Wearable ultrasound patch and signal processing method for intraoperative bleeding monitoring

Abstract

The present application discloses a wearable ultrasonic patch and signal processing method for intraoperative bleeding monitoring, relating to the field of wearable electronic manufacturing. The patch includes: a piezoelectric layer, a backing layer, a matching layer, and an acoustic lens layer; the piezoelectric layer is used to generate mechanical vibrations and receive ultrasonic echo signals; the mechanical vibrations are simultaneously transmitted in both forward and reverse directions in the form of ultrasonic waves through a coupling medium; the backing layer is located behind the piezoelectric layer and is used to absorb the reverse-propagating ultrasonic waves; the matching layer is located between the piezoelectric layer and the acoustic lens layer and is used to adjust the forward-propagating ultrasonic waves to obtain adjusted ultrasonic waves; the acoustic lens layer is in contact with human tissue and is used to focus the adjusted ultrasonic waves and inject them into human tissue, and inject the ultrasonic echo signals into the piezoelectric layer through the matching layer. The present application can monitor blood flow parameters in real time and continuously, and is suitable for the clinical needs of intraoperative bleeding monitoring.

Description

Technical Field

[0001] The present application relates to the field of wearable electronic manufacturing technology, and in particular to a wearable ultrasound patch and a signal processing method for intraoperative bleeding monitoring. Background Art

[0002] With the advancement of modern surgery, the mortality rate of patients undergoing surgery has been greatly reduced. However, massive bleeding during surgery is still the main cause of life-threatening events in critically ill patients. Therefore, continuous monitoring of the patient's bleeding status during surgery is crucial to prevent serious bleeding events.

[0003] During surgery, patients' physiological information is typically monitored using a physiological monitor, such as common parameters like electrocardiogram (ECG) and respiration. However, these parameters may not be immediately available when a patient experiences significant bleeding, hindering medical staff's ability to assess the patient's physiological status during surgery. Clinical sphygmomanometers measure peripheral blood pressure, which lags behind central blood pressure and prevents long-term real-time monitoring. Invasive blood pressure monitoring devices are also more harmful to patients and are not suitable in many situations.

[0004] In recent years, research on ultrasound technology in the field of non-invasive intraoperative monitoring has yielded promising results. However, current medical ultrasound equipment all uses rigid probes, which present several challenges in the application of continuous intraoperative bleeding monitoring. First, due to the curvature of the human surface and the irregularities of human tissue, rigid probes cannot completely adhere to human skin. During testing, professional physicians are required to use the probe to press the test tissue, and the test results may be deviated due to external forces. Second, the operation of handheld ultrasound probes is highly dependent on the operator's experience, and the acquired signals need to be actively observed and adjusted by the operator. Furthermore, existing ultrasound systems do not consider the application of long-term monitoring of the same part of the patient in actual use. Therefore, traditional ultrasound equipment cannot meet the needs of long-term monitoring of intraoperative bleeding. Summary of the Invention

[0005] The purpose of this application is to provide a wearable ultrasound patch and signal processing method for intraoperative bleeding monitoring, which can monitor blood flow parameters in real time and continuously and is suitable for the clinical needs of intraoperative bleeding monitoring.

[0006] To achieve the above objectives, this application provides the following solutions.

[0007] In a first aspect, the present application provides a wearable ultrasound patch for intraoperative bleeding monitoring, wherein the wearable ultrasound patch for intraoperative bleeding monitoring comprises: a piezoelectric layer, a backing layer, a matching layer, and an acoustic lens layer.

[0008] The piezoelectric layer is used to generate mechanical vibration and receive ultrasonic echo signals; the mechanical vibration is transmitted simultaneously in the forward and reverse directions in the form of ultrasonic waves through the coupling medium.

[0009] The backing layer is located behind the piezoelectric layer and is used to absorb the ultrasonic waves propagating in the reverse direction.

[0010] The matching layer is located between the piezoelectric layer and the acoustic lens layer, and is used to adjust the ultrasonic wave propagating in the forward direction to obtain the adjusted ultrasonic wave.

