Wearable dynamic and static blood supply monitoring device and method

Abstract

The invention relates to a wearable dynamic and static blood supply monitoring device and method.The device comprises a front-end testing module and a rear-end processing module, the front-end testing module is connected with the rear-end processing module through a front-end and rear-end connecting line, and the front-end testing module covers the skin of a patient; the front-end processing module comprises a pressure layer and a light transmitting and receiving layer, a pressure sensor is arranged on the pressure layer, a light emitting diode and a photoelectric detector are arranged on the light transmitting and receiving layer, the pressure layer is connected with the light transmitting and receiving layer through a front-end internal connecting wire, and packages are arranged on the two surfaces of the pressure layer and the light transmitting and receiving layer. The rear-end processing module comprises a signal collecting, processing and transmitting layer, a signal collecting, processing and transmitting part is arranged on the signal collecting, processing and transmitting layer, and packages are arranged on the two faces of the signal collecting, processing and transmitting layer. Compared with the prior art, non-invasive real-time monitoring of the skin blood supply state is achieved, and the thrombus type can be judged in time.

Description

Technical Field

[0001] The invention belongs to the technical field of medical biosensors and relates to a wearable dynamic and static blood circulation monitoring device and method. Background Art

[0002] Free flap transplantation is a common skin repair method in reparative and reconstructive surgery. It can be used to cover skin wounds caused by trauma, tumor resection, etc., and can also be used to repair large-area skin and soft tissue defects caused by scar correction. Free flap transplantation covers the affected area with a free flap and anastomoses the artery and vein with the main blood vessels of the affected area, which can achieve continuous blood supply to the flap and form new peripheral blood vessels. With the continuous improvement of microsurgical technology, the success rate of flap transplantation has reached a relatively high level, and many literatures claim that the survival rate is above 95%.

[0003] Although flap transplantation is relatively mature, its risks cannot be ignored. Blood flow disorder is the main reason for the failure of flap transplantation. Once it occurs, it is very easy for the transplanted flap to lose blood supply in a short period of time, causing microcirculation disorder. If rescue is not timely, it will cause necrosis of the transplanted flap. In clinical practice, the flap rescue rate is negatively correlated with the ischemic time. Therefore, it is very important for patients to conduct long-term blood flow monitoring after surgery.

[0004] At present, the postoperative monitoring methods for transplanted skin flaps are mainly divided into two categories: clinical monitoring and instrument monitoring. The clinical monitoring method mainly relies on the doctor's clinical experience, including observing the color, surface temperature, capillary reaction, tissue elasticity, and needle bleeding of the skin flap. Clinical observation is more accurate, but it is more subjective and depends on the clinical experience of the observer. It has poor mobility and cannot achieve long-term continuous monitoring. Therefore, there is a lag in the judgment of sudden situations such as blood circulation disorders, which may miss the best rescue time.

[0005] Instrument monitoring is another way to monitor flaps after surgery, which can be divided into traditional instrument monitoring methods and new instrument monitoring methods. Traditional instrument monitoring technology relies on large fixed medical equipment deployed in hospitals, while new instrument monitoring technology relies on small wearable portable electronic devices.

[0006] The traditional instrument monitoring technologies currently used mainly include color Doppler ultrasound, laser Doppler blood flowmeter, and transcutaneous oxygen partial pressure meter. The handheld Doppler ultrasound instrument is the most widely used auxiliary instrument. Its principle is that the ultrasound probe emits a set of ultrasonic waves to the human body and scans in a certain direction. The distance and nature of the organs can be judged by monitoring the delay time and strength of the echo. After that, the B-ultrasound image is formed after computer processing. The principle of color Doppler ultrasound is the same, but in terms of vascular imaging, color Doppler ultrasound adds red and blue colors to distinguish between veins and arteries, which can accurately quantify the inflow and outflow of blood flow. However, the resolution of Doppler ultrasound imaging technology is low, and it has certain skill requirements for operators. It requires professional medical staff to operate and judge. When monitoring patients after flap transplantation, it is necessary to understand the location of the vascular pedicle and anastomosis in advance to quantitatively monitor blood circulation. Laser Doppler imaging technology is slightly different from Doppler ultrasound imaging technology. It is based on the transmission of laser light through optical fiber. After the laser beam is scattered by the studied tissue, part of the light is absorbed. The wavelength of the laser hitting the blood cells changes, while the wavelength of the laser hitting the stationary tissue does not change. The intensity and frequency distribution of these wavelength changes are directly related to the number and movement speed of blood cells in the monitoring volume. Through the receiving optical fiber, this information is recorded and converted into electrical signals for analysis. Laser Doppler imaging technology has high accuracy in microcirculation monitoring, but its significant disadvantage is that the use of a single point for flow analysis may lead to high variability in the measured values, because the microvessels themselves are not uniform, and the flow can vary in space and time, so it cannot provide visible information on vascular morphology or density measurement. Transcutaneous oxygen partial pressure meters are mostly used to monitor local blood perfusion. The principle is to heat the local skin through the transcutaneous oxygen partial pressure detection probe, so that the local capillaries expand, so that the oxygen in the blood can overflow through the skin to the greatest extent, thereby measuring the oxygen partial pressure value on the skin surface, indirectly reflecting the oxygenation status of the tissue. However, since this method requires heating the skin and maintaining a high temperature, long-term monitoring cannot be achieved. In addition, due to the small amount of oxygen overflowing from the skin and being restricted by various factors, the measurement results are not stable.

