A method and system for blood pressure monitoring based on wearable ultrasound transducers

Abstract

The application relates to a wearable ultrasonic transducer-based blood pressure monitoring method and system, which comprises the following steps: obtaining ultrasonic continuous images of an artery to be monitored by an ultrasonic transducer, and acquiring continuous position change information of an arterial wall; obtaining continuous change information of an arterial diameter with time according to the continuous position change information of the arterial wall; and obtaining continuous blood pressure data according to an arterial diameter-blood pressure relationship and in combination with the continuous change information of the arterial diameter with time; wherein the establishment of the arterial diameter-blood pressure relationship is as follows: selecting a suitable superficial limb artery as a measurement area, and determining a calibration blood vessel; obtaining calibration information of the calibration blood vessel by using a sphygmomanometer and the ultrasonic transducer; obtaining an ultrasonic echo time difference between an arterial anterior wall and an arterial posterior wall by the ultrasonic transducer, and obtaining an arterial diameter; and fitting the calibration information and the arterial diameter to obtain the arterial diameter-blood pressure relationship. Compared with the prior art, the application realizes real-time continuous monitoring of the blood pressure of a human superficial artery.

Description

Technical Field

[0001] This invention relates to the field of real-time measurement and monitoring of human blood pressure, and in particular to a blood pressure monitoring method and system based on a wearable ultrasonic transducer. Background Technology

[0002] Traditional handheld ultrasound probes are mostly used in clinical medical imaging diagnosis. They are often large and poorly portable, which severely limits the application scenarios of ultrasound technology. In recent years, with the continuous maturation of portable wearable ultrasound technology, ultrasound transducers are developing towards portable and wearable designs.

[0003] Cardiovascular disease, along with cancer, respiratory diseases, and diabetes, is known as one of the four major chronic diseases, seriously endangering people's health. Arterial blood pressure is a key physiological parameter for assessing the cardiovascular system. The arterial blood pressure waveform contains a wealth of information about the dynamic cardiovascular state and can be used to diagnose or predict cardiovascular diseases. Each peak and trough in the arterial blood pressure waveform represents a specific cardiac activity, and continuous monitoring of these subtle waveform changes can provide a reliable basis for the diagnosis and prevention of cardiovascular diseases.

[0004] Currently, the main methods for measuring blood pressure include the cuff compression method, the volume compensation method, and the tension method. The cuff compression method is the most widely used blood pressure measurement method in the world, but this method can only measure blood pressure intermittently and cannot monitor blood pressure changes in real time, and the comfort level during the measurement process is relatively low. The volume compensation method is easily affected by skin condition and the measurement environment. The tension method often causes discomfort to patients because it requires squeezing the artery during the measurement process. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a blood pressure monitoring method and system based on a wearable ultrasonic transducer, which realizes real-time continuous monitoring of blood pressure in superficial arteries of the human body without the need to squeeze the arteries, thus improving comfort and being unaffected by skin condition and measurement environment.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A blood pressure monitoring method based on a wearable ultrasound transducer includes the following steps:

[0008] A continuous ultrasound image of the artery to be monitored is obtained through an ultrasound transducer, and continuous positional change information of the arterial wall is obtained based on the continuous ultrasound image.

[0009] The continuous change information of arterial diameter over time is obtained based on the continuous positional change information of the arterial wall;

[0010] Based on the arterial diameter-blood pressure relationship, continuous blood pressure data is obtained through the continuous change information of the arterial diameter over time;

[0011] The steps for establishing the arterial diameter-blood pressure relationship are as follows:

[0012] Select appropriate superficial limb arteries as the measurement area and determine the calibrated vessels;

[0013] The systolic and diastolic blood pressure of the calibrated blood vessel are obtained using a blood pressure monitor, and the arterial diameter corresponding to the systolic and diastolic blood pressure of the calibrated blood vessel is obtained using an ultrasonic transducer. The arterial systolic pressure, arterial diastolic pressure, arterial diameter corresponding to systolic pressure, and arterial diameter corresponding to diastolic pressure are used as calibration information.

