CN115336995A

CN115336995A - Low-energy-consumption flexible noninvasive blood flow monitoring device based on pulse current

Info

Publication number: CN115336995A
Application number: CN202210985902.XA
Authority: CN
Inventors: 邓宇君; 范士远; 谭晋韵; 彭林法; 来新民
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2022-08-16
Filing date: 2022-08-16
Publication date: 2022-11-15

Abstract

The invention relates to a low-energy-consumption flexible noninvasive blood flow monitoring device based on pulse current, which is a wearable noninvasive blood flow monitoring electronic device based on a thermodynamic principle and comprises a rear-end processing module (1), a lead (2) and a front-end testing module (3), wherein the rear-end processing module (1) is connected with the front-end testing module (3) through the lead (2); the rear-end processing module (1) comprises a top-layer package (11), a processing module (12) and a rear-end middle-layer package (13), which are sequentially stacked to form the rear-end processing module (1); the front-end test module (3) can be divided into a front-end middle-layer package (31), a test module (32) and a bottom-layer package (33) which are sequentially stacked to form the front-end test module (3). Compared with the prior art, the invention adopts pulse current to supply energy, realizes intermittent heating, effectively reduces energy consumption and prolongs the working time of devices; the temperature module is composed of mutually separated temperature unit arrays, has high mechanical flexibility, gives consideration to heat sources and sensing functions, and has the characteristics of simple structure and design integration.

Description

Low-energy-consumption flexible noninvasive blood flow monitoring device based on pulse current

Technical Field

The invention belongs to the technical field of medical sensors, and particularly relates to a low-energy-consumption flexible noninvasive blood flow monitoring device based on pulse current.

Background

Vascular disease has been near the first cause of death in human disease and monitoring of blood flow is critical in the clinical treatment of this type of disease. The traditional blood flow monitoring technology is mainly realized by monitoring large medical equipment in hospitals, and mainly comprises blood vessel Doppler ultrasound and digital subtraction angiography. However, these two monitoring methods require professional large medical equipment and do not allow the patient to easily and timely obtain the blood flow information.

Wearable blood flow monitoring technologies have attracted extensive attention, and are mainly classified into photoplethysmography, portable ultrasonic doppler, and thermodynamic analysis of blood flow. Among them, the photoplethysmography is a technique for detecting the change of the light transmittance of the skin caused by the blood pumping of the heart by using a photoelectric element to reflect the blood flow, and has the disadvantage of being mainly used for measuring the blood flow of the superficial subcutaneous blood vessel. Patent CN112426577A discloses an implantable photoplethysmography blood flow measuring device, which acquires data for 72 hours, requiring a long preparation time. The principle of the portable ultrasonic Doppler technology is similar to that of the traditional blood vessel ultrasonic Doppler technology, but the portable ultrasonic Doppler technology has the defect that portability and precision cannot be considered simultaneously, so that the flow monitoring precision is limited. Patents CN112155600A, CN204909456U, CN210931524U and CN213551925U disclose wrist strap type ultrasonic doppler blood flow velocity measurement equipment, which reduces the volume of the ultrasonic equipment. In the Flexible Doppler Ultrasound Device for the Monitoring of Blood Flow Velocity, which is published by the Vol.7, no.44,2021 of the Von snow team of Qinghua university, the ultrasonic probe is arranged on the Flexible substrate to form a Flexible Blood Flow Monitoring Device directly bonded with the skin, so that the volume of the Blood Flow Monitoring Device is further reduced, and the wearability is improved. The blood thermodynamic analysis technology is based on the thermodynamic principle to indirectly measure the blood flow, wherein a patent CN106999060A discloses a skin device for analyzing the temperature characteristic and the heat conduction characteristic; patent CN111970962A discloses a cerebrospinal fluid drainage tube flow measuring device, has expanded the application field of this technique. But the relation between the temperature difference upstream and downstream of the blood flow and the flow is not monotonous, and the continuous heating causes large energy consumption of the device and short wireless monitoring time.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a low-energy-consumption flexible noninvasive blood flow monitoring device based on pulse current, which adopts intermittent energy supply for heating, has the characteristics of low energy consumption, flexibility and the like, and can realize long-time monitoring of the skin surface blood flow.

