CN100466968C - Detection method of Korotkoff sound delay and pulse wave transit time blood pressure monitor and signal generator using it - Google Patents

Abstract

The detection method of the Korotkoff sound delay and pulse wave transit time blood pressure monitor and the signal generator using it, through the digital synthesis technology, the data of respiration, ECG, pulse wave and Korotkoff sound signals stored in the computer in advance are output as Various analog signals; and a cuff pulse wave pressure generating device controlled by a computer is set. According to the principle of detecting blood pressure by Korotkoff sound delay and pulse wave transit time, the relative amplitude of necessary signals and the relationship between various signals are determined. Relationship, form the simulated human body signal required for the detection process of the blood pressure monitor, and the Korotkoff sound delay time and pulse wave transit time signals that conform to the above principles, input these signals into the blood pressure monitor, and check whether the detection results of the blood pressure monitor are consistent with The setting data of the signal generator match. The invention can output a variety of analog signals that are coordinated with each other and conform to a certain relationship, and can detect the monitor that monitors the blood pressure of the human body by measuring the Korotkoff sound delay time and the pulse wave transit time.

Description

Detection method of Korotkoff sound delay and pulse wave transit time blood pressure monitor and signal generator using it

technical field

The invention belongs to a detection method and device for medical equipment, in particular to a detection method and device for an arterial blood pressure monitoring device.

Background technique

In the field of blood pressure measurement technology, it is generally accepted that pulse wave transit time can be used as a non-invasive and continuous method for measuring blood pressure. In 1922, it was discovered that pulse wave velocity (PWTV) or conduction time (PWTT) was related to arterial blood pressure, and also related to blood vessel volume and blood vessel wall elasticity; in 1957, it was proposed that within a certain range, PWTT and arterial pressure There is a linear relationship between blood pressure and BP. The relationship between PWTT and beat-to-beat arterial blood pressure BP can be expressed as:

BP=a+b*PWTT...(A)

Among them, BP is arterial blood pressure, PWTT is pulse wave transit time, a and b are undetermined regression coefficients, the size of a and b varies from person to person, but the same individual can determine this value in a short period of time. Individualized regression technology corrects the undetermined coefficients a and b, which can realize the continuous measurement of pulse wave transit time PWTT to estimate the continuous arterial blood pressure BP of each individual, but there is no good method for the correction of this regression coefficient.

The applicant of this patent discovered for the first time that there is a corresponding relationship between the Korotkoff sound delay time and the blood pressure of the human body. When the traditional auscultation method (also known as the Korotkoff sound method) measures blood pressure, the cuff needs to be pressurized to exceed the systolic pressure. At this time, the arterial wall under the cuff is compressed and closed, and no blood flows through the blood vessel. Then start to deflate slowly, see Figure 1. When the cuff pressure drops slightly below the systolic pressure, the first Korotkoff sound begins to appear, which corresponds to the opening moment of the artery. The following rules have been found through research: In a series of arterial opening moments, the first Korotkoff sound T1 is the farthest from the ECG R wave, and the subsequent Korotkoff sounds are closer and closer to the ECG R wave T2, T3... until the last Korotkoff sound It reaches the minimum value when the sound is pronounced. Similarly, if the rising point of the pulse wave in the cuff is used as a reference point (see Figure 2), the Korotkoff sound delay time TK can be defined as the time between the rising point of the pulse wave in the cuff and the place where the Korotkoff sound appears, Similarly, as the cuff pressure P decreases, the Korotkoff sound delay times T1, T2, T3... in each cardiac cycle become smaller and smaller. The reason for the above phenomenon is that the rise of the pressure wave in the artery is not a vertical rise, but a gradual process, so as the pressure in the cuff drops, the arterial wall opens earlier and earlier in each cardiac cycle. The Korotkoff sound is produced earlier and earlier, so relative to the fixed reference point in each corresponding cycle (such as the heart wave R or the rising point of the pulse wave in the cuff or other fixed reference points set), the Korotkoff sound Latency is also getting shorter. After research, it is also found that the change of the Korotkoff sound delay time caused by the change of cuff pressure when the blood pressure is constant is highly related to the change of the Korotkoff sound delay time caused by the change of blood pressure when the cuff pressure is constant, which can be approximated to the same size and direction. on the contrary.