[0014] The time difference between the ultrasound echoes of the anterior and posterior walls of the artery is obtained by using an ultrasound transducer, and the artery diameter is calculated based on the speed of sound in human blood pressure.

[0015] The calibration information and arterial diameter are fitted to obtain the corresponding arterial diameter-blood pressure relationship.

[0016] Furthermore, the superficial limb arteries include multiple types such as the brachial artery, radial artery, ulnar artery, or carotid artery.

[0017] Furthermore, the superficial limb artery is located 2–15 mm subcutaneously.

[0018] Furthermore, the center frequency of the ultrasonic transducer is 7–10 MHz, and the longitudinal limit resolution is 0.2–0.5 mm.

[0019] Furthermore, the arterial stiffness coefficient is obtained based on the arterial systolic pressure, arterial diastolic pressure, arterial diameter corresponding to systolic pressure, and arterial diameter corresponding to diastolic pressure.

[0020] Furthermore, the stiffness coefficient of the artery is as follows:

[0021]

[0022] In the formula, β is the arterial stiffness coefficient, p d For arterial diastolic pressure, p s D is the arterial systolic blood pressure. s D represents the arterial diameter corresponding to systolic blood pressure. d This represents the arterial diameter corresponding to diastolic blood pressure.

[0023] Furthermore, the arterial diameter-blood pressure relationship is as follows:

[0024]

[0025] In the formula, p(t) is the blood pressure value as a function of time, pd Where β is the diastolic blood pressure, β is the arterial stiffness coefficient, and D(t) is the arterial diameter as a function of time. d This represents the arterial diameter corresponding to diastolic blood pressure.

[0026] Furthermore, continuous positional change information of the arterial wall is obtained based on the ultrasound echo signal, including continuous positional change information of the anterior and posterior walls of the artery.

[0027] Furthermore, the continuous change information of the arterial diameter over time is obtained based on the continuous positional change information of the anterior and posterior walls of the artery.

[0028] According to another aspect of the present invention, a blood pressure monitoring system based on a wearable ultrasonic transducer is provided, comprising:

[0029] The arterial wall position information acquisition module is used to obtain continuous ultrasound images of the artery to be monitored through an ultrasound transducer, and to obtain continuous position change information of the arterial wall based on the continuous ultrasound images.

[0030] An artery diameter acquisition module is used to obtain continuous change information of artery diameter over time based on the continuous positional change information of the artery wall;

[0031] The blood pressure data acquisition module is used to obtain continuous blood pressure data based on the diameter-blood pressure relationship and the continuous change information of the artery diameter over time.

[0032] The steps for establishing the arterial diameter-blood pressure relationship are as follows:

[0033] Select appropriate superficial limb arteries as the measurement area and determine the calibrated vessels;

[0034] The systolic and diastolic blood pressure of the calibrated blood vessel are obtained using a blood pressure monitor, and the arterial diameter corresponding to the systolic and diastolic blood pressure of the calibrated blood vessel is obtained using an ultrasonic transducer. The arterial systolic pressure, arterial diastolic pressure, arterial diameter corresponding to systolic pressure, and arterial diameter corresponding to diastolic pressure are used as calibration information.

[0035] The time difference between the ultrasound echoes of the anterior and posterior walls of the artery is obtained by using an ultrasound transducer, and the artery diameter is calculated based on the speed of sound in human blood pressure.

[0036] The calibration information and arterial diameter are fitted to obtain the corresponding arterial diameter-blood pressure relationship.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. This invention relies on the advantages of wearable ultrasound technology, such as real-time imaging, high resolution, low cost, and rapid monitoring. It uses an ultrasound transducer to obtain the diameter information of blood vessels, and a blood pressure monitor to obtain the diastolic and systolic blood pressure of the arteries. After determining the arterial stiffness coefficient, the corresponding arterial diameter-blood pressure relationship formula is obtained by fitting. By measuring the continuous change of arterial diameter over time, real-time, continuous, and accurate blood pressure measurement is achieved, ensuring the accuracy and stability of blood pressure measurement.

