CN117442175B - Continuous noninvasive blood pressure measurement method and device - Google Patents

Abstract

The invention discloses a continuous noninvasive blood pressure measuring methodThe method and the device belong to the technical field of continuous noninvasive blood pressure measurement, and comprise the following steps: arranging a fingerstall and wearing the fingerstall on the root of a finger of a tested person, and inflating the fingerstall to a first preset pressure; step-type deflation is carried out on the pressure of the finger sleeve; obtaining an envelope curve according to pulse volume signals in the step-type deflation, and obtaining PPG according to the envelope curve _maxi And MAPi; repeating the test for several times to obtain average PPG under several times of pressure test _max And MAP; according to PPG _max And MAP adjusts the air pressure output to the fingerstall, acquires the pressure difference of the brachial artery blood pressure and the pulse pressure, and acquires the blood pressure of the tested person. According to the continuous noninvasive blood pressure measurement method, the brachial artery systolic pressure is measured through the upper arm sleeve and is used as a calibration system, the gradient attenuation of continuous finger blood pressure measured at the fingerstall is automatically calibrated, and a digital filter is constructed based on the system transfer function of the central artery blood pressure conducted to the finger arterial pressure to eliminate waveform distortion, so that accurate continuous blood pressure of a measured person is obtained.

Description

A continuous non-invasive blood pressure measurement method and device

Technical field

The invention belongs to the technical field of continuous non-invasive blood pressure measurement, and specifically relates to a continuous non-invasive blood pressure measurement method and device.

Background technique

When blood flows in blood vessels, the lateral pressure on the blood vessels is called blood pressure. Blood pressure usually refers to arterial blood pressure or systemic blood pressure and is an important vital sign. Blood pressure measurement is the main means to evaluate blood pressure levels, diagnose hypertension and observe antihypertensive effects. Accurate blood pressure measurement is the basis for grassroots hypertension management.

Among the commonly used blood pressure measurement methods, one is an upper arm cuff brachial artery sphygmomanometer that obtains a set of intermittent single blood pressure parameters based on oscillometric measurement. However, the patient's blood pressure may change drastically in a short period of time, and the interval between each measurement of the intermittent sphygmomanometer is at least 3 minutes, making it unable to accurately reflect the changing trend of human blood pressure. Another available method is to perform arterial puncture and catheterization to monitor continuous invasive blood pressure. However, invasive testing not only leads to complications such as hematoma, infection, thrombosis, and nerve damage, but is also expensive, time-consuming, and requires skilled medical staff. Insertion technology.

The existing patent technology CN108742574A discloses a non-invasive continuous blood pressure measuring instrument, which collects blood pressure data of the arm brachial artery through a cuff module and collects finger blood pressure data through a continuous blood pressure module, and uses the arm brachial artery blood pressure data to compare the finger blood pressure data. The converted arm brachial artery blood pressure data is adjusted. In this conversion adjustment process, it mainly uses a liquid level sensor to correct the offset between central arterial pressure and finger blood pressure. However, due to the influence of air pressure at different altitudes, there may be calculation errors in blood pressure measurements at different altitudes.

Contents of the invention

In view of one or more of the above defects or improvement needs of the prior art, the present invention provides a continuous non-invasive blood pressure measurement method and device to solve the problem of being unable to accurately obtain human blood pressure during the existing blood pressure measurement process.

In order to achieve the above objectives, the present invention provides a continuous non-invasive blood pressure measurement method, which includes the following steps:

S1. Set the upper arm cuff and wear it on the subject's arm, and obtain the arterial systolic pressure NIBP_S, arterial diastolic pressure NIBP_D and pulse pressure difference PP at the subject's brachial artery;

S2. Set the finger cot and wear it at the base of the subject's finger, inflate the finger cot and inflate it to the first preset pressure;

S3. Obtain the pressure at the finger cuff and the pulse volume signal at the finger at the corresponding pressure;

S4. Deflate the finger cuff pressure in a stepwise manner, and obtain the finger cuff pressure at each step and the pulse volume signal at the corresponding pressure;

S5. Obtain the envelope curve according to the pulse volume signal in the stepped deflation, obtain the maximum amplitude PPG _maxi of the envelope curve, obtain the corresponding finger cuff air pressure at the maximum amplitude PPG _maxi and use it as the mean arterial pressure MAPi of the finger;

S6. Repeat steps S1~S4 multiple times to obtain PPG _maxi and MAPi under multiple pressure tests, and obtain the average value of PPG _maxi , PPG _max , and the average value of MAPi;

S7. Adjust the air pressure output to the finger cuff according to PPG _max and MAP, and obtain the pulse pressure difference PP at the brachial artery;

S8. Obtain the subject's fingertip continuous blood pressure FAP (t) based on PPG _max , MAP and PP;

S9. Based on the calibration system of NIBP_S and NIBP_D, correct the fingertip continuous blood pressure FAP (t) to the brachial artery continuous blood pressure waveform BAP (t).

