission and the direction of blood flow. Specifically, the angle sensor is disposed within the housing 100 or integrated into the monitoring module and is signal-connected to the central control module 105. It can detect in real time the spatial angle formed between the emission axis direction of the detection energy beam (such as an ultrasound beam or laser beam) of the monitoring module during measurement and the mainstream direction of blood flow in the target blood vessel, correcting the angle parameter in blood flow velocity calculation. The angle sensor provides real-time and accurate angle parameters for blood flow velocity calculation based on the Doppler principle. Since Doppler frequency shift calculation is sensitive to the cosine value of the angle (usually denoted as θ), directly using a preset or estimated angle value will introduce significant errors. This embodiment, by integrating an angle sensor, can dynamically and automatically acquire the actual measured value of the angle during use and transmit this data to the central control module 105 in real time. Based on this, the central control module 105 performs precise vector angle compensation on the monitoring data (such as Doppler frequency shift), thereby significantly eliminating the system error caused by the uncertainty of the probe placement angle, and ultimately greatly improving the accuracy and reliability of blood flow velocity calculation, achieving professional-grade measurement accuracy with convenient operation.

[0149] In a preferred embodiment, the signal processing module included in the central control module 105 is configured to meet the specific requirements of high-performance blood flow monitoring. This module supports high-precision decoding of high-frequency Doppler frequency shift signals, with a decoding accuracy of at least 16 bits, effectively distinguishing minute frequency shifts ≤1Hz, thus adapting to the accurate measurement of low-velocity venous blood flow (e.g., 0.05-0.2m / s). The module incorporates adjustable filtering functions, including a high-pass filter (filter threshold adjustable within the range of 0.01-1kHz) for filtering out low-frequency noise such as vessel wall movement and a low-pass filter for suppressing environmental electromagnetic interference, ensuring the purity of the effective signal. To further enhance anti-interference capabilities, the module also integrates electromagnetic shielding and ultrasonic noise suppression units, effectively isolating signal crosstalk from external power supplies and other instruments, ensuring the stability of the frequency shift signal. Regarding display and output, the central control module 105 supports generating and displaying real-time blood flow velocity spectrum diagrams, and can automatically calculate and output derived data such as peak flow velocity, average flow velocity, and estimated blood flow, to meet the needs of real-time clinical observation and analysis.

[0150] Furthermore, the auxiliary system of the fistula monitoring device has also been optimized. Its power supply system boasts high stability, with operating voltage fluctuations controlled within ±5% to avoid changes in ultrasound transmission power or laser output power due to voltage fluctuations, which could affect the accuracy of frequency shift detection. The device incorporates a temperature control mechanism to ensure the probe contact surface temperature does not exceed 40℃, preventing skin burns from prolonged use. The overall operating temperature range is suitable for environments from 0-45℃. The entire device is designed for miniaturization and lightweight construction, making it suitable for handheld operation or tabletop use, and highly adaptable to various clinical applications such as bedside rapid testing, emergency assessment, and primary healthcare.

[0151] In one embodiment, the central control module 105 is configured to simultaneously receive and process monitoring data from at least two different types of listening modules. Specifically, the central control module 105 can acquire, for example, blood flow velocity data provided by the ultrasound component and vascular sound characteristic data provided by the auscultation module 300, or microcirculation flow velocity data provided by the laser component and larger vascular flow velocity data provided by the ultrasound component. The data processing algorithm built into the central control module 105 can perform cross-validation or data fusion calculations on the multiple sets of data from different physical principles and technical paths. The cross-validation refers to assessing the reliability of a single measurement result by comparing whether the blood flow state reflected by different data sources is physiologically consistent or contradictory; the fusion calculation refers to integrating multi-source information using data fusion algorithms (such as weighted average, Kalman filtering, or rule-based decision fusion) to generate a more comprehensive, accurate, or robust integrated evaluation result.

[0152] By leveraging the redundancy and complementarity of multimodal data, the overall reliability and diagnostic accuracy of fistula status assessment are significantly improved. Cross-validation mechanisms can identify potential misjudgments caused by limitations of a single technology or operational interference, while data fusion computing can comprehensively utilize the advantages of different technologies, such as combining quantitative velocity information from ultrasound with qualitative sound quality characteristics from auscultation, thereby providing richer and deeper pathophysiological insights than a single data source, ultimately assisting clinical users in making more accurate and confident judgments.

