CN115281625A - Wearable arteriovenous internal fistula tremor monitoring devices based on ripples feedback - Google Patents

Abstract

The invention relates to a wearable arteriovenous internal fistula tremor monitoring device based on wave feedback, which comprises a front-end testing module (1) and a rear-end processing module (2), wherein the front-end testing module (1) comprises a multilayer composite film formed by sequentially arranging a wave receiving and transmitting layer (11), a microstructure flexible layer (12), a plane reflection coating (13) and a plane flexible layer (14), and a wave transmitting and receiving device (15) arranged on the composite film, and the front-end testing module (1) is connected with the rear-end processing module (2) through a connecting wire (16). Compared with the prior art, the vibration sensor solves the problems that a patient is difficult to judge the existence of tremor independently and accurately, the traditional vibration sensor is not suitable for a human body and the like, avoids treatment delay caused by untimely reduction of internal fistula flow due to inconvenience of repeated appointment and examination in a medical institution, and remarkably reduces the risk of fistula blockage of a hemodialysis patient.

Description

Wearable arteriovenous internal fistula tremor monitoring devices based on ripples feedback

Technical Field

The invention belongs to the field of medical biosensors, and particularly relates to a wearable arteriovenous internal fistula tremor monitoring device based on wave feedback.

Background

The arteriovenous fistula is mainly used for the maintenance hemodialysis treatment of a patient with renal failure, and particularly comprises the steps of anastomosing an artery close to the wrist or the elbow of the patient with an adjacent vein to arterialize the anastomosed vein; the formed arteriovenous internal fistula is convenient for repeated puncture and can provide enough blood flow volume for hemodialysis treatment for a plurality of times per week.

Stenosis and thrombosis of an arteriovenous internal fistula are the most common complications after arteriovenous internal fistula formation. Some high risk patients have poor vascular conditions, the internal fistula occlusion can occur probably within a period of time after the internal fistula is newly built or repaired, if the repair is not timely, the patients can lose precious vascular resources, and the pain of repeated operations is also born. Therefore, there is a need for routine monitoring of the blood flow rate at an arteriovenous internal fistula of a renal failure maintenance hemodialysis patient, particularly a high risk patient, and if the blood flow rate is too low, it indicates a blockage risk at the arteriovenous internal fistula, measures are taken to dilate the blood vessel or eliminate the thrombus to restore the patency.

A characteristic clinical manifestation is accessible on the skin of arteriovenous fistula patients: internal fistula tremor. The arterial blood in the fistula, which folds back through the venous valve, causes turbulence, which is transmitted to the body surface in the form of tremors. Further, whether the blood vessel is unblocked can be judged according to the tremble strength at the internal arteriovenous fistula. Significant tremor indicates adequate blood flow in the fistula; a decrease or disappearance of tremor indicates poor blood flow within the fistula, at which time the test may only reach the internal fistula pulse and not tremor. Compared with blood flow radiography, tremor is an indirect fistula blood flow characterization index which is easier to measure, but in current clinical practice, except for the examination of the body by medical staff, no special equipment which is actually applied to palpation of internal fistula tremor exists.

In the existing tremor monitoring technology, the traditional monitoring method mainly comprises a laser Doppler vibration measurement technology and an electronic stethoscope technology. The laser Doppler vibration measurement technology measures the vibration frequency and the vibration amplitude of the skin of the body surface through laser, reflects the vibration intensity and infers whether the internal fistula is unobstructed or not. Patent publication No. CN111870252A discloses a superficial vascular tremor measurement method and device based on laser sensing, and the patent acquires superficial vascular tremor signals in a non-contact manner through a laser sensor, and then obtains pure tremor signals through reduction by means of median filtering and self-adaptive filtering. However, due to the problems of large equipment volume, inconvenient use and the like, the current clinical application is few, and the full-time monitoring cannot be realized. The electronic stethoscope picks up the noise (high-frequency mechanical vibration signal) that the torrent blood flow sent out in the internal fistula, compares the noise that picks up with the noise of normal internal fistula to judge the internal fistula state. Patent publication No. CN215227600U discloses an arteriovenous internal fistula blood flow detector, which judges the state of a fistula by analyzing noise signals picked up by an electronic stethoscope through artificial intelligence. However, there is a significant risk of misjudgment in diagnosis by artificial intelligence, and therefore, the internal fistula state cannot be judged by simply relying on artificial intelligence.

