Blood pressure measuring device air bag pressure self-adaptive adjusting method based on pulse wave analysis

Abstract

A blood pressure measuring device air bag pressure self-adaptive adjusting method based on pulse wave analysis belongs to the technical field of blood pressure measurement, and can adjust the pressure value of an air bag in a self-adaptive manner according to the current wearing and measuring environment of a blood pressure measuring device and the pulse wave signal quality. A proper pressure is maintained between a wearing device of the blood pressure measuring device and a measuring part, so that the amplitude and the quality of the pulse wave signal can still be relatively consistent when different users wear the blood pressure measuring device with different degrees of tightness.

Description

Technical Field

[0001] The present invention relates to the technical field of blood pressure measurement, and in particular to a pressure adaptive adjustment method of an air bag of a blood pressure measurement device based on pulse wave analysis. Background Art

[0002] Since traditional blood pressure measurement methods (Korotkoff sound auscultation method and oscillometric method) require very high pressure to block blood vessels during measurement, continuous blood pressure measurement cannot be achieved. Therefore, various pulse wave analysis methods based on lower pressure are receiving increasing attention.

[0003] In this disclosure, "pulse wave analysis method" refers to all the following blood pressure measurement methods: methods that do not require blocking blood flow in blood vessels, use sensors to collect one or more signals such as photoelectric volumetric pulse wave (PPG), electrocardiogram (ECG) signals, pressure pulse waves, and then calculate blood pressure through blood flow volume, pulse wave propagation time (or arrival time), location of characteristic points on the pulse wave, pulse wave waveform decomposition, machine learning, etc. Sensors for collecting pulse waves include: pressure sensors, photoelectric sensors, ultrasonic sensors, etc.

[0004] Sensors for collecting pulse wave signals are usually attached to annular structures such as watches or watchbands. If these sensors are used directly to collect pulse waves for calculating blood pressure, problems that may occur include: if the wearer wears the sensor too loosely, the sensor will not fit tightly against the skin, and there will be an air gap between the skin and the sensor. These problems will introduce interference from external ambient light, or make the sensor unable to effectively detect the pulse wave signal, ultimately causing the signal quality to deteriorate and become unusable. On the other hand, if the wearer wears the sensor too tightly against the skin, the wearing experience will deteriorate, and local blood vessels will be squeezed and ischemic, causing the quality of some sensor signals to deteriorate.

[0005] Therefore, in the pulse wave analysis method blood pressure measurement device, an air bag can be introduced to improve the above problems. Figure 6As shown, an example of a wristband blood pressure measuring device with a pulse wave sensor is shown, which includes: an airbag 3, an air pump assembly 1, and a flexible sensor unit 2; the airbag 3 is arranged on the lower surface of the wristband 5, the flexible sensor unit 2 is arranged on the lower surface of the airbag 3, and the air pump assembly 1 is placed in the watch housing; the flexible sensor unit 2 uses a direct bonding method to achieve the measurement of the pulse wave. When the watch is worn on the wrist 4 of the measured object, the flexible sensor unit 2 contacts the skin of the wrist 4, that is, the airbag 3 is located between the flexible sensor unit and the wristband 4, and the flexible sensor unit is located at the radial artery of the wrist; when not measuring, the wristband 5 remains in a relaxed state, that is, the airbag 3 is not inflated; when measurement is required, the pressure of the airbag 3 is adjusted by the air pump assembly 1, and the flexible sensor unit 2 is attached to the skin. The flexible sensor unit 2 can use a sensor array with multiple groups of sensors, and at least one group of sensors is located above the radial / ulnar artery after wearing.