[0011] The acoustic lens layer is in contact with human tissue, and is used to focus the adjusted ultrasonic waves and then inject them into the human tissue, and to inject the ultrasonic echo signals into the piezoelectric layer through the matching layer.

[0012] Optionally, the piezoelectric layer is made of soft lead zirconate titanate ceramic (Lead Zirconate Titanate-5H, PZT-5H); the piezoelectric layer includes a plurality of transducer array elements, and the plurality of transducer array elements are arranged linearly.

[0013] Optionally, the backing layer is made of a mixture of epoxy resin, glass microbeads and rubber particles.

[0014] Optionally, the matching layer is made of a mixture of epoxy resin, aluminum oxide and tungsten powder.

[0015] Optionally, the acoustic lens layer is made of silicone rubber material.

[0016] In a second aspect, the present application provides a wearable ultrasound patch signal processing method for intraoperative bleeding monitoring, and the wearable ultrasound patch signal processing method for intraoperative bleeding monitoring includes the following steps.

[0017] Acquire ultrasonic echo signals.

[0018] The ultrasonic echo signal is demodulated to obtain a demodulated signal.

[0019] The demodulated signal is integrated to obtain an integrated demodulated signal.

[0020] Based on the integrated demodulated signal, an average Doppler shift at the demodulation frequency position is calculated.

[0021] The Doppler blood flow velocity is calculated based on the average Doppler frequency shift at the demodulation frequency position.

[0022] Optionally, a calculation formula for demodulating the ultrasonic echo signal is as follows.

[0023] .

[0024] .

[0025] in, For the The in-phase component of the samples; is the input RF signal, which represents the ultrasonic echo signal in the array column direction; is the probe center frequency; is the frequency offset; For the The time corresponding to each sampling point.

[0026] Optionally, the expression of the integrated demodulated signal is as follows.

[0027] .

[0028] .

[0029] in, is the demodulated signal after integration; is the first accumulation window size, used to smooth the estimation results; Depth position on, on The sum of all in-phase components in the frame; is the sum of the corresponding orthogonal components; is the demodulated signal; is the real part, which represents the in-phase component obtained by orthogonal demodulation; is the imaginary part, which represents the orthogonal component obtained by orthogonal demodulation; is the imaginary unit, .

[0030] Optionally, the expression of the average Doppler shift at the demodulation frequency position is as follows.

[0031] .

[0032] .

[0033] in, is the average Doppler shift at the demodulation frequency position; is the real part of the integrated demodulated signal; is the imaginary part of the demodulated signal after integration; is the one-dimensional autocorrelation function; is the second accumulation window size; is the autocorrelation coefficient; is the demodulated signal after integration; is the conjugate function of the integrated demodulated signal.

[0034] The calculation formula of the Doppler blood flow velocity is as follows.

[0035] .

[0036] in, is the Doppler blood flow velocity; is the speed of sound; is the sampling time interval; is the pulse repetition time interval; is the corresponding value of the demodulation frequency relative to the center frequency; is the average Doppler shift at the demodulation frequency.

[0037] According to the specific embodiments provided in this application, this application discloses the following technical effects.

[0038] The present application provides a wearable ultrasonic patch and signal processing method for intraoperative bleeding monitoring. The wearable ultrasonic patch for intraoperative bleeding monitoring includes: a piezoelectric layer, a backing layer, a matching layer, and an acoustic lens layer. The piezoelectric layer is used to generate mechanical vibrations and receive ultrasonic echo signals. The mechanical vibrations are transmitted simultaneously in both forward and reverse directions in the form of ultrasonic waves through a coupling medium. The backing layer is located behind the piezoelectric layer and is used to absorb the reverse-propagating ultrasonic waves. The matching layer is located between the piezoelectric layer and the acoustic lens layer and is used to adjust the forward-propagating ultrasonic waves to obtain adjusted ultrasonic waves. The acoustic lens layer contacts human tissue and is used to focus the adjusted ultrasonic waves and inject them into human tissue, and then inject the ultrasonic echo signals into the piezoelectric layer through the matching layer. The patch can be stably attached to the patient's carotid artery for a long time, acquire the original carotid artery echo signals in real time, and then obtain Doppler blood flow velocity parameter data after signal processing. It can be used in clinical applications of intraoperative bleeding monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 A schematic diagram of the structural composition of a wearable ultrasound patch for intraoperative bleeding monitoring provided in one embodiment of the present application.

