A wearable capillary perfusion real-time non-invasive monitoring device

Abstract

The present application relates to a kind of wearable capillary perfusion real-time noninvasive monitoring device, including temperature acquisition module (1) and information processing module (2) connected by wireless communication, temperature acquisition module (1) includes sequentially stacked connection acquisition module top package (11), acquisition module upper layer (12), acquisition module middle package (13), acquisition module lower layer (14) and acquisition module bottom package (15), acquisition module upper layer (12) is connected with acquisition module lower layer (14) by wire (16);Temperature acquisition module (1) is directly contacted with skin above capillary, measures the temperature response of skin under heat source;Information processing module (2) analyzes temperature signal, calculates skin heat transfer coefficient by non-steady-state heat conduction principle, and then converts into skin capillary perfusion volume.Compared with prior art, the present application is small and light, suitable for wearing, suitable for real-time noninvasive monitoring of capillary perfusion under the overload condition of pilot.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of medical sensors, and relates to a wearable capillary perfusion real-time noninvasive monitoring device. BACKGROUND

[0002] Fighter pilots often encounter overload in the process of flight, and the degree of overload is usually measured in multiples of gravitational acceleration g. Ordinary people will faint under an overload of about 4g, while pilots need to withstand an overload of 8g or even as high as 10g in extreme conditions when performing tasks. During flight, the overload can be divided into positive overload and negative overload. In the case of positive overload, the aircraft is pulled up at a large angle to generate upward acceleration. The pilot's body is subjected to centrifugal force from the head to the feet, so that the blood collects in the lower body, causing the brain to lack oxygen, and then causing visual problems such as gray vision and black vision, and even causing temporary fainting. In the case of negative overload, the aircraft is inverted and dives to generate downward acceleration. The pilot's body is subjected to an inertial force that pushes the blood from the feet to the head, causing the brain to be hyperemic, and then causing problems such as brain tingling and red vision. The monitoring of the physiological condition of the pilot under overload is crucial and is one of the important ways to ensure the safety of the pilot.

[0003] At present, the physiological signals of pilots under overload are mainly monitored through electrocardiogram, pulse, blood oxygen saturation and other indicators. However, the above indicators are comprehensive representations of the whole body blood flow situation and cannot directly reflect the problems such as head hyperemia or ischemia of the pilot. The present patent proposes to monitor the capillary perfusion of the pilot's head skin in real time, so as to quickly reflect the blood flow condition of the head.

[0004] The measurement techniques of capillary perfusion mainly include laser Doppler imaging technology, fluorescence imaging technology, CT (Computed Tomography) perfusion imaging technology, and nuclear magnetic resonance technology. Laser Doppler blood flow monitor is a commonly used blood flow microcirculation perfusion measurement device in clinical practice, which can monitor the hemodynamic information such as tissue organ blood flow change, tissue oxygen partial pressure, and blood perfusion volume in real time. Patent CN104887216A discloses a multi-beam coherent human skin perfusion imaging system and method, which combines laser speckle contrast imaging and laser Doppler blood flow monitoring technology to obtain human body surface perfusion imaging. In addition, patent CN112037217A discloses an intraoperative blood flow imaging method based on fluorescence imaging, which identifies blood flow area through fluorescence imaging image, and further identifies blood perfusion related to pseudo-color imaging. Patents CN113850755A, CN113057658A, CN101779963A, and the like disclose devices, systems, and methods for obtaining high-quality images of brain CT perfusion imaging methods. Patent CN113379679A discloses a brain arterial wave intensity and wave power measurement method, terminal device, and computer readable storage medium, which obtains nuclear magnetic resonance images containing brain information and neck information, and constructs a brain hemodynamic model. However, the above-mentioned measurement techniques of capillary perfusion all rely on large medical equipment, which are not suitable for real-time monitoring of overload conditions of pilots during task execution.

[0005] In addition, there are new blood flow monitoring technologies based on thermodynamic principles in wearable blood flow monitoring, such as patent CN106999060A discloses a skin device for analyzing temperature characteristics and heat transfer characteristics, and patent CN111134652A discloses a multifunctional monitoring wrist guard for arteriovenous fistula of hemodialysis patients. However, the above-mentioned patents only face blood flow monitoring of a single main blood vessel, and cannot perform real-time measurement of capillary perfusion. SUMMARY

[0006] The purpose of the present application is to overcome the defects of the prior art and provide a wearable capillary perfusion real-time non-invasive monitoring device. The present application is based on thermodynamic principles, small and light, suitable for wearing, and can real-time non-invasively monitor the head capillary perfusion of pilots under overload conditions.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] The application provides a wearable capillary perfusion real-time noninvasive monitoring device, which comprises a temperature collection module and an information processing module which are connected through wireless communication for data and instruction transmission, wherein the temperature collection module comprises a collection module top package, a collection module upper layer, a collection module middle package, a collection module lower layer and a collection module bottom package which are connected in sequence, the collection module upper layer and the collection module lower layer are electrically connected through wires, and the information processing module comprises a processing module top package, a processing module core and a processing module bottom package which are connected in sequence.