[0007] Most of the new monitoring methods are small, portable wearable monitoring devices, which can be divided into implantable and non-implantable types. Patent US20130116575A1 discloses an implantable Doppler monitor, which is similar to Doppler ultrasound in principle and consists of three parts: a sensor strap, an acoustic wave transmitter and receiver, and a wireless signal transmission device. The sensor strap fixes the acoustic wave transmitter and receiver near the vascular anastomosis, and the wireless transmission device sends the received acoustic wave signal to the receiving end outside the body. Hexia Guo published a wireless implantable optical probe for continuous monitoring of oxygensaturation in flaps and organ grafts in Nature Communications ((2022)13:3009), which introduces an injectable flexible probe with a micro inorganic light-emitting diode and a photodetector that can measure absorbance gradients to accurately calculate the oxygenation levels of various tissues. DiLu also introduced an implantable blood flow sensor for flap monitoring in the article Implantable, wireless, self-fixing thermal sensors for continuous measurements of microvascular blood flow in flaps and organ grafts published in Biosensors and Bioelectronics (Volume 206, 15 June 2022, 114145). The main principle is to indirectly measure blood flow based on thermodynamics and fluid mechanics through blood flow thermodynamic analysis technology. The sensor includes a heater and multiple temperature sensors. It calculates the microperfusion volume by heating the flap tissue and measuring the temperature difference. At the same time, the sensor is designed with biodegradable barbs that can fix the probe to the surrounding tissue for easy removal after a period of use. However, implantable monitoring devices need to be placed in the body during surgery and removed after recovery, which will increase the doctor's operation time and cause the patient to suffer secondary trauma.

[0008] Compared with implantable flap monitoring devices, non-implantable wearable monitoring devices are more convenient to use. Patent US20220061714A1 discloses a transcutaneous oxygen partial pressure sensing device. The principle of the device is the same as that of a transcutaneous oxygen detector. By applying fluorescent materials and scattering materials to a flexible polymer substrate, an oxygenation film that can be directly bonded to the skin is made. With a heating device and a micro-LED light source transmitter and receiver, the skin oxygen partial pressure value can be measured. However, this device also has the problem that the heating temperature is too high and long-term monitoring cannot be achieved. Patent KR20220039478A also discloses a transcutaneous oxygen partial pressure monitoring sensor. By fixing the sensor patch on a strap that can be filled with liquid or gas, better fit to different body surfaces can be achieved. However, the sensor is limited to the binding and fixing method, and cannot be used for transplantation monitoring of flaps in certain special areas.

[0009] Bioelectrochemical sensors can also monitor transplanted skin flaps after surgery by detecting biochemical indicators such as pH, ion concentration, and bacteria. Wonryung Lee published a paper titled Conformable microneedle pH sensors via the integration of two different siloxane polymers for mapping peripheral artery disease in Science Advance (7 (2021) 6290), which introduced a microneedle sensor that integrates two different siloxane polymers. The polyaniline deposited on the microneedle can be used to detect the pH value of skin tissue. Yuji Gao published a paper titled A flexible multiplexed immunosensor for point-of-care in situ wound monitoring in Science Advance (7 (2021) 9614), which proposed a multi-channel and multi-parameter sensor platform based on microfluidics that can measure multiple biophysical and chemical parameters of wound fluid. Studies have shown that a wound bed pH value below 7.3 may be associated with skin graft failure, but the main cause of flap failure is thrombosis leading to impaired vascular hemodynamics. Therefore, monitoring flap transplantation by detecting biochemical indicators of the wound is not the best solution.

[0010] Measuring skin temperature and comparing skin color is another way to monitor flaps after surgery. Patent CN212326377U discloses an integrated flap observation and evaluation device, which is divided into two areas, one for displaying flap temperature and the other for flap colorimetry. However, the evaluation device requires human operation and identification, and does not fully achieve real-time monitoring.

[0011] Patent CN113729654A discloses an epidermal-attached sensor system for detecting blood flow status of postoperative skin flaps and reconstructed limbs, including a front-end status detection module and a back-end signal processing output module. The front-end status detection module collects the blood oxygen saturation and temperature status of the postoperative skin flaps and reconstructed limbs in real time, and uses a flexible packaging layer to encapsulate the printed circuit board. After chemical treatment of the surface of the flexible packaging layer, a pre-polymerized hydrogel solution is injected for cross-linking to obtain a hydrogel adhesion layer to ensure that it can be closely attached to the skin for a long time and avoid bacterial infection on the skin surface; the back-end signal processing output module processes the blood oxygen saturation and temperature data and sends them to a mobile terminal in real time. However, the device described in the patent can only realize static monitoring of patients after skin flap transplantation. It can give prompts based on the abnormalities of oxygen saturation and temperature for whether the patient has arteriovenous thrombosis, but no corresponding identification method is given for the specific site of blood flow embolism in the patient.

[0012] In summary, according to the survey results of existing patent technologies, professional medical equipment is large in size, and doctors prefer clinical monitoring methods, which limits the promotion of traditional flap monitoring technology; new monitoring technologies have low testing accuracy and limited application sites, which may cause secondary trauma to patients, making wearable flap monitoring technology not widely recognized. Summary of the invention

[0013] The purpose of the present invention is to provide a wearable dynamic and static blood circulation monitoring device and method in order to overcome at least one defect of the above-mentioned prior art. The present invention realizes non-invasive real-time monitoring of skin blood circulation status and can timely determine the type of thrombus.

[0014] The purpose of the present invention can be achieved by the following technical solutions:

[0015] One of the technical solutions of the present invention is to provide a wearable dynamic and static blood circulation monitoring device, which includes a front-end test module and a back-end processing module. The front-end test module is connected to the back-end processing module through a front-end and back-end connecting line. The front-end test module is covered on the patient's skin.

[0016] The front-end processing module includes a pressure layer and a light transceiver layer, a pressure sensor is arranged on the pressure layer, a light emitting diode and a photodetector are arranged on the light transceiver layer, the pressure layer is connected to the light transceiver layer through a front-end internal connection line, and both sides of the pressure layer and the light transceiver layer are provided with packaging,

[0017] The back-end processing module comprises a signal acquisition processing transmission layer, on which signal acquisition processing transmission components are arranged, and packages are provided on both sides of the signal acquisition processing transmission layer.

[0018] Furthermore, the pressure layer includes a pressure circuit substrate, on which a piezoelectric film sensor is arranged.

