Method for measuring blood pressure with staged pressure

Abstract

A method for measuring blood pressure includes the steps of placing a body part on a biometric monitoring device such that the body part covers a PPG module and a pressure sensor, instructing a user to adjust a force applied by the body part to the pressure sensor to achieve a series of discrete stage target pressures, a user is instructed to maintain the pressure applied to the pressure sensor at each discrete stage target pressure during a corresponding measurement period, and a blood pressure measurement is performed during one or more measurement periods. The biometric monitoring device may include a multi-wavelength PPG module and a pressure sensor. The biometric monitoring device is connected to a mobile computing device that executes an application that controls the biometric monitoring device.

Description

Cross-references to related applications

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 521,844, filed June 19, 2023, entitled “Method for measuring blood pressure using staged pressure,” the disclosure of which is incorporated herein by reference. Technical Field

[0002] This invention relates generally to measuring blood pressure, and more specifically (but not limited to) to methods for improving the quality of biosignals in blood pressure measurements. Background Technology

[0003] People are increasingly recognizing the importance of empowering individuals to better manage their own health. Despite the growing emphasis on personal health management, accurate, affordable, easy-to-use, and publicly accessible biometric measurement devices remain scarce. Integrating biometric measurement and monitoring capabilities into portable and widely used products such as keychains or mobile phones will significantly enhance people's ability to manage their health.

[0004] For example, blood pressure is a fundamental diagnostic parameter used worldwide to assess health status. Basic measurements of this vital sign include diastolic blood pressure (the lowest pressure observed during a pulse cycle) and systolic blood pressure (the highest pressure observed during a pulse cycle). Currently, there are at least three methods for measuring absolute arterial blood pressure without inserting a measuring device into an artery: auscultation, oscillometric, and volumetric clamp methods. There are also some relative measurement methods that can detect changes or trends in blood pressure, but these methods require calibration for each user.

[0005] Referring to the traditional oscillometric method for measuring blood pressure, automated blood pressure monitors (such as inflatable cuffs) are typically used to block blood flow in an artery, usually the brachial or radial (wrist) artery. The cuff is then deflated more slowly, allowing blood to begin flowing again. During deflation, flow is detected by observing the minute pressure fluctuations introduced into the cuff by the pulse.

[0006] To enhance user experience, alternatives to traditional cuffs have been developed that determine blood pressure by measuring photoplethysmography (PPG) signals from body parts (such as fingers) up to arterial occlusion. The pressure at the point of target arterial occlusion represents blood pressure, and the pulsatile arterial blood volume waveform can be used to calculate blood pressure and other biometrics. These alternative devices differ from automated blood pressure cuffs that rely on Korotkoff sounds rather than PPG signals to estimate blood pressure.

[0007] In most PPG-based measurement systems, one or more light-emitting diodes (LEDs) or other photoemitters emit light into the vascular structure, while one or more photoreceivers (e.g., photodiodes) measure the reflected or transmitted light generated by the photoemitters. For successful blood pressure estimation using the PPG method, acquiring a high-quality user PPG signal is crucial. The user's pulse can be assessed by measuring the alternating current (AC) signal caused by the periodic pulse, while limiting the influence of the non-periodic direct current (DC) signal caused by tissue within the target vascular structure and baseline blood flow.

[0008] Previously, determining blood pressure using PPG signals required the user to steadily increase the amount of pressure applied from a part of their body (e.g., a fingertip) until the pressure caused by the user-applied pressure occluded an artery, generating a PPG signal. Figure 1 illustrates a prior art testing protocol where the user is instructed to gradually and continuously increase the pressure applied from their fingertip to the biometric monitoring device until the target artery begins to occlude. In many cases, this process is time-consuming (e.g., 30 seconds) and requires the user to concentrate on gradually increasing the pressure applied from the body part to the signal acquisition device. If the user's attention is distracted or they lack sufficient strength or muscle control to gradually increase the applied pressure, the entire testing protocol must be restarted. Therefore, there is a need to improve the testing protocol for PPG blood pressure monitoring devices and to develop corresponding systems and methods. Summary of the Invention

[0009] In some embodiments, this disclosure relates to a method for measuring blood pressure using a biometric monitoring device comprising a PPG module and a pressure sensor, wherein the biometric monitoring device is connected to a mobile computing device executing an application for controlling the biometric monitoring device. The method includes the steps of: placing a body part on the biometric monitoring device such that the body part covers the PPG module and the pressure sensor; instructing a user to adjust the force applied to the pressure sensor by the body part to achieve an initial target pressure; and instructing the user to maintain the pressure applied to the pressure sensor at the initial target pressure during an initial measurement period.

