Blood pressure measurement system and method based on multi-airbag coordinated control and oscillation wave analysis

Abstract

The present invention provides a blood pressure measurement system and method based on multi-airbag coordinated control and oscillation wave analysis, relating to the field of medical device technology. The system comprises: an integrated cuff housing, an air pump, a solenoid valve, a pressure balancing device, and a microprocessor. The integrated cuff housing comprises a first airbag, a second airbag, and a third airbag. The air pump is first activated, and the multiple airbags are synchronously inflated to a preset initial pressure. The first and third airbag solenoid valves are then closed, and the pressure balancing device dynamically adjusts the micro-deflation valve to maintain constant pressure in the first and third airbags. The air pump continues to inflate until the pressure in the second airbag is higher than the systolic pressure level. The measurement method specifically includes a multi-airbag pressure measurement mode and a dual-airbag pressure measurement mode. The multi-airbag pressure measurement mode uses three airbags for simultaneous pressure measurement, while the dual-airbag pressure measurement mode pressurizes only the second and third airbags to achieve blood pressure measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a blood pressure measurement system and method based on multi-airbag coordinated control and oscillation wave analysis. Background Art

[0002] In the current field of electronic blood pressure monitors, most products use a single-balloon oscillometric method to measure blood pressure. These methods, including the amplitude coefficient method, the variable amplitude coefficient method, the inflection point method, and the coefficient difference ratio method, derive blood pressure values through empirical formulas, but they have significant limitations. Consequently, in recent years, a number of new blood pressure measurement methods have begun to be widely used.

[0003] Chinese utility model patent CN201977786U mainly emphasizes its dual-airbag structure design, which attempts to amplify the changes in the oscillation wave through the dual-airbag structure, but its focus is not on the filtering processing and algorithm of the oscillation wave. Only from visual inspection or simple measurement methods, only some cases with large changes can increase the accuracy of blood pressure measurement, and it is difficult to further find the characteristic changes and amplification effects of the distal oscillation wave. Secondly, whether it is the first airbag or the second airbag, we found through studying the changes in invasive blood pressure during cuff pressurization that when the cuff is pressurized, it will affect the invasive blood pressure under the cuff, causing the invasive systolic blood pressure (SBP) to increase by up to 20 mmHg. The invasive diastolic blood pressure (DBP) also changes significantly with the increase in cuff pressure. The invasive blood pressure at the distal end of the cuff changes more. Therefore, even if the first airbag can better highlight the changing characteristics of systolic blood pressure (SBP), its measurement effect and accuracy will inevitably be affected by the changes in blood pressure under the cuff and at the distal end of the cuff. In contrast, cuff pressurization has less effect on the invasive blood pressure proximal to the cuff. This patent does not make a comprehensive analysis of the changes in the dual-airbag oscillation waves, nor does it design an additional proximal third airbag as a standard airbag for pressure measurement. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a blood pressure measurement system and method based on multi-airbag coordinated control and oscillation wave analysis;

[0005] A blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis, comprising: an integrated cuff cover, an air pump, a solenoid valve, a pressure balancing device, and a microprocessor;

[0006] The integrated cuff cover is provided with a first airbag, a second airbag and a third airbag, wherein the first airbag is arranged at the distal end, the third airbag is arranged at the proximal end, and the second airbag is arranged between the first and third airbags, and the three airbags are arranged at intervals;

[0007] The air pump inflates the first airbag, the second airbag and the third airbag at the same time through the main air pipe at a constant pressure;

[0008] The solenoid valve includes a first airbag solenoid valve and a third airbag solenoid valve, which are respectively arranged at the connection between the main air pipe and the first airbag and the third airbag. The first airbag solenoid valve controls the inflation of the first airbag, and the third airbag solenoid valve controls the inflation of the third airbag.

[0009] The pressure balancing device includes a pressure sensor and a micro-deflation valve. The pressure sensors are respectively arranged in the first airbag and the third airbag, and are used to monitor the pressure in the first airbag and the third airbag in real time. The pressure in the first airbag and the third airbag is maintained constant by dynamically adjusting the opening and closing of the micro-deflation valve;

[0010] The microprocessor is connected to the inflation pump, the solenoid valve, the pressure sensor and the micro deflation valve to execute the inflation control logic;

[0011] The microprocessor integrates an oscillation wave analysis module for real-time acquisition of pressure data from the first airbag to the third airbag, identifying oscillation wave changes between the first airbag and the third airbag based on an elastic template matching method and obtaining blood pressure measurement results;

[0012] The first airbag, the second airbag and the third airbag are all rectangular in shape. The first airbag and the third airbag are of the same size, and the second airbag is larger than the first and third airbags. The airbag sizes can be adjusted in time according to actual conditions.

[0013] The inflation rate of the inflation pump is 3-10 mmHg / second.