[0019] Furthermore, the light transceiver layer includes a light circuit substrate, on which are arranged short-wave light emitting diodes and long-wave light emitting diodes arranged in parallel, and short-wave photodetectors and long-wave photodetectors arranged in two inner and outer layers around the light emitting diodes. The short-wave light emitting diodes and long-wave light emitting diodes respectively emit light of two different wavelengths, wherein the short-wave light emitting diodes emit short-wave red light, and the long-wave light emitting diodes emit long-wave near-infrared light. The short-wave photodetectors and long-wave photodetectors respectively absorb the two different wavelengths of light emitted by the light emitting diodes, wherein the short-wave photodetectors absorb short-wave red light, and the long-wave photodetectors absorb long-wave near-infrared light. Since oxygenated hemoglobin and deoxygenated hemoglobin in the blood absorb red light and near-infrared light respectively, two sets of long-wave and short-wave devices are provided to comprehensively calculate the blood oxygen saturation of the tissue.

[0020] As a preferred technical solution, the same type of photodetectors and light-emitting diodes have the same spacing, and a fixed spacing is maintained between two adjacent photodetectors.

[0021] As a preferred technical solution, the center of the piezoelectric sensor is concentric with the center of the light emitting diodes arranged in parallel.

[0022] Furthermore, the pressure layer is provided with pressure sensors arranged in a single arrangement or in a plurality of arrays.

[0023] Furthermore, the light transceiver layer is provided with light emitting diodes and photodetectors arranged in a single group or multiple groups in an array, and the photodetectors are arranged as a group around the light emitting diodes.

[0024] As a preferred technical solution, the pressure layer and the light transceiver layer present a circular or rectangular sheet structure, and a circular or rectangular piezoelectric film sensor is arranged on the pressure circuit substrate.

[0025] As a preferred technical solution, protrusions are provided at the edge positions of the pressure layer and the light transceiver layer, and the protrusions realize electrical connection between the pressure layer and the light transceiver layer by connecting the front-end internal connection wires.

[0026] As a preferred technical solution, the front end internal connection line extends vertically from the plane where the pressure layer and the light transceiver layer are located.

[0027] As a preferred technical solution, the shape of the protrusion includes circle or rectangle.

[0028] As a preferred technical solution, the signal acquisition, processing and transmission layer has a circular or rectangular sheet structure.

[0029] As a preferred technical solution, the protrusion of the light transceiver layer and the edge position of the signal acquisition processing transmission layer extend an interface, which realizes the electrical connection between the front-end test module and the back-end processing module by plugging the front-end and back-end connecting lines.

[0030] As a preferred technical solution, the front-end and rear-end connecting lines extend in parallel from the plane where the light transmitting and receiving layer and the signal acquisition, processing and transmission layer are located.

[0031] As a preferred technical solution, the shape of the interface includes circle or rectangle.

[0032] Furthermore, the signal acquisition, processing and transmission layer includes a signal circuit substrate, on which an antenna module, a microprocessor chip (MCU), a signal conditioning circuit and a battery are arranged. The signal conditioning circuit includes an analog-to-digital converter (ADC), an operational amplifier (AMP) and a low-pass filter (LPF). The pressure layer is connected to the light transceiver layer through a front-end internal connecting line, and then connected to the low-pass filter of the signal acquisition, processing and transmission layer through front-end and rear-end connecting lines. While powering the light-emitting diode, it collects voltage signals from the photodetector and the pressure sensor. The low-pass filter, operational amplifier, analog-to-digital converter, microprocessor chip and antenna module are connected in sequence. The battery supplies energy to the front-end test module and the signal acquisition, processing and transmission component. The raw signal (Raw Signal) of tissue oxygen saturation is divided into short-wave and long-wave signals, and is divided into three paths together with the pressure signal (Pressure Signal). The low-pass filter and operational amplifier are responsible for signal processing, and the analog-to-digital converter is responsible for signal acquisition and conversion. The oxygen saturation and pressure value data are obtained through processing by the microprocessor chip, and then the antenna module is responsible for sending the information to the mobile terminal.

[0033] As a preferred technical solution, the circuit substrate adopts a flexible printed circuit board (PCB), the circuit is engraved using a laser engraving machine, and the components are fixed on the circuit substrate by low-temperature solder paste hot air welding.

[0034] Further, the front-end processing module includes a front-end top package, a pressure layer, a front-end middle partition package, a light transceiver layer and a front-end bottom package, wherein the pressure layer is arranged between the front-end top package and the front-end middle partition package, and the light transceiver layer is arranged between the front-end middle partition package and the front-end bottom package;

[0035] The back-end processing module includes a back-end top package, a signal acquisition processing transmission layer and a back-end bottom package, and the signal acquisition processing transmission layer is arranged between the back-end top package and the back-end bottom package.

[0036] As a preferred technical solution, the pressure layer and the light transceiver layer are isolated by packaging, and are covered except for the protrusions to achieve external insulation.

[0037] Furthermore, the shape and size of the package match the pressure layer, the light transceiver layer and the signal acquisition, processing and transmission layer, and the materials are all made of flexible polymer material Ecoflex. Ecoflex has good tensile properties, waterproof properties and biocompatibility, and can be made into any shape as needed. Therefore, Ecoflex is selected as the packaging material of the device.

[0038] Furthermore, the device is placed on the body surface of the patient's transplanted skin flap, the front-end test module and the back-end processing module are arranged in a flat layout, connected but not overlapping, and the front-end test module is attached to the top of the transplanted skin flap.

[0039] As a preferred technical solution, the device is placed on the patient's limbs or trunk skin flaps.

[0040] As a preferred technical solution, the front-end test module is combined with the skin by bonding.

[0041] As a preferred technical solution, the back-end processing module is naturally placed flat on the skin of other parts, or is placed on a table or chair via a relatively long front-end and rear-end connecting line.