[0039] 2. This invention uses a wearable ultrasonic transducer to measure blood pressure in real time. The wearable ultrasonic transducer is highly integrated, lightweight and compact, breaking through the application scenario limitations of traditional ultrasonic probes. It can be worn on the human body and carried around. Blood pressure measurement is performed using the ultrasonic transducer without squeezing the arteries, which improves the comfort of blood pressure measurement. The portability of the wearable ultrasonic transducer makes it possible to use ultrasonic blood pressure measurement technology at home. Attached Figure Description

[0040] Figure 1 This is a schematic flowchart of a blood pressure monitoring method based on a wearable ultrasonic transducer proposed in this invention.

[0041] Figure 2 A schematic diagram of the brachial artery in the human arm;

[0042] Figure 3 M-mode echogenicity of porcine arteries was measured using a wearable ultrasound transducer.

[0043] Figure 4 The brightness distribution of a column of ultrasound signals in an M-mode echocardiogram of a pig artery.

[0044] Figure 5 This is a distribution map of data points within the normal blood pressure range obtained from the test, based on the arterial diameter-blood pressure curve obtained from the calibration information.

[0045] Legend: 1. Wearable ultrasound transducer; 2. Coupling layer; 3. Signal wire; 4. Brachial artery; 5. Muscle tissue; 6. Bone tissue; 7. Human arm; 8. Anterior wall of the artery; 9. Posterior wall of the artery. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0047] Example 1

[0048] This embodiment provides a blood pressure monitoring method based on a wearable ultrasonic transducer, such as... Figure 1 As shown, it includes the following steps:

[0049] S1. Obtain continuous ultrasound images of the artery to be monitored through an ultrasound transducer, and obtain continuous positional change information of the arterial wall based on the continuous ultrasound images.

[0050] This embodiment selects a human arm (7) as the research object, such as Figure 2 As shown.

[0051] In this embodiment, a wearable ultrasonic transducer 1 is composed of an array containing 32 independent array elements, and has structures such as an acoustic matching layer and a backing layer. It can transmit and receive ultrasonic signals through signal wires 3. The center frequency of the ultrasonic transducer is 7-10MHz, and the longitudinal resolution limit is 0.2-0.5mm.

[0052] The calibrated blood pressure monitor should be an electronic one. The coupling layer 2 should be made of a fluid silicone rubber or hydrogel product, with a thickness of less than 1 mm.

[0053] The brachial artery 4 of the human arm 7 is selected as the artery to be monitored, avoiding muscle tissue 5 and bone tissue 6. A coupling layer 2 is filled between the wearable ultrasound transducer and the skin to reduce the reflection and loss of ultrasound signals, and medical tape is used to fix it above the brachial artery 4 of the human arm 7.

[0054] Wearable ultrasound transducer 1 is used to obtain continuous M-mode ultrasound images of the target artery, and information on the continuous positional changes of the arterial wall is obtained based on the information in the images.

[0055] S2. Obtain information on the continuous change of arterial diameter over time based on the continuous positional change information of the arterial wall.

[0056] Based on the time difference of ultrasound echo between the anterior and posterior walls of the artery and the speed of sound in human arteries (1570 m / s), the artery diameter is calculated, and information on the continuous change of the artery diameter over time is obtained.

[0057] S3. Based on the relationship between arterial diameter and blood pressure, continuous blood pressure data is obtained by using the continuous change information of arterial diameter over time.

[0058] The steps to establish the arterial diameter-blood pressure relationship are as follows:

[0059] Select a suitable superficial limb artery as the measurement area and determine the marked vessel. The superficial limb artery is the brachial artery, radial artery, ulnar artery or carotid artery, with an artery diameter of 3 to 10 mm and located 2 to 15 mm below the skin.

