Subcutaneous hydrops change monitoring device and impedance value measuring method

Abstract

The invention belongs to the field of medical equipment, and particularly relates to a subcutaneous effusion change monitoring device and an impedance value measuring method. The electrode paste is detachably connected with the control unit and comprises a sheet-shaped carrier and an electrode plate, an electrode point used for installing the electrode plate is arranged on the upper surface of the sheet-shaped carrier, and a bonding layer is arranged on the lower surface of the sheet-shaped carrier; the electrode plate comprises a measuring electrode pair and at least two excitation electrode pairs arranged in parallel, all the excitation electrode pairs are used for applying excitation signals to form a cage-shaped field domain containing an equipotential wire harness, and a connecting line of the measuring electrode pairs is perpendicular to the equipotential wire harness, is located in the center of the cage-shaped field domain and is used for measuring a first voltage difference of the cage-shaped field domain; the control unit is configured to: provide power to the excitation electrode pair; and controlling the measuring electrode pair to measure the first voltage difference so as to obtain an impedance value of the cage-shaped field domain, and determining a subcutaneous effusion change monitoring result according to the change of the impedance value. The effect of noninvasively and accurately monitoring the change condition of subcutaneous hydrops is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of medical equipment, and in particular relates to a subcutaneous fluid accumulation change monitoring device and an impedance value measuring method. Background Art

[0002] Subcutaneous effusion can easily lead to the formation of tumors under the skin, local swelling, and higher than normal tissue, which will harm health. Common causes of subcutaneous effusion include the formation of subcutaneous hematoma after contusion, including chronic effusion formed by liquefaction of post-traumatic hematoma, and the appearance of effusion in the wound after surgery. The effusion can be bloody, purulent, or clear tissue exudate.

[0003] Traditional monitoring of subcutaneous fluid changes relies on doctors' clinical observations, imaging examinations, and laboratory tests. However, these methods usually require professional equipment and manual analysis, making it difficult to conduct real-time, portable, and continuous monitoring. With the continuous development of technologies such as the Internet of Things, sensor technology, big data, and artificial intelligence, subcutaneous fluid change monitoring technology is also constantly improving. In recent years, many subcutaneous subcutaneous fluid change monitoring devices have been developed.

[0004] Among them, the subcutaneous fluid change monitoring equipment is mostly subcutaneous bleeding monitoring equipment. Subcutaneous bleeding refers to the phenomenon that tiny blood vessels under the skin rupture and cause blood to seep into the surrounding tissues. This situation may be caused by trauma, surgery, anticoagulant therapy, blood coagulation dysfunction, etc.

[0005] Patent document CN 112437631 A discloses a directional and regional bioimpedance bleeding detection technology. The system of this technology includes: an introducer, which can be used to insert a catheter into a patient's blood vessel, and the introducer includes a hollow sheath to receive the catheter when the catheter is inserted into the blood vessel; a first plurality of electrodes, the first plurality of electrodes are arranged on the sheath; and a measuring device, the measuring device is coupled to the electrodes, and the measuring device is configured to: detect bleeding in the patient at a first area along the sheath by determining the impedance between a first pair of electrodes in the first plurality of electrodes; and detect bleeding in the patient at a second area along the sheath by determining the impedance between a second pair of electrodes in the first plurality of electrodes. However, this application requires inserting a catheter with electrodes into human tissue, which is an invasive solution. Only through surgery and magnetic resonance imaging can the mechanical sensor be introduced into the body, which has the risk of causing damage to the human body and is easy to cause psychological burden to the patient. At the same time, this invasive solution can only be used for patients lying in bed, affecting the normal life of the patient, and cannot be worn for daily monitoring. In addition, the host device and the electrode sensor need to be connected through wires, which may introduce the wire's own conduction impedance and external interference (such as industrial frequency). When in use, the host device needs to be hung on the patient, and the structural product design is unreasonable.

[0006] In view of this, it is necessary to develop a subcutaneous fluid effusion change monitoring device that can perform non-invasive measurements, has an integrated design, a small device size, and has good monitoring accuracy. Summary of the invention

[0007] The purpose of the present invention is to provide a subcutaneous effusion change monitoring device and an impedance value measurement method to solve the problems existing in the prior art, such as monitoring risks, data interference, unreasonable monitoring equipment structure, and inability to be worn for daily monitoring.

[0008] To achieve the above object, the present invention adopts the following technical solutions: According to a first aspect of the present invention, there is provided a subcutaneous fluid accumulation change monitoring device, comprising: Control unit; An electrode patch, detachably connected to the control unit, the electrode patch comprising a sheet carrier and an electrode sheet, the upper surface of the sheet carrier being provided with electrode points for mounting the electrode sheet, and the lower surface of the sheet carrier being provided with a fitting layer for fitting a target object; The electrode sheet comprises a measuring electrode pair (22) and at least two pairs of excitation electrode pairs (23) arranged in parallel, the at least two pairs of excitation electrode pairs (23) being used to apply an excitation signal of a preset frequency to form a cage-shaped field containing an equipotential line beam, and a central connecting line of the measuring electrode pair (22) being perpendicular to the equipotential line beam and located at a central position of the cage-shaped field, and being used to measure a first voltage difference of the cage-shaped field; The control unit is configured to: provide power to the excitation electrode pair (23) to form the cage-shaped field in the area to be monitored of the target object; control the measurement electrode pair (22) to measure the first voltage difference to obtain the impedance value of the area to be monitored, and determine the subcutaneous fluid accumulation change monitoring result according to the change of the impedance value.

[0009] In some embodiments, the ratio of the first spacing of each of the excitation electrode pairs to the second spacing of the measurement electrode pairs satisfies a preset multiple range. The cage-shaped field is divided into a first half and a second half by the perpendicular bisector of the straight line corresponding to the first spacing, the positive end of the measuring electrode pair and the positive ends of all the excitation electrode pairs are distributed in the first half, and the negative end of the measuring electrode pair and the negative ends of all the excitation electrode pairs are distributed in the second half.