As a further improvement of the present invention, the first preset pressure in step S2 is 100~250mmHg.

As a further improvement of the present invention, in the step S4, the air pressure of each stepped deflation is 3~10mm/ms, and the time of each stepped deflation is 200~500ms.

As a further improvement of the present invention, when the finger cuff pressure is deflated in steps in step S4, the final pressure value in the step deflation is 50 mmHg.

As a further improvement of the present invention, the number of repeated tests in step S6 is not less than 3 times.

As a further improvement of the present invention, the subject has finger cots on the roots of multiple fingers, and in step S6, PPG _maxi and MAPi are collected at different fingers.

As a further improvement of the present invention, in step S8, the continuous blood pressure FAP(t) of the subject's fingertip is calculated based on the mean arterial pressure difference MAP at the finger, the error gain K _P and the integral gain K _I.

As a further improvement of the present invention, the calculation method of K _P and K _I is:

(Formula 1)

Among them, k ₁ ~k ₅ are empirical coefficients.

As a further improvement of the present invention, the continuous blood pressure FAP(t) of the subject's fingertip is calculated as follows:

(Formula 2)

Wherein, the PPG(t) is the finger pulse volume signal under the current set pressure.

As a further improvement of the present invention, in the step S9, the continuous blood pressure FAP(t) of the subject's fingertip is corrected to the continuous blood pressure waveform BAP(t) of the brachial artery and reconstructed by the FIR filter.

As a further improvement of the present invention, in step S9, the continuous blood pressure of the subject's fingertips is corrected to the continuous blood pressure waveform of the brachial artery using the following formula:

(Formula 3)

Among them, FAP_S and FAP_D are the peak and trough values of the fingertip pulse continuous blood pressure waveform respectively.

This application also includes a continuous non-invasive blood pressure measurement device, which is used for the measurement of the above-mentioned continuous non-invasive blood pressure measurement method, which includes:

A control unit, the control unit is connected with an upper arm cuff and an air valve module; the upper arm cuff is used to test the blood pressure pulse pressure difference of the brachial artery; the air valve module is used to adjust the air pressure output according to the signal transmitted by the control unit;

The air valve module is respectively connected with a first finger cot and a second finger cot. The first finger cot and the second finger cot have the same structure, and the first finger cot and the second finger cot are used for The tester's pulse volume signal is obtained under the air pressure supply of the air valve module.

The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention have beneficial effects including:

(1) The continuous non-invasive blood pressure measurement method of the present invention first adopts the continuous step-down blood pressure measurement method to obtain the mean arterial pressure in the open-loop stage, and based on the pulse pressure difference measured by the upper arm cuff, the pulse volume signal of the mean arterial pressure is found. The maximum amplitude PPG _max is used to realize the adaptive adjustment of the parameters in the closed-loop servo control stage to adapt to the pulse volume signal under the mechanical response of a wide range of human fingers; then the upper arm cuff is used to measure the systolic blood pressure of the brachial artery as a calibration system to adjust the finger Continuous blood pressure is reconstructed into central arterial pressure to obtain the tester's accurate blood pressure.

Specifically, it obtains the mean arterial pressure of the finger artery by using a blood pressure reduction measurement method in the open-loop stage. It mainly inflates and pressurizes the finger cuff to compress the arterial blood vessel and completely occlude it, and then reduces the blood pressure so that The arterial blood vessels are in a state of closing - gradually opening - fully opening to achieve blood volume clamping. At the same time, the pulse volume signal is collected during the decompression process, and the average value of the maximum pulse volume signal PPG _max is obtained through multiple measurements; the pressure sensor is used to collect the airbag pressure of the finger cuff, and the mean arterial pressure MAP is calculated; finally, in the closed-loop stage, according to The brachial artery blood pressure pulse pressure difference PP measured by the upper arm cuff and the maximum pulse volume signal PPG _max recorded in the aforementioned open-loop stage adaptively adjust the pressure output to calculate the accurate blood pressure of the tester.