In the existing tremor monitoring technology, an emerging monitoring method is to use a flexible wearable pressure sensor. The category monitoring device places the pressure sensor on the body surface or is implanted near a blood vessel, the blood vessel generates acting force on the sensor during pulsation or tremor, and the tremor strength can be reversely obtained by analyzing the magnitude and the variation trend of the force to reflect the state of the fistula. The flexible wearable pressure sensor comprises three types, namely a capacitor type pressure sensor, a piezoelectric type pressure sensor and a resistor type pressure sensor. A Measurement of the model on the human arthrovenous Fistulas with a Flexible Capacitive Sensor, published by Luo Kan in Annual International Conference of the IEEE Engineering in Medicine and Biology Society (2021, pages 7324-7327), describes a skin-based Capacitive pressure Sensor that can be used for measuring fistula tremors in dialysis patients. A resistive Pressure sensor with conductive coating is introduced in a linear and high Pressure-Sensitive Electronic Skin Based on a bioinstrumented high temperature Structural Array published by Geun Yeol Bae in Advanced Materials (2016,28,5300-5306), a hemispherical microstructure with folds is formed on the surface of a film, a graphene coating is grown on the surface of the microstructure, and the measurement of the pulse at the wrist is realized. But the existing various flexible wearable pressure sensors have great defects: the capacitance type sensor needs a built-in power signal source, so that the miniaturization and the commercial popularization of the capacitance type sensor are influenced; the plating layer conductive resistance pressure sensor generally adopts materials such as graphene or carbon nano tubes and the like as a conductive plating layer, is influenced by the properties of the materials, has a short service life, and can generate zero drift and performance attenuation of sensitivity reduction after receiving a few cycles of cyclic load. Due to these drawbacks, such devices are currently in the laboratory phase.

According to the investigation result of the prior patent technology, the special medical equipment is huge in size, so that the popularization of the traditional tremor monitoring technology is limited; the emerging wearable blood flow monitoring technology is not widely accepted due to the defects of low testing precision and fatigue limit, large volume, inconvenience in wearing and the like.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a wearable arteriovenous internal fistula tremor monitoring device based on wave feedback, the device is flexible and wearable, and adopts a wave (comprising mechanical waves and electromagnetic waves) transmitting and receiving device, so that quantitative monitoring of body surface vibration caused by arteriovenous fistula tremor of a renal dialysis patient is realized, real-time non-invasive monitoring of fistula blockage and blockage conditions is indirectly realized, when fistula flow is reduced and thrombus is suspected, early warning can be timely given to doctors and patients, thrombus removal measures and blood vessel expansion measures can be taken as soon as possible, and the normality of the fistula and the health of the patients are ensured.

The purpose of the invention can be realized by the following technical scheme: a wearable arteriovenous internal fistula tremor monitoring device based on wave feedback is a wearable flexible biosensor for detecting the obstruction condition of an internal fistula route by quantitatively measuring the mechanical vibration waveform of arteriovenous internal fistula tremor of a renal dialysis patient. The device comprises a front-end test module and a rear-end processing module, wherein the front-end test module is a multilayer composite film, and comprises a wave receiving and transmitting layer, a microstructure flexible layer, a plane reflection coating and a plane flexible layer which are sequentially arranged from top to bottom, and a wave transmitting and receiving device arranged on the composite film, and the front-end test module and the rear-end processing module are connected through a connecting wire.

Furthermore, the wave receiving and transmitting layer, the microstructure flexible layer and the plane flexible layer are films made of flexible polymer materials, and comprise polydimethylsiloxane, polyimide and the like; the planar reflection coating is made of metal materials with strong binding force with the microstructure flexible layer and large wave reflection coefficient, and comprises gold, silver, copper and the like, and the thickness of the coating is 10-100 nanometers.