[0010] In some embodiments, the control unit further comprises a calibration unit configured to: The impedance value is collected and standardized, and the standardized impedance value is subjected to data filtering based on a preset filter function, and the processing result is used as the calibrated impedance value; Extracting target condition features based on the calibrated impedance value, and inputting the target condition features into a pre-trained model to obtain a probability of subcutaneous effusion change, and determining whether the probability of subcutaneous effusion change reaches a preset probability; In response to the probability of the subcutaneous effusion change reaching a preset probability, monitoring the decreasing rate of the calibrated impedance value, and determining the subcutaneous effusion change monitoring result of the to-be-monitored area according to the decreasing rate; Among them, the target condition features include width features, area features, depth features, kurtosis features, distribution map features and complexity features.

[0011] In some embodiments, a second electrode patch having the same structure as the electrode patch and forming a cage field with the same or different range as the electrode patch is also included. The second electrode patch can replace the electrode patch and is detachably connected to the control unit.

[0012] In some embodiments, the control unit further comprises a microprocessor configured to: converting the current flowing through the measuring electrode pair into a second voltage difference, collecting the first voltage difference and the second voltage difference, and performing discrete Fourier transform processing on the collected data to obtain a target voltage value and a target current value; Determining a voltage amplitude and a current amplitude based on the target voltage value and the target current value; The impedance value is obtained based on the voltage amplitude and the current amplitude.

[0013] In some embodiments, The control unit (1) further comprises an alarm status indicator light (3) and a buzzer (4) respectively connected to the calibration unit for communication, the alarm status indicator light (3) being used to trigger a light consistent with the alarm indication level according to the alarm indication of the calibration unit, and the buzzer (4) being used to trigger a sound effect consistent with the alarm indication level according to the alarm indication of the calibration unit; The calibration unit is further configured to: Determining whether the falling rate reaches a first threshold; If the drop rate reaches a first threshold, a first-level alarm indication is triggered, and the current calibrated impedance value is used as a reference impedance value, and the percentage change of the calibrated impedance value compared to the reference impedance value is continuously monitored; If the change percentage reaches a first preset percentage, a second-level alarm indication is triggered, and if the change percentage reaches a second preset percentage lower than the first preset percentage, a third-level alarm indication is triggered.

[0014] In some embodiments, the control unit further includes a three-axis acceleration sensor, which is communicatively connected to the calibration unit for measuring pitch angle information of the target object and sending it to the calibration unit so that the calibration unit calibrates the impedance value according to the pitch angle.

[0015] In some embodiments, the sheet carrier comprises a flexible, breathable material having a thickness ranging from 1 to 5 mm.

[0016] In some embodiments, the at least two pairs of excitation electrode pairs (23) include a first excitation electrode pair and a second excitation electrode pair, which are installed parallel to each other on the upper surface of the sheet carrier (2), and the measuring electrode pair (22) is installed at a position on the upper surface of the sheet carrier (2) that is equidistant from the first excitation electrode pair and the second excitation electrode pair, and the midpoint of the line connecting the measuring electrode pair (22), the midpoint of the line connecting the first excitation electrode pair, and the midpoint of the line connecting the second excitation electrode pair are all located on the same straight line.

[0017] Another aspect of the embodiment of the present invention further provides an impedance value measuring method, including: Applying an excitation signal of a preset frequency to the target object through at least two pairs of excitation electrodes to form a cage-shaped field containing equipotential wire bundles in the area to be monitored of the target object; A first voltage difference is obtained by measuring a pair of measuring electrodes located in the center of the cage-shaped field and having a center line perpendicular to the equipotential line bundle; The impedance value of the area to be monitored is determined according to the first voltage difference.

[0018] By adopting the above technical solution, the present invention has at least the following beneficial effects: The subcutaneous effusion change monitoring device provided by the present invention is optimized for medical device products using impedance measurement. The excitation electrode pairs and the measuring electrode pairs are arranged in a specific manner on the electrode patch, so that after the device is started, the excitation signal applied by the device forms a cage-shaped field to force the current to flow through the target object's area to be detected, avoiding the current diffusion to the surrounding tissues resulting in excessive measurement range, low sensitivity, and inaccurate measurement; the measuring electrode pairs are arranged according to the position where the cage-shaped field is formed to ensure that the measurement range is accurate and the signal sensitivity is optimal, and can only respond to the impedance changes caused by the subcutaneous effusion changes in the area to be detected, avoiding interference from the surrounding tissues to obtain accurate subcutaneous effusion change monitoring results, ensuring the accuracy and reliability of detecting subcutaneous effusion changes on the skin surface, and providing a high-reliability hardware foundation for non-invasive subcutaneous effusion change monitoring. By attaching the device to the skin, real-time monitoring of subcutaneous effusion changes can be achieved around the clock, providing timely reference for doctors and patients, and is particularly suitable for early warning of subcutaneous effusion changes in postoperative monitoring or emergency scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 A structural layout diagram of a subcutaneous fluid accumulation change monitoring device provided by an embodiment of the present invention; Figure 2 A schematic diagram of two pairs of excitation electrodes forming a cage-shaped field according to an embodiment of the present invention; Figure 3 A schematic diagram of a cage-shaped field formed by an arc-shaped excitation electrode pair provided in an embodiment of the present invention; Figure 4 A schematic diagram of a control unit circuit design provided by an embodiment of the present invention; Figure 5 A schematic diagram of impedance value-time variation for determining subcutaneous fluid accumulation under different conditions provided by an embodiment of the present invention; Figure 6 A schematic diagram of the distribution design of the excitation electrode pairs and the measurement electrode pairs in a sheet-shaped carrier provided by an embodiment of the present invention; Figure 7 A schematic diagram of an impedance value measurement method provided by an embodiment of the present invention.

[0021] Reference numerals list 1 control unit; 2 electrode sticker; 21 sheet carrier; 22 measuring electrode pair; 23 excitation electrode pair; 221 positive end of measuring electrode pair; 222 negative end of measuring electrode pair; 231 positive end of excitation electrode pair; 232 negative end of excitation electrode pair; 24 electrical connection wire of electrode sticker; 3 alarm status indicator light; 4 buzzer; 5 three-axis acceleration sensor; 6 lithium battery; 7 battery pull-out tab; 8 status indicator light; 9 reset button, 10 pot calibration button; 11 PCBA circuit board; 12 connection wire between control unit and sheet carrier; 13 positive electrode of lithium battery; 14 negative electrode of lithium battery. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0023] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents recorded in the specification so as to facilitate the understanding and reading of technical personnel in this field, and are not used to limit the conditions under which the present application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present application, should fall within the scope of the technical content disclosed in the present application.