[0060] Systolic and diastolic blood pressure are measured using a blood pressure monitor. The corresponding arterial diameters for systolic and diastolic blood pressure are obtained using an ultrasonic transducer. Systolic blood pressure, diastolic blood pressure, and the corresponding arterial diameters for systolic and diastolic blood pressure are used as calibration information.

[0061] The diameter-blood pressure relationship of the corresponding artery was fitted based on the calibration information.

[0062] In this embodiment, a pre-fixed wearable ultrasound transducer is used to acquire ultrasound signals from one cardiac cycle of the target artery. The systolic diameter D of the measured artery is then calculated based on the acquired ultrasound signals. s1 Diastolic pressure diameter D d1 Use a blood pressure monitor to measure the systolic blood pressure (P) of the artery in the ipsilateral arm (7th inch). s1 With diastolic blood pressure p d1 This serves as calibration information.

[0063] According to the calibrated arterial systolic pressure p s1 and its diameter D s1 and diastolic pressure p d1 and its diameter D d1 Based on the formula for calculating arterial stiffness, the stiffness coefficient β1 of the target artery is calculated and obtained.

[0064] The formula for calculating the arterial stiffness coefficient is as follows:

[0065]

[0066] In the formula, β is the arterial stiffness coefficient, p d For arterial diastolic pressure, p s D is the arterial systolic blood pressure. s D represents the arterial diameter corresponding to systolic blood pressure. d This represents the arterial diameter corresponding to diastolic blood pressure.

[0067] Based on the calculated hardness coefficient β1 and diastolic pressure p d1 and its diameter D d1 The formula for calculating the relationship between arterial diameter and blood pressure is y1 = p(t).

[0068] The relationship between artery diameter and blood pressure is as follows:

[0069]

[0070] In the formula, p(t) is the blood pressure value as a function of time, p d β is the diastolic pressure of the artery, D(t) is the arterial stiffness coefficient, and D(t) is the arterial diameter as a function of time. d This represents the arterial diameter corresponding to diastolic blood pressure.

[0071] Based on the formula y1=p(t) for the relationship between arterial diameter and blood pressure, the continuous changes in arterial systolic and diastolic blood pressure can be calculated. Through the data of continuous arterial systolic and diastolic blood pressure, physiological information such as heart rate can be calculated.

[0072] The distribution of data points within the normal blood pressure range obtained from the calibration information, based on the arterial diameter-blood pressure curve, is shown in the following figure. Figure 5 As shown, the error at all points is less than 3 mmHg. Figure 5 It can be seen that the blood pressure monitoring method based on a wearable ultrasonic transducer proposed in this embodiment has a good blood pressure monitoring effect.

[0073] Example 2

[0074] Since pig arteries are similar in structure and properties to human arteries, this embodiment selects an isolated pig artery as the artery to be monitored. After tightly connecting the pig artery with a rubber catheter, the two ends are connected to a pressurizing device and a pressure gauge, respectively. The wearable ultrasonic transducer is fixed 3 mm away from the upper wall of the artery. Both the ultrasonic transducer and the pig artery are in a 0.9% NaCl physiological saline solution.

[0075] Ultrasound signals from the anterior wall 8 and posterior wall 9 of the target artery were acquired using a pre-fixed wearable ultrasound transducer. With diastolic pressure of 75 mmHg and systolic pressure of 127.5 mmHg, the systolic diameter D of the artery was calculated based on the acquired ultrasound signals after pressure was applied. s2 Diastolic pressure diameter D d2 systolic pressure p s2 and diastolic pressure p d2 This serves as calibration information.

[0076] The calibrated arterial systolic pressure p was obtained s2 and its diameter D s2 and diastolic pressure p d2 and its diameter D d2 Based on the formula for calculating arterial stiffness, the stiffness coefficient β2 of the target artery is calculated and obtained; based on the calculated stiffness coefficient β2 and diastolic blood pressure p... d2 and its diameter D d2 The formula for calculating the relationship between arterial diameter and blood pressure is y2 = p'(t).