[0006] However, how to select and regulate the pressure of the airbag has become a key issue. For different users, the different wearing tightness and position of the blood pressure measuring device, as well as the different airbag pressures, will lead to inconsistent signal quality and different user experiences. Wearing it too tightly or with too much airbag pressure will make people uncomfortable and unable to wear it for a long time, and will affect the signal quality of the photoelectric sensor; wearing it too loosely or with too little airbag pressure will make the signal quality of the pressure pulse wave poor. Summary of the invention

[0007] The present disclosure provides a method for setting the airbag pressure of a blood pressure measuring device based on pulse wave analysis, which can automatically adapt to the wearing tightness of different users and keep the airbag pressure in a suitable state.

[0008] The present disclosure provides a method for adaptively adjusting the airbag pressure of a blood pressure measuring device, comprising the following steps:

[0009] S1, the airbag is continuously pressurized by inflation, or the airbag is continuously depressurized by deflation;

[0010] S2, during the process of pressurization or depressurization, continuously collects the signal of the pulse wave detection sensor;

[0011] S3, processing the acquired sensor signal, extracting the pulse wave signal, and selecting a suitable airbag pressure as the airbag pressure set for subsequent pulse wave data collection according to the required pulse wave signal quality standard;

[0012] During the data collection process of the pulse wave detection sensor, when it is found that the quality of the pulse wave signal does not meet the given requirements, the appropriate airbag pressure is automatically searched again according to the steps S1-S3, and the airbag is adjusted to the pressure, and data collection is performed again.

[0013] Furthermore, in the step S1, the pressurization or depressurization method includes: continuous pressure regulation or step pressure regulation, and the step pressure regulation means that after each pressurization or depressurization to a pressure value, the current pressure is maintained for a period of time, and the sensor signal is collected and processed.

[0014] Furthermore, when the blood pressure measurement device simultaneously uses more than one pulse wave detection sensor, the airbag pressurization or decompression in step S1 is correspondingly divided into multiple serial stages, so as to find a suitable airbag pressure for each sensor and use the suitable airbag pressure for each sensor in subsequent pulse wave data acquisition.

[0015] Furthermore, the step S3 specifically includes:

[0016] Processing the acquired sensor signal, including baseline removal and filtering, to extract the pulse wave signal sequence;

[0017] The pulse wave signal sequence is divided into periods, and then according to the required pulse wave signal quality standard, a suitable airbag pressure P is selected as the airbag pressure for subsequent pulse wave data collection.

[0018] Furthermore, in step S1, when the airbag is pressurized or depressurized by continuous pressure regulation: when the pressure meets a certain initial threshold, continuous pressure regulation is started at a relatively fixed speed; at this time, in step S3, the acquired sensor signal is processed once at a certain time interval, and only the newly added pulse wave signal sequence is processed each time; when the airbag pressure P with the signal quality meeting the requirements is found, the processing process is terminated.

[0019] Furthermore, in step S3:

[0020] When the pressure meets a certain initial threshold, the pressure is continuously adjusted at a speed of 1-10 mmHg / s, and then the sensor signal is processed every 2 seconds.

[0021] Furthermore, the pulse wave signal quality standard includes: the amplitude is greater than a certain threshold, and / or the burrs are less than a certain number.

[0022] Furthermore, in step S3, the method of selecting a suitable airbag pressure includes:

[0023] Select the minimum airbag pressure P that meets the signal quality standard;

[0024] Alternatively, the airbag pressure P corresponding to the last pulse period among a plurality of pulse periods that continuously meet the signal quality standard is selected.

[0025] The blood pressure measuring device using the above method comprises: a pulse wave detection sensor and a fixing device thereof, an air bag and an inflation and deflation control module thereof, a blood pressure calculation module based on a pulse wave analysis method, and further comprises:

[0026] The adaptive airbag pressure determination module is used to automatically start searching for a suitable airbag pressure again according to steps S1-S3 and adjust the airbag to the pressure and re-collect data when it is found that the quality of the pulse wave signal does not meet the given requirements during the data collection process of the pulse wave detection sensor.