[0024] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The term "or" is usually used to include the meaning of "and / or", unless the content clearly indicates otherwise.

[0025] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described based on the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. The terms "bottom", "top", "lower", "inside", and "outside" indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0027] The change of subcutaneous effusion in the present application refers to the appearance of bloody, purulent, or relatively clear tissue exudate in the subcutaneous tissue. The change of subcutaneous effusion is mainly characterized by a corresponding change in the impedance value of the subcutaneous tissue.

[0028] The present invention provides a device for monitoring changes in subcutaneous fluid accumulation. Figure 1 As shown, the subcutaneous fluid accumulation change monitoring device includes a control unit 1 and an electrode patch 2.

[0029] The electrode patch 2 is detachably connected to the control unit 1. The electrode patch 2 includes a sheet carrier 21 and an electrode sheet. The upper surface of the sheet carrier 21 is provided with electrode points for mounting the electrode sheet, and the lower surface of the sheet carrier 21 is provided with a fitting layer for fitting the target object. The electrode sheet includes a measuring electrode pair 22 and at least two pairs of excitation electrode pairs 23.

[0030] In one embodiment shown, the electrode patch 2 is a disposable electrode patch that can be detachably connected to the control unit 1. The disposable electrode patch 2 does not need to be reused between different patients, which is hygienic, safe, convenient, efficient, and improves the wearing comfort of the patient. The electrode patch 2 and the control unit 1 are an integrated design connected by a flexible flat cable. The overall thickness and volume of the device are small. Compared with the separate design of the host device and the electrode sensor in the prior art, it has the advantages of a light and thin design, improves the comfort of use, avoids the monitoring error caused by the introduction of wires, and improves the anti-interference ability of the whole device.

[0031] In the embodiment shown, Figure 1 As shown, the structural layout diagram of the subcutaneous effusion change monitoring device is illustrated. The control unit 1 uses a printed circuit board assembly hard board or FPC (Flexible Printed Circuit) as a carrier, and the hardware circuits such as the microcontroller circuit, lithium battery power circuit, and buzzer circuit are installed on the circuit board to serve as the control board of the control unit 1. The electrode patch 2 can use a sheet carrier 21 in combination with metal conductive rivets, solid gel and electrode sheets to achieve a portable monitoring effect of sticking to human skin. The sheet carrier 21 can be a flexible breathable material such as a non-woven fabric with a thickness range of 1-5mm or a woven fabric with double-sided tape, which has the advantages of being breathable, light and non-irritating, and can reduce the foreign body sensation caused by sticking to the skin for a long time. The solid gel is not easy to deform, harden, and has good moisture-proof and anti-fouling properties. It is arranged on the lower surface of the sheet carrier 21 for sticking to the skin of the target object, which can maintain stable contact between the skin and the electrode and reduce signal interference caused by body movement. The metal conductive rivet is arranged on the lower surface of the sheet carrier 21, and is used to connect the electrode sheet and the conductive adhesive layer to achieve the transmission of electrical signals between the biological tissue and the electrode sheet in the area to be detected. The metal conductive rivet is tightly combined with the sheet carrier 21 to ensure stable conductivity, and its corrosion resistance is good, which is suitable for long-term signal acquisition.

[0032] At least two pairs of excitation electrode pairs 23 in the electrode sheet are arranged in parallel. Parallel arrangement means that the connection line L1 of the positive electrode in each excitation electrode pair is arranged in parallel with the connection line L2 of the negative electrode in each excitation electrode pair. After applying an excitation signal of a preset frequency, the at least two pairs of excitation electrode pairs 23 arranged in parallel form a cage-shaped field containing equipotential line beams.

[0033] When detecting the position change of subcutaneous effusion, one implementation method is to place the electrode patch in the area to be monitored, and the area to be monitored is an area where the potential change of subcutaneous effusion will occur. In the related art, only a single excitation electrode pair is used to inject the excitation signal. When the current flows from F+ to F-, the path naturally diffuses to form a wider electric field distribution, and the impedance value reflected by the voltage difference measured by the measuring electrode pair located in the diffuse electric field will include all biological tissues through which the current flows, that is, the biological tissue in the area to be detected and its surrounding biological tissue. The current path is dispersed, resulting in an excessively large measurement area, and the signal in the area to be detected is "diluted" by the impedance of the surrounding biological tissue, resulting in the calculated impedance value being a comprehensive impedance, that is, the parallel result of the biological tissue in the area to be detected and the surrounding biological tissue, making it difficult to focus on the impedance change at the subcutaneous effusion change point.

[0034] The electrode sheet in the present invention uses at least two pairs of excitation electrode pairs and one pair of measuring electrode pairs. All electrode sheets need to be arranged in a specific array manner. The ultimate goal is to enable at least two pairs of excitation electrode pairs 23 to form a cage-shaped field containing equipotential wire bundles, so that the device can accurately monitor the changes in subcutaneous fluid accumulation in the area to be detected on the skin surface and alarm.

[0035] Specifically, Figure 2 For example, when the electrode sheet includes two pairs of symmetrically arranged excitation electrode pairs, the two pairs of excitation electrode pairs simultaneously apply excitation signals of preset frequencies, and form a cage field in the area to be detected by superimposing an electric field, wherein the range of the cage field is determined according to the distance between the positive and negative ends of the excitation electrode pairs and the relative positions between the two pairs of excitation electrode pairs. The lateral (referring to the direction perpendicular to the excitation electrode pairs) current components in the cage field cancel each other out, the longitudinal current components are superimposed and enhanced, the electric field is evenly distributed, the potential lines are dense and parallel, and a beam of equipotential lines perpendicular to the excitation electrode pairs is formed. The formation of the cage field forces the current to be confined in the area to be detected and forms a closed loop along the longitudinal flow, avoiding current diffusion and excessive attenuation of deep electrical signals. Figure 2 The dashed lines shown in the figure are equipotential lines, the black arrows are electric field lines, and the black dots are virtual centers of the cage-shaped field. Figure 3 The arc-shaped excitation electrode pair shown or more than two pairs of excitation electrode pairs can also form a similar cage field.