According to the above research results, in the patent application No. ZL200510071813.0 and PCT/CN2005/001210, the applicant of this patent proposed to use the parameter of Korotkoff sound delay time to obtain the aforementioned individualized undetermined regression coefficients a and b A method for estimating each individual's continuous arterial blood pressure BP using continuous measurement of the pulse wave transit time PWTT can be realized. This patent application also discloses a device for non-invasive and continuous detection of beat-by-beat arterial blood pressure using this method. During this process, the arrival time of the Korotkoff sound is detected by the Korotkoff sound sensor and input to the microprocessor, and the cardiac cycle signal is synchronously input to the microprocessor through the ECG electrode and the electrocardiogram circuit, thereby The time interval T _K value from the fixed reference point of each cardiac cycle (it can be the ECG R wave, or the starting point of the pulse wave in the cuff, etc.) to the starting point of the Korotkoff sound in this cycle can be measured, thus obtaining The function T _K (P) of Korotkoff sound delay time with the change of cuff pressure; in the actual measurement, the pressure P in the cuff is kept at a known state by the cuff pressure controller, and the known cuff Under pressure (Pm) conditions, measure the Korotkoff sound delay time (T _K ) value, according to the change of Korotkoff sound delay time caused by the change of cuff pressure when the blood pressure is constant, and the Korotkoff sound delay time caused by the change of blood pressure when the cuff pressure is constant The magnitude of the change in the delay time of the gratuitous sound is the same, and the direction is opposite. The blood pressure change in each cardiac cycle of TK is calculated relative to the blood pressure when the initial measurement (that is, when the T _K (P) function is obtained). The addition of the average blood pressure values measured during the _K (P) function is the actual blood pressure value of the cardiac cycle, and the undetermined coefficient b of the aforementioned equation A can also be determined by using this instrument.

The above-mentioned invention proposes a brand-new concept of arterial blood pressure measurement. Like other medical equipment, the above-mentioned blood pressure monitoring device also needs to be calibrated with corresponding detection instruments when manufacturing the above-mentioned blood pressure monitoring device. However, the existing ECG signal generator, blood pressure Devices such as signal generators cannot meet the requirements of the above-mentioned blood pressure monitor for multi-signal and multi-signal coordination and certain relationship.

Contents of the invention

The present invention aims to solve the above problems, and provides a detection method of Korotkoff sound delay and pulse wave transit time blood pressure monitor and a signal generator using it. The analog signal is used to detect the aforementioned monitor that monitors human blood pressure by measuring the Korotkoff sound delay time and pulse wave transit time.

For reaching above-mentioned purpose, the inventive method comprises the following content:

Set up a signal generating device with a computer as the central controller, and output the data of respiration, ECG, pulse wave, and Korotkoff sound signals pre-stored in the computer into corresponding respiration, ECG, pulse wave, and Korotkoff sound signals through digital synthesis technology. The analog signal of the Gross sound;

A cuff pulse wave pressure generating device controlled by a computer is set to generate a simulated cuff pulse wave pressure signal;

The data to be detected by the blood pressure monitor is set as a known quantity by the computer, according to the formula of the linear relationship between the pulse wave transit time and the arterial blood pressure BP: BP=a+b*PWTT, wherein: BP is the blood pressure value; a , b is the individual regression coefficient, PWTT is the pulse wave transit time; and according to the change of the Korotkoff sound delay time caused by the cuff pressure change when the blood pressure is constant, and the Korotkoff sound delay caused by the blood pressure change when the cuff pressure is constant Based on the principle that the time changes are the same in size and opposite in direction, determine the relative amplitude of various signals and the timing phase relationship between the signals, simulate the human body signal required for the detection process of the blood pressure monitor, and the pulse that conforms to the above formula and principle relationship The wave conduction time and Korotkoff sound delay time signals are input to the blood pressure monitor to check whether the detection result of the blood pressure monitor is consistent with the set data of the signal generating device.