[0027] Compared with the prior art, the beneficial effects of the present invention are: (1) it can adaptively adjust the pressure value of the airbag according to the current wearing and measuring environment of the blood pressure measuring device, so that an appropriate pressure is maintained between the wearing device and the wrist of the blood pressure measuring device, so that the amplitude and quality of the pulse wave signal can still be relatively consistent when different users wear the blood pressure measuring device with different tightness; (2) the airbag pressure adjustment process is automatically started according to the signal quality; (3) the airbag pressure value can be quickly selected and adjusted during the continuous pressurization (or depressurization) process; (4) the method is convenient and has good versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0029] Figure 1 An example of the signal of the pressure sensor during continuous pressurization is given;

[0030] Figure 2 This is an example of the pressure pulse wave signal extracted under the continuous pressurization mode;

[0031] Figure 3 It is the flow chart of air bag pressure adjustment under continuous pressure adjustment mode;

[0032] Figure 4 This is an example diagram of the pressure pulse wave signal under the step pressure regulation mode;

[0033] Figure 5 It is the flow chart of air bag pressure adjustment under step pressure regulation mode;

[0034] Figure 6 The overall structure diagram of a wristband blood pressure measuring device with a pulse wave sensor is shown in the figure below: 1-air pump assembly; 2-flexible sensor unit; 3-air bag; 4-wrist; 5-wristband;

[0035] Figure 7The present invention is a schematic diagram of the components of a blood pressure measurement device using the method disclosed in the present invention. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0037] The present disclosure provides a method for adaptively adjusting the airbag pressure of a blood pressure measurement device based on pulse wave analysis, the purpose of which is to select a suitable airbag pressure P so as to obtain a pulse wave signal of good quality for collecting the pulse wave signal for blood pressure calculation.

[0038] Applicable pulse wave detection sensors include pressure sensors, photoelectric sensors, radar wave sensors, ultrasonic sensors, magnetic induction sensors, etc. The airbag pressure P cannot be too large, because excessive pressure can easily make people feel uncomfortable and affect the quality of the photoelectric volume pulse wave signal; at the same time, it cannot be too small, because too small airbag pressure will make the wristband and wrist not fit tightly enough, resulting in poor signal quality of the pressure pulse wave.

[0039] In the first implementation mode, the process is as follows Figure 3 As shown, it mainly includes the following steps:

[0040] (1) The airbag is continuously pressurized (of course, continuous decompression can also be adopted starting from high pressure). During this process, the signal collected by the pressure sensor is as shown in the attached figure. Figure 1 As shown. The horizontal axis is time, and the vertical axis is pressure value. It can be seen that the pressure value is increasing. And when the airbag pressure reaches a certain level, some sawtooth oscillation waves will appear on the waveform, which is caused by the pulse.

[0041] (2) Remove the baseline and filter (bandpass) the above signal to extract the pulse wave, as shown in the attached figure. Figure 2 (compared to Figure 1 The part without signal in the front is cut off).

[0042] It can be seen that when the airbag pressure is relatively low, the amplitude of the pulse wave is small and there are more burrs. When the pressure increases to a certain level, the signal quality of the pulse wave becomes good.

[0043] (3) The pulse wave signal is divided into periods, and then, according to the required signal quality standard, an appropriate airbag pressure P is selected as the pressure setting of the airbag during subsequent data collection.

[0044] As for the signal quality standard, as a preference, it may be required that the amplitude is greater than a certain threshold, or that the burrs are less than a certain number, or a combination of the two.

[0045] For the selection of the airbag pressure P, it is preferred to select the minimum pressure P that meets the signal quality standard; or it can be the airbag pressure P corresponding to the last pulse cycle in which the pulse wave signal of two or more consecutive pulse cycles meets the signal quality standard. The purpose of this is to ensure a certain anti-interference ability.