[0009] Further, the material of the package is resin polydimethylsiloxane (PDMS), the shape is sheet-shaped rectangle or circle, and the thickness is 50-500 μm.

[0010] Further, the collection module upper layer comprises a collection module upper layer flexible circuit substrate and a collection module battery, a microcontroller and a power supply which are laid on the collection module upper layer flexible circuit substrate.

[0011] Further, the collection module lower layer comprises a collection module lower layer flexible circuit substrate and a heater and a temperature sensor which are laid on the collection module lower layer flexible circuit substrate in array arrangement, wherein the heater adopts one or both of a resistance element or a metal coil, is electrically connected with the power supply and is heated or cooled according to a fixed period, the temperature sensor adopts a thermistor, the temperature sensor adopts a whole layout or a split layout, the temperature sensor adopts one thermistor or a plurality of thermistors which are combined in array at a position corresponding to the heater.

[0012] Further, the microcontroller is electrically connected with the temperature sensor, adopts a single-chip microcomputer with wireless communication, is used for receiving a voltage signal from the temperature sensor, and transmits a temperature signal to the information processing module through wireless communication after conversion.

[0013] Further, the information processing module core part comprises a circuit substrate, a microprocessor chip, a wireless communication module and a battery.

[0014] Further, the microprocessor and the wireless communication chip adopt a small commercial single-chip microcomputer in a patch type package.

[0015] Further, the microprocessor analyzes the temperature signal, calculates a skin heat conduction coefficient through a non-steady-state heat conduction principle, converts the skin heat conduction coefficient into a skin capillary perfusion volume, and stores the data.

[0016] Further, the material of the circuit substrate is an insulating high-temperature-resistant polymer material polyvinyl alcohol (PVA), polyester (PET), polyimide (PI) or polyethylene naphthalate glycol (PEN), the shape is sheet-shaped rectangle or circle, and the area is 1-100 cm2 The components on the circuit substrate are connected through the matched circuit printed directly on the circuit substrate.

[0017] Further, in the device use, the temperature acquisition module is arranged on the body surface directly above the center of the capillary vessels of the pilot, the lower layer of the acquisition module is separated from the skin by only one layer of the bottom encapsulation of the acquisition module, and the information processing module is arranged on the clothes of the pilot on the chest or the thigh.

[0018] The perfusion degree of the capillary vessels of the human skin is closely related to the internal blood flow, that is, when the perfusion is weakened, the blood flow speed is slow, and when the perfusion is enhanced, the blood flow speed is fast. Therefore, when the heater is arranged on the skin surface, the temperature change rate of the skin heated under the constant power is related to the blood flow of the capillary vessels, and further related to the capillary vessel perfusion. Based on this, the skin heat conduction coefficient of the pilot is calculated by measuring the transient temperature rise response of the skin of the pilot head under the influence of the heater, and the physiological health status of the pilot under the overload is determined according to the head skin blood perfusion.

[0019] The mapping mathematical relationship of the application is:

[0020] The heat conduction coefficient λ is calculated from the analytical solution of the second type of boundary condition of the non-steady heat conduction of the semi-infinite plate. Since the heat conduction of the human blood vessels is much smaller than the heat conduction of the blood flow directly carrying heat flow transmission, the heat conduction of the blood flow at rest is ignored in the calculation, and there is a relationship

[0021]

[0022] Where λ is the heat conduction coefficient, Δt is the temperature difference, Δδ is the heat transfer distance, c is the specific heat capacity of blood, t is the temperature after heating, and t0 is the initial temperature.

[0023] That is,

[0024]

[0025] Where ρ is the blood flow density, is the average area of the local capillary vessels, is the average perfusion speed.

[0026] Simplified as

[0027]

[0028] Where

[0029]

[0030] K is the mapping coefficient, reflecting the mapping relationship between the blood flow perfusion and the heat conduction coefficient.