[0014] The inflation control logic, i.e., the blood pressure measurement method based on multi-airbag coordinated control and oscillation wave analysis, is specifically as follows:

[0015] Step S1: Initial inflation stage: the inflation pump is started, and multiple airbags are inflated synchronously to a preset initial pressure;

[0016] Step S2: airbag constant pressure stage: close the first airbag solenoid valve and the third airbag solenoid valve;

[0017] Step S3: The pressure balancing device dynamically adjusts the micro air release valve to maintain a constant pressure in the first airbag and the third airbag;

[0018] Step S4: Second airbag pressure boosting stage: the air pump continues to inflate until the pressure in the second airbag is higher than the systolic pressure level;

[0019] The blood pressure measurement method of multi-balloon coordinated control and oscillation wave analysis includes a multi-balloon pressure measurement mode and a dual-balloon pressure measurement mode; the multi-balloon pressure measurement mode uses three airbags to measure pressure simultaneously, specifically amplifying the change characteristics of systolic pressure SBP by the first airbag to identify systolic pressure SBP, measuring mean arterial pressure MAP by the second airbag, and amplifying the change characteristics of systolic pressure SBP and diastolic pressure DBP as a standard airbag to identify systolic pressure SBP and diastolic pressure DBP, and then correcting the three airbags to obtain a blood pressure value; the dual-balloon pressure measurement mode is to pressurize only the second airbag and the third airbag, that is, the first airbag is not pressurized, and the second and third airbags are pressurized according to the description of steps S4 and S1 respectively, and finally the second airbag measures mean arterial pressure MAP, the third airbag amplifies the change characteristics of systolic pressure SBP and diastolic pressure DBP to identify systolic pressure SBP and diastolic pressure DBP, and the second airbag corrects the third airbag to obtain a blood pressure value;

[0020] The oscillation wave analysis module specifically includes: a signal preprocessing unit, a signal quality assessment unit, and a feature point recognition unit;

[0021] The signal preprocessing unit first uses Fourier transform to determine the distribution characteristics of noise and effective signals; then uses a low-pass filter to remove high-frequency noise in the original oscillation wave signal, and uses a high-pass filter to remove the influence of baseline drift on the oscillation wave; uses Fourier transform to perform secondary analysis to provide a frequency band division basis for empirical wavelet transform; then uses the empirical wavelet transform method to eliminate artifacts; and finally uses normalization processing and non-normalization processing methods respectively. Normalization processing is used to adjust the amplitude difference between different waveforms and identify waveform feature changes; non-normalization processing is used to identify the amplitude difference of the oscillation wave.

[0022] The signal quality assessment unit includes data quality assessment of oscillation waves and data quality assessment related to inflation and deflation blood pressure measurement under high pressure. The data quality assessment under constant pressure is performed by extracting each oscillation wave under a preset constant pressure to construct a quality assessment template, matching the template signal with each waveform of this oscillation wave and calculating the DTW distance. The data usability is determined based on the average value of all DTW distances.

[0023] The data quality assessment of the oscillation wave is performed by extracting each waveform under all pressure ranges to construct a quality assessment template; the template signal is matched with each single-cycle waveform and the DTW distance is calculated, and the usability of the data is determined based on the average value of all DTW distances;

[0024] The data quality assessment related to the inflation and deflation blood pressure measurement under high pressure first calculates the average pressure position of the oscillation wave in the inflation state and the average pressure position in the deflation state. The position deviation between the two is calculated and compared with a preset threshold to determine whether the data is usable. The previous single-cycle waveform is selected as the template, and waveform template matching is performed between the single-cycle waveform and the corresponding template based on the DTW algorithm. The matching waveform is found and the blood pressure value is preliminarily estimated.

[0025] The feature point recognition unit first reads the second airbag oscillation wave and locates it using the variable amplitude coefficient method, that is, using the variable amplitude coefficient to determine the position range of the systolic pressure (SBP) and the diastolic pressure (DBP). The waveforms of the systolic pressure (SBP) and diastolic pressure (DBP) positions of the first and third airbag oscillation waves are used to estimate blood pressure based on the DTW algorithm, wherein the third airbag is used as the standard airbag, the first airbag oscillation wave assists in calculating the systolic pressure (SBP), and the second airbag oscillation wave assists in calculating the mean arterial pressure (MAP). The latter single-cycle waveform uses the previous single-cycle waveform as a template, and by identifying the oscillation wave morphology and amplitude changes, blood pressure is estimated based on the waveform template matching method;

[0026] Specifically:

[0027] For the normalized waveform, identify the changes in waveform morphological characteristics and mark the point with the maximum DTW value within the range of systolic pressure (SBP) and diastolic pressure (DBP) as D. norm .

[0028] For the non-normalized waveform, identify the amplitude change of the waveform and mark the point with the maximum DTW value within the range of systolic pressure SBP and diastolic pressure DBP as D non-norm .

[0029] Finally, the DTW distance calculated by combining the normalized and non-normalized oscillation wave signals is set, and the weighted calculation is performed to obtain the final D final ;

[0030] D final The corresponding second airbag pressure value at the same time of the oscillation wave is output as the systolic pressure SBP and the diastolic pressure DBP to achieve blood pressure measurement.

[0031] The beneficial effects of adopting the above technical solution are:

[0032] The present invention provides a blood pressure measurement system and method based on multi-airbag coordinated control and oscillation wave analysis. The system uses multiple airbags to amplify the characteristic changes in the oscillation waves of systolic blood pressure (SBP) and diastolic blood pressure (DBP). The oscillation wave analysis module uses an elastic template matching method to identify differences in oscillation wave amplitudes, thereby accurately identifying systolic and diastolic blood pressure. Through multi-airbag coordinated control and signal analysis, and by optimizing airbag inflation and deflation control and signal processing algorithms, the system effectively reduces measurement errors caused by uneven airbag deformation, ensures the stability of blood pressure data, and significantly improves blood pressure measurement accuracy. The system is suitable for measuring multiple areas, such as the arm and wrist. The system utilizes a flexible, breathable material to reduce skin pressure during measurement and avoid discomfort caused by prolonged measurement. An intelligent adaptive algorithm automatically adjusts measurement parameters based on the physiological characteristics of different users, making it suitable for people of different ages and health conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A diagram of a blood pressure measurement device based on multi-airbag coordinated control and oscillation wave analysis provided by an embodiment of the present invention;