[0010] In these embodiments, the method continues with the following steps: instructing the user to adjust the force applied to the pressure sensor from the body part to achieve one or more subsequent stage target pressures, wherein each of the one or more subsequent stage target pressures is greater than the previous stage target pressure; instructing the user to maintain the pressure applied to the pressure sensor at the target pressure of each subsequent stage during subsequent measurement periods; and performing blood pressure measurement during one of the subsequent measurement periods.

[0011] In other embodiments, this disclosure relates to a method for measuring blood pressure using a biometric monitoring device comprising a PPG module and a pressure sensor, wherein the biometric monitoring device is connected to a mobile computing device executing an application for controlling the biometric monitoring device. In such embodiments, the method includes the steps of: placing a body part on the biometric monitoring device such that the body part covers the PPG module and the pressure sensor; instructing a user to adjust the force applied to the pressure sensor by the body part to achieve a series of discrete-stage target pressures; instructing the user to maintain the pressure applied to the pressure sensor at each of the discrete-stage target pressures during corresponding measurement periods; and performing blood pressure measurements during one or more measurement periods. The method may further include: automatically determining a series of discrete-stage target pressures based on the user's past use of the biometric monitoring device, the user's demographic information, or the accuracy with which the user achieved target pressures in earlier discrete stages.

[0012] In other embodiments, this disclosure relates to a system for obtaining one or more biometric measurements from a user. The system includes a biometric monitoring device connected to a mobile computing device via a data connection. The biometric monitoring device includes a PPG module and a pressure sensor adapted to measure the force applied to the biometric monitoring device by the user. The mobile computing device is configured to execute an application that instructs the user to apply pressure to the pressure sensor according to a phased pressure scheme. In some cases, the application is configured to automatically adjust the phased pressure scheme based on the user's past use of the biometric monitoring device. Attached Figure Description

[0013] Figure 1 is a schematic diagram of an existing technology for measuring blood pressure using a PPG-based biometric monitoring device.

[0014] Figure 2 A PPG-based biometric monitoring device suitable for measuring blood pressure is described.

[0015] Figure 3 This is a flowchart of a method for measuring blood pressure using staged pressure.

[0016] Figure 4 This is a schematic diagram of a staged pressure scheme for measuring blood pressure, performed according to an exemplary embodiment.

[0017] Figure 5 This is a flowchart illustrating the process of using an alternative method for measuring blood pressure using staged pressure. Detailed Implementation

[0018] Turning Figure 2The diagram illustrates a biometric monitoring device 100, ideally suited for measuring physiological parameters such as blood pressure, pulse, blood oxygen saturation, or other biometrics. Unless otherwise specified, the term "biometric" as used herein refers to a measurable physiological parameter. The biometric monitoring device 100 includes a body 102 and a finger slot 104 configured to position a user's fingertip onto the biometric monitoring device 100. The biometric monitoring device 100 also includes one or more light emitters 106, one or more light receivers 108, and one or more control circuits 110 electrically connected to the light emitters 106 and light receivers 108. The light emitters 106, light receivers 108, and control circuits 110 collectively constitute a PPG module 112. The biometric monitoring device 100 may also include a pressure sensor 114 configured to measure the force applied to the biometric monitoring device 100 by the fingertip. The pressure sensor 114 is also connected to the control circuitry 110. Although... Figure 2 The biometric monitoring device 100 is designed for use on a user's fingertips, but it is understood that the biometric monitoring device 100 can also be configured for use on other vascular body parts, including toes, wrists, ears, arms, and neck.

[0019] In an exemplary embodiment, the photoelectric emitter 106 is a light-emitting diode (LED) configured to output light (e.g., green, red, infrared light) at a selected controllable intensity (amplitude) according to a command signal from the control circuitry 110. In the same exemplary embodiment, the light receiver 108 is a photodiode configured to output a voltage signal to the control circuitry 110 in response to detecting light. The signal strength generated by the light receiver 108 can be tuned or adjusted to increase or decrease the sensitivity and output of the light receiver 108. The PPG module 112 can be configured to emit and detect light of multiple wavelengths or a single wavelength. Although in Figure 2 The control circuit 110, the optical transmitter 106, and the optical receiver 108 are depicted as separate interconnected components, but it should be understood that these components can also be placed on the same circuit board with integrated connectivity.

[0020] Biometric monitoring device 100 is configured to connect to mobile computing device 116, which may be a smartphone, tablet, watch, or personal computer. Biometric monitoring device 100 can connect to mobile computing device 116 via wired or wireless connection (e.g., Bluetooth). In some cases, biometric monitoring device 100 and mobile computing device 116 are integrated to form a single, modular mobile monitoring device. Biometric monitoring device 100 and mobile computing device 116 together constitute a biometric monitoring system.