The purpose of the invention can be realized by the following technical scheme:

the utility model provides a flexible blood flow monitoring devices that does not have wound of low energy consumption based on pulse current, the device is based on the wearing formula of thermodynamics principle does not have blood flow monitoring electron device of wound, includes rear end processing module, wire and front end test module, front end test module package, test module and bottom package including the front end middle level that stacks in proper order, test module include the test circuit base to and the temperature module of tiling on the test circuit base, rear end processing module pass through the wire with front end test module and be connected.

Further, the temperature module is an array temperature unit, the temperature unit is formed by coiling metal wires, the temperature units are connected through a matching circuit, and the test circuit substrate is a flexible sheet made of an insulating high-temperature-resistant polymer material and comprises but is not limited to PDMS or PI.

Further, the matching circuit is a flexible bending structure using metal wires (including but not limited to gold, copper and aluminum).

Compared with a complete metal sheet, the array structure formed by the mutually separated temperature units can improve the flexibility of the front-end test module. The temperature unit acts as a heat source under the action of joule heat, and simultaneously, because the resistance value of the temperature resistance effect can also reflect the temperature, the temperature unit acts as both the heat source and the temperature sensing function, so that the structure of the test module is effectively simplified. In addition, the temperature unit is connected with pulse current, intermittent energy supply is adopted for heating, the steady-state temperature is obtained through a temperature-time curve, and the mapping relation between the flow and the temperature is obtained through the resistance temperature rise rule under different flows. Compared with direct current, the time required for the temperature rise curve based on the pulse current to reach a steady state is shorter, the resolution ratio is higher, the energy consumption is low, and the endurance time of the device can be prolonged.

Further, the temperature unit material is a metal wire (including but not limited to gold, copper and aluminum), the shape of the temperature unit includes but not limited to circle, rectangle, diamond, ellipse, sector and hexagon, and the array of the temperature unit includes but not limited to linear array and circumferential array.

Furthermore, the rear-end processing module comprises a top-layer package, a processing module and a rear-end middle-layer package which are sequentially stacked; the processing module comprises a processing circuit substrate, and a wireless communication module, a microprocessor chip, a battery module and a signal conditioning circuit which are fixed on the processing circuit substrate.

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

Furthermore, the battery module supplies power to the temperature module in a pulse current mode, the battery module comprises a battery and a triode, the triode is controlled to be turned on and off by a microprocessor chip, pulse heating is carried out on the temperature module, and the battery is a button battery.

Furthermore, the edges of the processing module and the testing module are provided with interfaces for external connectors, and the interfaces of the testing module can provide electric energy for the temperature unit on one hand and can transmit the voltage value of the temperature unit on the other hand for measuring the resistance value of the temperature unit; in the front-end test module, the package is uniformly covered on the surface of the temperature module, so that the positions except the interface are insulated from the outside.

Furthermore, the testing module is connected with a tested arm of a Wheatstone bridge through an external connector interface, the Wheatstone bridge is connected with a low-pass filter, the low-pass filter is connected with an operational amplifier, the operational amplifier is connected with an analog-to-digital converter, the analog-to-digital converter is connected with a microprocessor chip, and the microprocessor chip is connected with the wireless communication module.

Further, the front-end test module is in contact with the patient's skin (including but not limited to van der waals adhesion, cross-stick adhesion, couplant adhesion); the back end processing module is stacked on the front end testing module or is linked and placed at the far end through a flexible flat cable.

Compared with the prior art, the invention has the following advantages:

(1) The invention is based on pulse current energy supply, realizes intermittent heating, effectively reduces energy consumption and prolongs the working time of devices;

(2) The temperature module consists of temperature unit arrays which are separated from each other, wherein the temperature units are formed by coiling metal conducting wires, are connected through a telescopic bending structure and have high mechanical flexibility;

(3) The temperature module of the invention has heat source and sensing functions, namely, the function of the heat source is exerted through the joule heat effect, the temperature sensing function is exerted through the temperature resistance effect, and the temperature module has the characteristics of simple structure and integrated design.

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 comparison of the temperature-time curves of the pulse current and the DC current in example 1;

FIG. 4 is a schematic view showing blood flow measurement at the dorsum of foot in example 1;

FIG. 5 shows the structural design of the front end test module in example 1;

fig. 6 is a structural design scheme of a front-end test module in example 2.