[0034] Wherein: 1-first airbag, 2-second airbag, 3-third airbag, 4-main air pipe, 5-solenoid valve, 6-pressure balance device, 7-pressure sensor, 8-micro deflation valve, 9-microprocessor, 10-oscillation wave analysis module, 11-inflator pump;

[0035] Figure 2 A schematic diagram of a device measurement method provided by an embodiment of the present invention;

[0036] Figure 3 A block diagram of the hardware system provided by an embodiment of the present invention;

[0037] Figure 4 A block diagram of a signal preprocessing unit according to an embodiment of the present invention;

[0038] Figure 5 A block diagram of an implementation of a signal quality assessment unit provided in an embodiment of the present invention;

[0039] Figure 6 A schematic diagram of a single-cycle waveform template matching method provided by an embodiment of the present invention;

[0040] Figure 7 A comparison diagram of the first airbag oscillation waveform and the normal oscillation waveform provided in an embodiment of the present invention;

[0041] Among them, (a) - first airbag oscillation waveform, (b) - normal oscillation waveform;

[0042] Figure 8 A second airbag oscillation waveform diagram provided by an embodiment of the present invention;

[0043] Figure 9A comparison diagram of the diastolic pressure portion of the third airbag oscillation waveform and the normal oscillation waveform provided in an embodiment of the present invention;

[0044] Among them, (a) - diastolic pressure part of the third balloon oscillation waveform, (b) - normal oscillation waveform;

[0045] Figure 10 A comparison diagram of the systolic pressure portion of the third airbag oscillation waveform and the normal oscillation waveform provided in an embodiment of the present invention;

[0046] Among them, (a) is the systolic pressure part of the third airbag oscillation waveform, and (b) is the normal oscillation waveform. DETAILED DESCRIPTION

[0047] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0048] The present invention uses the third bladder as a standard. Research has found that due to variations in invasive pressure, the oscillation waves of the first and second bladders are not true blood pressure oscillations and are therefore inaccurate. However, invasive blood pressure changes below the third bladder are minimal, so the third bladder is used as the standard bladder for measurement. The third bladder amplifies the systolic and diastolic blood pressure (DBP) variations of the second bladder, with the diastolic DBP variation being particularly pronounced. The algorithm analyzes the oscillation characteristics of all three bladders in both the time and frequency domains, based on the oscillation waves of the third bladder, and is able to identify characteristic variations in the vast majority of cases. The characteristic variations of the second bladder's oscillation wave serve as a rough coordinate to assist in determining the characteristic variations of the third bladder's oscillation wave. Even if its position is distorted, the fact that it is not a standard bladder does not affect the overall accuracy of the results. Studies on invasive blood pressure have also found that the characteristics of the first bladder's oscillation wave frequently change over time, affecting blood pressure values; whereas the characteristics of the third bladder remain constant. A comparative analysis of 42 invasive blood pressure data sets and hundreds of auscultatory blood pressure data sets shows that the third bladder, designed based on hemodynamic principles, measures blood pressure values with the highest accuracy. Finally, by using the oscillation waves of the three air bags for collaborative analysis, the third air bag oscillation wave is used to accurately identify the blood pressure.

[0049] Conventional blood pressure monitors currently on the market typically use a single-balloon design, made of a single balloon wrapped in biocompatible fabric. The balloon extends to the outside through a trachea tube for inflation and deflation. The multi-balloon cuff provided by the present invention is a measuring band made of three independent balloons sewn together at a certain distance, such as Figure 1As shown, each cuff has an air tube leading out, connected to the same air pump for simultaneous inflation and deflation. The first and third airbags are identical in size, while the second airbag is larger. It can be used like any other standard cuff, depending on the intended use and size, and can be worn on the upper arm, wrist, leg, or even on the ankle or finger for blood pressure measurement.

[0050] A blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis, the hardware system is as follows Figure 3 As shown, it includes: an integrated cuff cover, an air pump 11, a solenoid valve 5, a pressure balancing device 6, and a microprocessor 9;

[0051] The integrated cuff cover is provided with a first airbag 1, a second airbag 2 and a third airbag 3, wherein the first airbag 1 is arranged at the distal end, the third airbag 3 is arranged at the proximal end, the second airbag 2 is arranged between the first airbag 1 and the third airbag 3, and the three airbags are arranged at intervals;

[0052] The air pump 11 simultaneously inflates the first airbag 1, the second airbag 2 and the third airbag 3 at a constant pressure through the main air pipe 4;

[0053] The solenoid valve 5 includes a first airbag solenoid valve and a third airbag solenoid valve, which are respectively arranged at the connection between the main air pipe and the first airbag 1 and the third airbag 3. The first airbag solenoid valve controls the inflation of the first airbag 1, and the third airbag solenoid valve controls the inflation of the third airbag 3.

[0054] The pressure balancing device 6 includes a pressure sensor 7 and a micro-deflation valve 8. The pressure sensors 7 are respectively arranged in the first airbag 1 and the third airbag 3, and are used to monitor the pressure in the first airbag 1 and the third airbag 3 in real time. The pressure in the first airbag 1 and the third airbag 3 is maintained constant by dynamically adjusting the opening and closing of the micro-deflation valve 8.