The further scheme of the inventive method comprises:

The signal generating device outputs a signal expressing the pulse wave transit time (PWTT) in the following way: by controlling the time interval between two characteristic points expressing the pulse wave transit time in each cardiac cycle to output the corresponding pulse wave For the transit time signal, the pulse wave transit time PWTT of the known blood pressure setting is determined by the following formula:

PWTT=(BP-a)/b

Among them: BP is the set blood pressure value; a and b are the set regression coefficients.

The further scheme of the inventive method comprises:

Output the signal expressing the Korotkoff sound delay time (T _K ) as follows:

In each cardiac cycle, the Korotkoff sound delay time is expressed by controlling the time interval from the fixed reference point to the Korotkoff sound arrival moment. The Korotkoff sound delay time (T _K ) is based on the set blood pressure value and the cuff Real-time pressure value, as well as the relationship curve between Korotkoff sound delay time and blood pressure stored in the computer.

The further scheme of the inventive method comprises:

Output the cuff pulse wave signal when simulating oscillometric blood pressure measurement as follows:

Inflate the cuff of the blood pressure monitor to be measured to be greater than the systolic pressure, and then gradually deflate and decompress. The signal generating device controls the cuff pulse wave generating device to generate an analog oscillometric blood pressure measurement according to the pressure change value of the cuff. The cuff pulse wave pressure signal, the change law is: when the cuff pressure drops from greater than the systolic pressure to less than the diastolic pressure, the pulse amplitude of the simulated cuff pulse wave increases gradually until the cuff pressure is equal to the mean pressure, The amplitude reaches a maximum, and then, as the cuff pressure decreases, the pulse amplitude gradually decreases.

The structure of the device of the present invention is: a central control computer is provided, and it is characterized in that: a memory for storing data including electrocardiogram, pulse wave, respiration and Korotkoff sound waveform is provided, and the computer passes a digital/analog converter and an analog The signal conditioning circuit is connected with the human body analog signal output end; a cuff pulse wave pressure signal generating device controlled by a computer is also provided, and the cuff pulse wave pressure signal generating device is connected with the pressure signal output end.

For the blood pressure monitor that monitors the blood pressure of the human body according to the Korotkoff sound delay time and pulse wave transit time, the method and device of the present invention can generate a variety of analog signals that can meet the requirements of the monitoring process of the blood pressure monitor and conform to the corresponding relationship. In order to realize the detection of such instruments.

The further solution of the present invention can generate signals expressing characteristic parameters such as pulse wave propagation time, Korotkoff sound delay time, and oscillometric cuff pulse wave variation law, and complete the monitoring of the human body through the pulse wave propagation time and Korotkoff sound delay time. Performance testing of relevant instruments for taking arterial blood pressure.

Description of drawings

Figure 1. Schematic diagram of the Korotkoff sound delay time T _K when the cuff pressure P drops and the R wave of the electrocardiogram is used as a reference point

Figure 2. Schematic diagram of the Korotkoff sound delay time TK when the cuff pressure P drops, taking the rising starting point of the pulse wave in the cuff as a reference point

Fig. 3, block schematic diagram of embodiment of arterial blood pressure measurement device

Fig. 4, the structure schematic diagram of the embodiment of the Korotkoff sound delay and pulse wave transit time signal generator of the present invention

Fig. 5, the cuff pulse wave signal generation schematic diagram of the present invention method

Fig. 6, the schematic diagram of pulse wave transit time PWTT signal output mode of the present invention method

Fig. 7, the schematic diagram of the signal waveform generated by the detection method of the blood pressure monitor in working mode 1-2 of the method embodiment of the present invention

Fig. 8. The functional relationship diagram of Korotkoff sound delay time T _K as the cuff pressure drops and the fitted quadratic T _K (P) curve

Fig. 9. The curve diagram of dT _K /dP obtained according to the T _K (P) fitting curve shown in Fig. 8 along with the cuff pressure P

Fig. 10 is a schematic diagram of the signal waveform generated by the detection method of the blood pressure monitor in working mode 2-2 of the method embodiment of the present invention

Figure 11: Schematic diagram of the signal waveform generated by the detection of the blood pressure monitor in working mode 3-2 of the method embodiment of the present invention

specific implementation plan

Example 1

This example is a kind of device that adopts the method of the present invention-the Korotkoff sound delay time and pulse wave transit time signal generator.