[0031] Compared with the prior art, the application has the following advantages:

[0032] (1) The present application is based on the principle of thermodynamics, and uses arrayed heaters and temperature sensors to continuously heat the skin at low temperature and measure the temperature in real time, so as to realize real-time measurement of the in-plane skin thermal conductivity distribution;

[0033] (2) The present application establishes the mapping relationship between capillary perfusion and skin thermal conductivity, and realizes real-time monitoring of capillary perfusion through temperature signal monitoring;

[0034] (3) The present application uses wireless communication, is small and light, can be worn on the body, and is suitable for real-time non-invasive monitoring of capillary perfusion of pilots under overload conditions. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a structure schematic view of the temperature acquisition module of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application.

[0036] Figure 2 It is an exploded view of the temperature acquisition module of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application.

[0037] Figure 3 It is a position arrangement diagram of the array heater and the temperature sensor in the temperature acquisition module of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application.

[0038] Figure 4 It is a design scheme diagram of the central circular heater of the temperature acquisition module of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application.

[0039] Figure 5 It is a structure schematic view of the information processing module of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application.

[0040] Figure 6 It is an exploded view of the information processing module of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application.

[0041] Figure 7 It is an effect schematic view of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application worn on the neck of a pilot.

[0042] Figure 8 It is a structure logic diagram of the wearable capillary perfusion real-time non-invasive monitoring device in the embodiment of the present application.

[0043] Marking in the figure:

[0044] 1 - temperature acquisition module, 11 - acquisition module top package, 12 - acquisition module upper layer, 121 - acquisition module upper layer flexible circuit substrate, 122 - acquisition module battery, 123 - microcontroller, 124 - power supply, 13 - acquisition module middle package, 14 - acquisition module lower layer, 141 - acquisition module lower layer flexible circuit substrate, 142 - temperature sensor, 143 - circular heater, 144 - resistance heater, 15 - acquisition module bottom package, 16 - wire, 2 - information processing module, 21 - processing module top package, 22 - processing module core, 221 - processing module circuit substrate, 222 - microprocessor, 223 - wireless communication chip, 224 - processing module battery, 23 - processing module bottom package. DETAILED DESCRIPTION

[0045] The application will be described in detail below with specific examples. The examples are implemented on the premise of the technical solution of the application, and detailed implementation and specific operation processes are given, but the protection scope of the application is not limited to the following examples.

[0046] The equipment used in the following examples is conventional equipment in the field unless otherwise specified; the reagents used are commercially available products or prepared by conventional methods in the field unless otherwise specified; and the processes not described in detail in the following examples can be achieved by conventional experimental methods in the field.

[0047] Example:

[0048] A wearable capillary perfusion real-time noninvasive monitoring device, such as Figure 1 , 2, 5 and 6, including the top package 11 of the acquisition module, the upper layer 12 of the acquisition module, the middle package 13 of the acquisition module, the lower layer 14 of the acquisition module, the bottom package 15 of the acquisition module, the top package 21 of the processing module, the core 22 of the processing module and the bottom package 23 of the processing module; wherein the upper layer 12 of the acquisition module includes the flexible circuit substrate 121 of the upper layer of the acquisition module, the battery 122 of the acquisition module, the microcontroller 123 and the periodic square wave power supply 124, the lower layer 14 of the acquisition module includes the flexible circuit substrate 141 of the lower layer of the acquisition module, the temperature sensor 142, the circular heater 143 and the resistance heater 144, the core 22 of the processing module includes the circuit substrate 221 of the processing module, the microprocessor 222, the wireless communication chip 223 and the battery 224 of the processing module. The top package 11 of the acquisition module, the upper layer 12 of the acquisition module, the middle package 13 of the acquisition module, the lower layer 14 of the acquisition module and the bottom package 15 of the acquisition module are all in the shape of a rectangular sheet, and are sequentially stacked to form the temperature acquisition module 1; the top package 21 of the processing module, the core 22 of the processing module and the bottom package 23 of the processing module are all in the shape of a rectangular sheet, and are sequentially stacked to form the information processing module 2. The top package 11 of the acquisition module, the middle package 13 of the acquisition module and the upper layer 12 of the acquisition module are bonded; the upper layer 12 of the acquisition module and the lower layer 14 of the acquisition module are electrically connected by the connecting wire 16; the middle package 13 of the acquisition module, the bottom package 15 of the acquisition module and the lower layer 14 of the acquisition module are bonded; the top package 21 of the processing module, the bottom package 23 of the processing module and the core 22 of the processing module are bonded.