[0055] The microprocessor 9 is connected to the inflation pump 11, the solenoid valve 5, the pressure sensor 7 and the micro deflation valve 8, and is used to execute the inflation control logic;

[0056] The microprocessor 9 integrates an oscillation wave analysis module 10 for collecting pressure data from the first airbag to the third airbag in real time, identifying the oscillation wave changes of the first airbag and the third airbag based on the elastic template matching method and obtaining the blood pressure measurement result;

[0057] The first, second, and third airbags are all rectangular in shape. The first and third airbags are identical in size, measuring 300 mm in length and 30 mm in width. The second airbag is larger than the first and third airbags, measuring 300 mm in length and 50 mm in width. The airbag sizes can be adjusted as needed based on actual conditions, for example, by varying the size of the airbags based on the length and thickness of different body parts or the length and thickness of different limbs of different people within the same body part.

[0058] The inflation rate of the inflation pump is 3-10 mmHg / second.

[0059] The inflation control logic is a blood pressure measurement method based on multi-airbag coordinated control and oscillation wave analysis, specifically:

[0060] Step S1: Initial inflation stage: The air pump is started, and the multiple airbags are inflated synchronously to a preset initial pressure. In this embodiment, the preset initial pressure is 50 mmHg-70 mmHg;

[0061] Step S2: airbag constant pressure stage: close the first airbag solenoid valve and the third airbag solenoid valve;

[0062] Step S3: The pressure balancing device dynamically adjusts the micro deflation valve to maintain constant pressure in the first airbag and the third airbag; the pressure balancing device dynamically deflates to offset the pressure increase caused by soft tissue compression;

[0063] Step S4: Second airbag pressure boosting stage: the air pump continues to inflate until the pressure in the second airbag is higher than the systolic pressure level;

[0064] The blood pressure measurement method of multi-balloon coordinated control and oscillation wave analysis includes a multi-balloon pressure measurement mode and a dual-balloon pressure measurement mode; the multi-balloon pressure measurement mode uses three airbags to measure pressure simultaneously, that is, the first airbag amplifies the change characteristics of systolic pressure SBP to identify systolic pressure SBP, the second airbag measures mean arterial pressure MAP, and the third airbag acts as a standard airbag to amplify the change characteristics of systolic pressure SBP and diastolic pressure DBP to identify systolic pressure SBP and diastolic pressure DBP, and then the three airbags are calibrated with each other to obtain a blood pressure value; the dual-balloon pressure measurement mode is to pressurize only the second airbag and the third airbag, that is, the first airbag is not pressurized, and the second and third airbags are pressurized as described in steps S4 and S1 above, and finally the second airbag measures mean arterial pressure MAP, and the third airbag amplifies the change characteristics of systolic pressure SBP and diastolic pressure DBP to identify systolic pressure SBP and diastolic pressure DBP, and at the same time, the second airbag can also calibrate the third airbag to obtain an accurate blood pressure value;

[0065] The oscillation wave analysis module specifically includes: a signal preprocessing unit, a signal quality assessment unit, and a feature point recognition unit;

[0066] The signal preprocessing unit: the signal preprocessing implementation process is as follows Figure 4As shown, the distribution characteristics of noise and effective signals are first determined by Fourier transform; then high-frequency noise such as high-frequency interference in the original oscillation wave signal is removed by low-pass filtering, and the influence of baseline drift on the oscillation wave is removed by high-pass filtering; Fourier transform is used for secondary analysis to provide a basis for frequency band division for empirical wavelet transform; then the empirical wavelet transform method is used to eliminate artifacts caused by various factors; finally, normalization and non-normalization processing methods are used respectively. Normalization processing is used to adjust the amplitude difference between different waveforms to facilitate subsequent template matching and identify waveform feature changes; non-normalization processing method is used to identify the amplitude difference of oscillation waves.

[0067] The signal quality evaluation unit: Figure 5 As shown, it includes data quality assessment of oscillation waves and data quality assessment related to inflation and deflation blood pressure measurement under large pressure. Data quality assessment under constant pressure is constructed by extracting each oscillation wave under a preset constant pressure to construct a quality assessment template, matching the template signal with each waveform of this oscillation wave and calculating the DTW distance. The data usability is determined based on the average value of all DTW distances.

[0068] The data quality assessment of the oscillation wave is performed by extracting each waveform under all pressure ranges to construct a quality assessment template; the template signal is matched with each single-cycle waveform and the DTW distance is calculated, and the usability of the data is determined based on the average value of all DTW distances;

[0069] The data quality assessment related to the inflation and deflation blood pressure measurement under high pressure first calculates the average pressure position of the oscillation wave in the inflation state and the average pressure position in the deflation state. The position deviation between the two is calculated and compared with a preset threshold to determine whether the data is usable. The previous single-cycle waveform is selected as the template, and waveform template matching is performed between the single-cycle waveform and the corresponding template based on the DTW algorithm. The matching waveform is found and the blood pressure value is preliminarily estimated.

[0070] The data quality assessment module of the oscillation wave in this embodiment constructs a quality assessment template by extracting waveforms under all pressure ranges. First, extract the single-cycle waveform Xpressure(i) after normalization under each pressure range, take the waveform of the first single-cycle oscillation wave as the assessment template Ypressure, use the assessment template Ypressure to match the single-cycle oscillation wave Xpressure(i) under each pressure range, and calculate the DTW distance Dpressure between each single-cycle waveform Xpressure(i) and the assessment template Ypressure. Similarly, take the waveform of each single-cycle oscillation wave under other pressures as the assessment template Ypressure, and calculate the DTW distance Dpressure between the single-cycle waveform Xpressure(i) under each pressure range and the assessment template Ypressure. Take the average value of all DTW distances And compare it with the preset threshold. The data is available when it is less than the preset threshold, otherwise the signal is unavailable.