[0036] The connection line of the measuring electrode pair 22 is perpendicular to the equipotential line bundle and is located at the center of the cage field, and is used to measure the first voltage difference of the cage field. The control unit is configured to: provide power to the excitation electrode pair 23 to form a cage field in the target object's monitored area, control the measuring electrode pair 22 to measure the first voltage difference to obtain the impedance value of the monitored area, and determine the subcutaneous fluid accumulation change monitoring result according to the change of the impedance value.

[0037] The measuring electrode pair 22 is arranged in the central position of the cage field, and the connection line of the measuring electrode pair is perpendicular to the equipotential line bundle, which can maximize the capture of electrical signals and has high measurement sensitivity and signal resolution. Because the subcutaneous effusion change tissue is rich in electrolytes (such as blood), the resistivity is significantly lower than the surrounding biological tissue, which is equivalent to a minimum equivalent resistance. When the amount of subcutaneous effusion in the area to be detected changes, the cage field constrains the electric field so that the current preferentially flows through the lowest resistance path (i.e., the subcutaneous effusion change tissue). In the equivalent circuit model, the minimum equivalent resistance corresponding to the subcutaneous effusion change point becomes the dominant branch in the parallel circuit. At this time, the change in the voltage difference measured by the measuring electrode reflects the impedance change of the subcutaneous effusion change point, which greatly reduces the interference of the surrounding biological tissue, thereby accurately determining the change of subcutaneous effusion in the area to be detected. The design of the cage field formed by the excitation electrode pair solves the problems of large measurement range and insufficient sensitivity in the related technology, can focus on the impedance change of subcutaneous effusion, and significantly improves the accuracy and reliability of subcutaneous effusion change monitoring.

[0038] The subcutaneous effusion change monitoring device provided by the present invention arranges the excitation electrode pair and the measuring electrode pair on the electrode patch in a specific manner, so that after the device is started, the excitation signal applied by the device forms a cage-shaped field to force the current to flow through the target object's area to be detected, avoiding the current diffusion to the surrounding tissues resulting in excessive measurement range, low sensitivity, and inaccurate measurement; the measuring electrode pair is arranged according to the position where the cage-shaped field is formed to ensure that the measurement range is accurate and the signal sensitivity is optimal, and can only respond to the impedance change caused by the subcutaneous effusion change in the area to be detected, avoiding interference from the surrounding tissues to obtain accurate subcutaneous effusion change monitoring results, ensuring the accuracy and reliability of detecting subcutaneous effusion changes on the skin surface, providing a high-reliability hardware foundation for non-invasive subcutaneous effusion change monitoring, and realizing all-weather real-time monitoring of subcutaneous effusion changes by attaching the device to the skin, providing timely reference for doctors and patients, and is particularly suitable for early warning of subcutaneous effusion changes in postoperative monitoring or emergency scenarios.

[0039] Furthermore, the present invention can also be optimized for medical device products using impedance measurement: the electrode patch and the control unit are integrated into an integrated design to reduce the size of the device. The electrode patch can be designed to be ultra-thin so that the device can be worn on the skin for a long time like a plaster.

[0040] In some embodiments, the ratio of the first spacing of each excitation electrode pair 23 to the second spacing of the measuring electrode pair 22 satisfies a preset multiple range, and the cage field is divided into a first half and a second half by the perpendicular bisector of the straight line corresponding to the first spacing, and the positive end 221 of the measuring electrode pair and the positive ends 231 of all the excitation electrode pairs are distributed in the first half, and the negative end 222 of the measuring electrode pair and the negative ends 232 of all the excitation electrode pairs are distributed in the second half.

[0041] In the embodiment shown, Figure 1 and Figure 6 As shown, each excitation electrode pair 23 includes a positive terminal 231 for applying an excitation signal F+ and a negative terminal 232 for applying an excitation signal F-. The first spacing is the distance between the positive terminal 231 and the negative terminal 232 of the excitation electrode pair 23, and the second spacing is the distance between the positive terminal 221 and the negative terminal 222 of the measuring electrode pair 22. The positive terminals 231 of all the excitation electrode pairs 23 are located in the same half of the cage field and are interconnected through electrical connection lines 24, and the negative terminals 232 of all the excitation electrode pairs 23 are located in the other half of the cage field and are interconnected through another electrical connection line 24.

[0042] In the illustrated embodiment, in terms of bioelectrical impedance detection, such as subcutaneous bleeding monitoring, the signal transmitted from the impedance change in the deep tissue to the skin surface is weak, which makes deep bleeding monitoring more difficult and easily masked by noise. Therefore, a reasonable arrangement of electrodes is particularly important for achieving high-precision non-invasive monitoring of subcutaneous bleeding on the skin surface. The position deviation of the electrode sheet may lead to inaccurate monitoring area, so a larger measurement range is required, but sufficient sensitivity should be maintained to avoid excessive measurement range and low sensitivity. In addition, bleeding detection requires comparison of the impedance value before bleeding and the impedance value after bleeding, but the actual current change before and after bleeding is not obvious and the error is large, so it is necessary to improve the signal resolution. The present invention adopts a four-electrode method and designs a reasonable arrangement of electrode sheets, which can effectively solve the problems of insufficient sensitivity, range and resolution during skin surface monitoring. The four-electrode method is F+, F-, S+, S-. The excitation electrode pair 23 is an outer electrode, and a sine wave of an excitation signal with a preset frequency is applied after each start-up of the device. The preset frequency can be 50khz. The measuring electrode pair 22 is an inner electrode, which collects the voltage difference between the two points to reflect the impedance change of the area to be detected. When the first spacing of the excitation electrode pair is too far, it is easy to make the voltage difference obtained by the measuring electrode pair change less. In order to improve the signal resolution, the first spacing should be appropriately reduced. After design and verification, when the ratio of the first spacing to the second spacing meets the preset multiple range, the electric field strength of the area to be detected can be effectively enhanced to improve the signal resolution. When the spacing between the positive end 221 and the negative end 222 in the measuring electrode pair 22 is smaller, that is, the second spacing, the steeper the electric field gradient, the more sensitive to local impedance changes, but it is easy to limit the measurement range and only cover shallow or small monitoring areas. In order to improve the accuracy of the bleeding monitoring area, it is necessary to appropriately enlarge the second spacing. After design and verification, when the second spacing meets the spacing range shown in Table 1 below, it can ensure that the monitoring area is accurate and maintain sufficient sensitivity. Before and after actual bleeding, the current changes very little, mainly because the voltage difference of the measuring electrode pair 22 changes greatly, so in order to improve signal quality, the impedance change can also be replaced by monitoring the voltage difference change. The first spacing range of the excitation electrode pair 23 and the second spacing range of the measuring electrode pair 22 are shown in Table 1 below. It can be seen from Table 1 that in some preferred embodiments, the first spacing range is 4~20cm, the second spacing range is 2~14cm, and the preset multiple range is [1.4,2].