(2) The continuous non-invasive blood pressure measurement method of the present invention first draws an envelope curve through the pulse volume signal obtained by the closed-loop stage test and the pressure at the finger cuff, and obtains its maximum amplitude PPG _maxi and the corresponding amplitude position through the envelope curve drawing. The mean arterial pressure MAPi; and through multiple repeated tests, the average maximum amplitude PPG _max of the current tester and the mean arterial pressure MAP at the corresponding amplitude are obtained, and the air pressure output at the finger cuff is adjusted through the PPG _max and the mean arterial pressure MAP. , and combined with the brachial artery blood pressure pulse pressure difference PP collected by the upper arm cuff to obtain the adjustment coefficient error gain (K _P ) and integral gain (K _I ) corresponding to the tester's brachial artery blood pressure and finger blood pressure, and finally based on _KP and K _I The blood pressure waveform at the tester's finger is reconstructed into the blood pressure waveform of the brachial artery to obtain the tester's corresponding continuous blood pressure. It can be seen from the digital artery blood pressure waveform and brachial artery blood pressure waveform reconstructed by the filter of this application that the two waveforms are roughly equivalent, eliminating the pressure gradient changes in the conduction process caused by arterial narrowing between the brachial artery and the digital artery. It corrects the distortion of the brachial artery blood pressure waveform, achieves stable measurement of the brachial artery blood pressure waveform through the finger artery blood pressure waveform, and accurately obtains the blood pressure waveform of the subject's brachial artery.

Description of the drawings

Figure 1 is a schematic diagram of the overall structure of a continuous non-invasive blood pressure measurement device in an embodiment of the present invention;

Figure 2 is a schematic structural diagram of the middle finger cot according to the embodiment of the present invention;

Figure 3 is a schematic diagram of the unfolded structure of the finger cot according to the embodiment of the present invention;

Figure 4 is a schematic plan view of the finger cot according to the embodiment of the present invention;

Figure 5 is a schematic structural diagram of a finger cot wrapping a finger in an embodiment of the present invention;

Figure 6 is a schematic diagram of the filter amplitude-frequency response curve for reconstructing central arterial pressure in an embodiment of the present invention;

Figure 7 is a schematic diagram of the waveform curve before and after continuous blood pressure reconstruction of the finger in the embodiment of the present invention.

In all drawings, the same reference numerals represent the same technical features, specifically:

110. Control unit; 111. Air valve module; 112. Upper arm cuff; 113. First finger cuff; 114. Second finger cuff; 115. Cable; 116. Arm strap;

201. Protective layer; 202. Flexible circuit board; 203. Infrared LED emitting tube; 204. Photoelectric receiving tube; 205. First Velcro; 206. Second Velcro; 207. Airbag; 208. Air outlet.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axis" The orientations or positional relationships indicated by "radial direction", "circumferential direction", etc. are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply the device or device referred to. Elements must have a specific orientation, be constructed and operate in a specific orientation and therefore are not to be construed as limitations of the invention.

In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

In the present invention, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection", "fixing" and other terms should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection. , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interactive relationship between two elements, unless otherwise specified limitations. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise expressly stated and limited, a first feature being "on" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. touch. Furthermore, the terms "above", "above" and "above" the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "below" and "beneath" the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.

Example:

Please refer to Figures 1 to 7. The continuous non-invasive blood pressure measurement device in the preferred embodiment of the present invention includes a control unit 110. The control unit 110 is connected to an upper arm cuff 112 and an air valve module 111; where the upper arm cuff 112 is used to test the brachial artery. The blood pressure pulse pressure difference; the air valve module 111 is used to adjust the output of air pressure according to the signal transmitted by the control unit 110 . At the same time, the air valve module 111 is connected to a first finger cot 113 and a second finger cot 114 respectively. The first finger cot 113 and the second finger cot 114 have the same structure, and the first finger cot 113 and the second finger cot 114 are both Used to obtain the tester's pulse volume signal under the air pressure supply of the air valve module.