The structure of this device is shown in Figure 4: it is provided with a central control single-chip microcomputer, a memory for storing data including ECG, pulse wave, respiration, and Korotkoff sound waveform, and the single-chip microcomputer communicates with Human body analog signal output connection;

The structure of the cuff pulse wave pressure signal generating device in this example is as follows: an air storage device is provided, its input end is connected with an inflatable motor controlled by a single-chip microcomputer, and the output end is connected with the cuff through an air circuit switch controlled by a single-chip microcomputer.

The generation method of physiological signal adopting this device is:

Respiration, ECG, pulse wave, Korotkoff sound delay time and other signals are generated by digital synthesis technology. The details are as follows: store the signals of one period of respiration, ECG, pulse wave and Korotkoff sound signal on the single-chip microcomputer in advance according to a certain respiration rate and heart rate, and then interpolate and generate the single-period data of each waveform according to the set heart rate and respiration rate. Periodic cycle output and D/A conversion to obtain continuous analog waveforms of each signal. After each signal is adjusted by the conditioning circuit, the signal that can be used by the blood pressure monitoring instrument is outputted, and the amplitude of each signal and the time sequence phase relationship among them are controlled by the computer.

The formation method of cuff pulse wave is (referring to Fig. 5):

After inflating the cuff and air storage tank of the signal generator through the detected blood pressure monitoring instrument, the gas circuit switch is turned off. In a cardiac cycle, the single-chip microcomputer controls the motor to inflate the air storage tank. The air pressure increase range of the air storage tank. After the inflation is completed, according to the program setting at a specific moment in the next cardiac cycle, the gas circuit switch is turned on. The gas follows the pressure difference and enters the cuff from the air storage tank. When the pressure at both ends is basically equal, Turn off the air circuit switch, then open the slow deflation valve of the cuff to release the gas flowing into the cuff from the gas storage tank (when the cuff pressure is equal to the pressure before inflation, close the deflation valve), thus the cuff The pressure produces a pulse change that can be used to simulate a cuff pulse wave. In the above process, after turning off the air circuit switch, turn on the motor to inflate the air storage tank, wait for the next cardiac cycle, open the air circuit switch, repeat the action, and the amplitude and output timing phase of the cuff pulse wave are controlled by the computer.

Example 2

This example is several specific implementation working modes of the method of the present invention.

Aiming at several main detection processes of blood pressure monitoring using Korotkoff sound delay time and pulse wave transit time disclosed in ZL200510071813.0 and PCT/CN2005/001210 patent applications, this example sets several working modes suitable for different detection processes. The following describes them one by one:

1. This working mode is aimed at the following detection process of the blood pressure monitor: After the blood pressure monitor obtains the PWTT coefficients a and b in the calculation formula, it calculates the blood pressure value BP by measuring PWTT.

1-1. Brief description of the detection process of the blood pressure monitor:

According to the relationship between PWTT and beat-by-beat arterial blood pressure BP:

BP=a+b*PWTT...(A)

Where BP is arterial blood pressure, PWTT is pulse wave transit time, and a and b are regression coefficients

After obtaining the regression coefficients a and b in the formula, the blood pressure monitor measures the pulse wave transit time of the human body beat by beat, thereby obtaining the beat-by-beat arterial blood pressure BP of the human body.