[0153] In one embodiment, the ultrasonic circuit, central control circuit, temperature control circuit, and display screen are integrated on the same circuit board 324. The ultrasonic circuit is primarily responsible for processing signals related to the ultrasonic module 200, such as generating electrical signals to drive the ultrasonic probe to emit ultrasonic waves, and receiving and converting the reflected waves from the ultrasonic probe into electrical signals, and performing preliminary processing. The central control circuit is responsible for the overall control of the entire fistula monitoring device, coordinating the operation of various components, processing data, and enabling data interaction with external mobile devices, among other key functions. The temperature control circuit focuses on controlling the temperature of the heating element 108 in the heating module, ensuring its safe, stable, and precise release of heat energy. The display screen is used to intuitively display the device's operating status, test results, and other information to the user.

[0154] By integrating multiple functional circuits and a display screen onto a single circuit board 324, and through rational circuit wiring and component layout, a tight and orderly connection is established between these different functional circuits and components, forming a highly integrated circuit system. This greatly optimizes the internal spatial layout of the fistula listening device, effectively reducing the space occupied by the circuit board 324 and connecting lines, making the internal structure of the device more compact. This facilitates the overall miniaturization of the device, making it easy to carry and use flexibly in different medical scenarios. It also reserves more space for other possible functional expansions or component installations, improving the utilization efficiency of the device's internal space. The short-distance connections between circuits on the same circuit board 324 shorten the signal transmission path, reducing problems such as signal attenuation, interference, and transmission delays that may be caused by excessively long lines or too many interfaces.

[0155] In one embodiment, the fistula listening device further includes a battery module electrically connected to the circuit board 324 and used to supply power to the circuit board 324. As the energy source for the entire fistula listening device, the battery module provides stable power support to the various functional modules on the circuit board 324. The battery module may include a first battery 106 and a battery casing 107, with the first battery 106 mounted and fixed within the housing 100 via the battery casing 107. The first battery 106 may be a rechargeable battery, and a charging port may be provided on the housing 100 for charging the rechargeable battery.

[0156] In one embodiment, a first button 104 is provided on the upper shell 102, and a second button 110 is provided on the side of the shell 100. The first button 104 controls the start and stop of the fistula monitoring device. When the first button 104 is pressed, the power system of the device is started, and each functional module (such as the ultrasound module 200, the central control module 105, etc.) is powered on and enters the initialization state, ready to perform ultrasound detection of the fistula. Pressing the button again turns off the device, stops all operating functions, and enters the shutdown state to save power and extend the service life of the device. The second button 110 controls the temperature of the heating module. By pressing the second button 110, the heating temperature of the heating module can be increased or decreased, or switched between different preset temperature levels, thereby meeting the different needs of patients under different ambient temperatures or for different degrees of warmth, providing patients with a more comfortable experience, and also accurately controlling the temperature to avoid discomfort to patients or affecting the normal operation of the device due to excessively high or low temperatures.

[0157] In the description of this specification, the use of terms such as "Embodiment 1," "this embodiment," or "in one embodiment" indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example; moreover, the specific features, structures, materials, or characteristics described may be combined in any appropriate manner in one or more embodiments or examples.

[0158] In the description of this specification, the terms "connection," "installation," "fixing," "setting," and "having" are interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0159] In the description of this specification, relational terms such as “first” and “second” are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0160] The above description of the embodiments is intended to enable those skilled in the art to understand and apply the technology of this invention. Those skilled in the art can easily make various modifications to these examples and apply the general principles described herein to other embodiments without creative effort. Therefore, this invention is not limited to the above embodiments. Modifications in the following situations should be within the scope of protection of this invention: ① New technical solutions implemented based on the technical solution of this invention and combined with existing common knowledge, where the technical effects of the new technical solution do not exceed the technical effects of this invention; ② Equivalent substitutions of some features of the technical solution of this invention using known technology, resulting in the same technical effects as those of this invention; ③ Extendable technical solutions based on the technical solution of this invention, where the substantive content of the extended technical solution does not exceed the technical solution of this invention; ④ Equivalent transformations made using the content of this specification and drawings, directly or indirectly applied to other related technical fields.