Further, the front end test module comprises four films of each layer, wherein the wave receiving and transmitting layer, the plane reflection coating and two side surfaces of the plane flexible layer are all planes, one side surface of the microstructure flexible layer is provided with a microstructure, the surface with the microstructure is tightly bonded with the plane reflection coating, the other side surface of the plane reflection coating is bonded with the plane flexible layer, and the wave transmitting and receiving device is arranged on the surface of the wave receiving and transmitting layer.

Further, the microstructure flexible layer is a double-layer polymer film formed with one or more base microstructures on a plane film, wherein the base microstructures are in the shape of a cylinder, a triangular pyramid, a quadrangular pyramid, a hemisphere or a semi-ellipsoid, and the height of a characteristic dimension is 10-90 micrometers. The microstructure can be prepared by referring to Tunable Superhydrocationcity from 3D hierarchical Nano-Wrinkled Micro-Pyramidal architechures, published by Zhang Weixin on Advanced Functional Materials (2021, 2101068), which can be prepared by the following method: firstly, prefabricating a microstructure nickel mold by using a photoetching method, controlling the thickness of a polymer film by using a rotary coating machine, then impressing the microstructure nickel mold on the polymer film, and finally enabling the nickel mold to be separated without damage by using a thermosetting technology, thus preparing the polymer film containing the microstructure.

Further, the basic microstructures on the microstructure flexible layer are arranged in an array, and the array is a circumferential array, a linear array or a random array.

Further, the surface of the base microstructure on the microstructure flexible layer is a porous structure, and the porous structure can be prepared by a filling material foaming method during forming.

Furthermore, the edge of the wave receiving and transmitting layer extends to the periphery to obtain an external electrode. And etching the metal wire from the wave transmitting and receiving device to the external electrode, and connecting the metal wire with the back-end processing module through a connecting wire.

Further, the back-end processing module comprises: the back end processing module circuit board comprises a circuit substrate, a signal conditioning circuit, a microprocessor chip, a battery and a wireless communication module, wherein the signal conditioning circuit is arranged on the circuit substrate and consists of a Wheatstone bridge, a low-pass filter, an operational amplifier and an analog-to-digital converter.

Furthermore, the circuit substrate is made of hard insulating materials or flexible insulating materials, a Wheatstone bridge and a low-pass filter in the signal conditioning circuit are made of resistance-capacitance networks, the operational amplifier, the analog-to-digital converter, the microprocessor chip and the wireless communication module are small commercial modules packaged in a surface mount mode, and the battery is a button battery.

Furthermore, the front end test module is connected to the signal conditioning circuit of the rear end processing module through a connecting line to realize the electrical connection of the two modules, the two modules adopt a tiled layout, namely the front end test module is positioned at a fistula tremor position, the rear end processing module is adjacent to the front end test module but not overlapped or tiled on the skin of a patient at a certain distance, or the rear end processing module is tiled on a table and a chair by lengthening the solid connecting line.

Compared with the prior art, the invention has the following beneficial effects:

(1) According to the pressure sensor based on the wave feedback, the thickness of the microstructure flexible layer in the front-end testing module is changed along with the internal fistula tremor, so that the measured signal of the wave transmitting and receiving device is changed, the measured internal fistula tremor signal is represented, and then the comparison with the normal internal fistula tremor signal is carried out, and the internal fistula blockage opening condition is judged. The pyramid-shaped and hemispherical microstructures in the microstructure flexible layer have strong deformation capacity under the condition of small pressure changes such as pulse and vascular tremor, so that the sensitivity higher than that of a traditional pressure sensor can be achieved, and real-time quantitative monitoring of internal fistula tremor of dialysis patients is realized. The plane reflection coating in the front-end test module is easier to reflect the wave signals than the skin surface of the human body, so that the wave receiving device can measure the signals more strongly and is convenient for data processing; the plane flexible layer is soft, and can reduce the uncomfortable feeling generated when the plane flexible layer is attached to the surface of the skin of a human body.