Specifically, the structures of the first finger cot 113 and the second finger cot 114 in this application both include a protective layer 201. The protective layer 201 is used to wrap around and stick to the base of the tester's finger; one side of the protective layer 201 is provided with a flexible Circuit board 202. The flexible circuit board 202 is provided with an infrared LED emitting tube 203 and a photoelectric receiving tube 204. The infrared LED emitting tube 203 is used to cooperate with the photoelectric receiving tube 204 to obtain the pulse volume signal at the finger; at the same time, both sides of the protective layer 201 The first Velcro 205 and the second Velcro 206 are respectively provided on the sides. The first Velcro 205 and the second Velcro 206 are used for bonding to wrap the base of the finger. One side of the protective layer 201 is also provided with an air bag 207. The air bag 207 is connected to the air valve module 111 for adjusting the pressure of the finger cuff. At the same time, the air bag 207 is provided with an openable and closable air outlet 208 to realize the stepped style of the finger cuff. Deflation.

Further, the flexible circuit board 202 in this application is connected to the air valve module 111 through the cable 115, and the air valve module 111 is connected to the control unit 110 through the cable 115 to realize control and signal acquisition of each component through the control unit 110. Correspondingly, a gas pipe for transmitting gas is also provided between the gas valve module 111 and the first finger cuff 113 and the second finger cuff 114 .

Furthermore, as a preferred embodiment of the present invention, the air valve module 111 in this application is also connected with an arm strap 116. The arm strap 116 is used to strap the air valve module 111 to the tester's arm.

Further, based on the continuous non-invasive blood pressure measurement device in this application, this application corresponds to a continuous non-invasive blood pressure measurement method, which includes the following steps:

S1. Set the upper arm cuff 112 and wear it on the subject's arm, and obtain the arterial systolic pressure NIBP_S, arterial diastolic pressure NIBP_D and pulse pressure difference PP at the subject's brachial artery;

S2. Set the finger cot and wear it at the base of the subject's finger, inflate the finger cot and inflate it to the first preset pressure;

S3. Obtain the pressure at the finger cuff and the pulse volume signal at the finger at the corresponding pressure;

S4. Deflate the finger cuff pressure in a stepwise manner, and obtain the finger cuff pressure at each step and the pulse volume signal at the corresponding pressure;

S5. Obtain the envelope curve according to the pulse volume signal in the stepped deflation, obtain the maximum amplitude PPG _maxi of the envelope curve, obtain the finger cuff air pressure corresponding to the maximum amplitude PPG _maxi and use it as the mean arterial pressure MAPi of the finger; specifically Ground, the envelope curve is obtained from the pulse volume signal using the Hilbert transform method.

S6. Repeat steps S2~S5 multiple times to obtain PPG _maxi and MAPi under multiple stress tests, and obtain the average value of PPG _maxi and the average value of PPG _max and MAPi;

S7. Adjust the air pressure output to the finger cuff according to PPG _max and MAP, and obtain the pulse pressure difference PP at the brachial artery;

S8. Obtain the subject's fingertip continuous blood pressure FAP (t) based on PPG _max , MAP and PP;

S9. Based on the calibration system of NIBP_S and NIBP_D, correct the fingertip continuous blood pressure FAP (t) to the brachial artery continuous blood pressure waveform BAP (t).

The continuous non-invasive blood pressure measurement method of the present invention first adopts the continuous step-down blood pressure measurement method to obtain the mean arterial pressure in the open-loop stage, and based on the pulse pressure difference measured by the upper arm cuff, the maximum amplitude of the pulse volume signal at the mean arterial pressure is found. PPG _max to achieve adaptive adjustment of parameters in the closed-loop servo control stage to adapt to the pulse volume signal under a wide range of human finger mechanical responses; and then use the upper arm cuff 112 to measure the systolic blood pressure of the brachial artery as a calibration system to continuously Blood pressure is reconstructed into central arterial pressure to obtain the tester's accurate blood pressure. Specifically, this application mainly obtains the parameter relationship between the pulse volume signal and the finger cuff pressure in the tester's current environment during the open-loop stage, obtains its average value through multiple tests, and corrects the current tester based on the obtained PPG _max and MAP. The finger cuff air pressure is finally corrected to the blood pressure waveform at the finger by the brachial artery blood pressure pulse pressure difference at the upper arm cuff 112, and the blood pressure waveform at the brachial artery of the tester is reconstructed to obtain the tester's continuous blood pressure.

Further preferably, the first preset pressure in step S2 of this application is 100~250mmHg. The first preset pressure range here is an appropriate systolic blood pressure range selected according to different groups of people, and is adaptively selected according to testers of different ages and physical conditions. The first preset pressure here is to meet the tester's step-by-step deflation during the test process to ensure that the arteries and blood vessels present a closed-gradually open-fully open state during the open-loop process to achieve blood volume reduction. Clamp.