[0043] Table 1

[0044] The subcutaneous fluid effusion change monitoring device provided by the present invention arranges the individual electrode sheets in a specific array manner, which can achieve high-sensitivity, wide-range coverage and high-resolution monitoring of deep subcutaneous fluid effusion changes on the skin surface, significantly improving the reliability of the monitoring results.

[0045] In some embodiments, the control unit 1 also includes a microprocessor, which is configured to: convert the current flowing through the measuring electrode pair 22 into a second voltage difference, collect the first voltage difference and the second voltage difference, and perform discrete Fourier transform processing on the collected data to obtain a target voltage value and a target current value; determine the voltage amplitude and the current amplitude based on the target voltage value and the target current value; and obtain the impedance value based on the voltage amplitude and the current amplitude.

[0046] In the embodiment shown, Figure 4 As shown, after the device is powered on, an AC excitation signal of known frequency and amplitude can be applied to the unknown impedance through the excitation electrode pair, and the current flowing through the potential subcutaneous effusion change point and the voltage difference (i.e., the first voltage value) at the potential subcutaneous effusion change point can be measured through the measuring electrode pair 22. The microprocessor includes a TIA (trans-impedance amplifier), an ADC (digital-to-analog converter), and a digital filter. The current at the potential subcutaneous effusion change point is converted into a voltage that can be measured by the ADC, i.e., the second voltage difference, through the TIA. The ADC samples the first voltage difference and the second voltage difference to obtain discrete time series data, and performs DFT discrete Fourier transform on each discrete time series data. DFT is performed according to the time series data corresponding to the first voltage difference to calculate the target voltage value, and DFT is performed according to the time series data corresponding to the second voltage difference to calculate the target current value. Because DFT can decompose data into sine and cosine components of different frequencies, the target voltage and target current values ​​obtained are complex data containing real and imaginary parts, which describe the amplitude and phase of the measured signal. Therefore, the voltage amplitude and current amplitude can be obtained by extracting the real and imaginary parts of the target voltage and target current. The voltage and current at the potential subcutaneous effusion change point can be obtained based on the voltage amplitude and current amplitude. The voltage and current at the potential subcutaneous effusion change point can be combined with the following formula 1 to calculate the impedance value:

[0047] in, is the impedance value, is the voltage at the point of potential subcutaneous fluid change, is the current at the potential subcutaneous fluid change point, is the value of the high speed TIA gain resistor in Ω.

[0048] In the embodiment shown, blood vessel damage can cause fluid (such as blood) between human tissues to flow into the interstitial space, increasing the local conductivity and thus reducing the impedance value. The digital filter can continuously calculate the change trend of the impedance value to monitor the change of subcutaneous fluid accumulation so as to trigger the corresponding level of alarm in time.

[0049] The subcutaneous fluid effusion change monitoring device provided by the present invention performs non-invasive monitoring of subcutaneous fluid effusion changes in the skin epidermis based on the characteristic that the impedance value changes with the change of subcutaneous fluid effusion. It can be used for monitoring subcutaneous fluid changes in internal organs and subcutaneous fluid changes in deep tissue injuries. It can provide all-weather real-time monitoring data to provide reference for doctors and users.

[0050] Taking subcutaneous bleeding monitoring as an example, Figure 5 As shown in the figure, when using impedance value changes to monitor subcutaneous bleeding, multiple judgment conditions are also needed to judge bleeding and non-bleeding, so as to improve the accuracy of monitoring data and reduce false positives. The judgment conditions include the following 4 points: (1) Impedance drop rate. Figure 5 As shown in A, by calculating the slope of the impedance value changing over time, slow bleeding, acute bleeding and interference can be distinguished. The impedance drop rate slope value is within a certain range, such as 3~40% / min, which may be the bleeding condition to be monitored, that is, slow bleeding. If the impedance value changes too quickly, it is either acute bleeding that can be judged manually or interference. If the impedance value changes too slowly, it may be caused by changes in the contact impedance of the electrode patch or baseline drift such as temperature, and it is not real bleeding. (2) Impedance change amplitude and change rate. Figure 5 As shown in B, by calculating the ratio and absolute value of the impedance before and after bleeding, the impedance fluctuation caused by interference such as body movement and contact impedance change is eliminated. The ratio and absolute value of the impedance before and after bleeding are within a certain range, such as 2-10%, which may be the bleeding situation to be monitored. Too low impedance changes may be interference such as body movement or contact impedance change. (3) How long does the impedance change last? Figure 5 As shown in C, by setting the duration threshold of bleeding, short-term interference is eliminated and long-term impedance drift is prevented from being misjudged as bleeding. Only when the impedance change duration is within a certain range, such as 20s~30min, it may be the bleeding situation to be monitored. If the impedance change duration is too short, it may be interference such as body movement. If the impedance change duration is too long, it may not be human bleeding. (4) Complexity of impedance drop curve. Figure 5 As shown in D, by calculating the kurtosis of the impedance drop curve, sample entropy and other characteristics, we can determine whether it conforms to the typical bleeding pattern. In actual clinical bleeding sites, the internal human blood pressure, external pressure, and increased hematoma pressure in the tissue after bleeding will change the bleeding rate. The complexity of blood pressure changes within a certain range, such as a kurtosis of 2~30 and a sample number of 0.2~0.8, may be the bleeding situation to be monitored.

[0051] According to the above judgment conditions, four types of features, namely, impedance drop slope, impedance drop area, impedance drop depth, and impedance drop complexity, are used to predict bleeding and non-bleeding, and a pre-trained model is constructed in combination with a machine learning algorithm. The machine learning algorithm includes but is not limited to support vector machine SVM, adboost and other algorithms, and the model modelV is obtained through training.