[0046] For the specific real-time processing process, as a preferred embodiment, when the airbag pressure reaches the initial threshold P 0 After that, the pressure is adjusted continuously at a certain speed, such as 5 mmHg / s, and then the processing is cyclically performed at a specific time interval t (such as 2 seconds) (i.e., it is processed once every t seconds). Each time, only the newly added pulse wave signal sequence is processed. When the airbag pressure P with the signal quality meeting the requirements is found, the processing process ends.

[0047] Among them, P 0 It is an empirical value, generally set to 30-40 mmHg. Under this pressure, the pressure pulse wave signal has a small amplitude and poor quality. 0 After that, the pressure sensor signal is processed; in addition, when the airbag pressure reaches P 0 After that, each time the signal is processed, only the newly added signal is processed. This can save time and avoid excessive pressure causing discomfort to the human body.

[0048] In the second implementation:

[0049] During the inflation process, a step-by-step pressurization method is used (or a step-by-step decompression method is used during the deflation process) to find the airbag pressure P that can obtain a pulse wave signal of reliable quality.

[0050] Step-by-step pressurization means that after each pressure value is increased to a certain value, the current pressure is maintained for a period of time, so that the pulse wave signal can be stably collected by the sensor, thereby making the detection and judgment of the signal quality more accurate.

[0051] A typical pressure pulse wave signal is shown in the attached figure. Figure 4 As shown, it can be seen that because the airbag pressure value is stable, the periodicity of the pressure pulse wave signal is better, which is more conducive to accurately judging the signal quality.

[0052] During the step-by-step pressure increase process, once the quality of the pulse wave signal is found to meet the requirements, the pressure can be stabilized at the current value and the pulse wave data collection process can be started. Figure 5 shown.

[0053] In the third implementation:

[0054] Considering that the data acquisition module may be equipped with multiple sensors for pulse wave acquisition at the same time, such as using pressure sensors and photoelectric sensors at the same time, the requirements for wearing tightness may be different. For example, the pressure sensor needs to be worn tightly to obtain a good quality signal, while the photoelectric sensor cannot be worn too tightly, otherwise if the airbag pressure is too high, the blood vessels will be squeezed, which will make the signal worse. In this case, the adaptive airbag pressure adjustment scheme can be divided into two serial stages: first, the airbag pressure P suitable for the photoelectric sensor is determined by the aforementioned method. 1 ; Then find the airbag pressure P suitable for the pressure sensor 2 Then, in the subsequent data collection process, P 1 and P 2 Collect photoelectric volume pulse wave and pressure pulse wave signals.

[0055] According to the embodiments of the present disclosure, the core point of the adaptation is to adjust the fit between the wearing device (such as a watchband) and the measuring part (such as a wrist) of the blood pressure measuring device by inflating the airbag to different pressures. When blood pressure measurement is not performed, the airbag is not inflated, and the watch can be worn relatively loosely and more comfortably; when blood pressure measurement is required, the airbag is inflated to a pre-set airbag pressure value P, and data collection and blood pressure calculation are performed; for the same person, the wearing tightness at different times may be different, and thus the pressure value P at different times may be different, which is one meaning of adaptation; moreover, the airbag pressure value P is different for each person, which is another meaning of adaptation.

[0056] When the airbag pressure is adjusted to an appropriate state, if the signal quality does not meet the requirements due to changes in human posture, etc., the above process will be restarted and the pressure will be adaptively adjusted again.

[0057] Therefore, through the adaptive adjustment of the airbag pressure, an appropriate pressure can be maintained between the wearing device and the measuring part of the blood pressure measuring device, so that the amplitude and quality of the pulse wave signal can still remain relatively consistent when different users wear it with different tightnesses. This is very important for accurately measuring blood pressure using the pulse wave analysis method.

[0058] An example of a blood pressure measurement device based on the above method is shown in the attached figure. Figure 7 As shown, in addition to the pulse wave detection sensor and its fixing device, the air bag and its inflation and deflation control module, and the blood pressure calculation module based on the pulse wave analysis method, it also includes:

[0059] An adaptive airbag pressure determination module applies the method disclosed in the present invention to control the airbag inflation and deflation control module to pressurize or depressurize the airbag, obtains the signal collected by the pulse wave detection sensor in the process, and determines the appropriate airbag pressure as the airbag pressure set for subsequent pulse wave data collection.