[0049] In a preferred embodiment, the flexible circuit substrate 121 of the upper layer of the acquisition module, the flexible circuit substrate 141 of the lower layer of the acquisition module and the circuit substrate 221 of the processing module can adopt a flexible sheet of an insulating high-temperature-resistant polymer material such as polyvinyl alcohol, polyester, polyimide or poly naphthalene dimethyl glycol ester, and in the present embodiment, polyimide is preferred, with an area of 1-100 cm 2 , and in the present embodiment, 10 cm 2 ; the circular heater 143 adopts a resistance wire, the resistance heater 144 adopts a negative temperature coefficient (NTC) thermistor, and the components on the circuit substrate are connected by corresponding matching copper wires printed directly on the flexible circuit substrate 121 of the upper layer of the acquisition module, the flexible circuit substrate 141 of the lower layer of the acquisition module and the circuit substrate 221 of the processing module, and the packaging material is resin polydimethylsiloxane with a thickness of 50-500 μm, and in the present embodiment, 100 μm is preferred.

[0050] In the present embodiment, as Figure 2As shown, the upper layer 12 of the collection module is connected with the lower layer 14 of the collection module through the wire 16, so that the circular heater 143, the resistance heater 144 and the power supply 124 are connected, realizing periodic power supply to the heater and thus realizing periodic heating and cooling of the heater. The other part of the wire 16 connects the temperature sensor 142 and the corresponding port of the microcontroller 123.

[0051] In the present embodiment, as shown in Figure 3 The circular heater 143 is located at the center of the flexible circuit substrate 141 of the lower layer of the collection module, and the resistance heater 144 is arranged in a circular array with the temperature sensor 142.

[0052] In the present embodiment, as shown in Figure 7 In use of the device, the temperature collection module 1 is placed on the body surface directly above the center of the capillary vessels of the pilot's neck, and the lower layer 14 of the collection module is separated from the skin only by the bottom encapsulation 15 of the collection module. The information processing module 2 can be adhered to the clothes on the pilot's chest or thigh.

[0053] In the present embodiment, the microcontroller 123 is a single-chip microcomputer with wireless communication. In the present embodiment, the microcontroller 123 is an STM32W type single-chip microcomputer. The microprocessor 222 and the wireless communication chip 223 are small commercial single-chip microcomputers with patch type packaging. In the present embodiment, the microprocessor 222 is an ARM processor, and the wireless communication chip 223 is a Bluetooth (BLE). The collection module battery 122 provides working voltage for the microcontroller 123, the power supply 124, the temperature sensor 142, the circular heater 143 and the resistance heater 144. In the present embodiment, the collection module battery 122 is a 5V lithium battery. The processing module battery 224 provides working voltage for the microprocessor 222 and the wireless communication chip 223. In the present embodiment, the processing module battery 224 is a 3V lithium battery.

[0054] In the present embodiment, the temperature sensor 142 is an NTC thermistor, and the resistance value decreases with the increase of temperature. The circular heater 143 is a circular resistance wire, as shown in Figure 4

[0055] As shown in Figure 8 ​As shown, the device periodically heats the skin surface through the circular heater 143 and the circular array of resistance heaters 144, and measures the temperature at multiple locations on the skin surface through the array of temperature sensors 142. The voltage signals output by the temperature sensors 142 are then transmitted to the microcontroller 123 through the supporting circuit and the wire 16, the voltage signals are converted into resistance signals by the microcontroller 123, and the corresponding temperatures are calculated through the resistance values of the thermistors and the fitting formula for temperature. The temperature signals are then transmitted to the wireless communication chip 223 by the Bluetooth module of the microcontroller 123. The wireless communication chip 223 transmits the temperature signals to the microprocessor 222, the microprocessor 222 calculates the thermal conductivity coefficient of the skin according to the second type of boundary condition analysis of non-steady-state heat conduction, obtains the perfusion condition of the pilot's head capillary through the mapping relationship, stores the data, and finally transmits the information to the cloud server through the wireless communication chip 223.