The labels in the figure are:

1-a back-end processing module; 2-a wire; 3-front end test module; 11-top layer encapsulation; 12-a processing module; 13-rear end middle layer packaging; 31-front end middle layer encapsulation; 32-a test module; 33, bottom layer packaging; 121-processing the circuit substrate; 122 — a wireless communication module; 123-a microprocessor chip; 124-a battery; 125-signal conditioning circuitry; 321-temperature module; 322-test circuit substrate.

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 is to be understood that the specific embodiments described herein are merely 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 used in the present invention are all commonly available commercial products in the art, such as:

PDMS package was SYLGARD184 PDMS membrane, manufactured by Dow Corning, USA;

the operational amplifier adopts OPA2277UA precision operational amplifier produced by Dezhou instruments in America;

the analog-to-digital converter adopts ADS1148 sixteen-bit analog-to-digital converter produced by Texas instruments of America;

the wireless communication module adopts an HC05 Bluetooth module;

the microprocessor chip adopts STM32F103C8T6 series chips produced by Italian semiconductor company;

the wheatstone bridge, low pass filter, use components that are conventional in the art.

Example 1

The pulse current based low-energy consumption flexible non-invasive blood flow monitoring device as shown in fig. 1 and fig. 2 comprises three parts, namely a back-end processing module 1, a lead 2 and a front-end testing module 3. The back-end processing module 1 can be divided into a top-layer PDMS package 11, a processing module 12, and a back-end middle-layer PDMS package 13, wherein the processing module 12 includes a processing circuit substrate 121, a wireless communication module 122, a microprocessor chip 123, a battery module 124, and a signal conditioning circuit 125; the front end test module 3 can be divided into a front end middle layer PDMS package 31, a test module 32, and a bottom layer PDMS package 33, wherein the front end test module 3 includes a temperature module 321 and a test circuit substrate 322. The top PDMS package 11, the processing module 12 and the back end middle PDMS package 13 are all in a sheet shape and are stacked in sequence to form a back end processing module 1 of the device; the front-end middle-layer PDMS package 31, the test module 32 and the bottom-layer PDMS package 33 are also in a sheet shape and are sequentially stacked to form the front-end test module 3 of the device; the back end processing module 1 and the front end testing module 3 are electrically connected by virtue of the lead 2.

In a preferred embodiment, the test circuit substrate 322 of the front-end test module 3 is a flexible sheet of insulating high-temperature-resistant polymer material (in this embodiment, SYLGARD184 PDMS film manufactured by US Corning Inc.), and the supporting circuit is a copper wire directly printed on the test circuit substrate 322.

In this embodiment, the temperature module 321 is an array of temperature units, the temperature units are small mosquito-repellent incense coil areas formed by winding thin copper wires, as shown in fig. 5, the small mosquito-repellent incense coil areas are circular, 9 temperature units are laid on the test circuit substrate 322, and the array is a 3 × 3 rectangular structure.

In this embodiment, the test module 32 comprises an array of temperature cells, the axes of symmetry of which are parallel to the vessel centerline; there are concentrated external connector interfaces at the edges of the processing module 12 and the testing module 32, and the two connector interfaces are connected by a wire 2 (as shown in fig. 2), wherein the wire connects the temperature module 321 and the battery module 124 to realize power supply to the temperature unit, and the wire also connects the temperature module 321 and the signal conditioning circuit 125 to transmit voltage data of the temperature unit, so as to obtain resistance value information of the temperature unit.

In this embodiment, the processing circuit substrate 121 of the back-end processing module 1 is made of a flexible insulating material (in this embodiment, a SYLGARD184 polydimethylsiloxane film manufactured by the american dianning company is selected), the signal conditioning circuit 125 includes a wheatstone bridge, a low-pass filter, an operational amplifier and an analog-to-digital converter, the wheatstone bridge and the low-pass filter employ a resistor-capacitor network, the operational amplifier employs a precision operational amplifier, the analog-to-digital converter employs a 16-bit ADS1148 analog-to-digital converter, the wireless communication module 122 employs an HC05 bluetooth module, the microprocessor chip 123 employs an STM32F103C8T6 chip, and the battery of the battery module 124 employs a button battery.