(2) The device is a flexible wearable biosensor for detecting whether an internal fistula blood vessel is unblocked or not by quantitatively measuring the mechanical vibration waveform of the tremor of the arteriovenous internal fistula of a renal failure maintenance hemodialysis patient. The invention solves the problems that the patient is difficult to autonomously and accurately judge the existence of tremor, the traditional vibration sensor is not suitable for the human body and the like, can realize the technical effect of monitoring the blockage state of the internal fistula in real time, meets the requirement of timely giving an alarm to medical personnel and kidney dialysis patients when the internal fistula becomes stricter, avoids treatment delay caused by untimely reduction of the internal fistula flow due to the inconvenience of repeated appointment and examination in a medical institution, and obviously reduces the fistula blockage risk of the hemodialysis patient.

(3) The device provided by the invention adopts the flexible microstructure sensor, and reflects the internal fistula tremor signal based on the principle that the tremor deformation of the flexible microstructure changes the propagation paths of light waves and ultrasonic waves in the flexible microstructure, so that the received wave feedback signal changes synchronously. The device adopts a split type structure, is divided into a flexible front-end testing module and a rigid rear-end processing module, and utilizes the flexible micro-structure sensor to replace a rigid MEMS accelerometer, so that the dead weight of the measuring part is reduced to be within 1 gram. The shadow of equipment dead weight to internal fistula tremble measurement has been reduced, because the energy of human internal fistula tremble is less, so the reduction of equipment dead weight can alleviate its own influence to internal fistula tremble, improves the discernment correct rate of tremble signal.

(4) The invention improves the comfort level of a user, adopts the flexible sensor to replace a rigid sensor, is easier to be adhered to the skin of a human body, can reduce the discomfort level of the user, adopts the film patch type configuration to replace the wrist sleeve type configuration, is difficult to compress the internal fistula, has lower acting force on the internal fistula, and is beneficial to protecting the internal fistula.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is an exploded view of fig. 1.

Fig. 3 is a schematic diagram of the effect of the present invention on the arm of a patient.

Fig. 4 is a schematic diagram of the back-end processing module according to the present invention.

Fig. 5 is a schematic view of a microstructured flexible layer according to example 1 of the present invention. .

Fig. 6 is a view showing the state of the original fistula in which the front test module was fitted to the skin in example 1 of the present invention.

FIG. 7 is a view showing a state in which the front end test module is applied to the skin to tremor the fistula in example 1 of the present invention.

Fig. 8 is a schematic diagram of a microstructure flexible layer in a pyramid-shaped rectangular pyramid microstructure array in example 2 of the present invention.

Fig. 9 is an enlarged view of the porous pyramid microstructure of fig. 8.

Fig. 10 is a view showing the state of the original fistula in which the front test module was fitted to the skin in example 2 of the present invention.

FIG. 11 is a view showing a state in which the front test module is applied to the skin to tremor the fistula in example 2 of the present invention.

In the above drawings, the reference numerals denote:

the device comprises a 1-front-end test module, an 11-wave receiving and transmitting layer, a 12-microstructure flexible layer, a 13-plane reflection coating, a 14-plane flexible layer, a 15-wave transmitting and receiving device, a 16-connecting line, a 2-rear-end processing module, a 21-top PDMS package, a 22-rear-end processing module circuit board, a 221-signal conditioning circuit, a 222-micro processing chip, a 223-battery, a 224-wireless communication module, a 225-circuit substrate and a 23-bottom PDMS package.

Detailed Description

The purpose, technical solution and advantages of the embodiments of the present invention will be described in further detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The various components and raw materials employed in the present invention are all commonly available commercial products in the art, such as:

the wave transmitting and receiving layer 11 and the planar flexible layer 14 are made of commercially available flexible polymer materials, such as: commercially available PDMS; the microstructure flexible layer 12 is made of commercially available PDMS, a pre-fabricated microstructure nickel mold is stamped on the PDMS, and a PDMS film containing a microstructure is prepared after thermal curing.