[0042] One of the technical solutions of the present invention is to provide a wearable static and dynamic blood circulation monitoring method, which uses the device to perform static and dynamic non-invasive real-time monitoring of the patient's skin blood circulation status, and the method comprises the following steps:

[0043] In static monitoring mode, the light emitted by the LED is transmitted through the epidermis to the dermis. The dermis is rich in capillary networks. The oxygenated hemoglobin and deoxyhemoglobin in the blood in the capillary network absorb light. After being partially absorbed, the light is received by the photodetector after reflection. After receiving the light, the photodetector will cause the change of current in the circuit. The optical signal is converted into an electrical signal. The electrical signal is collected and processed by the back-end processing module to obtain the blood oxygen saturation (StO2) of the tissue. The blood oxygen saturation of the tissue reflects the blood circulation effect of the skin. The blood circulation in the skin is good, and the blood oxygen saturation in the tissue is the initial value. When the skin has blood circulation disorder due to arterial or venous blockage, the blood oxygen content in the tissue will decrease relative to the initial value. The approximate state of the skin blood circulation can be obtained by comparing the initial value.

[0044] In the dynamic pressing mode, when pressure is applied to the front-end processing module, the resistance of the piezoelectric sensor will change, and the electrical signal will be collected and processed by the back-end processing module to obtain the pressure value; the subcutaneous blood vessels will form a brief ischemia due to the pressure, and when the pressure is released, the blood will fill into the blood vessels again; in the process of forming the ischemic environment and restoring congestion, the tissue blood oxygen value changes dynamically, and because the arteries and veins have different blood flow conditions, the location and severity of the blockage are judged by different recovery curves.

[0045] As a preferred technical solution, the red light and near-infrared light emitted by the short-wave light-emitting diode and the long-wave light-emitting diode are transmitted through the epidermis to the dermis. The dermis is rich in a capillary network. The oxygenated hemoglobin and deoxygenated hemoglobin in the blood rich in the capillary network absorb red light and near-infrared light of different wavelengths. After being partially absorbed, the red light and near-infrared light are reflected and received by the short-wave photodetector and the long-wave photodetector.

[0046] As a preferred technical solution, the photodetector will cause a change in the current in the circuit after receiving light, and the light signal will be converted into an electrical signal. The electrical signal will obtain the corresponding light absorption value through the back-end processing module. By calculating the proportion of absorbed light, the content of oxygenated hemoglobin and deoxygenated hemoglobin in the blood can be obtained, and then the blood oxygen saturation of the tissue can be calculated.

[0047] As a preferred technical solution, the initial value of tissue blood oxygen is uploaded to the communication device through the wireless transmission function of Bluetooth or WiFi, and the real-time blood oxygen value in the tissue is also wirelessly transmitted to the communication device in real time. The patient or medical staff reads the corresponding information through the application software.

[0048] As a preferred technical solution, when the finger applies pressure on the front-end processing module, the resistance of the piezoelectric film sensor will change, the electrical signal will be collected and processed by the back-end processing module and then wirelessly transmitted to the communication device, and the pressure value can be checked through the application software.

[0049] As a preferred technical solution, according to a preset ischemic pressure value interval, after maintaining the effective pressure for a certain period of time, the subcutaneous blood vessels are compressed to form a transient ischemia.

[0050] As a preferred technical solution, the pressure value range that can achieve the ischemic effect is pre-calculated through simulation and uploaded to the server. The mobile terminal obtains the effective pressure value range from the server and prompts the effectiveness of the compression in real time.

[0051] As a preferred technical solution, tissue blood oxygen saturation information is wirelessly transmitted to the communication device, which obtains the mapping relationship between the arteriovenous blood flow recovery value and the tissue blood oxygen saturation value obtained in advance through computational fluid dynamics (CFD) simulation from the server, and uses the mapping relationship to determine the blocked end. The patient or medical staff reads the corresponding information through the application software.

[0052] As a preferred technical solution, when the patient's blood circulation is normal, compression creates a short period of ischemia, and the blood oxygen level of the tissue will gradually decrease. After the compression is released, the blood oxygen level will gradually rise. However, due to the rapid influx of arterial blood, an overshoot process will occur and gradually return to the original blood oxygen level.

[0053] When the patient presents with venous obstruction, compression mainly causes the blockage of arterial blood, and the blood oxygen level will drop faster than the normal level. At the same time, after releasing the compression, due to the influx of arterial blood and the influence of venous obstruction, the blood cannot flow out of the vein in time, the blood oxygen level rises rapidly, the overshoot phenomenon will be more significant, and then gradually returns to normal;

[0054] When the patient's artery is blocked, pressing mainly causes venous blood blockage, and the rate of decrease in blood oxygen value will be lower than the normal level. At the same time, after releasing the pressure, due to the blockage of the artery, the rate of arterial blood inflow is limited, overshoot will not occur, and the blood oxygen value will gradually return to normal.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] (1) The present invention adopts a flexible wearable design, and adopts a method combining tissue oxygen saturation monitoring and pressure monitoring to achieve static and dynamic non-invasive real-time monitoring of the blood supply status of the skin, such as free flap transplant patients, after surgery. The blood supply status of the transplanted flap of the patient can be timely grasped. When arterial and venous thrombosis occurs, causing the risk of flap ischemia or congestion, the type of thrombus can be timely determined, and medical staff and patients can be warned, so that medication or surgery can be taken as soon as possible to intervene, thereby ensuring the survival of the transplanted flap and the health of the patient;

[0057] (2) The present invention can realize two different monitoring modes based on tissue oxygen saturation monitoring and pressure monitoring. The first monitoring mode is static use based on tissue oxygen saturation monitoring. The light transceiver component can measure the content of oxygenated hemoglobin and deoxygenated hemoglobin in the tissue, and then calculate the tissue oxygen saturation (StO2). When the skin blood supply is good, the tissue oxygen saturation should be maintained at a high level. By comparing with the normal blood oxygen value, it can be roughly judged whether the patient's skin blood supply is normal. The second monitoring mode is dynamic use based on tissue oxygen saturation monitoring combined with pressure monitoring. Since both venous blockage and arterial blockage of the skin can cause the tissue to be in a state of hypoxia, the ischemic state can be artificially created by lightly pressing the skin with fingers, and the skin blood return state can be monitored to determine the blocked end. The pressure component can display the local pressure value. When the required pressure is reached, it is released after being maintained for a fixed time. The tissue blood oxygen recovery state measured by the light transceiver component during the recovery process is observed. Since there are differences between venous blood and arterial blood, the location and severity of the blockage can be determined by the recovery speed.