[0071] To assess the data quality related to inflation and deflation blood pressure measurements, we first calculate the average pressure position of the oscillation wave envelope in the inflation state, Loc1. Next, we calculate the average pressure position of the oscillation wave envelope in the deflation state, Loc2. The positional deviation between the two, Loc = |Loc1-Loc2|, is calculated. When Loc is less than the preset threshold, the data is usable; otherwise, the signal is unusable.

[0072] The feature point recognition unit is as follows: Figure 6 As shown, the second balloon oscillation wave is first read and located using the variable amplitude coefficient method. This method uses the variable amplitude coefficient to determine the position range of systolic blood pressure (SBP) and diastolic blood pressure (DBP). The waveforms of the first and third balloon oscillation waves within the systolic blood pressure (SBP) and diastolic blood pressure (DBP) positions are then used to estimate blood pressure using the DTW algorithm. The third balloon is used as a standard balloon to amplify the characteristics of systolic blood pressure (SBP) and diastolic blood pressure (DBP) variations. The first balloon oscillation wave assists in calculating systolic blood pressure (SBP), while the second balloon oscillation wave assists in calculating mean arterial pressure (MAP). The second single-cycle waveform is used as a template to identify the oscillation wave morphology and amplitude variations, and blood pressure is estimated using the waveform template matching method.

[0073] Specifically:

[0074] For the normalized waveform, identify the changes in waveform morphological characteristics and mark the point with the maximum DTW value within the range of systolic pressure (SBP) and diastolic pressure (DBP) as D. norm .

[0075] For the non-normalized waveform, identify the amplitude change of the waveform and mark the point with the maximum DTW value within the range of systolic pressure SBP and diastolic pressure DBP as D non-norm .

[0076] Finally, the DTW distance calculated by combining the normalized and non-normalized oscillation wave signals is set, and the weighted calculation is performed to obtain the final D final ;

[0077] D final The corresponding second airbag pressure value at the same time of the oscillation wave is output as the systolic pressure SBP and the diastolic pressure DBP to achieve blood pressure measurement.

[0078] In this embodiment, waveform template matching is performed between a single-cycle waveform and the previous waveform based on the DTW algorithm. Specifically:

[0079] First, read the second airbag oscillation wave and use the variable amplitude coefficient method to locate the position. That is, use the variable amplitude coefficient to roughly determine the position range of SBP and DBP. Specifically:

[0080] Step A1: First, take the maximum value of the oscillation wave envelope as MAP, and divide the amplitude coefficient into three ranges according to the cuff pressure corresponding to the maximum value of the oscillation wave envelope. That is, for the three ranges of the maximum value of the oscillation wave envelope > 100 mmHg, 100 mmHg ≥ the maximum value of the oscillation wave envelope ≥ 80 mmHg, and the maximum value of the oscillation wave envelope < 80 mmHg, calculate the empirical value ranges of the systolic pressure coefficient and the diastolic pressure coefficient according to formulas (1) and (2): , ;in, K s is the systolic blood pressure coefficient; K d is the diastolic pressure coefficient; A SBP is the envelope amplitude corresponding to the location of systolic blood pressure SBP; A DBP is the envelope amplitude corresponding to the location of diastolic pressure DBP; A MAP is the envelope amplitude corresponding to the location of the mean pressure MAP;

[0081] Step A2: Use the empirical range of the systolic and diastolic pressure coefficients to calculate the amplitudes of the envelopes corresponding to the systolic and diastolic pressure positions, A(SBP) and A(DBP), according to the variations of formulas (1) and (2).

[0082] Next, the waveform template matching method is used to identify the waveforms of the first and third airbag oscillation waves SBP and DBP, thereby achieving accurate blood pressure calculation. Taking SBP as an example, the first single-cycle waveform in the located SBP range is selected as the standard waveform, and the other single-cycle waveforms in the range are used to perform waveform template matching with the standard waveform based on the DTW method. Specifically:

[0083] Step B1: For the standard single-cycle waveform p with a time series length of n and the single-cycle waveform t with a length of m to be matched, establish an n The matrix of m, such as Figure 6 As shown. Calculate the distance d between the sampling point of s and the sampling point of t corresponding to each unit matrix respectively ( i , j ) = ( p i - t j ) 2 , i=1,2…n, j=1,2…m. Each matrix element (i,j) represents a point p i and t j alignment.

[0084] Step B2: Find a path W that passes through several grid points in the matrix. The grid points that the path passes through are the points where p and t are aligned. The cumulative distance D of all grid points in the path is the total distance between the matching points p and t. The ultimate goal of matching is to find a path with the smallest cumulative distance. Define path W = w1, w2, ... w k ,…w K , max(n,m)≤K<m+n-1. In order to satisfy the order of point alignment and the continuity and monotonicity of the path, there are only three cases for the next grid point at the current position (i,j): (i+1,j), (i,j+1), or (i+1,j+1). Under this condition, the minimum cumulative path is defined according to formula (3): ;

[0085] Step B3: Calculate the cumulative distance. This is the sum of the distance d(i, j) of the current grid point and the minimum cumulative distance that can reach that point, which is defined by formula (4) as follows: ;

[0086] Step B4: Similarly, perform template matching on each of the other single-cycle waveforms with the previous single-cycle waveform. Each single-cycle waveform matching result yields a D. Find the maxD with the largest SBP position range. The second cuff pressure corresponding to this waveform is the systolic pressure.