1-2. For the detection process of the above 1-1 of the blood pressure monitor, this working mode uses the signal generator to generate a standard signal that simulates the pulse wave transit time of the human body beat by beat. The method is:

First set a blood pressure value, the signal generator outputs the corresponding pulse wave transit time signal according to this set value, the generation method of the pulse wave transit time is:

Referring to Figure 6, the pulse wave transit time (PWTT) is expressed by the time interval from the peak value of the ECG R wave to the starting point of the pulse wave signal, and the timing starts from the output of the ECG R wave. When the pulse wave transit time of the set blood pressure is reached, Output the starting point of the pulse wave and subsequent waveforms. The pulse wave transit time for setting blood pressure is determined by the following formula:

PWTT=(BP-a)/b

Among them: BP is the set blood pressure value; a, b are the set coefficients.

In this working mode, the signal generator generates signals such as ECG, respiration, and pulse wave, simulating the time relationship between human ECG and pulse wave under normal conditions and when the blood pressure value is stable, and expressing the simulated pulse wave conduction by the above method Time, the signal is input to the blood pressure monitor, which can detect whether the PWTT calculated by the blood pressure monitor and the blood pressure value BP are consistent with the value set by the signal source, so as to judge the performance of the blood pressure monitor.

The schematic diagram of each signal waveform generated in this 1-2 working mode is shown in Figure 7, wherein the amplitude of each signal can remain unchanged, and only the pulse wave transit time PWTT can be expressed through the timing phase relationship between ECG and pulse wave.

2. This working mode is aimed at the following detection process of the blood pressure monitor: the blood pressure monitor obtains the Korotkoff sound delay time function curve and obtains the systolic blood pressure, diastolic blood pressure and mean pressure calculated by the oscillometric method through the cuff pulse wave.

2-1. Brief description of the detection process of the blood pressure monitor:

—Fix the cuff and the sensor at the far end of the cuff on the upper arm of the subject, use the oscillometric method to obtain the systolic blood pressure, diastolic blood pressure and mean arterial blood pressure BP ₀ of the subject, and record the synchronized pulse wave propagation time PWTT ₀ ;

-A series of Korotkoff sound delay times T and corresponding cuff pressure P values (seeing Fig. 1) obtained in the complete deflation process of the cuff form a function T _K (P); to form the discrete data of this function Quadratic curve fitting obtains a T _K (P) fitting curve (see Fig. 8) of a Korotkoff sound delay time T changing with the cuff pressure P, and calculates the difference to the above T _K (P) fitting curve to obtain When the unit pressure (1mmHg) changes, the corresponding Korotkoff sound delay time changes to form a new function sequence g(P) (see Figure 9).

After obtaining the above individualized functional relationship, according to the change of the delay time of the Korotkoff sound caused by the change of the cuff pressure when the blood pressure is constant, the change of the delay time of the Korotkoff sound caused by the change of the blood pressure when the cuff pressure is constant has the same size and opposite direction This principle can convert the variation of the Korotkoff sound delay time T _Km obtained under a certain cuff pressure Pm into the corresponding variation of arterial blood pressure (according to g(Pi)=dT _K /dP=dT _K / dBpi calculation)

2-2. For the above-mentioned 2-1 detection process of the blood pressure monitor, this working mode generates the Korotkoff sound delay time function curve simulating the human body and the cuff pulse wave signal for the oscillometric method through the signal generator. The method is :

The signal generator generates signals such as ECG, respiration, pulse wave, Korotkoff sound, etc. Simultaneously, the simulated cuff pressure pulse wave is generated, and the computer coordinates the signals to generate the Korotkoff sound delay time function curve and Cuff pulse wave signal for oscillometric method;

The generation method of the oscillometric cuff pulse wave is:

The process of inflating the cuff greater than the systolic pressure and gradually deflation is realized by the blood pressure monitoring instrument. After the blood pressure monitoring instrument is inflated and gradually deflated, the signal generating device is controlled by a computer to generate the cuff pulse wave; this example adopts the method of Example 1 The cuff pulse wave generating device, the change of the cuff pulse wave amplitude is controlled by the length of the pumping time of the control motor. The longer the pumping time, the greater the pressure difference and the larger the pulse amplitude; the shorter the pumping time, the smaller the pressure difference. The smaller the pulse amplitude;