Claims

1. A fistula monitoring device, characterized in that, include: The shell, whose interior forms a first accommodating space; A monitoring module is disposed at one end of the housing. The monitoring module is used to detect the blood flow velocity of the fistula and generate corresponding monitoring data. A central control module is placed within the first accommodating space. The central control module receives the monitoring data and outputs the monitoring data or outputs result information generated based on the monitoring data.

2. The fistula monitoring device according to claim 1, characterized in that, The monitoring module includes one or more of an ultrasonic component, a laser component, or a magnetic resonance component integrated on or detachably connected to the housing.

3. The fistula monitoring device according to claim 2, characterized in that, The monitoring module includes an ultrasonic component, which includes an ultrasonic circuit and an ultrasonic probe. The ultrasonic circuit is connected to the central control module and the ultrasonic probe respectively. The ultrasonic probe emits ultrasonic waves and receives reflected waves.

4. The fistula monitoring device according to claim 3, characterized in that, The ultrasonic probe includes a probe housing, an ultrasonic transmitter for emitting ultrasonic waves, and an ultrasonic receiver for receiving reflected waves. One end of the housing has a first opening communicating with the first accommodating space. The ultrasonic probe is at least partially housed in the first opening. The ultrasonic transmitter and the ultrasonic receiver are both located on the side of the probe housing near the first accommodating space. The end face of the probe housing facing away from the first accommodating space is neither parallel nor perpendicular to the plane where the ultrasonic transmitter is located. The end face of the probe housing facing away from the first accommodating space is parallel to the plane where the ultrasonic receiver is located.

5. The fistula monitoring device according to claim 4, characterized in that, The ultrasonic probe has an ultrasonic frequency range of 2-10MHz, and / or the ultrasonic probe supports dual-mode switching between pulse wave and continuous wave, and / or the ultrasonic probe has a beam width ≤2mm.

6. The fistula monitoring device according to claim 2, characterized in that, The monitoring module includes a laser component, which includes a laser emitter and a photodetector that are respectively connected to the central control module via signals. The laser emitter is used to emit laser light, and the photodetector is used to receive scattered light.

7. The fistula monitoring device according to claim 6, characterized in that, The wavelength of the laser emitter is selected from 633nm or 780-850nm, and the output power is 1-5mW; and / or The laser emitter has a spectral linewidth ≤ 1 nm and a divergence angle ≤ 1 mrad; and / or The laser emitter operates at a voltage of 3.3-5V and has a static current of ≤10mA.

8. The fistula monitoring device according to claim 7, characterized in that, The photodetector is a photodiode with a responsivity ≥ 0.8 A / W and a dark current ≤ 1 nA; or the photodetector is a photomultiplier tube with a magnification ≥ 10. 6 Response speed ≥ 100MHz, rise time ≤ 3ns.

9. The fistula monitoring device according to any one of claims 1-8, characterized in that, It also includes an auscultation module, which is connected to or integrated into the housing, and is used to collect auscultation signals from the fistula and generate corresponding auscultation data.

10. The fistula monitoring device according to claim 9, characterized in that, The auscultation module includes a stethoscope head, a stethoscope circuit, a transmission cable, and a connector connected in sequence. The auscultation module is plugged into the housing through the connector and is connected to the central control module through the connector. The stethoscope head includes a first cover, a first outer shell, and a first diaphragm. The first outer shell is made of metal, and the first diaphragm is disposed at the end of the first outer shell through the first cover and is used to receive the vibration signal of the fistula.

11. The fistula monitoring device according to claim 10, characterized in that, The connector is a waterproof plug; and / or the first diaphragm is made of polyethersulfone or silicone rubber with a thickness between 0.05-0.2mm and a vibration response frequency between 20-2000Hz; and / or the surface of the first housing is provided with anti-slip texture.

