A home blood vessel hardness and blood pressure combined detection method and system based on four-cuff pressure wave and finger clip dual-wavelength PPG fusion

Abstract

The present application relates to the technical field of blood vessel health detection, and discloses a family blood vessel hardness and blood pressure combined detection method and system based on four-cuff pressure wave and finger clip dual-wavelength PPG fusion. The method collects pressure signals through synchronous inflation and deflation of four limb cuffs, and synchronously collects dual-wavelength PPG signals, pre-processes multi-channel signals, detects feature points, and aligns time, calculates blood pressure, ankle-brachial index and pulse wave velocity, and based on pulse wave velocity, ankle-brachial index and PPG waveform characteristics, weighted calculation or rule determination is carried out to obtain blood vessel hardness evaluation results. When the signal quality does not meet the preset condition, a retest prompt or a detection result with a confidence mark is output.

Description

Technical Field

[0001] This invention relates to the field of vascular health detection and non-invasive physiological parameter measurement technology, and in particular to a home-based method and system for the combined detection of vascular stiffness and blood pressure based on the fusion of four-cuff pressure wave and finger clip dual-wavelength PPG. Background Technology

[0002] Current home blood pressure or vascular stiffness monitoring methods mostly rely on a single signal source. When analyzing using simple cuff pressure oscillation waves, the extraction of propagation time difference is easily affected by body movement, inconsistent cuff tightness, and changes in local blood flow. When analyzing using simple PPG signals, the propagation path and absolute propagation distance are difficult to constrain, and it is also quite sensitive to the wearing status.

[0003] Existing limb cuff devices can obtain parameters such as ankle-brachial index and brachial pulse wave velocity, but these devices are typically geared towards hospitals or health checkup institutions. For home use, there are still requirements regarding size, operational procedures, and the stability of multi-channel signals. Therefore, a detection scheme based on the combined use of four-cuff pressure waves and PPG signals is needed to achieve joint detection of blood pressure and vascular stiffness. Summary of the Invention

[0004] This invention provides a home-based method and system for the joint detection of vascular stiffness and blood pressure based on the fusion of four-cuff pressure waves and finger clip dual-wavelength PPG, which is used to realize the joint acquisition, processing and output of multi-channel pressure waves and PPG signals.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: On the one hand, a home-based method for jointly detecting vascular stiffness and blood pressure based on the fusion of four-cuff pressure waves and finger-clip dual-wavelength PPG is provided. This method includes: wearing cuffs on the left upper arm, right upper arm, left ankle, and right ankle of the subject, and wearing finger-clip dual-wavelength PPG probes on the fingers; simultaneously inflating to a preset stop pressure, and simultaneously acquiring four-cuff static pressure signals, four-cuff pressure oscillation signals, and dual-wavelength PPG signals during controlled deflation; preprocessing, feature point detection, time alignment, and validity determination of the multi-channel signals; obtaining left and right arm blood pressure parameters, left and right ankle blood pressure parameters, ankle-brachial index, and arm-ankle pulse wave velocity; and performing weighted calculations or rule-based determinations based on pulse wave velocity, ankle-brachial index, and PPG waveform characteristics to obtain vascular stiffness assessment results.

[0006] On the other hand, a home-based combined detection system for implementing the above method is provided. The system includes at least a four-cuff air path module, a pressure acquisition module, a finger clip dual-wavelength PPG acquisition module, a control module, a data processing module, and a result output module.

[0007] Furthermore, the four cuffs adopt an independent air circuit structure, with each circuit equipped with an air pump, a digital pressure sensor, a slow-speed venting valve, and a fast-speed pressure relief valve.

[0008] Furthermore, PPG employs a dual-wavelength sampling structure using both red and infrared light to assist in the localization of pulse wave feature points and waveform quality assessment.

[0009] Furthermore, multi-channel data is aligned using a unified clock or a unified timestamp.

[0010] Furthermore, in addition to outputting blood pressure, ankle-brachial index, and brachial pulse wave velocity, it can also output signal quality level, retest prompts, or risk stratification results.

[0011] Compared with existing technologies, this invention achieves the calculation of blood pressure, ankle-brachial index and pulse wave velocity by jointly acquiring and processing the pressure wave of the four cuffs and the dual-wavelength PPG signal of the finger clip, and obtains the vascular stiffness assessment results based on multiple parameters. Attached Figure Description

[0012] Figure 1 This is a block diagram of the overall system structure.

[0013] Figure 2 This is a schematic diagram of the independent air passage structure for the four sleeves.

[0014] Figure 3 This is a schematic diagram of the joint testing process.

[0015] Figure 4 This is a schematic diagram of a finger clip dual-wavelength PPG acquisition structure.

[0016] Figure 5 This is a schematic diagram of the data processing and fusion evaluation process. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0018] Example 1: System Structure.