[0087] For the normalized waveform, the main focus is on identifying changes in waveform morphological characteristics, and the point with the maximum DTW value within the SBP and DBP position range is marked as maxD. norm .

[0088] For non-normalized waveforms, the amplitude change of the waveform is mainly identified, and the maximum DTW value within the SBP and DBP position range is marked as maxD non-norm .

[0089] Finally, the D(w) calculated by integrating the normalized and non-normalized oscillation wave signals is set to the weight parameter. The weight w of the normalized result can be set according to the preset norm and the unnormalized result weight w non−norm Calculate the final blood pressure value to satisfy w norm +w non−norm =1. maxD final It is obtained through weighted calculation, and the calculation formula is as follows: ;

[0090] Blood pressure calculation: maxD final The corresponding second airbag pressure values at the same time of the oscillation wave are output as SBP and DBP.

[0091] According to a specific embodiment of the present invention, a method for measuring blood pressure using the multi-balloon measuring belt of the present invention is as follows: Figure 2 As shown, a multi-balloon measurement belt is placed on the subject's upper arm. The air tubes of the belt's three airbags are connected to the same inflation pump. A solenoid valve is installed between the first and third airbags and the inflation pump. Both airbags are equipped with a pressure sensor and a deflation valve. The pump and valves are controlled by a drive circuit connected to a microprocessor (MCU) for inflation and deflation. The air pressure of the airbags is converted into a voltage signal by the pressure sensor and amplification circuit. This voltage signal is then input to the MCU, which includes an analog-to-digital conversion module. The MCU then performs accurate operational control, analyzes the data, and displays the analysis results.

[0092] When used for arm measurement, the second airbag has two functions. The first is to apply external force to the brachial artery during the pressurization process. Since the proximal brachial artery under the cuff is unevenly pressurized, there is a blood surge when the pressure at the proximal end of the cuff is greater than the systolic pressure. At the same time, there is also a blood surge from the heart to the upper arm, which can be sensed by the third airbag. The second is to cut off the brachial artery to avoid the interference of the blood surge from the heart to the upper arm on the oscillation wave of the first airbag. The function of the first airbag is to detect and pick up the vibration of the brachial artery below the second airbag and send it to the MCU for analysis. The function of the third airbag is to detect and pick up the vibration of the brachial artery above the second airbag and send it to the MCU for analysis. At the start of measurement, the pump inflates the first, second, and third airbags simultaneously. When the first and third airbags are inflated to a level below the diastolic pressure (50-70 mmHg), the solenoid valve between the two airbags and the pump closes, allowing the pump to continue inflating only the second airbag. As the second airbag continues to inflate, the pressure inside the first and third airbags increases due to soft tissue compression and other factors. The pressure sensors in these two airbags sense this and transmit it to the MCU, which in turn controls its internal deflation valves to deflate, maintaining constant pressure in the first and third airbags. The second airbag continues to inflate at a fixed rate to a level above the systolic pressure (usually ensuring a linear increase in the pressure curve). At this point, there is no oscillation signal from the first airbag. When the second balloon is pressurized to the diastolic pressure level, blood flow in the brachial artery begins to be restricted, blood surge proximally increases, and the amplitude of the oscillation wave of the third balloon begins to increase, corresponding to the pressure in the second balloon being equal to the diastolic pressure. As the pressure in the second balloon continues to rise, the amplitude of the oscillation wave under the first balloon decreases. When the amplitude disappears, brachial artery blood flow is completely interrupted, and the corresponding pressure in the second balloon is equal to the systolic pressure. The relevant pressure values are converted and calculated by the MCU to obtain the required readings. Once the results are obtained, the multiple balloons are deflated simultaneously, completing the blood pressure measurement.

[0093] Of course, the measuring belt of the present invention can also be used to measure blood pressure in other parts of the human body, such as wrists, legs, arms, fingers, ankles and other parts of the human body where blood pressure needs to be measured. Its working principle is the same or similar to that of upper arm measurement.

[0094] When measuring blood pressure with a traditional airbag cuff, due to the presence of proximal blood flow surge, pulsation in the proximal blood vessels can still be felt even after the pressure is increased to a level higher than the systolic pressure, thereby generating oscillation waves. Therefore, in order to shield this interference as much as possible, the multiple airbags designed in the present invention must be isolated from each other and not affect each other, but the distance must also be close enough to ensure that the cuff volume does not exceed the preset range, thereby achieving more accurate measurement.

[0095] Experimental results show that the blood pressure values measured by this method are basically consistent with the blood pressure measured by auscultation of Korotkoff sounds, confirming that when the human body condition is relatively stable, this measurement method is basically unaffected by upstream blood flow surges. It can find the characteristic points of blood pressure more easily than other non-invasive indirect blood pressure measurement methods and measure blood pressure more accurately.

[0096] Based on the theoretical derivation and experimental results above, it can be determined that in this single-cuff, multi-balloon blood pressure measurement device, the pressure in the second balloon corresponding to the start of the oscillation wave amplitude increase detected by the third balloon is equal to the diastolic pressure, and the pressure in the second balloon corresponding to the disappearance of the oscillation wave detected by the first balloon is equal to the systolic pressure. Furthermore, the operating principle shows that this method is also applicable to wrists, legs, arms, fingers, ankles, and other parts of the body where blood pressure needs to be measured.