[0021] Mobile computing device 116 provides instructions to the user via application 118. Application 118 guides the user to measure blood pressure using biometric monitoring device 100. Application 118 may include visual references 120, which serve as guidelines or limits for applying pressure. Figure 2 In the image, visual reference 120 is displayed on either side of line 122, which represents the actual force applied by the user's finger to pressure sensor 114. Application 118 can move visual reference 120 up or down to indicate to the user that the amount of pressure applied to pressure sensor 114 by their finger is increasing or decreasing. It will be understood that in... Figure 2 In this drawing, the mobile computing device 116 and the biometric monitoring device 100 are not drawn to scale. The application 118 may be stored on the mobile computing device 116 or the biometric monitoring device 100.

[0022] Go to Figure 3 The diagram illustrates a process flowchart for a biometric measurement method using a phased pressure scheme or method 200. Scheme 200 can be stored in application 118 and executed by mobile computing device 116. The method begins at step 202, where application 118 instructs the user to place a body part (e.g., the user's fingertip) on pressure sensor 114 and apply force to match a first-stage target pressure. At step 206, the scheme determines whether the user has reached the first-stage target pressure. If the first-stage target pressure has not been reached, method 200 returns to step 202. If the first-stage target pressure is successfully reached, method 200 proceeds to step 206, where step 206 determines whether the PPG module 112 can detect the user's pulse when the user applies force to pressure sensor 114 at the first-stage target pressure. If a pulse is detected, method 200 can proceed to step 208, where biometric monitoring device 100 performs a measurement using the pulsation feature detected by PPG module 112.

[0023] If the user's pulse is not detected in step 206, or if additional measurements are required, method 200 proceeds to step 210, where the user is instructed to apply force to pressure sensor 114 to match the target pressure for the subsequent stage. Method 200 continues with step 212 until the target pressure for the subsequent stage is reached, or the test protocol times out. Once the target pressure for the subsequent stage is reached, method 200 proceeds to step 214, where it is determined whether the PPG module 112 can detect the user's pulse when the user applies force to pressure sensor 114 at the target pressure for the subsequent stage. If a pulse is detected, method 200 can proceed to step 216, where the biometric monitoring device 100 uses the pulsation (AC) characteristic detected by the PPG module 112 for measurement. Method 200 can cycle through steps 210-216 until a sufficient number of measurements have been performed based on the PPG signal generated by the PPG module 112 to calculate the user's blood pressure or other desired biometric parameters.

[0024] Figure 4 This is a schematic diagram illustrating the pressure change over time in method 200. (Example) Figure 4 As shown, the pressure is initially increased to the first-stage target pressure 218. The user can then adjust the pressure as instructed to match subsequent stage target pressures 220, 222, and 224. Between each discrete stage target pressure 218, 220, 222, and 224, the user can decrease or increase the pressure applied to the pressure sensor 114. The user can maintain the applied force at one or more discrete stage target pressures 218-224 during the measurement period 226 as instructed, so that the PPG module 212 obtains the PPG signal at each target pressure. Figure 4 As shown, each of the discrete stage target pressures 218, 220, 222 and 224 is discontinuous with the other discrete stage target pressures.

[0025] In some embodiments, method 200 includes an optional step of instructing the user to adjust the force applied to pressure sensor 114 by a body part to an initial stage target pressure 218, followed by instructing the user to reduce the force applied to pressure sensor 114 by a body part to an intermediate stage target pressure 228. In this case, the intermediate stage target pressure 228 is less than the initial stage target pressure 218. Therefore, in an exemplary embodiment, method 200 includes: instructing the user to adjust the force applied to pressure sensor 114 by a body part to achieve a series of discrete stage target pressures; instructing the user to maintain the pressure applied to pressure sensor 114 at each of the discrete stage target pressures during corresponding measurement periods; and then performing blood pressure measurements during one or more measurement periods. This is significantly different from prior art methods that require the user to gradually and continuously increase the force applied to the blood flow occlusion device.

[0026] Go to Figure 5 The diagram illustrates a process flow of an alternative embodiment of a phased stress testing scheme 300, which uses a biometric monitoring device 100 and a mobile computing device 116 to measure blood pressure. In step 302, the application 118 instructs the user to apply a first-stage stress to the biometric monitoring device 100. Method 300 waits in step 306 for the first-stage stress to be reached. If the first-stage stress is not reached within a predetermined time period, method 300 may terminate or restart.