[0060] The above technical scheme is only an exemplary embodiment of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the application methods and principles disclosed in the present invention, and it is not limited to the method described in the above specific embodiment of the present invention. Therefore, the method described above is only preferred and does not have a restrictive meaning.

Claims

1. A method for adaptively adjusting the airbag pressure of a blood pressure measuring device based on pulse wave analysis, comprising the following steps: S1, the airbag is continuously pressurized by inflation, or the airbag is continuously depressurized by deflation; S2, during the process of pressurization or depressurization, continuously collects the signal of the pulse wave detection sensor; S3, processing the acquired sensor signal, extracting the pulse wave signal, and then selecting a suitable airbag pressure as the airbag pressure set for subsequent pulse wave data collection according to the required pulse wave signal quality standard; During the data collection process of the pulse wave detection sensor, when it is found that the quality of the pulse wave signal does not meet the given requirements, the appropriate airbag pressure is automatically searched again according to the steps S1-S3, and the airbag is adjusted to the pressure, and data collection is performed again.

2. The method according to claim 1, characterized in that In step S1, the pressurization or depressurization method includes: continuous pressure regulation or step pressure regulation, and the step pressure regulation means that after each pressurization or depressurization to a pressure value, the current pressure is maintained for a period of time, and the sensor signal is collected and processed.

3. The method according to claim 2, characterized in that When the blood pressure measurement device uses more than one pulse wave detection sensor at the same time, the airbag pressurization or depressurization in step S1 is correspondingly divided into multiple serial stages, so as to find a suitable airbag pressure for each sensor respectively, and use the respective suitable airbag pressure in the subsequent pulse wave data acquisition.

4. The method according to claim 2 or 3, characterized in that: The step S3 specifically includes: Processing the acquired sensor signal, including baseline removal and filtering, to extract the pulse wave signal sequence; The pulse wave signal sequence is divided into periods, and then according to the required pulse wave signal quality standard, a suitable airbag pressure P is selected as the airbag pressure for subsequent pulse wave data collection.

5. The method according to claim 4, characterized in that In step S1, when the airbag is pressurized or depressurized by continuous pressure regulation: when the pressure meets a certain initial threshold, continuous pressure regulation is started at a relatively fixed speed. At the same time, in step S3, the acquired sensor signal is processed once at a certain interval, and only the newly added pulse wave signal sequence is processed each time. When the airbag pressure P with the required signal quality is found, the processing process is terminated.

6. The method according to claim 5, characterized in that In step S3: When the pressure meets a certain initial threshold, the pressure is continuously adjusted at a speed of 1-10 mmHg / s, and then the sensor signal is processed every 2 seconds.

7. The method according to any one of claims 1 to 6, characterized in that: The pulse wave signal quality standard includes: the amplitude is greater than a certain threshold, and / or the burrs are less than a certain number.

8. The method according to claim 1, characterized in that In step S3, the method of selecting a suitable airbag pressure includes: Select the minimum airbag pressure P that meets the signal quality standard; Alternatively, the airbag pressure P corresponding to the last pulse period among a plurality of pulse periods that continuously meet the signal quality standard is selected.

9. A blood pressure measurement device based on pulse wave analysis using the method of any one of claims 1 to 8, comprising: The pulse wave detection sensor and its fixing device, the air bag and its inflation and deflation control module, and the blood pressure calculation module based on the pulse wave analysis method are characterized in that they also include: The adaptive airbag pressure determination module is used to automatically start searching for a suitable airbag pressure again according to steps S1-S3 and adjust the airbag to the pressure and re-collect data when it is found that the quality of the pulse wave signal does not meet the given requirements during the data collection process of the pulse wave detection sensor.

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