[0097] Different from existing single-balloon cuffs, dual-balloon double-cuffs, and dual-balloon single-cuffs for blood pressure measurement, the present invention provides a new type of cuff for blood pressure measurement devices, which includes three independent airbags. Compared with the existing technology, the present invention has the following advantages: First, the measuring belt of the present invention overcomes the interference of proximal blood flow surge during traditional single-balloon pressure measurement and the measurement error caused by the distance between the airbags in multi-balloon multi-measurement belts, and can accurately measure the systolic and diastolic blood pressure of the human body; Second, based on the changes in invasive blood pressure discovered during the cuff pressurization process, the invasive blood pressure under the third airbag designed by the present invention fluctuates the least when the second airbag is pressurized. By using the third airbag as a standard airbag, the accuracy of the blood pressure measurement results is increased; Finally, the first and third airbags of the present invention only need to be pressurized to a pressure lower than the diastolic pressure, which significantly improves the measurement comfort compared to other multi-cuff or multi-balloon devices.

[0098] Example: Arm blood pressure measurement:

[0099] The cuff is wrapped around the upper arm, with the first airbag located distal to the elbow. The microprocessor activates the inflation pump, inflating the multiple airbags to 60 mmHg. The first and third airbag solenoid valves are closed, and the pressure balancing device maintains constant pressure in the first and third airbags.

[0100] The second airbag continues to inflate to 180mmHg. During this process: when the second airbag pressure reaches 80mmHg (diastolic pressure), the amplitude of the third airbag oscillation wave increases by 30%; when the second airbag pressure reaches 120mmHg (systolic pressure), the first airbag oscillation wave disappears; the microprocessor outputs systolic pressure 120mmHg and diastolic pressure 80mmHg. The experimental results are visualized as follows Figure 7-10 As shown, the second airbag oscillation wave in the figure is the normal oscillation wave.

[0101] like Figure 7As shown in (a) and (b), it can be seen that when the second airbag is pressurized to the systolic pressure level, the oscillation wave of the first airbag disappears, and the systolic pressure characteristics change significantly compared with the normal oscillation wave; Figure 8 It can be seen that the systolic and diastolic pressures measured by the amplitude coefficient method are mostly empirically based on the range of pressure value changes. Only the mean arterial pressure corresponds to the maximum amplitude, and the measurement results are relatively accurate; Figure 9 (a), (b) and Figure 10 (a) and (b) show that when the second airbag is pressurized to the diastolic pressure level, the amplitude of the third airbag oscillation wave begins to increase, and the diastolic pressure characteristics of the normal oscillation wave change significantly. When the second airbag is pressurized to the systolic pressure level, the first and second peak shapes of the third airbag oscillation wave change, and the systolic pressure characteristics of the normal oscillation wave change significantly.

[0102] Experimental data: 50 subjects were measured and the error between this device and the auscultation method was less than ±3 mmHg, with a consistency of 98%.

[0103] The above description is merely an illustration of the preferred embodiments of the present disclosure and the technical principles employed. Those skilled in the art should understand that the scope of the invention encompassed by the embodiments of the present disclosure is not limited to technical solutions formed by specific combinations of the aforementioned technical features. It also encompasses other technical solutions formed by any combination of the aforementioned technical features or their equivalents, without departing from the aforementioned inventive concept. For example, a technical solution formed by replacing the aforementioned features with (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure.