[0041] Figure 2This is a diagram of the application environment of a wearable ultrasound patch signal processing method for intraoperative bleeding monitoring in one embodiment of the present application.

[0042] Figure 3 A flowchart of a wearable ultrasound patch signal processing method for intraoperative bleeding monitoring provided in one embodiment of the present application.

[0043] Figure 4 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] To address the existing problems of ultrasound equipment using rigid probes and relying heavily on professional physicians for intraoperative bleeding monitoring, which is not conducive to continuous real-time monitoring, this application provides a wearable ultrasound patch and signal processing method for intraoperative bleeding monitoring. The patch can fit tightly on the human neck, acquire the original carotid artery echo signal in real time, and then obtain Doppler blood flow velocity parameter data after signal processing. This patch can be used in clinical applications of intraoperative bleeding monitoring.

[0046] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0047] like Figure 1 As shown, a wearable ultrasound patch for intraoperative bleeding monitoring is provided, wherein the wearable ultrasound patch for intraoperative bleeding monitoring includes: a piezoelectric layer, a backing layer, a matching layer, and an acoustic lens layer.

[0048] The piezoelectric layer is used to generate mechanical vibration and receive ultrasonic echo signals; the mechanical vibration is transmitted simultaneously in the forward and reverse directions in the form of ultrasonic waves through the coupling medium.

[0049] The piezoelectric layer is the core component of this ultrasound probe. Made of soft lead zirconate titanate ceramic (PZT-5H), it offers advantages such as high electromechanical coupling coefficient, stable performance, and low manufacturing cost. Due to the piezoelectric effect, when an electric field is applied to the two PZT electrodes, mechanical vibrations along the thickness direction are generated. These vibrations propagate through the coupling medium as waves. The waves reflected from human tissue are converted into electrical signals and collected and stored.

[0050] The backing layer is located behind the piezoelectric layer and is used to absorb the ultrasonic waves propagating in the reverse direction.

[0051] The backing layer, located behind the piezoelectric layer, is made of a mixture of epoxy resin and highly sound-absorbing glass microbeads and rubber particles. Because the piezoelectric layer transmits ultrasonic waves in both the forward and reverse directions when it vibrates mechanically, the backing layer absorbs the reverse-propagating ultrasonic waves, preventing them from reflecting back at the rear interface and interfering with the forward-propagating ones. The backing layer effectively suppresses the coda oscillations of the pulsed ultrasonic wave, increasing the bandwidth of the pulse signal and thus improving the probe's imaging resolution.

[0052] The matching layer is located between the piezoelectric layer and the acoustic lens layer, and is used to adjust the ultrasonic wave propagating in the forward direction to obtain the adjusted ultrasonic wave.

[0053] The matching layer, located between the piezoelectric layer and the acoustic lens layer, is made of a mixture of epoxy resin, aluminum oxide, and tungsten powder. Due to the significant difference in acoustic impedance between the piezoelectric layer (~30 MRayls) and human tissue (~1.5 MRayls), ultrasound waves have difficulty propagating directly from the piezoelectric layer into human tissue. Therefore, a matching layer is required to act as a transition between the two, thereby improving ultrasound transmission efficiency. By adjusting the thickness and impedance of the matching layer, the incident and reflected waves are 180° out of phase, causing destructive interference between the two, thus canceling out the reflection effect at the interface.