The planar reflection coating 13 is prepared by a magnetron sputtering process, i.e. incident ions generated by low-pressure inert gas glow discharge bombard the surface of a coated target material, so that target material atoms are sputtered and deposited on a coated substrate to form a coated film. The process is used to plate a layer of highly reflective material, including but not limited to gold, silver, copper, etc., on the side of the planar flexible layer 14 opposite the microstructured flexible layer 12.

The wave transmitting and receiving means 15 employs commercially available light emitting diodes and photo resistors.

The top PDMS package 21 and the bottom PDMS package 23 are SYLGARD184 PDMS membranes manufactured by Dow Corning, USA; in the signal conditioning circuit 221, an OPA2277UA precision operational amplifier manufactured by texas instruments, usa is used as an amplifier; the analog-to-digital converter adopts ADS1148 sixteen-bit analog-to-digital converter manufactured by Texas instruments of America; the Wheatstone bridge and the low-pass filter adopt the conventional components in the field; the micro-processing chip 222 is an STM32F103C8T6 series chip manufactured by Italian semiconductor.

Example 1

The wearable arteriovenous internal fistula tremor monitoring device shown in fig. 1 and 2 comprises a front-end testing module 1 and a rear-end processing module 2. The front-end testing module 1 comprises a wave receiving and transmitting layer 11, a microstructure flexible layer 12, a plane reflection coating 13, a plane flexible layer 14, a photodiode, a photoresistor 15 and a connecting wire 16; the back-end processing module 2 comprises a top PDMS package 21, a back-end processing module circuit board 22, and a bottom PDMS package 23, wherein the back-end processing module circuit board 22 is the core of the module, and comprises a signal conditioning circuit 221, a microprocessor chip 222, a battery 223, a wireless communication module 224, and a circuit substrate 225. The wave receiving and transmitting layer 11, the microstructure flexible layer 12 and the planar flexible layer 14 are all in a sheet shape, and a layer of high-reflectivity substance including but not limited to gold, silver and copper is plated on the large plane of one side of the microstructure flexible layer 12 with the microstructure to form a planar reflection plating layer 13. The photodiode and the photoresistor 15 are welded at the center of the wave transmitting and receiving layer 11. An interface is expanded at the edge of the wave receiving and transmitting layer 11, a connecting wire 16 is welded on the interface, and the interface extends outwards vertically and is connected to a signal conditioning circuit 221 of the rear-end processing module 2, so that the electrical connection of the two modules is realized.

In this embodiment, as shown in fig. 2, the wave transmitting and receiving layer 11, the microstructure flexible layer 12, and the planar flexible layer 14 of the front end test module 1 are made of a flexible insulating polymer material PDMS, and after the surface is activated by plasma bombardment, a magnetron sputtering process is used to plate silver on the opposite plane of the microstructure flexible layer 12, so as to form the planar reflective coating 13. The connecting wire 16 is a copper wire and is soldered to the external electrode of the wave transmitting and receiving layer 11 by a reflow soldering process.

In this embodiment, as shown in fig. 5, a columnar microstructure array with a height of 45 μm is formed on the microstructure flexible layer 12 of the front end test module 1, and one side of the columnar array is in direct contact with the planar reflective coating 13.

In this embodiment, the circuit substrate 225 of the back-end processing module 2 is made of a flexible insulating material, in this embodiment, a SYLGARD184 polydimethylsiloxane film manufactured by the american donning corporation is selected, the signal conditioning circuit 221 includes a wheatstone bridge, a low-pass filter, an amplifier and an analog-to-digital converter, the wheatstone bridge and the low-pass filter employ a resistor-capacitor network, the amplifier employs a precision operational amplifier, the analog-to-digital converter employs a 12-bit analog-to-digital converter, the microprocessor chip 222 employs an STM32F103C8T6 chip, the battery 223 employs a button battery, and the wireless communication module 224 employs an HC05 bluetooth module.

In this embodiment, the wave transceiver layer 11 of the front end test module 1 is connected to the measured arm of the wheatstone bridge of the signal conditioning circuit 221 in the back end processing module 2 through the connection line 16, the wheatstone bridge is connected to the low pass filter, the low pass filter is connected to the operational amplifier, the operational amplifier is connected to the analog-to-digital converter, the analog-to-digital converter is connected to the microprocessor chip 222, the microprocessor chip 222 is connected to the wireless communication module 224, and the battery 223 supplies power to all IC components.