Further preferably, in step S4 of the present application, the step-by-step deflation rate is 3~10mm/ms, and the step-by-step deflation time is 200~500ms. The purpose of controlling the stepwise deflation rate and time here is to achieve changes in the tester's arterial blood vessels from closing to gradually opening to fully opening.

Furthermore, as a preferred embodiment of the present invention, when the finger cuff pressure is deflated in steps in step S4 in this application, the final pressure value in the step deflation is 50 mmHg. During the actual test process, 50mmHg basically corresponds to the fully open state of the tester's arterial blood vessels. Through the transition of the arterial blood vessels from the closed to the fully open stage, the envelope curve of the tester's pulse volume signal can be obtained.

Further preferably, the number of repetitions in the above-mentioned step S6 shall not be less than 3 times. The maximum amplitude PPG _max and finger mean arterial pressure MAP obtained through repeated tests can basically accurately represent the tester's accurate pulse volume signal and the mean arterial pressure difference at the finger.

Further preferably, in this application, the subject has finger cots at the bases of multiple fingers, and the PPG _maxi and MAPi at different fingers can be collected in the above step S6. Due to the inherent disadvantages of the volume clamp method, it requires continuous pressure on the fingers during the measurement process, which can easily lead to numbness of the fingers. On the one hand, it will cause discomfort to the tester, and on the other hand, it will affect the blood pressure test at the finger cuff. accuracy. Therefore, this application sets up multiple finger cots to test the blood pressure and pulse volume signals at the base of different fingers respectively, so as to alleviate the discomfort of the tester and improve the accuracy of the blood pressure test.

Further preferably, in step S8 of the present application, the blood pressure of the subject is calculated based on the error gain K _P , the integral gain K _I and the mean arterial pressure MAP of the finger under multiple measurements.

Specifically, the calculation methods of the above K _P and K _I are:

(Formula 1)

Among them, k ₁ ~ k ₅ here are all empirical coefficients. The final fingertip continuous blood pressure and brachial artery continuous blood pressure are mainly obtained through different blood pressure measurement methods, and then k ₁ ~ k ₅ are obtained through reverse derivation.

Further preferably, in this application, the continuous blood pressure FAP(t) of the subject's fingertip is calculated by the following method:

(Formula 2)

Among them, PPG (t) is the finger pulse volume signal under the current set pressure. In this application, the continuous blood pressure FAP(t) of the subject's fingertip is the change of the subject's fingertip blood pressure within the duration, so here PPG(t) is the pulse volume signal obtained through the envelope curve under the corresponding test pressure condition. .

Further preferably, in step S9, the continuous blood pressure of the subject's fingertip is corrected to the brachial artery continuous blood pressure waveform BAP(t) reconstructed by the FIR filter.

Further preferably, in the above step S9, the continuous blood pressure of the subject's fingertip is corrected to the continuous blood pressure waveform of the brachial artery by the following formula:

(Formula 3)

Among them, FAP_S and FAP_D are the peak and trough values of the fingertip pulse continuous blood pressure waveform respectively.

Further, as shown in Figure 6, the arterial pressure waveform is gradually conducted from the brachial artery to the finger artery. Due to the narrowing of the artery, the diastolic blood pressure decreases and the systolic blood pressure occasionally increases. Pulse wave distortion (mainly caused by reflections) and pressure gradients (caused by blood flow in the resistance vascular tree) can lead to differences in finger and brachial artery pressures that can limit the clinical application of finger pressure measurements. In this application, the brachial artery pressure wave can correct the waveform distortion caused by the arterial pressure waveform being transmitted from the brachial artery to the finger artery through a universal filter as shown in Figure 6 . Based on the amplitude-frequency response curve as shown in Figure 6, starting from the frequency domain, the FIR filter can be easily designed. The filter coefficients can be obtained using the fdatool toolbox of matlab, and finally the filtering function is implemented through the control unit to obtain the finger The corresponding central arterial pressure waveform under the arterial pressure waveform.

Further, Figure 7 shows the finger arterial pressure waveform FAP(t) before and after filtering and the reconstructed central arterial pressure waveform BAP(t). It can be seen from the digital artery blood pressure waveform and brachial artery blood pressure waveform reconstructed by the filter of this application that the two waveforms are roughly equivalent, eliminating the pressure gradient changes in the conduction process caused by arterial narrowing between the brachial artery and the digital artery. It corrects the distortion of the brachial artery blood pressure waveform, achieves stable measurement of the brachial artery blood pressure waveform through the finger artery blood pressure waveform, and accurately obtains the blood pressure waveform of the subject's brachial artery.