[0019] like Figure 1As shown, the combined detection system of the present invention includes a subject-worn end, a four-cuff airway module, a PPG acquisition module, a control module, a data processing module, and a result output module. The subject-worn end includes a left upper arm cuff 1, a right upper arm cuff 2, a left ankle cuff 3, a right ankle cuff 4, and a finger clip dual-wavelength PPG probe 5. The four-cuff airway module is used to achieve synchronous inflation and controlled deflation. The PPG acquisition module is used to acquire dual-wavelength PPG waveforms from the finger area. The control module is used for pump valve control, pressure sampling, PPG sampling timing management, and multi-channel timestamp management. The data processing module is used to perform signal preprocessing, parameter calculation, and vascular stiffness assessment. The result output module is used to output the detection results.

[0020] like Figure 2 As shown, a single-path air circuit includes at least an air pump 6, a cuff 7, a digital pressure sensor 8, a slow-release valve 9, and a fast-release valve 10. The four air circuits employ independent actuators, allowing the cuffs of the left upper arm, right upper arm, left ankle, and right ankle to be pressurized synchronously and to be individually adjusted or rapidly depressurized. Specifically, the air pump 6 inflates the cuff 7; the digital pressure sensor 8 collects the static pressure within the cuff and the superimposed pulse oscillation component; the slow-release valve 9 releases air according to a preset slope; and the fast-release valve 10 rapidly depressurizes upon measurement completion, abnormal termination, or safe overpressure.

[0021] Example 2: Detection process.

[0022] like Figure 3 As shown, the detection process of the present invention includes synchronous inflation 11, constant pressure brief pause 12, slow deflation at a set slope 13, acquisition of pressure oscillation waves of four cuffs 14, synchronous acquisition of dual-wavelength PPG of finger clips 15, time alignment and quality control 16, blood pressure / ABI / PWV calculation 17, and output results 18.

[0023] In practice, the subject is in a resting sitting or supine position. Four cuffs are secured to the left and right upper arms and ankles respectively, with the PPG probe clipped to the fingers. The control module first drives the four air pumps to inflate synchronously until the preset cutoff pressure is reached; after reaching the cutoff pressure, it can remain stable for a short period; then it enters a slow deflation phase, with a deflation rate of 1 mmHg / s to 5 mmHg / s. If significant body movement, sensor detachment, abnormal pressure increase, or user-initiated termination occurs during the test, the rapid pressure relief valve is activated for rapid pressure release.

[0024] During the slow deflation phase, the pressure acquisition module continuously acquires the static pressure and pulse oscillation components of each cuff. Simultaneously, the PPG acquisition module acquires red PPG and infrared PPG signals. The two PPG signals are amplified and filtered by the analog front-end before entering the analog-to-digital converter, and then processed by the digital processing unit for DC removal, bandpass filtering, and artifact suppression.

[0025] Example 3: Waveform processing and feature extraction.

[0026] like Figure 4 As shown, the finger clip dual-wavelength PPG probe includes at least a red LED 19, an infrared LED 20, a photodetector 21, and finger tissue 22; its output is processed by an AFE analog front-end, an ADC, and digital filtering to form a PPG waveform and a quality index 23. The PPG waveform is used to assist in identifying the pulse initiation point, the point of maximum upward slope, the peak, and the dicrotic notch; the quality index is used to evaluate whether the current waveform is usable.

[0027] For cuff pressure waves, the pulsating component can be separated from the hydrostatic signal first, followed by bandpass filtering, baseline drift removal, abnormal pulse elimination, and period consistency analysis. For PPG signals, DC component removal, bandpass filtering, motion artifact suppression, and dual-wavelength consistency analysis can be performed. Subsequently, at least one of the following points—wave foot, wave crest, maximum rise slope, and second derivative extremum—is detected in the pressure oscillation wave and PPG waveform. Target feature points for propagation time difference calculation are selected based on the consistency of multi-source feature points.

[0028] Example 4: Parameter calculation and fusion evaluation.

[0029] like Figure 5 As shown, the data processing and fusion assessment process includes raw signal input 24, preprocessing filtering 25, feature point detection 26, blood pressure and ABI calculation 27, time difference calculation 28, vessel length estimation 29, baPWV calculation 30, and fusion scoring and risk classification 31.

[0030] Blood pressure parameters can be obtained through the oscillation method, envelope fitting method, or empirical coefficient method. It can output the systolic blood pressure of the left upper arm, right upper arm, left ankle, and right ankle, and can also further output diastolic blood pressure and mean pressure. The ankle-brachial index (ABI) can be expressed as one or more of the following: the ratio of the left ankle systolic blood pressure to the higher systolic blood pressure of either arm, the ratio of the right ankle systolic blood pressure to the higher systolic blood pressure of either arm, or a one-to-one correspondence between the left and right ankles and the left and right arms.

[0031] The propagation time difference ΔT can be obtained by the difference in arrival times of the characteristic points at the arm and ankle. The arm-ankle propagation distance L can be estimated using an empirical formula based on height, or it can be the difference between the distance from the heart to the ankle (Lb) and the distance from the heart to the arm (La), i.e., L = Lb - La. Subsequently, baPWV is obtained according to the formula PWV = L / ΔT. Further, at least one of the following parameters can be used for weighted calculation or rule-based determination with pulse wave velocity and ankle-brachial index to output the vascular stiffness assessment result.