[0056] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. Those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to go through creative labor. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art within the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A wearable capillary perfusion real-time non-invasive monitoring device, characterized in that, The device comprises a temperature acquisition module (1) and an information processing module (2) connected through wireless communication, wherein the temperature acquisition module (1) comprises a top encapsulation (11), an upper layer (12), a middle encapsulation (13), a lower layer (14) and a bottom encapsulation (15) connected in sequence, the upper layer (12) and the lower layer (14) are electrically connected through a wire (16), and the information processing module (2) comprises a top encapsulation (21), a core (22) and a bottom encapsulation (23) connected in sequence; The lower layer (14) comprises a first heater, a second heater and a temperature sensor (142), wherein the first heater and the second heater are periodically heated and cooled, the first heater is located at the center of the lower layer (14), the second heater and the temperature sensor (142) are arranged in a circular array, and the temperature sensor (142) is arrayed and combined with the second heater at the corresponding position. The perfusion degree of capillary vessels of human skin is closely related to the blood flow therein, that is, when the perfusion is weakened, the blood flow speed is slow; when the perfusion is enhanced, the blood flow speed is fast; therefore, when a heater is arranged on the skin surface, the temperature change rate of the skin heated at a constant power is related to the blood flow of the capillary vessels, and further related to the capillary vessel perfusion. Based on this, by measuring the transient temperature rise response of the skin of the pilot's head under the influence of the heater, the skin heat conduction coefficient is calculated, and the blood perfusion of the head skin is correspondingly determined to determine the physiological health status of the pilot under overload. The heat transfer coefficient is calculated by the analytical solution of the second type of unsteady heat conduction boundary condition of semi-infinite plate Based on the principle of thermodynamics, the heater and the temperature sensor arranged in an array are used to continuously heat the skin at a low temperature and measure the temperature in real time, so that the real-time measurement of the in-plane skin heat conduction performance distribution is realized. Because the heat conduction of human blood vessels is much smaller than the heat flow transmission directly carried by blood flow, the heat conduction of blood flow at rest is ignored in calculation, and there is a relationship ， wherein The mapping relationship between the capillary vessel perfusion and the skin heat conduction coefficient is established, and the real-time monitoring of the capillary vessel perfusion is realized through temperature signal monitoring. is the thermal conductivity, Δ t is the temperature difference, Δ The material of the encapsulation is resin polydimethylsiloxane, the shape is sheet-shaped, and the thickness is 50-500 μm. is the heat transfer distance, c is the specific heat capacity of blood, t is the temperature after heating, t 0 is the initial temperature; The upper layer (12) comprises an upper layer flexible circuit substrate (121), and a battery (122), a microcontroller (123) and a power supply (124) laid on the upper layer flexible circuit substrate (121). ， wherein The lower layer (14) comprises a lower layer flexible circuit substrate (141), and a heater and a temperature sensor (142) laid on the lower layer flexible circuit substrate (141) in an array, wherein the heater adopts one or both of a resistance element and a metal coil, and is heated or cooled according to a fixed period through electrical connection with the power supply (124), the temperature sensor (142) adopts a thermistor, the temperature sensor (142) adopts a split type layout, and the temperature sensor (142) adopts a plurality of thermistors arrayed and combined at the corresponding position of the heater. is the blood flow density, is the local capillary mean area, is the mean perfusion speed; ​ ， ​ ， k for mapping coefficients, reflecting the mapping relationship between blood perfusion and the heat conduction coefficient; ​ ​ 2. The wearable capillary perfusion real-time noninvasive monitoring device according to claim 1, wherein, ​ 3. The wearable capillary perfusion real-time noninvasive monitoring device of claim 1, wherein, ​ 4. The wearable capillary perfusion real-time noninvasive monitoring device of claim 3, wherein, ​ 5. The wearable capillary perfusion real-time noninvasive monitoring device of claim 4, wherein, The microcontroller (123) is electrically connected with the temperature sensor (142), adopts a single-chip microcomputer with wireless communication, is used for receiving a voltage signal from the temperature sensor (142), and transmits a temperature signal to an information processing module (2) through wireless communication after conversion.

6. The wearable capillary perfusion real-time noninvasive monitoring device of claim 4, wherein, The processing module core (22) comprises a processing module circuit substrate (221) and a microprocessor (222), a wireless communication chip (223) and a processing module battery (224) tiled on the processing module circuit substrate (221).

7. The wearable capillary perfusion real-time noninvasive monitoring device of claim 6, wherein, The microprocessor (222) and the wireless communication chip (223) adopt a small commercial single-chip microcomputer with a patch type package.

8. The wearable capillary perfusion real-time noninvasive monitoring device of claim 6, wherein, The microprocessor (222) analyzes the temperature signal, calculates a skin heat conduction coefficient through a non-steady-state heat conduction principle, converts the skin heat conduction coefficient into a skin capillary blood perfusion volume, and stores the data.

9. The wearable capillary perfusion real-time noninvasive monitoring device of claim 6, wherein, The material of the circuit substrate is insulating high-temperature-resistant polymer material polyvinyl alcohol, polyester, polyimide or polynaphthalene dimethyl glycol ester, and the shape is sheet-shaped with an area of 1-100 cm 2 The components on the circuit substrate are connected through the matched circuit printed directly on the circuit substrate.

10. The wearable capillary perfusion real-time noninvasive monitoring device of claim 1, wherein, The temperature collection module (1) is arranged on a body surface directly above a center of a pilot's neck capillary vessel, a lower layer (14) of the collection module is separated from the skin by only a collection module bottom package (15), and the information processing module (2) is arranged on a piece of clothing on the pilot's chest or thigh.

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