[0054] The acoustic lens layer is in contact with human tissue, and is used to focus the adjusted ultrasonic waves and then inject them into the human tissue, and to inject the ultrasonic echo signals into the piezoelectric layer through the matching layer.

[0055] The acoustic lens layer is located at the outermost layer of the probe and is the part that directly contacts the human body. It is made of a soft silicone rubber material with high ultrasonic transparency. Array probes typically achieve ultrasonic focusing in the lateral direction (Azimuth, X-axis) through channel-delayed excitation and reception. In the longitudinal direction (Elevation, Y-axis), the ultrasound waves form a diverging wide beam. This results in the dispersion of ultrasonic energy and makes it difficult to locate the section. The acoustic lens, through its curved geometric design, optimizes the directivity of the ultrasound waves, achieving an effect similar to ultrasonic focusing, thereby increasing the strength of the ultrasound signal and the resolution of the imaging system.

[0056] In addition, it should be noted that the wearable ultrasound patch used for intraoperative bleeding monitoring has a linear arrangement of transducer array elements with a spacing of 0.2mm between the array elements, which is approximately the length of one wavelength. This design can improve the patch's phased focusing capability and increase the patch's scanning range. The maximum thickness of the acoustic lens material is 2mm, corresponding to a horizontal focus of 15mm. The overall length of the patch is 12mm, the width is 8mm, and the thickness is 4mm, making it small and thin.

[0057] This application provides a wearable ultrasound patch for intraoperative bleeding monitoring. Using wearable electronics manufacturing technology, the patch successfully achieves wearable manufacturing of an ultrasound probe. The patch can be stably attached to the patient's carotid artery for a long period of time without restricting the patient's movement.

[0058] The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring provided in the embodiment of the present application can be applied to Figure 2 In the application environment shown. Among them, the terminal 102 communicates with the server 104 through the network. The data storage system can store the data that the server 104 needs to process. The data storage system can be set up separately, integrated on the server 104, or placed on the cloud or other servers. The terminal 102 can send the acquired ultrasonic echo signal to the server 104. After the server 104 receives the ultrasonic echo signal, the server 104 demodulates the ultrasonic echo signal to obtain a demodulated signal; integrates the demodulated signal to obtain an integrated demodulated signal; based on the integrated demodulated signal, calculates the average Doppler frequency shift at the demodulation frequency position; based on the average Doppler frequency shift at the demodulation frequency position, calculates the Doppler blood flow velocity. The server 104 can feed back the obtained Doppler blood flow velocity to the terminal 102. In addition, in some embodiments, the wearable ultrasound patch signal processing method for intraoperative bleeding monitoring can also be implemented independently by the server 104 or the terminal 102. For example, the terminal 102 can directly perform signal processing on the ultrasonic echo signal, or the server 104 can obtain the ultrasonic echo signal from the data storage system and perform signal processing on the ultrasonic echo signal.

[0059] The terminal 102 may be, but is not limited to, various desktop computers, laptop computers, smart phones, and tablet computers. The server 104 may be implemented as an independent server or a server cluster consisting of multiple servers, or a cloud server.

[0060] In an exemplary embodiment, Figure 3As shown, a wearable ultrasound patch signal processing method for intraoperative bleeding monitoring is provided. The method is executed by a computer device, specifically a computer device such as a terminal or a server, or a terminal and a server. In the embodiment of the present application, the method is applied to Figure 2 The server 104 in the example is used for explanation, and the steps include the following steps S1 to S5.

[0061] S1: Acquire ultrasonic echo signals.

[0062] S2: Demodulate the ultrasonic echo signal to obtain a demodulated signal.

[0063] S3: Integrate the demodulated signal to obtain an integrated demodulated signal.

[0064] S4: Based on the integrated demodulated signal, calculate and obtain an average Doppler shift at the demodulation frequency position.

[0065] S5: Calculate the Doppler blood flow velocity based on the average Doppler frequency shift at the demodulation frequency position.