In this embodiment, the round copper wire unit of the test module 32 is connected to the tested arm of the wheatstone bridge through the external connector interface, 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 123, the microprocessor chip 123 is connected to the wireless communication module 122, and the battery module 124 supplies power to all IC elements.

In the present embodiment, the pulse current is used to heat the metal unit, and the temperature-time curve shown in fig. 3 is obtained by comparing the direct current with the same peak power density, so that it can be seen that the pulse current has a shorter time to reach the steady state than the direct current, and consumes less electric energy.

In this embodiment, as shown in figure 4, in use of the device, the device is placed directly over the blood vessels of the dorsum of the foot of the patient, with only one bottom PDMS encapsulation 33 between the test module 32 and the patient's skin.

In this embodiment, the front-end testing module 3 and the back-end processing module 1 jointly implement three functions, including: converting signals, processing signals and sending signals. The resistance value of the copper wire mosquito-repellent incense disc of the front-end test module 3 can change along with the increase of the temperature, so that a Wheatstone bridge WB in the signal conditioning circuit 125 is unbalanced, a voltage signal carrying a temperature signal of a test point is output, high-frequency noise is filtered by a low-pass filter, the voltage value of the signal is amplified by an operational amplifier and is converted into a digital signal by an analog-to-digital converter, and the digital signal is transmitted to the microprocessor chip 123 for standby transmission; the microprocessor chip 123 delivers blood flow information to the patient's communication device through the wireless communication module 122, and the communication device calculates the flow size through the relationship between the temperature variation amplitude and the flow, and the patient reads the information through the application software.

Example 2

The pulse current based low-energy consumption flexible non-invasive blood flow monitoring device as shown in fig. 1 and fig. 2 comprises three parts, namely a back-end processing module 1, a lead 2 and a front-end testing module 3. The back-end processing module 1 can be divided into a top-layer PDMS package 11, a processing module 12, and a back-end middle-layer PDMS package 13, wherein the processing module 12 includes a processing circuit substrate 121, a wireless communication module 122, a microprocessor chip 123, a battery module 124, and a signal conditioning circuit 125; the front end test module 3 can be divided into a front end middle layer PDMS package 31, a test module 32, and a bottom layer PDMS package 33, wherein the front end test module 3 includes a temperature module 321 and a test circuit substrate 322. The top PDMS package 11, the processing module 12 and the back end middle PDMS package 13 are all in a square sheet shape and are sequentially stacked to form a back end processing module 1 of the device; the front-end middle-layer PDMS package 31, the test module 32 and the bottom-layer PDMS package 33 are all in a circular sheet shape and are sequentially stacked to form the device front-end test module 3; the back end processing module 1 and the front end testing module 3 are electrically connected by virtue of the lead 2.

In a preferred embodiment, the testing circuit substrate 322 of the front-end testing module 3 is a flexible thin sheet made of insulating high-temperature-resistant polymer material (in this embodiment, SYLGARD184 polydimethylsiloxane film manufactured by american-dow corning corporation is selected), the temperature module 321 is a combination of hexagonal copper sheet units with a circular overall shape, and the supporting circuit is a copper wire directly printed on the testing circuit substrate 322.

In this embodiment, the temperature module 321 is an array of temperature units, the temperature units are small mosquito-repellent incense coil areas formed by winding thin copper wires, as shown in fig. 6, the small mosquito-repellent incense coil areas are regular hexagons, and the temperature units are circumferentially arrayed and tiled on the test circuit substrate 322.

In this embodiment, the test module 32 comprises a set of temperature units, which are distributed in a circle, and the projection of the center of the circle is located on the center line of the blood vessel; there are concentrated external connector interfaces at the edges of the processing module 12 and the testing module 32, and the two connector interfaces are connected by a wire 2 (as shown in fig. 2), wherein the wire connects the temperature module 321 and the battery module 124 to realize power supply to the temperature unit, and the wire also connects the temperature module 321 and the signal conditioning circuit 125 to transmit voltage data of the temperature unit, so as to obtain resistance value information of the temperature unit.