[0077] Wearable ultrasound transducers are used to obtain continuous M-mode ultrasound images of the target artery. Based on the information in the images, continuous positional changes of the anterior wall 8 and posterior wall 9 of the artery are obtained. The continuous change in arterial diameter over time is then obtained based on the positional difference between the arterial walls. For example... Figure 3 The image shows an M-mode ultrasound echo of an isolated porcine artery measured by a wearable ultrasound transducer. The horizontal axis represents the positional changes of the anterior wall 8 and posterior wall 9 of the artery over time, while the vertical axis represents the distance of the arterial wall from the ultrasound transducer.

[0078] The brightness distribution of a series of ultrasound signals in an M-mode echocardiogram of an isolated porcine artery is shown below. Figure 4 As shown, the arterial diameter information can be obtained by the positional difference between the anterior wall 8 and the posterior wall 9 of the artery.

[0079] Based on the obtained arterial diameter-blood pressure relationship formula y2=p'(t), the continuous systolic and diastolic blood pressure changes of the artery are calculated.

[0080] The rest is the same as in Example 1.

[0081] Example 3

[0082] This embodiment provides a blood pressure monitoring system based on a wearable ultrasonic transducer, including:

[0083] The arterial wall position information acquisition module is used to obtain continuous ultrasound images of the artery to be monitored through an ultrasound transducer, and to obtain continuous position change information of the arterial wall based on the continuous ultrasound images.

[0084] The artery diameter acquisition module is used to obtain the continuous change information of artery diameter over time based on the continuous positional change information of the artery wall;

[0085] The blood pressure data acquisition module is used to obtain continuous blood pressure data based on the diameter-blood pressure relationship and the continuous change information of arterial diameter over time.

[0086] The steps for establishing the arterial diameter-blood pressure relationship are as follows:

[0087] Select appropriate superficial limb arteries as the measurement area and determine the calibrated vessels;

[0088] The systolic and diastolic blood pressure of the calibrated blood vessel are obtained using a sphygmomanometer, and the corresponding arterial diameters for systolic and diastolic blood pressure are obtained using an ultrasonic transducer. The arterial systolic pressure, arterial diastolic pressure, and corresponding arterial diameters for systolic and diastolic blood pressure are used as calibration information.

[0089] The time difference between the ultrasound echoes of the anterior and posterior walls of the artery is obtained by using an ultrasound transducer, and the artery diameter is calculated based on the speed of sound in human blood pressure.

[0090] The calibration information and arterial diameter are fitted to obtain the corresponding arterial diameter-blood pressure relationship.

[0091] The rest is the same as in Example 1.

[0092] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method of wearable ultrasound transducer based blood pressure monitoring, characterized in that, The method comprises the following steps: obtaining continuous position change information of an arterial wall from continuous ultrasound images of an artery to be monitored obtained by an ultrasonic transducer; obtaining continuous change information of an arterial diameter over time from the continuous position change information of the arterial wall; obtaining continuous blood pressure data from the continuous change information of the arterial diameter over time according to an arterial diameter-blood pressure relationship; The establishment of the arterial diameter-blood pressure relationship comprises the following steps: selecting a suitable superficial limb artery as a measurement area and determining a calibration blood vessel; obtaining systolic arterial pressure and diastolic arterial pressure of the calibration blood vessel by using a sphygmomanometer, obtaining systolic arterial diameter and diastolic arterial diameter corresponding to the systolic arterial pressure and the diastolic arterial pressure by using an ultrasonic transducer, taking the systolic arterial pressure, the diastolic arterial pressure, the systolic arterial diameter and the diastolic arterial diameter as calibration information, and obtaining a stiffness coefficient of the artery according to the systolic arterial pressure, the diastolic arterial pressure, the systolic arterial diameter and the diastolic arterial diameter, wherein the stiffness coefficient of the artery is as follows: wherein is the stiffness coefficient of the artery, is the diastolic pressure of the artery, is the systolic pressure of the artery, is the arterial diameter corresponding to the systolic pressure, is the arterial diameter corresponding to the diastolic pressure; obtaining an arterial diameter from a time difference of ultrasound echo of an arterial anterior wall and an arterial posterior wall obtained by the ultrasonic transducer and a sound velocity in human blood pressure; fitting the calibration information and the arterial diameter to obtain a corresponding arterial diameter-blood pressure relationship, wherein the arterial diameter-blood pressure relationship is as follows: wherein is a blood pressure value as a function of time, is an arterial diastolic pressure, is a stiffness coefficient of the artery, is an arterial diameter as a function of time, is a diastolic pressure corresponding arterial diameter.