[0027] Once the first stage pressure is reached, method 300 proceeds to step 306, which determines whether arterial occlusion has occurred. If arterial occlusion occurs, method 300 proceeds to step 308, which measures blood pressure and other biometric data. If the first stage pressure does not result in arterial occlusion, the method continues to step 310, which instructs the user to temporarily relax and reduce the force applied to the pressure sensor 114 with their finger.

[0028] After the relaxation period ends, the method moves to step 312, where application 118 instructs the user to apply force to pressure sensor 114 to match the next pressure phase. Upon reaching the next pressure phase in step 314, method 300 proceeds to step 316, which determines whether arterial occlusion has occurred. If arterial occlusion occurs in the new pressure phase, method 300 moves to step 308 and performs a blood pressure measurement. If arterial occlusion does not occur in step 316, method 300 iteratively cycles through steps 310-316 for each pressure phase until arterial occlusion occurs.

[0029] In some embodiments, the steps for staged pressure measurements are automatically adjusted and optimized based on prior blood pressure or other biometric measurements obtained by a particular user using the biometric monitoring device 100. For example, if the biometric monitoring device 100 has previously obtained a subject's systolic blood pressure measurement in the range of 110 to 140 mmHg, the biometric monitoring device 100 can be configured to automatically adjust the testing protocol to instruct the subject to take measurements at a range of pressures that are likely to produce valid values ​​(taking into account the subject's previous blood pressure measurements), while excluding some or all pressures that are unlikely to produce valid values. This adaptive testing protocol can reduce the time and number of measurements required to obtain accurate blood pressure measurements from the subject.

[0030] In some embodiments, the steps of the biometric monitoring device 100 are automatically adjusted for a specific user based on their demographic characteristics. For example, for users with a higher body mass index (BMI), higher stress values ​​can be used to set the stages, since subjects with higher BMIs generally have higher blood pressure.

[0031] In some embodiments, the biometric monitoring device 100 is configured to automatically adjust the number of steps and / or the intensity of each step based on the user's ability to accurately apply a specified pressure to the biometric monitoring device 100. If the application 118 detects a large pressure tracking error in the user's response to the indicated pressure, the number of steps may need to be increased to obtain an accurate measurement. If the user is able to accurately apply the specified pressure to the biometric monitoring device 100 with their finger, the application can be configured to automatically reduce the number of steps to obtain a reliable blood pressure measurement. In this way, scheme 200 may include automatically and adaptively determining the number of steps, the pressure level used in each step, and the time the user must remain on each step based on a variety of factors, including the user's own prior data, the user's demographic data, and historical data from other users.

[0032] Therefore, application 118 can be configured to automatically optimize scheme 200 to obtain accurate blood pressure measurements of the subject more quickly based on the subject's physiological data and experience using the biometric monitoring device 100. Application 118 includes a self-training function that enables the biometric monitoring device 100 to assess the subject's blood pressure more quickly by utilizing additional physiological information and user experience.

[0033] In the foregoing specification, the present invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and alterations can be made to the specification without departing from the broader scope of the invention as defined by the appended claims. Therefore, this specification should be considered exemplary rather than restrictive. For example, different biometric monitoring devices, PPG modules, pressure sensors, mobile computing devices, applications, target pressures, and measurement cycles not specifically identified or described in this disclosure, or not evaluated in particular embodiments, should still be included within the scope of the present invention.

[0034] This invention may suitably comprise, consist of, or substantially consist of the invented elements, and may be practiced without any undisclosed elements. As used herein, unless the context explicitly specifies otherwise, the singular forms “a,” “an,” and “the” are also intended to include the plural forms. As used herein, the term “about” with respect to a given parameter includes that value and has the meaning specified by the context (e.g., it includes the degree of error associated with the measurement of the given parameter). As used herein, the term “and / or” includes any and all combinations of one or more of the listed items associated with it.

Claims

1. A method for measuring blood pressure using a biometric monitoring device including a PPG module and a pressure sensor, wherein the biometric monitoring device is connected to a mobile computing device executing an application for controlling the biometric monitoring device, the method comprising the following steps: Place a body part on the biometric monitoring device such that the body part covers the PPG module and the pressure sensor; The user is instructed to adjust the force applied to the pressure sensor from the body part to achieve the initial target pressure. Instruct the user to maintain the pressure applied to the pressure sensor at the target pressure during the initial measurement period; The user is instructed to adjust the force applied to the pressure sensor from a body part to achieve one or more subsequent stage target pressures, wherein each of the one or more subsequent stage target pressures is greater than the previous stage target pressure; Instruct the user to maintain the pressure applied to the pressure sensor at the target pressure in each subsequent measurement period; and Blood pressure was measured during one of the subsequent measurement periods.