[0066] By implementing the above steps S1 to S5, blood flow velocity parameters can be monitored in real time and continuously. Therefore, the present application can be applied to clinical applications of intraoperative bleeding monitoring.

[0067] As an optional implementation, in step S2, the following steps are specifically included.

[0068] First, the ultrasound echo signal set is defined as List A two-dimensional array of rows, using Represents an element in an array. The signal is then demodulated using triangular quadrature demodulation. Quadrature demodulation is a signal processing method that phase-delays and superimposes ultrasonic RF signals. The demodulated signal retains the single-sideband spectrum, making mathematical operations on complex signals simpler. Triangular quadrature demodulation multiplies the ultrasonic echo signal by a trigonometric function to produce a demodulated signal at a preset demodulation frequency. The calculation formula for quadrature demodulation of an ultrasonic echo signal is shown below.

[0069] (1).

[0070] (2).

[0071] in, For the The in-phase component of the samples; is the input RF signal, which represents the ultrasonic echo signal in the array column direction; is the probe center frequency; is the frequency offset; For the The time corresponding to each sampling point.

[0072] Will The demodulated signal is expressed as follows.

[0073] (3).

[0074] in, is the demodulated signal; is the real part, which represents the in-phase component obtained by orthogonal demodulation; is the imaginary part, which represents the orthogonal component obtained by orthogonal demodulation; is the imaginary unit, .

[0075] As an optional implementation, step S3 specifically includes the following steps.

[0076] The one-dimensional autocorrelation estimator only retains a complex value in each sample and uses it for subsequent calculations, so the obtained results need to be accumulated. Directly calculate all sampling points and set the accumulation window The magnitude is 1, and the integrated demodulated signal is expressed as follows.

[0077] (4).

[0078] in, is the demodulated signal after integration; is the first accumulation window size, used to smooth the estimation results; Depth position on, on The sum of all in-phase components in the frame; is the sum of the corresponding orthogonal components.

[0079] The expression of the one-dimensional autocorrelation function is shown below.

[0080] (5).

[0081] in, is the one-dimensional autocorrelation function; is the second accumulation window size; is the autocorrelation coefficient; is the demodulated signal after integration; is the conjugate function of the integrated demodulated signal.

[0082] In step S4, the average Doppler shift at the demodulation frequency position can be calculated using the one-dimensional autocorrelation function.

[0083] (6).

[0084] in, is the average Doppler shift at the demodulation frequency position; is the real part of the integrated demodulated signal; is the imaginary part of the demodulated signal after integration.

[0085] In step S5, after the Doppler frequency shift is calculated, it can be substituted into the parameter formula to calculate the Doppler blood flow velocity.

[0086] (7).

[0087] in, is the Doppler blood flow velocity; is the speed of sound; is the sampling time interval; is the pulse repetition time interval; is the corresponding value of the demodulation frequency relative to the center frequency. For the convenience of calculation, in this embodiment, it is assumed that the echo frequency will not shift relative to the center frequency. Set to 1. Substituting into the above formula, the Doppler blood flow velocity can be obtained as follows.

[0088] (8).

[0089] in, is the in-phase component at the next time point; is the orthogonal component at the next time point.

[0090] The signal processing method of the wearable ultrasound patch for intraoperative bleeding monitoring provided in this application can monitor blood flow velocity parameters in real time and continuously, and can be applied to clinical applications of intraoperative bleeding monitoring.

[0091] The present application also provides an application scenario, which applies the above-mentioned wearable ultrasound patch signal processing method for intraoperative bleeding monitoring. Specifically: The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring provided in this embodiment can be applied in surgical operation scenarios. The surgical operation scenario includes a patch wearing link and a signal processing link; first, the wearable ultrasound patch is tightly attached to the human neck and the real-time acquisition of the original echo signal begins; then, the acquired original echo signal is input into a pre-set signal processing method to obtain the Doppler blood flow velocity.

[0092] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 4As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store ultrasonic echo signals. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a wearable ultrasound patch signal processing method for intraoperative bleeding monitoring is implemented.