2. The wearable ultrasound transducer-based blood pressure monitoring method of claim 1, wherein, The superficial limb artery comprises one of a brachial artery, a radial artery, an ulnar artery or a carotid artery.

3. The wearable ultrasound transducer-based blood pressure monitoring method of claim 2, wherein, The superficial limb artery is located between 2 mm and 15 mm below the skin.

4. The wearable ultrasound transducer-based blood pressure monitoring method of claim 1, wherein, The ultrasonic transducer has a central frequency of 7-10 MHz and a longitudinal limit resolution of 0.2-0.5 mm.

5. The wearable ultrasound transducer-based blood pressure monitoring method of claim 1, wherein, The continuous position change information of the arterial wall comprises continuous position change information of an arterial anterior wall and an arterial posterior wall.

6. The wearable ultrasound transducer-based blood pressure monitoring method of claim 5, wherein, The continuous change information of the arterial diameter over time is obtained from the continuous position change information of the arterial anterior wall and the arterial posterior wall.

7. A blood pressure monitoring system based on a wearable ultrasonic transducer, comprising: an arterial wall position information acquisition module configured to obtain continuous ultrasound images of an artery to be monitored by an ultrasonic transducer and obtain continuous position change information of an arterial wall from the continuous ultrasound images; an arterial diameter acquisition module configured to obtain continuous change information of an arterial diameter over time from the continuous position change information of the arterial wall; a blood pressure data acquisition module configured to obtain continuous blood pressure data from the continuous change information of the arterial diameter over time according to a diameter-blood pressure relationship; The establishment of the arterial diameter-blood pressure relationship comprises the following steps: selecting a suitable superficial limb artery as a measurement area and determining a calibration blood vessel; The systolic arterial pressure and the diastolic arterial pressure of the calibration blood vessel are obtained by using a sphygmomanometer, the systolic pressure corresponding arterial diameter and the diastolic pressure corresponding arterial diameter of the calibration blood vessel are obtained by using an ultrasonic transducer, the systolic arterial pressure, the diastolic arterial pressure, the systolic pressure corresponding arterial diameter and the diastolic pressure corresponding arterial diameter are taken as calibration information, the stiffness coefficient of the artery is obtained according to the systolic arterial pressure, the diastolic arterial pressure, the systolic pressure corresponding arterial diameter and the diastolic pressure corresponding arterial diameter, and the stiffness coefficient of the artery is as follows: wherein is the stiffness coefficient of the artery, is the diastolic pressure of the artery, is the systolic pressure of the artery, is the arterial diameter corresponding to the systolic pressure, is the arterial diameter corresponding to the diastolic pressure; The ultrasonic echo time difference between the anterior wall of the artery and the posterior wall of the artery is obtained by using an ultrasonic transducer, and the arterial diameter is calculated according to the sound velocity in the human blood pressure; The corresponding arterial diameter-blood pressure relationship is fitted by using the calibration information and the arterial diameter, and the arterial diameter-blood pressure relationship is as follows: wherein is a blood pressure value as a function of time, is an arterial diastolic pressure, is a stiffness coefficient of the artery, is an arterial diameter as a function of time, is a diastolic pressure corresponding arterial diameter.

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