[0052] The following describes the preparation process of the pre-trained model: The first step is data collection. Collect bioimpedance data in different situations, such as animal experiments, simulated tooling, and clinical simulation data, and slice the data into impedance data segments with a preset duration, such as 3 minutes, of subcutaneous fluid changes and no subcutaneous fluid changes; Step 2: Data standardization. Two time windows are used for data standardization to eliminate the influence of individual differences. The data standardization formula is X2=W1*X / (W2*X), where X is the initial impedance data segment, X2 is the standardized impedance data segment, and W1 and W2 are window functions respectively; Step 3: Data filtering. The impedance data segment obtained in the second step is filtered by a preset filter function consisting of a relaxation factor and a filter threshold to eliminate impedance fluctuations caused by factors other than subcutaneous fluid changes. The preset filter function is X3=X2 / [1+k*exp(x2+C)], where X3 is the filtered impedance data segment, i.e., the processing result, k is the relaxation factor, and C is the filter threshold, which is determined according to the impedance drop rate when the subcutaneous fluid changes the slowest; Step 4: Feature extraction. In a fixed time window (e.g., within 3 minutes), extract six types of conditional features as shown in Table 2; Step 5: Machine learning modeling. The conditional features extracted in the fourth step are used as model input, and the SVM, Adaboost and other algorithms are used to train the model to determine the changes in subcutaneous fluid accumulation, and the final subcutaneous fluid accumulation change discrimination model Model V is obtained, that is, the pre-trained model.

[0053] Table 2

[0054] After obtaining the pre-trained model, the impedance value obtained by real-time monitoring of the control unit 1 is used to determine the change of subcutaneous fluid accumulation. Since the body composition and skin contact impedance of different human bodies are different, the calculated impedance value needs to be calibrated first, that is, the standardization processing and data filtering processing in the second to third steps above. The target condition characteristics of the real-time impedance value are extracted through the process of the fourth step above. The target condition characteristics are input into the pre-trained model to obtain the probability of subcutaneous fluid accumulation change. When the probability of subcutaneous fluid accumulation change reaches the preset probability (such as 95%), the real-time subcutaneous fluid accumulation change judgment result is a subcutaneous fluid accumulation change, otherwise it is a non-subcutaneous fluid accumulation change.

[0055] The subcutaneous effusion change monitoring device provided by the present invention realizes the judgment of subcutaneous effusion changes and non-subcutaneous effusion changes through impedance value analysis by a calibration unit, and solves the problem that the traditional single threshold method is susceptible to interference and has a high false alarm rate by combining multi-dimensional feature extraction and machine learning classification algorithm. It can dynamically capture the spatiotemporal characteristics of impedance changes, distinguish between real subcutaneous effusion changes and interference events, and improve the accuracy and reliability of device monitoring.

[0056] In the illustrated embodiment, the control unit 1 further includes an alarm status indicator light 3 and a buzzer 4 which are respectively communicatively connected to the calibration unit, the alarm status indicator light 3 being used to trigger a light consistent with the alarm indication level according to the alarm indication of the calibration unit, and the buzzer 4 being used to trigger a sound effect consistent with the alarm indication level according to the alarm indication of the calibration unit; the calibration unit is further configured to: determine whether the descent rate reaches a first threshold; if the descent rate reaches the first threshold, trigger a first-level alarm indication, and use the current calibrated impedance value as the reference impedance value, and continue to monitor the percentage change of the calibrated impedance value compared to the reference impedance value; if the percentage change reaches a first preset percentage, trigger a second-level alarm indication, and if the percentage change reaches a second preset percentage lower than the first preset percentage, trigger a third-level alarm indication.

[0057] In the illustrated embodiment, after the device is powered on, the control unit 1 performs a series of self-tests to ensure normal function. Then the microprocessor is started to monitor the change of subcutaneous fluid accumulation, which uses a digital filter to collect, convert and calculate the change of biological impedance value, and calibrates the calculation result through the calibration unit. If the real-time subcutaneous fluid accumulation change judgment result of the calibration unit is a subcutaneous fluid accumulation change, the rate of impedance value decrease is continuously monitored to determine whether the rate of decrease of the impedance value reaches the prescribed slope threshold, i.e., the first threshold, such as 3% / min. The first threshold satisfies the range of 3~40% / min, which can be set according to the actual application. When the rate of decrease of the impedance value reaches the first threshold, the calibration unit will trigger a first-level alarm indication and save the impedance value at this time as a benchmark for measuring the change process of subcutaneous fluid accumulation, i.e., the benchmark impedance value. If the change of subcutaneous fluid accumulation continues to develop, the impedance value continues to decrease, and after the decrease exceeds the first preset percentage relative to the benchmark impedance value, such as 85%, a second-level alarm indication will be triggered. Furthermore, if the change of subcutaneous fluid accumulation continues to develop, and after the decrease exceeds the second preset percentage relative to the benchmark impedance value, such as 70%, a third-level alarm indication will be triggered.

[0058] In the illustrated embodiment, the alarm status indicator light 3 may be a 3-level LED indicator light. Figure 2As shown, the alarm status indicator light 3 and the buzzer 4 are respectively connected to the microprocessor for communication. According to the first-level alarm indication of the microprocessor, the first-level sound and light alarm is triggered. According to the second-level alarm indication of the microprocessor, the second-level sound and light alarm with stronger auditory and visual effects than the first-level sound and light alarm is triggered. According to the third-level alarm indication of the microprocessor, the third-level sound and light alarm with the highest intensity is triggered.

[0059] The subcutaneous effusion change monitoring device provided by the present invention adopts real-time data analysis combined with graded alarm to realize rapid alarm of subcutaneous effusion changes of different severity.

[0060] In some embodiments, a second electrode patch is further included. In one embodiment, the structure of the second electrode patch is the same as that of the electrode patch 2 and the range of the cage-shaped field formed is also the same. The second electrode patch can replace the electrode patch 2 and is detachably connected to the control unit 1. In another embodiment, the structure of the second electrode patch is the same as that of the electrode patch 2, but the range of the cage-shaped field formed may be different.