[0058] (3) The light photodetectors for measuring oxygen saturation in the present invention are multiple groups, and are arranged in an array around light photodiodes, which can improve the light absorption efficiency, improve the measurement accuracy of oxygenated hemoglobin and deoxygenated hemoglobin content in tissues, and improve the calculation accuracy of tissue oxygen saturation;

[0059] (4) The packaging of the present invention is both comfortable to wear and the packaging design uses a flexible polymer material Ecoflex, which has excellent tensile properties, waterproof properties and biocompatibility. The use of this material to package the device can make the device more skin-friendly and comfortable to wear;

[0060] (5) The present invention adopts a non-invasive wearing method, which is easy to wear and has a wide range of uses. It can monitor various parts of the body, such as the limbs and trunk, and can meet the needs of most skin flap transplant patients and patients with skin blood circulation disorders;

[0061] (6) The device proposed in the present invention is small and portable, easy to use, and only needs to be attached to the skin to be tested, and the status can be checked through a mobile terminal, so that accurate postoperative monitoring of each patient can be achieved; the present invention delivers skin blood circulation status information to patients and medical staff wirelessly, and medical staff can remotely monitor the vital signs of multiple patients at the same time. When abnormalities are found, they can also perform a simple assessment of the patient's condition, which can greatly reduce the work pressure of medical staff and enable patients to receive timely treatment, thereby reducing the patient's postoperative risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1This is a schematic diagram of the three-dimensional structure of the wearable dynamic and static blood circulation monitoring device in Example 1 of the present invention;

[0063] Figure 2 This is a schematic diagram of the exploded structure of the wearable dynamic and static blood circulation monitoring device in Example 1 of the present invention;

[0064] Figure 3 is a schematic structural diagram of the pressure layer in Example 1 of the present invention;

[0065] Figure 4 This is a schematic diagram of the structure of the light transmitting and receiving layer in Example 1 of the present invention;

[0066] Figure 5 This is a schematic diagram of the composition of the back-end processing module in Example 1 of the present invention;

[0067] Figure 6 This is a schematic diagram of the installation of the wearable dynamic and static blood circulation monitoring device in Example 1 of the present invention attached to the transplanted skin flap of the patient's arm;

[0068] Figure 7 This is a schematic diagram of the installation of the wearable dynamic and static blood flow monitoring device in Example 1 of the present invention attached to the transplanted skin flap of the patient's leg;

[0069] Figure 8 This is a schematic diagram of the state of the front-end test module attached to the transplanted skin flap in the static long-term monitoring mode in Example 1 of the present invention;

[0070] Fig. 9 Schematic diagram of the monitoring effect of blood oxygen saturation (StO2) after static free flap transplantation in Example 1 of the present invention;

[0071] Fig.10 This is a schematic diagram of a state in which the front-end test module is attached to the transplanted skin flap in the dynamic pressing mode in Example 1 of the present invention;

[0072] Fig.11 This is a schematic diagram of the monitoring effect of blood oxygen saturation after dynamic free flap transplantation in Example 1 of the present invention;

[0073] Fig.12 This is a schematic diagram of the exploded structure of the wearable dynamic and static blood circulation monitoring device in Example 2 of the present invention;

[0074] Fig.13 is a schematic structural diagram of the pressure layer in Example 2 of the present invention;

[0075] Fig.14 Schematic diagram of the structure of the light transmitting and receiving layer in Example 2 of the present invention.

[0076] Description of the markings in the figure:

[0077] 1—front-end top package, 2—pressure layer, 3—front-end middle partition package, 4—light transceiver layer, 5—front-end bottom package;

[0078] 21—piezoelectric film sensor, 22—pressure circuit substrate;

[0079] 23—front end internal connection line;

[0080] 41—optical circuit substrate, 42—short-wave photodetector, 43—long-wave photodetector, 44—short-wave light emitting diode, 45—long-wave light emitting diode;

[0081] 6—front and rear end connection line;

[0082] 7—back-end top packaging, 8—signal acquisition processing transmission layer, 9—back-end bottom packaging;

[0083] 81—signal circuit substrate, 82—antenna module, 83—microprocessor chip, 84—signal conditioning circuit, 85—battery. DETAILED DESCRIPTION

[0084] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0085] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are used to describe common objects, which only refer to different instances of the same object, and are not intended to imply that the objects described in this way must adopt a given order, whether in time, space, order or any other way.

[0086] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0087] Embodiment 1:

[0088] A wearable dynamic and static blood circulation monitoring device, such as Figure 1 and Figure 2 As shown, it includes a front-end test module and a back-end processing module. The front-end test module is connected to the back-end processing module via a front-end and back-end connecting line 6. The front-end test module is covered on the patient's skin.

[0089] The front-end processing module includes a pressure layer 2 and a light transceiver layer 4. A single pressure sensor is arranged on the pressure layer 2. A single group of light-emitting diodes and photodetectors are arranged on the light transceiver layer 4. The pressure layer 2 is connected to the light transceiver layer 4 through a front-end internal connection line 23. Both sides of the pressure layer 2 and the light transceiver layer 4 are provided with packaging.