[0032] Example 5: Effectiveness Control and Output.

[0033] This invention includes a validity determination mechanism. This mechanism can determine the validity of data based on at least one of the following indicators: waveform period consistency, peak-valley discernibility, dual-wavelength correlation, body motion noise level, and cuff oscillation amplitude stability. When the detection is invalid, the user can be prompted to re-wear the cuff or PPG probe, re-execute the inflation / deflation process, or include a confidence level marker in the output results.

[0034] The final output may include at least: blood pressure in both arms, blood pressure in both ankles, ABI, baPWV, vascular stiffness assessment results, signal quality level, and a prompt indicating whether to retest.

[0035] It should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or modifications made in form using the concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A home-based method for jointly detecting vascular stiffness and blood pressure based on the fusion of four-cuff pressure waves and finger clip dual-wavelength PPG, characterized in that, Includes the following steps: S1. Wear cuffs on the left upper arm, right upper arm, left ankle and right ankle of the subject, and wear finger clip-type dual-wavelength PPG probes on the fingers; S2. Drive the four cuffs to inflate synchronously to the preset blocking pressure and enter the controlled deflation stage; S3. During the controlled venting phase, the static pressure signal of the four cuffs, the pressure oscillation signal of the four cuffs, and the finger clip dual-wavelength PPG signal are simultaneously acquired. S4. Preprocess the pressure oscillation signal and the PPG signal, detect feature points and align time to obtain the pulse wave arrival time difference, left and right arm blood pressure parameters and left and right ankle blood pressure parameters. S5. Calculate the pulse wave velocity based on the pulse wave arrival time difference and the arm-ankle propagation distance, and calculate the ankle-brachial index based on the ankle systolic pressure and the arm systolic pressure. S6. Based on the pulse wave velocity, ankle-brachial index and PPG waveform characteristics, perform weighted calculation or rule determination to obtain the vascular stiffness assessment result and output the blood pressure detection result.

2. The method according to claim 1, characterized in that, Each of the four cuffs is equipped with an independent air pump, a slow-speed venting valve, and a fast-speed pressure relief valve, so that the four cuffs can simultaneously execute the detection process and perform pressure regulation or abnormal pressure relief respectively.

3. The method according to claim 1, characterized in that, The controlled venting phase employs a slow venting strategy with a controllable slope, with a venting rate of 1 mmHg / s to 5 mmHg / s. In the event of abnormal overpressure, excessive body motion interference, measurement termination, or user-initiated termination of measurement, rapid pressure relief is performed via a quick-release valve.

4. The method according to claim 1, characterized in that, The preprocessing includes: bandpass filtering, baseline drift removal, and abnormal pulse removal of the pressure oscillation signal; DC component removal, bandpass filtering, and motion artifact suppression of the PPG signal; the feature point detection includes at least the wave foot point or the point of maximum rise slope.

5. The method according to claim 1, characterized in that, The time alignment is achieved through at least one of the following methods: using a unified clock on the microcontroller to synchronously timestamp the four cuff pressure sampling channels and the PPG sampling channels; or performing unified resampling and time base correction on the multi-channel data in the host computer.

6. The method according to claim 1, characterized in that, The pulse wave velocity is calculated according to PWV=L / ΔT, where ΔT is the time difference between the arrival of the pulse wave in the arm and ankle, and L is the propagation distance in the arm and ankle. When the signal quality does not meet the preset conditions, a retest prompt or a detection result with a confidence level is output.

7. A home-based system for jointly detecting vascular stiffness and blood pressure based on the fusion of four-cuff pressure waves and finger clip dual-wavelength PPG, characterized in that, include: The four-cuff airway module is used to connect to the left upper arm cuff, right upper arm cuff, left ankle cuff, and right ankle cuff respectively, and to perform synchronous inflation, controlled deflation, and rapid depressurization; the pressure acquisition module is used to acquire the static pressure signal and pressure oscillation signal of the four cuffs; the finger clip dual-wavelength PPG acquisition module is used to acquire the red light PPG signal and infrared light PPG signal of the subject's fingers; the control module is used to control the four-cuff airway module and the tissue multi-channel synchronous sampling. The data processing module is used to perform preprocessing, feature extraction, time difference calculation, blood pressure calculation, ankle-brachial index calculation, pulse wave velocity calculation, and vascular stiffness assessment on the four-cuff pressure wave and dual-wavelength PPG signals; the result output module is used to output the vascular stiffness assessment results and blood pressure detection results.

8. The system according to claim 7, characterized in that, Each of the four-cuff pneumatic circuit modules includes an air pump, cuff, digital pressure sensor, slow-release valve, and fast-release valve; the finger clip dual-wavelength PPG acquisition module includes a red light emitting unit, an infrared light emitting unit, and a photoelectric detection unit.

9. The system according to claim 7, characterized in that, The data processing module is used to perform weighted calculations or rule-based judgments based on the pulse wave velocity, ankle-brachial index, and PPG waveform characteristics to obtain the vascular stiffness assessment results, and to output a retest prompt when the signal quality does not meet the preset conditions.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method according to any one of claims 1 to 6.

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