The computer of the signal generator controls the change amplitude of the cuff pulse wave according to the following rules according to the real-time cuff pressure value of the blood pressure monitor: when the cuff pressure drops from greater than the systolic pressure to less than the diastolic pressure, the The pulse amplitude generated by pulse pulsation gradually increases until the cuff pressure is equal to the average pressure, and the amplitude reaches the maximum. Then, as the cuff pressure decreases, the pulse amplitude gradually decreases; Algorithm, when the cuff pressure is equal to the systolic pressure, the pulse wave amplitude of the cuff is 50% of the average pressure; when the average pressure is reached, the pumping time is the longest and the pulse generated is the largest; when the cuff pressure is equal to the diastolic pressure, the pulse wave amplitude is 75% of mean pressure time.

The Keshi tone delay time T _K signal is output in the following way:

The Korotkoff sound delay time T _K signal is expressed by the time interval from the starting point of the cuff pulse wave to the arrival time of the Korotkoff sound, and the timing starts from the starting point of the output cuff pulse wave. When the Korotkoff sound delay time of the set blood pressure is reached, Output the starting point of the Korotkoff sound signal and subsequent waveforms. Referring to FIG. 2 , the Korotkoff sound delay time T _K is obtained by looking up the relationship curve between blood pressure and Korotkoff sound delay time stored in the computer according to the set blood pressure value and the real-time pressure value in the cuff.

The process is as follows: first, the Korotkoff sound delay time function curve is sampled and then stored in the memory of the single-chip computer. Different processing is performed according to the different modes set to obtain the corresponding Korotkoff sound delay time.

For this 2-2 working mode: according to the pre-set blood pressure systolic pressure and diastolic pressure value, systolic blood pressure corresponds to the maximum value of Korotkoff sound delay, diastolic pressure corresponds to the minimum value of Korotkoff sound delay, and the curve is proportional to the pressure Divide to obtain the relationship curve between blood pressure and delay time, and store it in the single-chip computer in the form of a list. When the real-time pressure of the cuff is greater than the systolic pressure, no Korotkoff sound signal is generated. When the cuff pressure is between the systolic pressure and the diastolic pressure, Look up the table in the stored relationship curve between blood pressure and delay time to obtain the corresponding Korotkoff sound delay time. When the cuff pressure is lower than the diastolic pressure, the Korotkoff sound delay time is constant and equal to the Korotkoff sound delay time when the diastolic pressure is reached.

The schematic diagram of each signal waveform generated in this 2-2 working mode is shown in FIG. 10 .

After the signal generated by the above method is input into the blood pressure monitor, the blood pressure monitor can calculate the Korotkoff sound delay time function curve through the aforementioned 2-1 detection process, and obtain the systolic and diastolic blood pressure calculated by the oscillometric method through the cuff pulse wave The reliability of the blood pressure monitor can be checked by comparing these calculation results with the Korotkoff sound delay time function curve set by the signal generating device, the systolic pressure, diastolic pressure, and average pressure of blood pressure.

3. This working mode is aimed at the following detection process of the blood pressure monitor:

The delay time determines the regression coefficient b in the formula BP=a+b*PWTT.

3-1. Brief description of the testing process of the blood pressure monitor being tested:

The cuff pressure is roughly controlled at the average pressure level between the systolic pressure and the diastolic pressure, and the delay time series of beat-by-beat Korotkoff sounds and the pulse wave propagation time corresponding to each delay time are obtained; during the measurement process, let The subject takes deep breaths continuously, randomly takes out two sets of data, and calculates the delay time change ΔT between two points;

According to the function sequence T _K (P) obtained from the aforementioned Korotkoff sound delay time function curve (see Figure 8), the difference is calculated for the T _K (P) fitting curve, and the corresponding Korotkoff sound when the unit pressure (1mmHg) changes is obtained The change of the delay time (see Figure 9) forms a new function sequence g(P), obtains the g value under the corresponding cuff pressure, and estimates the arterial blood pressure variation ΔBP1 between these two points and the synchronous pulse wave propagation time ΔPWTT1, the regression coefficient b1=ΔBP1/ΔPWTT1 can be obtained.