In this embodiment, as shown in fig. 3, when the device is used, the device is placed on the body surface of the arm of a patient, the front end test module 1 is placed on the arteriovenous interface of the arteriovenous internal fistula, and one side of the planar flexible layer 14 is in contact with the skin. The back end processing module 2 is naturally lapped on the skin at other parts, and both modules are adhered to the skin or adhered to the skin after smearing couplant.

In the present embodiment, as shown in fig. 6 to 7, the wave transmitting and receiving device 15 is a light emitting diode and a photo resistor. The light emitting diode stably emits light after being electrified, light rays are reflected by the plane reflection coating 13 after passing through the microstructure flexible layer 12 and received by the photoresistor, and an initial resistance value is obtained. When no external force is applied to the front end test module 1 and the arteriovenous fistula is not pulsating or tremor, the thickness of the microstructure flexible layer 12 is kept constant, and the photoresistance value is also kept constant, and the resistance between the two connecting lines 16 at this time is recorded as R0 (as shown in fig. 6). When arteriovenous fistula starts to beat or tremble, the fistula drives the body surface skin to vibrate, at the moment, the planar reflective coating 13 starts to move up and down, the thickness of the microstructure flexible layer 12 is increased or decreased, the light intensity received by the photoresistor is decreased or increased, the photoresistor value is increased or decreased, and the resistance between the two connecting wires 16 is recorded as R1 (shown in figure 7). It can be known that R1 fluctuates up and down with R0 as the equilibrium position, i.e., the front-end test module 1 converts the skin vibration signal into the resistance signal.

In the present embodiment, as shown in fig. 1 and fig. 4, the front-end testing module 1 and the back-end processing module 2 jointly implement three functions, including: converting signals, processing signals and sending signals. The resistance value of the front-end testing module 1 changes, so that a wheatstone bridge in the signal conditioning circuit 221 of the back-end processing module 2 is unbalanced, a voltage signal carrying an amplitude signal is output, high-frequency noise is filtered by a low-pass filter, the voltage value of the signal is amplified by an operational amplifier, the signal is converted into a digital signal by an analog-to-digital converter, and the digital signal is transmitted to the microprocessor chip 222 for sending; the microprocessor chip 222 delivers amplitude information to the patient's communication device through the wireless communication module 224.

Example 2

The wearable arteriovenous internal fistula tremor monitoring device shown in fig. 1 and 2 comprises a front-end testing module 1 and a rear-end processing module 2. The front-end test module 1 comprises a wave receiving and transmitting layer 11, a microstructure flexible layer 12, a plane reflection coating 13, a plane flexible layer 14, an MEMS ultrasonic probe 15 and a connecting wire 16; the back-end processing module 2 comprises a top PDMS package 21, a back-end processing module circuit board 22, and a bottom PDMS package 23, wherein the back-end processing module circuit board 22 is the core of the module, and comprises a signal conditioning circuit 221, a microprocessor chip 222, a battery 223, a wireless communication module 224, and a circuit substrate 225. The wave receiving and transmitting layer 11, the microstructure flexible layer 12 and the planar flexible layer 14 are all in a sheet shape, and a layer of high-reflectivity substance including but not limited to gold, silver and copper is plated on the large plane of one side of the microstructure flexible layer 12 with the microstructure to form a planar reflection plating layer 13. The center of the wave transmitting and receiving layer 11 is welded with a MEMS ultrasonic probe 15. An interface is expanded at the edge of the wave receiving and transmitting layer 11, a connecting wire 16 is welded on the interface, and the interface extends outwards vertically and is connected to a signal conditioning circuit 221 of the rear-end processing module 2, so that the electrical connection of the two modules is realized.