Claims

1. A blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis, characterized in that: include: Integrated cuff cover, air pump, solenoid valve, pressure balance device, microprocessor; The integrated cuff cover is provided with a first airbag, a second airbag and a third airbag, wherein the first airbag is arranged at the distal end, the third airbag is arranged at the proximal end, and the second airbag is arranged between the first and third airbags, and the three airbags are arranged at intervals; The air pump inflates the first airbag, the second airbag and the third airbag at the same time through the main air pipe at a constant pressure; The solenoid valve includes a first airbag solenoid valve and a third airbag solenoid valve, which are respectively arranged at the connection between the main air pipe and the first airbag and the third airbag. The first airbag solenoid valve controls the inflation of the first airbag, and the third airbag solenoid valve controls the inflation of the third airbag. The pressure balancing device includes a pressure sensor and a micro-deflation valve. The pressure sensors are respectively arranged in the first airbag and the third airbag, and are used to monitor the pressure in the first airbag and the third airbag in real time. The pressure in the first airbag and the third airbag is maintained constant by dynamically adjusting the opening and closing of the micro-deflation valve; The microprocessor is connected to the inflation pump, the solenoid valve, the pressure sensor and the micro deflation valve to execute the inflation control logic; The microprocessor integrates an oscillation wave analysis module for real-time acquisition of pressure data from the first airbag to the third airbag, identifying oscillation wave changes between the first airbag and the third airbag based on an elastic template matching method and obtaining blood pressure measurement results; The oscillation wave analysis module specifically includes: a signal preprocessing unit, a signal quality assessment unit, a feature point recognition unit, and a blood pressure calculation unit; The signal preprocessing unit: first uses Fourier transform to determine the distribution characteristics of noise and effective signals; then uses low-pass filtering to remove high-frequency noise in the original oscillation wave signal, and uses high-pass filtering to remove the influence of baseline drift on the oscillation wave; uses Fourier transform to perform secondary analysis to provide a basis for frequency band division for empirical wavelet transform; then uses empirical wavelet transform to eliminate artifacts; finally, uses normalization and non-normalization methods respectively, normalization is used to adjust the amplitude difference between different waveforms to identify waveform feature changes; non-normalization is used to identify the amplitude difference of the oscillation wave; The signal quality assessment unit includes data quality assessment of oscillation waves and data quality assessment related to inflation and deflation blood pressure measurement under high pressure. The data quality assessment under constant pressure is performed by extracting each oscillation wave under a preset constant pressure to construct a quality assessment template, matching the template signal with each waveform of this oscillation wave and calculating the DTW distance. The data usability is determined based on the average value of all DTW distances. The feature point recognition unit first reads the second airbag oscillation wave and locates it using the variable amplitude coefficient method, that is, using the variable amplitude coefficient to determine the position range of the systolic pressure (SBP) and the diastolic pressure (DBP). The waveforms of the systolic pressure (SBP) and diastolic pressure (DBP) positions of the first and third airbag oscillation waves are used to estimate blood pressure based on the DTW algorithm, wherein the third airbag is used as the standard airbag, the first airbag oscillation wave assists in calculating the systolic pressure (SBP), and the second airbag oscillation wave assists in calculating the mean arterial pressure (MAP). The latter single-cycle waveform uses the previous single-cycle waveform as a template, and by identifying the oscillation wave morphology and amplitude changes, blood pressure is estimated based on the waveform template matching method; The feature point recognition unit is specifically: For the normalized waveform, identify the changes in waveform morphological characteristics and mark the point with the maximum DTW value within the range of systolic pressure (SBP) and diastolic pressure (DBP) as D. norm ; For the non-normalized waveform, identify the amplitude change of the waveform and mark the point with the maximum DTW value within the range of systolic pressure SBP and diastolic pressure DBP as D non-norm ; Finally, the DTW distance calculated by combining the normalized and non-normalized oscillation wave signals is set, and the weighted calculation is performed to obtain the final D final ; D final The corresponding second airbag pressure value at the same time of the oscillation wave is output as the systolic pressure SBP and diastolic pressure DBP to achieve blood pressure measurement; The blood pressure calculation unit D final The corresponding second airbag pressure value at the same time of the oscillation wave is output as the systolic pressure and the diastolic pressure.

2. A blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis according to claim 1, characterized in that: The first airbag, the second airbag and the third airbag are all rectangular in shape. The first airbag and the third airbag are of the same size, and the second airbag is larger than the first airbag and the third airbag. The airbag size is adjusted in time according to actual conditions.

3. The blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis according to claim 1, characterized in that: The inflation rate of the inflation pump is 3-10 mmHg / second.

4. The blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis according to claim 1, characterized in that: The data quality assessment of the oscillation wave is performed by extracting each waveform under all pressure ranges to construct a quality assessment template; the template signal is matched with each single-cycle waveform and the DTW distance is calculated, and the usability of the data is determined based on the average value of all DTW distances; The data quality assessment related to the inflation and deflation blood pressure measurement under high pressure first calculates the average pressure position of the oscillation wave in the inflation state and the average pressure position in the deflation state, calculates the position deviation between the two and compares it with a preset threshold to determine whether the data is usable; selects the previous single-cycle waveform as a template, and uses the single-cycle waveform and its corresponding template based on the DTW algorithm to perform waveform template matching, finds a matching waveform and preliminarily estimates the blood pressure.

5. The blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis according to claim 1, characterized in that: The inflation control logic, i.e., the blood pressure measurement method based on multi-airbag coordinated control and oscillation wave analysis, specifically includes: Step S1: Initial inflation stage: the inflation pump is started, and multiple airbags are inflated synchronously to a preset initial pressure; Step S2: airbag constant pressure stage: close the first airbag solenoid valve and the third airbag solenoid valve; Step S3: The pressure balancing device dynamically adjusts the micro air release valve to maintain a constant pressure in the first airbag and the third airbag; Step S4: Second airbag pressure boosting stage: the air pump continues to inflate until the pressure in the second airbag is higher than the systolic pressure level.

6. The blood pressure measurement system based on multi-airbag coordinated control and oscillation wave analysis according to claim 1, characterized in that: The blood pressure measurement method of multi-airbag coordinated control and oscillation wave analysis includes a multi-airbag pressure measurement mode and a dual-airbag pressure measurement mode; The multi-balloon pressure measurement mode uses three balloons to measure pressure simultaneously, with the third balloon serving as the standard balloon. The variation characteristics of systolic blood pressure (SBP) and diastolic blood pressure (DBP) are amplified to obtain the standard blood pressure. Simultaneously, the first balloon's oscillation wave amplifies the variation characteristics of systolic blood pressure (SBP) to correct the systolic blood pressure (SBP), and the second balloon's oscillation wave is used to identify mean arterial pressure (MAP). The three balloons then calibrate each other to obtain the blood pressure value. The dual-airbag pressure measurement mode is to pressurize only the second airbag and the third airbag, that is, the first airbag is not pressurized, and the second airbag and the third airbag are pressurized according to the description of steps S4 and S1 respectively. Finally, the mean arterial pressure MAP is measured by the second airbag, and the third airbag amplifies the change characteristics of the systolic pressure SBP and the diastolic pressure DBP to identify the systolic pressure SBP and the diastolic pressure DBP. The blood pressure value is obtained by correcting the third airbag through the second airbag.

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