2. The method according to claim 1, further comprising the following step: After instructing the user to adjust the force applied to the pressure sensor by the body part to achieve the initial stage target pressure, the user is instructed to reduce the force applied to the pressure sensor by the body part to an intermediate stage target pressure, wherein the intermediate stage target pressure is less than the initial stage target pressure.

3. The method according to claim 1, further comprising the following step: Determine whether the user's pulse can be detected by the PPG module during the initial measurement period.

4. The method according to claim 3, further comprising the following steps: If the user's pulse can be detected by the PPG module during the initial measurement period, biometric measurements are obtained from the user.

5. The method of claim 4, wherein the step of obtaining the biometric measurement from the user during the initial measurement period includes obtaining a pulse rate measurement or an oxygen saturation measurement.

6. The method according to claim 3, further comprising the following step: In each subsequent measurement period, the PPG module is able to detect the user's pulse.

7. The method according to claim 1, further comprising the following step: Before instructing the user to maintain the pressure applied to the pressure sensor at the initial stage target pressure during the initial measurement period, it is determined whether the user has applied sufficient force to the pressure sensor to achieve the initial stage target pressure.

8. The method according to claim 7, further comprising the following step: If the user fails to reach the initial target pressure during the initial attempt, the command to apply sufficient force to the pressure sensor to reach the initial target pressure is repeatedly issued to the user.

9. The method of claim 1, wherein the step of instructing the user to adjust the force applied to the pressure sensor by a body part to achieve one or more subsequent stage target pressures further comprises: The target pressures for one or more subsequent stages are determined based on the user's ability to achieve the target pressure for the initial stage.

10. The method of claim 1, wherein the step of instructing the user to adjust the force applied to the pressure sensor by a body part to achieve one or more subsequent stage target pressures further comprises: The target pressures for one or more subsequent stages are determined based on the results of the user's past use of the biometric monitoring device.

11. The method of claim 1, wherein the step of instructing the user to adjust the force applied to the pressure sensor by a body part to achieve one or more subsequent stage target pressures further comprises: The target pressures for one or more subsequent stages are determined based on demographic information about the users.

12. The method of claim 1, wherein the step of instructing the user to adjust the force applied to the pressure sensor by a body part to achieve one or more subsequent stage target pressures further comprises: The target stress for one or more subsequent stages is determined based on the user's Body Mass Index (BMI).

13. A method for measuring blood pressure using a biometric monitoring device including a PPG module and a pressure sensor, wherein the biometric monitoring device is connected to a mobile computing device executing an application for controlling the biometric monitoring device, the method comprising the steps of: Place a body part on the biometric monitoring device such that the body part covers the PPG module and the pressure sensor; The user is instructed to adjust the force applied to the pressure sensor from a body part to achieve a series of discrete target pressure stages; Instructs the user to maintain the pressure applied to the pressure sensor at each of the discrete target pressures during the corresponding measurement period; as well as Blood pressure measurements are performed during one or more of the aforementioned measurement periods.

14. The method of claim 13, further comprising the step of: If the user's pulse can be detected by the PPG module during any of the measurement periods, then biometric measurements are obtained from the user.

15. The method of claim 13, wherein the step of instructing the user to adjust the force applied to the pressure sensor by a body part to achieve the target pressure of the series of discrete stages further comprises: The series of discrete-stage target pressures are automatically determined based on the user's past use of the biometric monitoring device.

16. The method of claim 1, wherein the step of instructing the user to adjust the force applied to the pressure sensor by a body part to achieve the series of discrete target pressures further comprises: The series of discrete-stage target pressures are automatically determined based on demographic information about the users.

17. The method of claim 1, wherein the step of instructing the user to adjust the force applied to the pressure sensor by a body part to achieve the series of discrete target pressures further comprises: The target stress for the series of discrete stages is automatically determined based on the user's body mass index (BMI).

18. A system for obtaining one or more biometric measurements from a user, the system comprising: Biometric monitoring device, wherein the biometric monitoring device includes: PPG module; and A pressure sensor adapted to measure the force applied by the user to the biometric monitoring device; and A mobile computing device connected to the biometric monitoring device, wherein the mobile computing device is configured to execute an application that instructs a user to apply pressure to the pressure sensor according to a phased pressure scheme.

19. The system of claim 18, wherein the staged pressure scheme instructs the user to apply a series of pressures to the pressure sensor to satisfy a series of discrete target pressures, wherein each of the discrete target pressures is discontinuous with respect to the others.

20. The system of claim 18, wherein the application is configured to automatically adjust the phased stress scheme based on the user's past use of the biometric monitoring device.

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