In this embodiment, as shown in fig. 2, the wave transmitting and receiving layer 11, the microstructure flexible layer 12, and the planar flexible layer 14 of the front end test module 1 are made of a flexible insulating polymer material PDMS, and after the surface is activated by plasma bombardment, a magnetron sputtering process is used to plate copper on the opposite plane of the microstructure flexible layer 12, so as to form the planar reflective coating 13. The connecting wire 16 is made of copper wire and is soldered to the external electrode of the wave transmitting and receiving layer 11 by a reflow soldering process.

In this embodiment, as shown in fig. 8-9, the microstructured flexible layer 12 of the front end test module 1 was formed with an array of porous pyramidal rectangular-pyramid microstructures having a height of 45 microns, the apexes of which were in direct contact with the planar reflective coating 13.

In this embodiment, the circuit substrate 225 of the back-end processing module 2 is made of a flexible insulating material, in this embodiment, a SYLGARD184 polydimethylsiloxane film manufactured by the american national corning company is selected, the signal conditioning circuit 221 includes a low-pass filter, an amplifier and an analog-to-digital converter, the low-pass filter is a resistor-capacitor network, the amplifier is a precision operational amplifier, the analog-to-digital converter is a 12-bit analog-to-digital converter, the microprocessor chip 222 is an STM32F103C8T6 chip, the battery 223 is a button battery, and the wireless communication module 224 is an HC05 bluetooth module.

In this embodiment, the wave transceiver layer 11 of the front-end test module 1 is connected to the low-pass filter of the signal conditioning circuit 221 in the back-end processing module 2 through the connection line 16, the low-pass filter is connected to the operational amplifier, the operational amplifier is connected to the analog-to-digital converter, the analog-to-digital converter is connected to the microprocessor chip 222, the microprocessor chip 222 is connected to the wireless communication module 224, and the battery 223 supplies power to all IC components.

In this embodiment, as shown in fig. 3, when the device is used, the device is placed on the body surface of the arm of a patient, the front end test module 1 is placed on the arteriovenous interface of the arteriovenous internal fistula, and one side of the planar flexible layer 14 is in contact with the skin. The back end processing module 2 is naturally lapped on the skin at other parts, and both modules are adhered to the skin or adhered to the skin after being coated with couplant.

In the present embodiment, as shown in fig. 10 to 11, the wave transmitting and receiving device 15 is a MEMS ultrasonic probe. The ultrasonic probe is electrified to stably emit ultrasonic waves, the ultrasonic waves are reflected by the plane reflection coating 13 after passing through the microstructure flexible layer 12 and are received by the ultrasonic probe, and an initial sound pressure value is obtained. When no external force is applied to the front end test module 1 and the arteriovenous fistula is not pulsating or trembling, the thickness of the microstructure flexible layer 12 is kept constant, and the initial sound pressure value is also kept constant. When the arteriovenous fistula starts to beat or tremble, the fistula drives the body surface skin to vibrate, the planar reflective coating 13 starts to move up and down at the moment, the thickness of the microstructure flexible layer 12 is increased or reduced, the sound pressure received by the ultrasonic probe is reduced or increased and fluctuates up and down near the initial sound pressure value, and the front-end test module 1 converts the skin vibration signal into a sound pressure signal.

In the present embodiment, as shown in fig. 1 and fig. 4, the front-end testing module 1 and the back-end processing module 2 jointly implement three functions, including: converting signals, processing signals and sending signals. The front-end test module 1 outputs a sound pressure signal, then filters high-frequency noise through a low-pass filter, amplifies the signal through an operational amplifier, converts the signal into a digital signal through an analog-to-digital converter, and transmits the digital signal to the microprocessor chip 222 for transmission; the microprocessor chip 222 delivers amplitude information to the patient's communication device through the wireless communication module 224.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the above teachings. Therefore, the technical solutions that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection determined by the claims.

Claims (10)

1. The utility model provides a wearable arteriovenous internal fistula tremor monitoring devices based on ripples feedback, a serial communication port, the device is through the mechanical vibration waveform of quantitative measurement renal dialysis patient arteriovenous internal fistula tremor, surveys the wearable flexible biosensor of interior fistula sweetgum fruit unblock condition, including front end test module (1) and rear end processing module (2), wherein front end test module (1) includes sets gradually the multilayer composite film that forms by ripples receiving and dispatching layer (11), micro-structure flexible layer (12), plane reflection coating (13), plane flexible layer (14) to and the ripples transmission and receiving arrangement (15) that set up on this composite film, front end test module (1) and rear end processing module (2) pass through connecting wire (16) and connect.