[0061] In the embodiment shown, the electrode patch 2 is set as a detachable module, and the user can freely replace the electrode patch with different electrode sheet spacing according to the monitoring requirements (such as detection depth and size of the area to be detected, etc.). By replacing the electrode patch 2, the first spacing of the excitation electrode pair 23 and the second spacing of the measuring electrode pair 22 are adjusted to optimize the electric field distribution and signal quality in different monitoring scenarios. The subcutaneous effusion change monitoring device in this embodiment solves the problem that the traditional subcutaneous effusion change monitoring device with fixed electrodes cannot be adapted to the diversified detection scenarios for adjustment once it is produced.

[0062] In some embodiments, the control unit 1 further includes a three-axis acceleration sensor 5, which is communicatively connected to the calibration unit for measuring pitch angle information of the target object and sending it to the calibration unit so that the calibration unit calibrates the impedance value according to the pitch angle.

[0063] In the embodiment shown, different postures of the human body may lead to different electrode pressures, affecting impedance measurement. By adding a three-axis acceleration sensor 5 to the control unit 1, the wearer's body movement can be sensed in real time, and the impedance value can be calibrated through the calibration unit to improve the accuracy of determining the change of subcutaneous subcutaneous effusion, and the results of subcutaneous subcutaneous effusion change monitoring can be given more accurately. The three-axis acceleration sensor 5 calibrates the impedance value by measuring the wearer's pitch angle combined with a specific algorithm such as an activity calculation algorithm to reduce the false triggering alarm of the device due to body movement.

[0064] The subcutaneous effusion change monitoring device provided by the present invention can effectively improve the reliability of subcutaneous effusion change monitoring through the acceleration sensor 5, help distinguish between real subcutaneous effusion changes and body movement interference, achieve more accurate medical monitoring, and improve early monitoring and warning capabilities.

[0065] In some embodiments, the sheet carrier 21 comprises a flexible, breathable material having a thickness ranging from 1-5 mm.

[0066] In some embodiments, Figure 6 As shown, at least two pairs of excitation electrode pairs 23 include a first excitation electrode pair and a second excitation electrode pair, which are installed parallel to each other on the upper surface of the sheet carrier 21, and the measuring electrode pair 22 is installed at a position equidistant from the first excitation electrode pair and the second excitation electrode pair on the upper surface of the sheet carrier 21, and the midpoint of the line connecting the measuring electrode pair 22, the midpoint of the line connecting the first excitation electrode pair, and the midpoint of the line connecting the second excitation electrode pair are all located on the same straight line.

[0067] In some embodiments, the control unit 1 further includes a lithium battery 6 and a battery pull-out tab 7 which are connected to each other. The lithium battery 6 is used to provide power, and the battery pull-out tab 7 is used to control the on and off of the power.

[0068] The subcutaneous fluid effusion change monitoring device provided by the present invention provides long-term stable power support, so that the device can operate independently without the need for external power connection, thereby improving portability, being able to conveniently control the power switch, reducing battery loss, being on standby at all times, and improving flexibility of use.

[0069] In some embodiments, the control unit 1 also includes a status indicator light 8, a reset button 9 and a pot piece calibration button 10. The status indicator light 8 is used to indicate the operating status of the device, and the operating status includes normal operating status, standby status and abnormal status. The reset button 9 is used to restore the device in an abnormal operating status to an initial state; the pot piece calibration button 10 is acted upon by external force to trigger a calibration program to calibrate the impedance value.

[0070] In the illustrated embodiment, the status indicator light 8 enables the wearer or medical staff to quickly understand the device status and avoid misjudgment caused by device failure or malfunction. Among them, the normal operating state is a state in which the excitation electrode pair can apply AC excitation electrodes and the measuring electrode pair can measure electrical signals, and the standby state is a low-power state when no measurement or operation is performed after power-on. The abnormal state is a state in which the AC excitation signal cannot be output or the output signal is unstable, or the response electrical signal generated by the excitation signal cannot be accurately measured, or the alarm is triggered by error. The reset button 9 manually restores to the initial state when the device is abnormal, ensuring that the device can quickly resume normal operation and ensuring the stability and maintainability of the device. The initial state is a state in which no AC excitation electrodes are applied and no electrical signals are collected after power-on. The calibration procedure includes the aforementioned calibration operations or common calibration algorithms to ensure the consistency of subcutaneous fluid effusion change monitoring in different individuals and different environments, and reduce false alarms and missed reports.

[0071] The subcutaneous fluid effusion change monitoring device provided by the present invention is optimized for medical device products using impedance measurement, and realizes non-invasive and all-weather real-time monitoring of subcutaneous subcutaneous fluid effusion changes, providing doctors and patients with accurate and reliable reference in a timely manner.

[0072] Based on the same inventive concept, according to another aspect of the present invention, Figure 7 As shown, an embodiment of the present invention further provides an impedance value measurement method, which specifically includes the following steps: Step S100, applying an excitation signal of a preset frequency to the target object through at least two pairs of excitation electrode pairs 23, so as to form a cage-shaped field containing equipotential wire bundles in the area to be monitored of the target object; Step S200, obtaining a first voltage difference by measuring a measuring electrode pair 22 located in the center of the cage field and with a center line perpendicular to the equipotential line bundle; Step S300: determining the impedance value of the area to be monitored according to the first voltage difference.

[0073] The impedance value measurement method of the present invention arranges the excitation electrode pair and the measuring electrode pair in a specific manner so that the excitation signal applied by the excitation electrode pair forms a cage-shaped field in the target object's detection area, so that the current only flows through the detection area, avoiding the current diffusion to the surrounding tissues leading to the problem of too large measurement range, low sensitivity, and inaccurate measurement. The measuring electrode pair is arranged according to the position of the cage-shaped field formation to ensure that the measurement range is accurate and the signal sensitivity is optimal. The measured voltage difference can accurately reflect the impedance change caused by the change of subcutaneous fluid accumulation in the detection area, avoid the interference of surrounding tissues, and thus calculate the accurate impedance value, providing a highly reliable solution for non-invasive subcutaneous fluid accumulation change monitoring, which can be used in the technology of detecting subcutaneous subcutaneous fluid accumulation changes on the skin surface to provide timely reference for doctors and patients.