[0090] The back-end processing module includes a signal acquisition processing transmission layer 8, on which signal acquisition processing transmission components are arranged, and packages are provided on both sides of the signal acquisition processing transmission layer 8;

[0091] The pressure layer 2 and the light transceiver layer 4 present a circular sheet structure, and a pair of protrusions are arranged at the edge positions of the pressure layer 2 and the light transceiver layer 4. The shapes of the two protrusions are selected to be rectangular. The two protrusions realize the electrical connection between the pressure layer 2 and the light transceiver layer 4 by connecting the front internal connection line 23. The front internal connection line 23 extends vertically from the plane where the pressure layer 2 and the light transceiver layer 4 are located;

[0092] The signal acquisition processing transmission layer 8 presents a rectangular sheet structure, and a pair of interfaces are extended from the protrusion of the light transceiver layer 4 and the edge of the signal acquisition processing transmission layer 8. The shapes of the two interfaces are rectangular. The two interfaces realize the electrical connection between the front-end test module and the back-end processing module by plugging the front-end and rear-end connecting wires 6. The front-end and rear-end connecting wires 6 extend in parallel from the plane where the light transceiver layer 4 and the signal acquisition processing transmission layer 8 are located;

[0093] The front-end processing module includes a front-end top package 1, a pressure layer 2, a front-end middle partition package 3, a light transceiver layer 4 and a front-end bottom package 5. The pressure layer 2 is arranged between the front-end top package 1 and the front-end middle partition package 3, and the light transceiver layer 4 is arranged between the front-end middle partition package 3 and the front-end bottom package 5. The pressure layer 2 and the light transceiver layer 4 are isolated by packaging, and are covered except for protrusions to achieve external insulation;

[0094] The back-end processing module includes a back-end top package 7, a signal acquisition processing transmission layer 8 and a back-end bottom package 9, and the signal acquisition processing transmission layer 8 is arranged between the back-end top package 7 and the back-end bottom package 9;

[0095] The shape and size of the package match the pressure layer 2, the light transceiver layer 4 and the signal acquisition processing transmission layer 8. The materials used are all flexible polymer materials Ecoflex. Ecoflex has good tensile properties, waterproof properties and biocompatibility, and can be made into any shape according to needs. Therefore, Ecoflex is selected as the packaging material of the device;

[0096] like Figure 3 As shown, the pressure layer 2 includes a pressure circuit substrate 22, a circular one-piece piezoelectric film sensor 21 is arranged at the center of the pressure circuit substrate 22, the pressure circuit substrate 22 uses a flexible printed circuit board (PCB), the circuit is engraved by a laser engraving machine, and the piezoelectric film sensor 21 is fixed on the pressure circuit substrate 22 by low-temperature solder paste hot air welding;

[0097] Considering sensitivity and integrated design, the piezoelectric film sensor 21 uses the FER402 film pressure sensor of Interlink Electronics, which has a sensitivity range of 0.2-20N and has a high sensitivity;

[0098] like Figure 4 As shown, the light transceiver layer 4 includes a light circuit substrate 41, two short-wave light emitting diodes 44 and long-wave light emitting diodes 45 arranged in parallel are arranged at the center of the light circuit substrate 41, and eight short-wave photodetectors 42 and long-wave photodetectors 43 arranged around the light emitting diodes in two layers, the inner and outer layers, are arranged at the edge. The short-wave light emitting diodes 44 and the long-wave light emitting diodes 45 emit two different wavelengths of light, respectively, wherein the short-wave light emitting diodes 44 emit short-wave red light, and the long-wave light emitting diodes 45 emit long-wave near-infrared light, and the short-wave photodetectors 42 and the long-wave photodetectors 43 absorb the two wavelengths emitted by the light emitting diodes, respectively. Light of different wavelengths, wherein the four short-wave photodetectors 42 arranged in the inner layer absorb short-wave red light, and the four long-wave photodetectors 43 arranged in the outer layer absorb long-wave near-infrared light. Since the oxygenated hemoglobin and deoxygenated hemoglobin in the blood absorb red light and near-infrared light respectively, two sets of long-wave and short-wave devices are set to comprehensively calculate the blood oxygen saturation of the tissue. The light circuit substrate 41 uses a flexible printed circuit board, and the circuit is engraved using a laser engraving machine. The short-wave light-emitting diode 44, the long-wave light-emitting diode 45, the short-wave photodetector 42 and the long-wave photodetector 43 are fixed on the light circuit substrate 41 by low-temperature solder paste hot air welding;

[0099] The distance between the same type of photodetectors and light-emitting diodes is the same, and the distance between two adjacent photodetectors is kept fixed;

[0100] Considering the miniaturization and integration design, the short-wave light-emitting diode 44 and the long-wave light-emitting diode 45 are TCSD14-660 and TCSD14-850 of III-V Materials, respectively, and the short-wave photodetector 42 and the long-wave photodetector 43 are T1197P6 of Vishay Semiconductors. The size of the light-emitting diode and the photodetector are both micrometer-level, smaller than the millimeter-level, so that the multi-point arrangement of the device can be realized;

[0101] The center of the piezoelectric film sensor 21 is concentric with the centers of the short-wave light-emitting diode 44 and the long-wave light-emitting diode 45;

[0102] like Figure 5 As shown, the signal acquisition, processing and transmission layer 8 includes a signal circuit substrate 81, on which an antenna module 82, a microprocessor chip (MCU) 83, a signal conditioning circuit 84 and a battery 85 are arranged. The signal conditioning circuit 84 includes an analog-to-digital converter (ADC), an operational amplifier (AMP) and a low-pass filter (LPF). The pressure layer 2 is connected to the light transceiver layer 4 through the front-end internal connection line 23, and then connected to the low-pass filter of the signal acquisition, processing and transmission layer 8 through the front-end and rear-end connection lines 6. While powering the light-emitting diode, the voltage signals of the photodetector and the pressure sensor are collected. The low-pass filter, operational amplifier, analog-to-digital converter, microprocessor chip 83 and antenna module 82 are connected in sequence. The battery 85 supplies energy to the front-end test module and the signal acquisition, processing and transmission components. The raw signal (Raw Signal) of tissue oxygen saturation is divided into short-wave and long-wave signals, which are connected to the pressure signal (Pressure The signal is divided into three paths, and the low-pass filter and operational amplifier are responsible for signal processing, and the analog-to-digital converter is responsible for signal acquisition and conversion. The oxygen saturation and pressure value data are obtained by processing by the microprocessor chip 83, and then the antenna module 82 is responsible for sending the information to the mobile terminal. The signal circuit substrate 81 uses a flexible printed circuit board, and the circuit is engraved by a laser engraving machine. The antenna module 82, the microprocessor chip 83, the signal conditioning circuit 84 and the battery 85 are fixed on the optical circuit substrate 41 by hot air welding with low-temperature solder paste;