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements, etc., made within the spirit and principles of the present invention, All should be included in the protection scope of the present invention.

Claims (9)

1. A continuous non-invasive blood pressure measurement method, comprising the steps of:

s1, setting an upper arm sleeve and wearing the upper arm sleeve on an arm of a tested person to obtain arterial systolic pressure NIBP_S, arterial diastolic pressure NIBP_D and pulse pressure difference PP of the brachial artery of the tested person;

s2, arranging a fingerstall and wearing the fingerstall on the root of a finger of a tested person, and inflating the fingerstall to a first preset pressure;

s3, acquiring pressure at the finger stall and pulse volume signals at the finger when the pressure corresponds to the pressure;

s4, carrying out step-type deflation on the finger cuff pressure, and respectively obtaining the finger cuff pressure and pulse volume signals at corresponding pressure positions in each step section;

s5, obtaining an envelope curve according to the pulse volume signal in the step-type deflation, and obtaining the maximum amplitude PPG of the envelope curve _maxi Obtaining the maximum amplitude PPG _maxi The position corresponds to the finger cuff air pressure and is used as the mean arterial pressure MAPi of the finger;

s6, repeating the steps S2-S5 for a plurality of times to obtain the PPG under a plurality of pressure tests _maxi And MAPi, obtain PPG _maxi Average value PPG of (1) _max And MAPi average MAP;

s7, according to PPG _max And MAP adjusts and outputs to the air pressure of the finger stall, and the pulse pressure difference PP of the brachial artery is taken;

s8, according to PPG _max MAP and PP acquire continuous fingertip blood pressure FAP (t) of a tested person;

wherein the continuous fingertip blood pressure FAP (t) of the tested person is based on the average arterial pressure difference MAP and the error gain K at the finger _P And integral gain K _I Calculated, the K is _P And K is equal to _I The calculation mode of (a) is as follows:

(equation 1)

Wherein k is ₁ ~k ₅ Is an experience coefficient;

the FAP (t) is calculated by the following method:

(equation 2)

Wherein the PPG (t) is a pulse volume signal at the finger under the current set pressure;

s9, correcting the fingertip continuous blood pressure FAP (t) into a brachial artery continuous blood pressure waveform BAP (t) according to the NIBP_ S, NIBP _D serving as a calibration system.

2. The method according to claim 1, wherein the first preset pressure in the step S2 is 100-250 mmhg.

3. The method according to claim 2, wherein in the step S4, the step deflation rate is 3-10 mmhg/S each time, and the step deflation time is 200-500 ms each time.

4. A continuous non-invasive blood pressure measurement method according to any of claims 1 to 3, wherein, when the cuff pressure is step-deflated in step S4, the final pressure value in the step-deflation is 50mmHg.

5. The continuous non-invasive blood pressure measurement method according to claim 4, wherein the number of repeated tests in step S6 is not less than 3.

6. A continuous non-invasive blood pressure measurement method according to any of claims 1 to 3, wherein the root parts of a plurality of fingers of the subject are provided with finger cuffs, and the PPG is performed on different fingers in step S6 _maxi And MAPi.

7. The continuous non-invasive blood pressure measurement method according to claim 1, wherein the fingertip continuous blood pressure FAP (t) of the subject is corrected to the brachial artery continuous blood pressure waveform BAP (t) in step S9, and the continuous blood pressure waveform BAP (t) is reconstructed by an FIR filter.

8. The continuous non-invasive blood pressure measurement method according to claim 1, wherein the fingertip continuous blood pressure of the subject in step S9 is corrected to a brachial artery continuous blood pressure waveform by the following formula:

(equation 3)

Wherein FAP_S and FAP_D are respectively the wave crest and wave trough values of the fingertip continuous blood pressure waveform.

9. A continuous non-invasive blood pressure measuring apparatus for use in the measurement of the continuous non-invasive blood pressure measuring method as claimed in any one of claims 1 to 8, comprising:

the control unit is connected with the upper arm sleeve and the air valve module; the upper arm sleeve is used for testing the blood pressure and pulse pressure difference of the brachial artery; the air valve module is used for adjusting air pressure output according to the transmission signal of the control unit;

the air valve module is respectively connected with a first finger sleeve and a second finger sleeve, the first finger sleeve and the second finger sleeve have the same structure, and the first finger sleeve and the second finger sleeve are used for acquiring pulse volume signals of a tester under the air pressure supply of the air valve module.