12. The fistula monitoring device according to claim 9, characterized in that, The auscultation module includes a second housing, a second cover, a second diaphragm, and a microphone assembly. The second housing and the second cover form a second accommodating space. The second diaphragm is disposed at the end of the second housing through the second cover and is used to receive vibration signals from the fistula. The microphone assembly is located within the second accommodating space and is used to receive vibration signals transmitted by the second diaphragm. When the auscultation module is separated from the housing, the microphone assembly is connected to the central control module via a wireless communication signal. The surface of the second housing is provided with contacts. When the auscultation module is connected to the housing, the microphone assembly is electrically connected to the central control module through the contacts.

13. The fistula monitoring device according to claim 12, characterized in that, The sound receiving assembly includes a stethoscope cavity, a guide tube, and a sound receiving element. The stethoscope cavity has openings at both ends. One end of the stethoscope cavity is covered with the second diaphragm, and the other end of the stethoscope cavity is connected to one end of the guide tube. The sound receiving element extends into the other end of the guide tube.

14. The fistula monitoring device according to claim 13, characterized in that, The stethoscope module also includes a circuit board, and the microphone is disposed on one side of the circuit board. When the microphone extends into one end of the guide tube, the circuit board seals that end of the guide tube.

15. The fistula monitoring device according to claim 14, characterized in that, The stethoscope cavity is made of plastic, and the inner wall of the stethoscope cavity is covered with an embedded layer made of metal.

16. The fistula monitoring device according to claim 15, characterized in that, The fistula listening device further includes a speaker, which is installed within the second accommodating space and electrically connected to the circuit board. A horn hole is provided at the end of the second housing away from the second diaphragm, and the speaker is positioned directly opposite the horn hole; and / or The speaker is installed in the first accommodating space and electrically connected to the central control module. The housing is provided with a speaker hole, and the speaker is positioned directly opposite the speaker hole.

17. The fistula monitoring device according to any one of claims 1-8 or 10-16, characterized in that, The fistula listening device also includes an electrothermal module disposed within the first accommodating space, the electrothermal module being capable of heating at least one side of the housing.

18. The fistula monitoring device according to any one of claims 1-8 or 10-16, characterized in that, The fistula monitoring device also includes an angle sensor, which is used to detect and correct the angle between the direction of sound wave or laser emission and the direction of blood flow.

19. A fistula listening device, characterized in that, include: The shell, whose interior forms a first accommodating space; A monitoring module is disposed at one end of the housing. The monitoring module is used to detect the blood flow velocity of the fistula and generate corresponding monitoring data. The monitoring module includes one or more of the following: an ultrasound component, a laser component, or a magnetic resonance component integrated on or detachably connected to the housing. Auscultation module, which is connected to or integrated into the housing, is used to collect auscultation signals from the fistula and generate corresponding auscultation data; A central control module is placed within the first accommodating space. The central control module receives the monitoring data and auscultation data, and outputs the monitoring data or outputs result information generated based on the monitoring data.

20. The fistula monitoring device according to claim 19, characterized in that, The auscultation module includes a second housing, a second cover, a second diaphragm, and a microphone assembly. The second housing and the second cover form a second accommodating space. The second diaphragm is disposed at the end of the second housing through the second cover and is used to receive vibration signals from the fistula. The microphone assembly is located within the second accommodating space and is used to receive vibration signals transmitted by the second diaphragm. When the auscultation module is separated from the housing, the microphone assembly is connected to the central control module via a wireless communication signal. The surface of the second housing is provided with contacts. When the auscultation module is connected to the housing, the microphone assembly is electrically connected to the central control module through the contacts. The sound receiving assembly includes a stethoscope cavity, a guide tube, and a sound receiving element. The stethoscope cavity has openings at both ends. One end of the stethoscope cavity is covered with the second diaphragm, and the other end of the stethoscope cavity is connected to one end of the guide tube. The sound receiving element extends into the other end of the guide tube, and the guide tube is made of a soft sound-insulating material. The stethoscope module also includes a circuit board, and the microphone is disposed on one side of the circuit board. When the microphone extends into one end of the guide tube, the circuit board seals that end of the guide tube. The stethoscope cavity is made of plastic, and the inner wall of the stethoscope cavity is covered with an inner layer, which is formed by stamping or stretching a metal sheet.

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