2. The wearable arteriovenous fistula tremor monitoring device based on wave feedback of claim 1, wherein the wave transmitting and receiving layer (11), the microstructure flexible layer (12) and the planar flexible layer (14) are thin films made of flexible polymer materials, including Polydimethylsiloxane (PDMS), polyimide (PI), etc.; the planar reflection coating (13) is made of metal materials which have strong bonding force with the microstructure flexible layer (12) and large wave reflection coefficient, and comprises gold, silver, copper and the like, and the thickness of the coating is 10-100 nanometers.

3. The wearable arteriovenous internal fistula tremor monitoring device based on wave feedback according to claim 1 or 2, wherein the wave transmitting and receiving layer (11), the planar reflective coating (13) and the planar flexible layer (14) are planar on both side surfaces, one side surface of the microstructured flexible layer (12) is provided with a microstructure, the side surface with the microstructure is tightly bonded with the planar reflective coating (13), the other side surface of the planar reflective coating (13) is bonded with the planar flexible layer (14), and the wave transmitting and receiving device (15) is mounted on the surface of the wave transmitting and receiving layer (11).

4. The wearable arteriovenous fistula tremor monitoring device of claim 1 wherein the microstructured flexible layer (12) is a two-layer polymeric film formed on a planar film with one or more base microstructures that are cylindrical, triangular, rectangular, hemispherical, or semi-ellipsoidal in shape and have a characteristic dimension of 10 to 90 microns in height.

5. The wearable arteriovenous fistula tremor monitoring device of claim 4, wherein the base microstructures on the microstructured flexible layer (12) are arranged in an array, the array being a circumferential array, a linear array, or a random array.

6. The wearable arteriovenous fistula tremor monitoring device of claim 1, wherein the primary microstructured surface of the microstructured flexible layer (12) is porous and is formed by foaming with a filler material.

7. The wearable arteriovenous fistula tremor monitoring device based on wave feedback of claim 1, wherein the edge of the wave transmitting and receiving layer (11) is expanded to the periphery to obtain an external electrode; metal wires are etched from the wave transmitting and receiving device (15) to the external connection electrode and are connected with the back-end processing module (2) through a connecting wire (16).

8. A wearable arteriovenous fistula tremor monitoring device based on wave feedback according to claim 1, wherein the backend processing module (2) comprises: the device comprises a top PDMS package (21), a back-end processing module circuit board (22) and a bottom PDMS package (23), wherein the back-end processing module circuit board (22) comprises a circuit substrate (225), and a signal conditioning circuit (221), a microprocessor chip (222), a battery (223) and a wireless communication module (224) which are arranged on the circuit substrate and are composed of a Wheatstone bridge, a low-pass filter, an operational amplifier and an analog-to-digital converter.

9. The wearable arteriovenous fistula tremor monitoring device based on wave feedback of claim 8, wherein the circuit substrate (225) is made of a hard insulating material or a flexible insulating material, the Wheatstone bridge and the low-pass filter in the signal conditioning circuit (221) are made of a resistor-capacitor network, the operational amplifier, the analog-to-digital converter and microprocessor chip (222) and the wireless communication module (224) are made of a patch-type packaged small-sized commercial module, and the battery (223) is made of a button battery.

10. A wearable arteriovenous fistula tremor monitoring device based on wave feedback according to claim 8, characterized in that the front end test module (1) is connected to the signal conditioning circuit (221) of the rear end processing module (2) via a connecting wire (16) to electrically connect the two modules, and the two modules are laid out in a flat manner, that is, the front end test module (1) is located at the fistula tremor position, and the rear end processing module (2) is laid on the skin of the patient simultaneously adjacent to the front end test module (1) but not overlapped or spaced apart, or the rear end processing module (2) is laid on a table or chair by lengthening the solid connecting wire.

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