[0093] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0094] In an exemplary embodiment, a computer device is further provided, including a memory and a processor. The memory stores a computer program, and the processor implements the above method embodiments when executing the computer program.

[0095] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which implements the above-mentioned method embodiments when executed by a processor.

[0096] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the above method embodiments are implemented.

[0097] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0098] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above-mentioned embodiments. In particular, any reference to memory, database, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0099] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

[0100] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A wearable ultrasound patch signal processing method for intraoperative bleeding monitoring, characterized in that: The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring includes: Acquiring ultrasonic echo signals; Demodulating the ultrasonic echo signal to obtain a demodulated signal; Integrating the demodulated signal to obtain an integrated demodulated signal; Based on the integrated demodulated signal, an average Doppler shift at the demodulation frequency position is calculated; Calculating the Doppler blood flow velocity based on the average Doppler frequency shift at the demodulation frequency position; The calculation formula for demodulating the ultrasonic echo signal is: ； ； in, For the The in-phase component of the samples; is the input RF signal, which represents the ultrasonic echo signal in the array column direction; is the probe center frequency; is the frequency offset; For the The time corresponding to each sampling point; The expression of the integrated demodulated signal is: ； ； in, is the demodulated signal after integration; is the first accumulation window size, used to smooth the estimation results; Depth position on, on The sum of all in-phase components in the frame; is the sum of the corresponding orthogonal components; is the demodulated signal; is the real part, which represents the in-phase component obtained by orthogonal demodulation; is the imaginary part, which represents the orthogonal component obtained by orthogonal demodulation; is the imaginary unit, ; The expression of the average Doppler shift at the demodulation frequency position is: ； ； in, is the average Doppler shift at the demodulation frequency position; is the real part of the integrated demodulated signal; is the imaginary part of the demodulated signal after integration; is the one-dimensional autocorrelation function; is the second accumulation window size; is the autocorrelation coefficient; is the demodulated signal after integration; is the conjugate function of the integrated demodulated signal.

2. The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring according to claim 1 is characterized in that: The calculation formula of the Doppler blood flow velocity is: ； in, is the Doppler blood flow velocity; is the speed of sound; is the sampling time interval; is the pulse repetition time interval; is the corresponding value of the demodulation frequency relative to the center frequency; is the average Doppler shift at the demodulation frequency.

3. The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring according to claim 1, characterized in that: The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring is implemented based on a wearable ultrasound patch for intraoperative bleeding monitoring. The wearable ultrasound patch for intraoperative bleeding monitoring includes: a piezoelectric layer, a backing layer, a matching layer, and an acoustic lens layer; The piezoelectric layer is used to generate mechanical vibration and receive ultrasonic echo signals; the mechanical vibration is transmitted simultaneously in the forward and reverse directions in the form of ultrasonic waves through the coupling medium; The backing layer is located behind the piezoelectric layer and is used to absorb the back-propagating ultrasonic waves; The matching layer is located between the piezoelectric layer and the acoustic lens layer, and is used to adjust the forward propagating ultrasonic wave to obtain an adjusted ultrasonic wave; The acoustic lens layer is in contact with human tissue, and is used to focus the adjusted ultrasonic waves and then inject them into the human tissue, and to inject the ultrasonic echo signals into the piezoelectric layer through the matching layer.

4. The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring according to claim 3 is characterized in that: The piezoelectric layer is made of soft lead zirconium titanate ceramics; the piezoelectric layer includes a plurality of transducer array elements, and the plurality of transducer array elements are arranged linearly.

5. The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring according to claim 3 is characterized in that: The backing layer is made of a mixture of epoxy resin, glass microbeads and rubber particles.

6. The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring according to claim 3, characterized in that: The matching layer is made of a mixture of epoxy resin, aluminum oxide and tungsten powder.

7. The wearable ultrasound patch signal processing method for intraoperative bleeding monitoring according to claim 3, characterized in that: The acoustic lens layer is made of silicone rubber material.

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