[0103] The analog-to-digital converter uses the 12-bit analog-to-digital converter ADS1120 from Texas Instruments, the operational amplifier uses the precision operational amplifier OPA2333, the low-pass filter uses a resistor-capacitor network, the antenna module 82 uses the Mini2.45GHz Antenna from Johnson, which can improve the receiving and sending range of Bluetooth or WiFi wireless transmission signals, the microprocessor chip 83 uses the ESP32-C3 chip from Espressif, which is inexpensive and has both low-power Bluetooth and WiFi functions, and can realize wireless data transmission, and the battery 85 uses a 3V button battery;

[0104] like Figure 6 and Figure 7 As shown, when the device is in use, the device is placed on the body surface of the patient's transplanted skin flap, such as the lower arm or calf transplanted skin flap, and the front-end test module and the back-end processing module are arranged in a flat manner, connected but not overlapping, and the front-end test module is attached to the top of the transplanted skin flap and combined with the skin by bonding. The back-end processing module is naturally placed flat on the skin of other parts, and can also be placed on a table or chair via a longer front-end and rear-end connecting line 6.

[0105] A wearable static and dynamic blood flow monitoring method is provided, which uses the above device to perform static and dynamic non-invasive real-time monitoring of the blood flow status of a free flap transplant patient after surgery, and the specific steps are as follows:

[0106] like Figure 8 and Fig. 9 As shown, in the static long-term monitoring mode, the red light and near-infrared light emitted by the short-wave light emitting diode 44 and the long-wave light emitting diode 45 located at the center of the light transceiver layer 4 are transmitted to the dermis through the epidermis. The dermis is rich in a capillary network. The oxygenated hemoglobin and deoxyhemoglobin in the blood rich in the capillary network absorb red light and near-infrared light of different wavelengths. After being partially absorbed, the red light and near-infrared light are reflected and received by the short-wave photodetector 42 and the long-wave photodetector 43. After receiving the light, the photodetector will cause a change in the current in the circuit, and the optical signal is converted into an electrical signal. The electrical signal is collected and processed by the back-end processing module to obtain the corresponding light absorption value. By calculating the absorbed The ratio of light collection can be used to obtain the content of oxygenated hemoglobin and deoxygenated hemoglobin in the blood, and then the blood oxygen saturation (StO2) of the tissue can be calculated. The blood oxygen saturation of the tissue reflects the blood supply effect of the transplanted flap. When the flap transplantation operation is just completed, the blood supply in the flap tissue is good, and the blood oxygen saturation in the tissue is the initial value. When the flap has blood supply obstruction due to arterial or venous blockage, the blood oxygen content in the tissue will decrease relative to the initial value. The initial value of tissue blood oxygen can be uploaded to the mobile terminal through the wireless transmission function of Bluetooth or WiFi, and the real-time blood oxygen value in the tissue can also be wirelessly transmitted to the mobile terminal in real time. By comparing the initial value, the approximate state of the flap blood supply can be obtained, and the patient or medical staff can read the corresponding information through the application software.

[0107] like Fig.10 and Fig.11As shown, in the dynamic pressing mode, when the finger applies pressure on the front-end processing module, the resistance of the piezoelectric film sensor 21 will change, and the electrical signal can be wirelessly transmitted to the mobile terminal after being collected and processed by the back-end processing module, and the pressure value can be viewed through the application software; the pressure value interval that can achieve the ischemic effect is pre-calculated by simulation and uploaded to the server, and the mobile terminal obtains the effective pressure value interval from the server and prompts the pressing effectiveness in real time. After maintaining the effective pressure for a certain period of time, the subcutaneous blood vessels form a transient ischemia due to the pressure; when the pressure is released, the blood is refilled into the blood vessels; in the process of forming the ischemic environment and restoring the congestion, the tissue blood oxygen value changes dynamically. Since the arterial blood vessels and the venous blood vessels have different blood flow conditions, the location and severity of the blockage can be judged by different recovery curves; the tissue blood oxygen saturation information is wirelessly transmitted to the mobile terminal, and the mobile terminal obtains the mapping relationship between the arteriovenous blood flow recovery value and the tissue blood oxygen saturation value obtained in advance by computational fluid dynamics (CFD) simulation from the server, and uses the mapping relationship to judge the blocked end, and the patient or medical staff reads the corresponding information through the application software;

[0108] When the patient's blood circulation is normal, the skin flap is pressed to create a short period of ischemia, and the blood oxygen level of the tissue will gradually decrease. After the pressure is released, the blood oxygen level will gradually rise. However, due to the rapid influx of arterial blood, an overshoot process will occur and gradually return to the original blood oxygen level.

[0109] When the patient presents with venous obstruction, compression mainly causes the blockage of arterial blood, and the blood oxygen level will drop faster than the normal level. At the same time, after releasing the compression, due to the influx of arterial blood and the influence of venous obstruction, the blood cannot flow out of the vein in time, the blood oxygen level rises rapidly, the overshoot phenomenon will be more significant, and then gradually returns to normal;

[0110] When the patient's artery is blocked, pressing mainly causes venous blood blockage, and the rate of decrease in blood oxygen value will be lower than the normal level. At the same time, after releasing the pressure, due to the blockage of the artery, the rate of arterial blood inflow is limited, overshoot will not occur, and the blood oxygen value will gradually return to normal.

[0111] Embodiment 2:

[0112] A wearable dynamic and static blood flow monitoring device is more suitable for monitoring large-area flap transplantation, which is basically the same as Example 1, except that Figure 12 to Figure 14As shown, the pressure layer 2 is provided with a plurality of pressure sensors arranged in a square array and connected to each other, the light transceiver layer 4 is provided with a plurality of groups of light emitting diodes and photodetectors arranged in a square array and connected to each other, the inner and outer layers of the photodetectors are arranged as a group around the light emitting diodes, and the tissue blood oxygen saturation information at different positions of the flap can be collected respectively, and the fingers can also apply pressure at any position on the device, the pressure layer 2 and the light transceiver layer 4 present a rectangular sheet structure, the pressure circuit substrate 22 is provided with a square multi-piece piezoelectric film sensor 21, the short-wave photodetectors 42 are arranged in the outer layer, and the long-wave photodetectors 43 are arranged in the inner layer;

[0113] Considering sensitivity and integrated design, the piezoelectric film sensor 21 uses the FER406 thin film pressure sensor from Interlink Electronics, which has a sensitive range of 0.2-20N and has high sensitivity.