In this embodiment, the hexagonal copper wire unit of the test module 32 is connected to the tested arm of the wheatstone bridge through the external connector interface, 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 123, the microprocessor chip 123 is connected to the wireless communication module 122, and the battery module 124 supplies power to all IC elements.

In this embodiment, when the device is in use, the device is placed on the surface of the patient's carotid artery, the center of the front end test module 3 is projected on the axis of the blood vessel, and only one bottom layer of PDMS package 33 is arranged between the test module 32 and the patient's skin.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that modifications may be made to the embodiments and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. The utility model provides a flexible noninvasive blood flow monitoring device of low-power consumption based on pulse current, its characterized in that, the device is based on thermodynamic principle's wearing formula does not have blood flow monitoring electron device of creating, including rear end processing module (1), wire (2) and front end test module (3), front end test module (3) including front end middle level encapsulation (31), test module (32) and bottom encapsulation (33) that stack in proper order, constitute front end test module (3), test module (32) include test circuit basement (322) to and tiling temperature module (321) on test circuit basement (322), rear end processing module (1) be connected through wire (2) with front end test module (3).

2. The device for low-energy-consumption flexible noninvasive blood flow monitoring based on pulse current as claimed in claim 1, characterized in that the temperature modules (321) are array temperature units, the temperature units are coiled by metal wires, the temperature units are connected by matching circuits, the test circuit substrate (322) is a flexible sheet made of insulating high-temperature-resistant polymer material, including but not limited to PDMS or PI.

3. The device for low-energy-consumption flexible noninvasive blood flow monitoring based on pulse current of claim 2, characterized in that the supporting circuit is a flexible bending structure using metal wires, and the metal wires are made of gold, copper or aluminum.

4. The device as claimed in claim 2, wherein the temperature unit is made of metal wire, the shape of the temperature unit includes circle, rectangle, diamond, ellipse, fan, hexagon, and the array of temperature units includes linear array and circular array.

5. The pulse current-based low-energy-consumption flexible noninvasive blood flow monitoring device of claim 1 is characterized in that the back-end processing module (1) comprises a top-layer package (11), a processing module (12) and a back-end middle-layer package (13) which are sequentially stacked; the processing module (12) comprises a processing circuit substrate (121), and a wireless communication module (122), a microprocessor chip (123), a battery module (124) and a signal conditioning circuit (125) which are fixed on the processing circuit substrate (121).

6. The device for low-energy-consumption flexible non-invasive blood flow monitoring based on pulse current as claimed in claim 5, wherein the processing circuit substrate (121) is made of hard insulating material or flexible insulating material, the signal conditioning circuit (125) comprises a Wheatstone bridge, a low-pass filter, an operational amplifier and an analog-to-digital converter, the Wheatstone bridge and the low-pass filter are made of resistance-capacitance network, and the operational amplifier, the analog-to-digital converter, the wireless communication module (122) and the microprocessor chip (123) are made of small commercial module packaged in patch type.

7. The device for flexible noninvasive blood flow monitoring of low energy consumption based on pulse current as claimed in claim 6, characterized in that said battery module (124) supplies pulse current to said temperature module (321), said battery module (124) comprises battery and transistor, said temperature module (321) is heated by pulse by controlling on/off of transistor with microprocessor chip (123), said battery is button cell.

8. A low energy consumption flexible non-invasive blood flow pulsed current based monitoring device according to claim 5 or 6, characterized in that the processing module (12) and the testing module (32) are provided with external connector interfaces at their edges, which are connected by a lead (2).

9. The pulse current-based low-energy-consumption flexible noninvasive blood flow monitoring device of claim 8 is characterized in that the testing module (32) is connected with a tested arm of a Wheatstone bridge through an external connector interface, the Wheatstone bridge is connected with a low-pass filter, the low-pass filter is connected with an operational amplifier, the operational amplifier is connected with an analog-to-digital converter, the analog-to-digital converter is connected with a microprocessor chip (123), and the microprocessor chip (123) is connected with a wireless communication module (122).

10. A pulsed current based low energy consumption flexible non-invasive blood flow monitoring device according to claim 1, characterized in that the front end test module (3) is in contact with the skin of the patient; the rear processing module (1) is stacked on the front testing module (3) or is linked and placed at the far end through a flexible flat cable.