[0074] The above are exemplary embodiments disclosed in the present invention. The order in which the above embodiments of the present invention are disclosed is for description only and does not represent the advantages and disadvantages of the embodiments. However, it should be noted that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope disclosed in the embodiments of the present invention (including the claims) is limited to these examples. Various changes and modifications may be made without departing from the scope defined in the claims. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0075] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A subcutaneous effusion change monitoring device, characterized in that: include: Control unit (1); An electrode patch (2) detachably connected to the control unit (1), the electrode patch (2) comprising a sheet-shaped carrier (21) and an electrode sheet, the upper surface of the sheet-shaped carrier (21) being provided with electrode points for mounting the electrode sheet, and the lower surface of the sheet-shaped carrier (21) being provided with a bonding layer for bonding to a target object; The electrode sheet comprises a measuring electrode pair (22) and at least two pairs of excitation electrode pairs (23) arranged in parallel, the at least two pairs of excitation electrode pairs (23) being used to apply an excitation signal of a preset frequency to form a cage-shaped field containing an equipotential line beam, and the connecting line of the measuring electrode pair (22) is perpendicular to the equipotential line beam and is located at the center of the cage-shaped field, and is used to measure a first voltage difference in the cage-shaped field; The control unit is configured to: provide power to the excitation electrode pair (23) to form the cage-shaped field in the area to be monitored of the target object; control the measurement electrode pair (22) to measure the first voltage difference to obtain the impedance value of the area to be monitored, and determine the subcutaneous fluid accumulation change monitoring result according to the change of the impedance value.

2. The subcutaneous effusion change monitoring device according to claim 1, characterized in that: The ratio of the first spacing of each of the excitation electrode pairs to the second spacing of the measurement electrode pairs meets a preset multiple range, The cage-shaped field is divided into a first half and a second half by a perpendicular bisector of a straight line corresponding to the first spacing, the positive end (221) of the measuring electrode pair and the positive ends (231) of all the excitation electrode pairs being distributed in the first half, and the negative end (222) of the measuring electrode pair and the negative ends (232) of all the excitation electrode pairs being distributed in the second half.

3. The subcutaneous effusion change monitoring device according to claim 1, characterized in that: The control unit (1) further comprises a calibration unit, wherein the calibration unit is configured to: The impedance value is collected and standardized, and the standardized impedance value is subjected to data filtering based on a preset filter function, and the processing result is used as the calibrated impedance value; Extracting target condition features based on the calibrated impedance value, and inputting the target condition features into a pre-trained model to obtain a probability of a subcutaneous effusion change, and determining whether the probability of a subcutaneous effusion change reaches a preset probability; In response to the probability of the subcutaneous effusion change reaching a preset probability, monitoring the decreasing rate of the calibrated impedance value, and determining the subcutaneous effusion change monitoring result of the to-be-monitored area according to the decreasing rate; The target condition features include width features, area features, depth features, kurtosis features, distribution map features and complexity features.

4. The subcutaneous effusion change monitoring device according to claim 1, characterized in that: It also includes a second electrode patch having the same structure as the electrode patch (2) and forming a cage-shaped field with a range that is the same as or different from that of the electrode patch (2); the second electrode patch can replace the electrode patch (2) and is detachably connected to the control unit (1).

5. The subcutaneous effusion change monitoring device according to claim 1, characterized in that: The control unit (1) further comprises a microprocessor, wherein the microprocessor is configured to: converting the current flowing through the measuring electrode pair (22) into a second voltage difference, Collecting the first voltage difference and the second voltage difference, and performing discrete Fourier transform processing on the collected data to obtain a target voltage value and a target current value; Determining a voltage amplitude and a current amplitude based on the target voltage value and the target current value; The impedance value is obtained based on the voltage amplitude and the current amplitude.

6. The subcutaneous effusion change monitoring device according to claim 3, characterized in that: The control unit (1) further comprises an alarm status indicator light (3) and a buzzer (4) respectively connected to the calibration unit for communication, the alarm status indicator light (3) being used to trigger a light consistent with the alarm indication level according to the alarm indication of the calibration unit, and the buzzer (4) being used to trigger a sound effect consistent with the alarm indication level according to the alarm indication of the calibration unit; The calibration unit is further configured to: Determining whether the falling rate reaches a first threshold; If the drop rate reaches a first threshold, a first-level alarm indication is triggered, and the current calibrated impedance value is used as a reference impedance value, and the percentage change of the calibrated impedance value compared to the reference impedance value is continuously monitored; If the change percentage reaches a first preset percentage, a second-level alarm indication is triggered, and if the change percentage reaches a second preset percentage lower than the first preset percentage, a third-level alarm indication is triggered.

7. The subcutaneous effusion change monitoring device according to claim 3, characterized in that: The control unit (1) further comprises a three-axis acceleration sensor (5), which is communicatively connected to the calibration unit and is used to measure pitch angle information of the target object and send the information to the calibration unit, so that the calibration unit calibrates the impedance value according to the pitch angle.

8. The subcutaneous effusion change monitoring device according to claim 1, characterized in that: The sheet-like carrier (21) comprises a flexible breathable material with a thickness ranging from 1 to 5 mm.

9. The subcutaneous effusion change monitoring device according to claim 1, characterized in that: The at least two pairs of excitation electrode pairs (23) include a first excitation electrode pair and a second excitation electrode pair, which are mounted parallel to each other on the upper surface of the sheet carrier (21); the measuring electrode pair (22) is mounted on the upper surface of the sheet carrier (21) at positions equidistant from the first excitation electrode pair and the second excitation electrode pair, and the midpoint of the line connecting the measuring electrode pair (22), the midpoint of the line connecting the first excitation electrode pair, and the midpoint of the line connecting the second excitation electrode pair are all located on the same straight line.

10. A method for measuring impedance, characterized in that: include: Applying an excitation signal of a preset frequency to the target object through at least two pairs of excitation electrodes (23) to form a cage-shaped field containing equipotential wire beams in the area to be monitored of the target object; A first voltage difference is obtained by measuring a pair of measuring electrodes (22) located at the center of the cage-shaped field and with a center line perpendicular to the equipotential line bundle; The impedance value of the area to be monitored is determined according to the first voltage difference.

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