[0114] A wearable dynamic and static blood circulation monitoring method, the same as that in Example 1.

[0115] This embodiment can realize multi-position precise monitoring of large-area transplanted skin flaps. The overall blood circulation effect diagram of the large-area skin flap can be obtained by drawing a tissue oxygen saturation position cloud map. At the same time, through the pressure feedback at different positions, the location of arteriovenous thrombosis can be judged more accurately.

[0116] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A wearable dynamic and static blood circulation monitoring device, characterized in that: The device comprises a front-end testing module and a back-end processing module. The front-end testing module is connected to the back-end processing module via a front-end and back-end connecting line (6). The front-end testing module is covered on the patient's skin. The front-end processing module comprises a pressure layer (2) and a light transceiver layer (4), a pressure sensor is arranged on the pressure layer (2), a light emitting diode and a photodetector are arranged on the light transceiver layer (4), the pressure layer (2) is connected to the light transceiver layer (4) via a front-end internal connection line (23), and both sides of the pressure layer (2) and the light transceiver layer (4) are provided with packaging. The back-end processing module comprises a signal acquisition processing transmission layer (8), on which signal acquisition processing transmission components are arranged, and packages are provided on both sides of the signal acquisition processing transmission layer (8).

2. A wearable dynamic and static blood circulation monitoring device according to claim 1, characterized in that: The pressure layer (2) comprises a pressure circuit substrate (22), on which a piezoelectric film sensor (21) is arranged.

3. A wearable dynamic and static blood circulation monitoring device according to claim 1, characterized in that: The light transceiver layer (4) comprises a light circuit substrate (41), on which are arranged short-wave light emitting diodes (44) and long-wave light emitting diodes (45) in parallel, and short-wave photodetectors (42) and long-wave photodetectors (43) arranged in two layers, inner and outer, around the light emitting diodes.

4. A wearable dynamic and static blood circulation monitoring device according to claim 1, characterized in that: The pressure layer (2) is provided with pressure sensors arranged in a single arrangement or in a plurality of arrays.

5. A wearable dynamic and static blood circulation monitoring device according to claim 1, characterized in that: The light transceiver layer (4) is provided with light emitting diodes and photoelectric detectors arranged in a single group or multiple groups in an array, and the photoelectric detectors are arranged as a group around the light emitting diodes.

6. A wearable dynamic and static blood flow monitoring device according to claim 1, characterized in that: The signal acquisition, processing and transmission layer (8) comprises a signal circuit substrate (81), on which an antenna module (82), a microprocessor chip (83), a signal conditioning circuit (84) and a battery (85) are arranged; the signal conditioning circuit (84) comprises an analog-to-digital converter, an operational amplifier and a low-pass filter; the low-pass filter, the operational amplifier, the analog-to-digital converter, the microprocessor chip (83) and the antenna module (82) are connected in sequence.

7. A wearable dynamic and static blood circulation monitoring device according to claim 1, characterized in that: The front-end processing module comprises a front-end top package (1), a pressure layer (2), a front-end middle partition package (3), a light transceiver layer (4) and a front-end bottom package (5), wherein the pressure layer (2) is arranged between the front-end top package (1) and the front-end middle partition package (3), and the light transceiver layer (4) is arranged between the front-end middle partition package (3) and the front-end bottom package (5); The back-end processing module comprises a back-end top package (7), a signal acquisition processing transmission layer (8) and a back-end bottom package (9), wherein the signal acquisition processing transmission layer (8) is arranged between the back-end top package (7) and the back-end bottom package (9).

8. The wearable dynamic and static blood circulation monitoring device according to claim 1, characterized in that: The shape and size of the package match the pressure layer (2), the light transceiver layer (4) and the signal acquisition, processing and transmission layer (8), and the materials used are all flexible polymer material Ecoflex.

9. A wearable dynamic and static blood circulation monitoring device according to claim 1, characterized in that: The device is placed on the body surface of the patient's transplanted skin flap. The front-end test module and the back-end processing module are arranged in a flat layout, connected but not overlapping, and the front-end test module is attached to the top of the transplanted skin flap.

10. A wearable dynamic and static blood circulation monitoring method, characterized in that: The method uses the device according to any one of claims 1 to 9 to perform static and dynamic non-invasive real-time monitoring of the patient's skin blood flow status, and the method comprises the following steps: In static monitoring mode, the light emitted by the LED is transmitted through the epidermis to the dermis. The dermis is rich in capillary networks. The oxygenated hemoglobin and deoxyhemoglobin in the blood in the capillary network absorb light. After being partially absorbed, the light is received by the photodetector after reflection. After receiving the light, the photodetector will cause the change of current in the circuit, and the optical signal is converted into an electrical signal. The electrical signal is collected and processed by the back-end processing module to obtain the blood oxygen saturation of the tissue. The blood oxygen saturation of the tissue reflects the blood circulation effect of the skin. The blood circulation in the skin is good, and the blood oxygen saturation in the tissue is the initial value. When the skin has blood circulation disorder due to arterial or venous blockage, the blood oxygen content in the tissue will decrease relative to the initial value. The skin blood circulation status is obtained by comparing the initial value. In the dynamic pressing mode, when pressure is applied to the front-end processing module, the resistance of the piezoelectric sensor will change, and the electrical signal will be collected and processed by the back-end processing module to obtain the pressure value; the subcutaneous blood vessels will form a brief ischemia due to the pressure, and when the pressure is released, the blood will fill into the blood vessels again; in the process of forming an ischemic environment and restoring congestion, the tissue blood oxygen value changes dynamically, and because the arteries and veins have different blood flow conditions, the location of the blockage is determined by different recovery curves.

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