3-2. For the above 3-1 detection process of the blood pressure monitor, this working mode generates ECG, respiration, pulse wave, Korotkoff sound and other signals through the signal generator, and generates analog cuff pressure pulse wave; The relationship between each signal when the belt pressure is stabilized between the systolic and diastolic pressures, and the blood pressure changes caused by deep breathing.

The specific relationship of each signal is: the amplitude of the Korotkoff sound delay time signal and the cuff pulse wave signal is determined by the cuff pressure, the amplitude of the ECG, respiration and pulse wave signals remains unchanged, and the blood pressure signal BP is modulated by respiration, simulating When the blood pressure changes during deep breathing, the pulse wave propagation time changes accordingly with the blood pressure. When the cuff pressure is between the systolic pressure and the diastolic pressure and remains basically constant, the delay time signal of the Korotkoff sound delay time according to the cuff pressure Time rate of change to produce corresponding changes.

The specific modulation method is: in each cardiac cycle (R wave peak value), detect the respiratory signal amplitude at this time, and then generate a blood pressure variation ΔBP proportional to the respiratory amplitude. As mentioned above, the pulse wave transit time changes according to the change of ΔBP, and the Korotkoff sound delay time also changes according to the change of ΔBP, that is, the pulse wave transit time and the Korotkoff sound delay time will change synchronously according to the breathing, Thus, the change process of pulse wave transit time and Korotkoff sound delay time caused by the change of blood pressure caused by deep breathing is simulated.

The process is as follows: first, the Korotkoff sound delay time function curve is sampled and then stored in the memory of the single-chip computer. Different processing is performed according to the different modes set to obtain the corresponding Korotkoff sound delay time. For this 3-2 working mode: first, store the difference curve of blood pressure and Korotkoff sound delay time on the single-chip microcomputer, that is, under a certain pressure, the change amount of Korotkoff sound delay time caused by the change of unit pressure, at the same time, as mentioned above 2-2 The method described in the working mode obtains the relationship curve between the blood pressure and the Korotkoff sound delay time. The cuff pressure at this time is between the systolic and diastolic pressures, close to the mean pressure. At this time, the pressure value BP for calculating the pulse wave transit time PWTT is the blood pressure value at the real-time pressure of the cuff plus the variation ΔBP proportional to the amplitude of the respiratory signal corresponding to the peak value of the R wave in this cycle; and thus calculate the corresponding Pulse wave transit time PWTT. Look up the corresponding Korotkoff sound delay time Tkb from the real-time pressure value of the cuff in the relationship curve Tk(P) of the blood pressure and the Korotkoff sound delay time, and then look up the table on the differential curve to obtain the Korotkoff sound corresponding to the real-time pressure value of the cuff The variation of the Korotkoff sound delay time, and the product of the Korotkoff sound variation and ΔBP to obtain ΔTk, and the finally obtained Korotkoff sound delay time corresponding to the cycle is the sum of ΔTk and Tkb. In this way, the variation of Korotkoff sound delay time caused by breathing can be simulated.

After inputting the signal generated by the above method into the blood pressure detection instrument, the blood pressure monitoring instrument can calculate the coefficient b in the calculation formula of the pulse wave transit time PWTT according to the signal detected by the detection process 3-1, and then combine the working mode 2-1 to calculate Coefficient a. Comparing the two coefficients with the set value of the signal source can test the accuracy of the blood pressure monitoring instrument.

The schematic diagram of each signal waveform generated in this 3-2 working mode is shown in FIG. 11 .

Example 3

The difference from embodiment 2 is that in the 2-2 working mode, embodiment 2 expresses the Korotkoff sound delay time T _K signal with the time interval from the cuff pulse wave starting point to the Korotkoff sound arrival moment, and this example is The Korotkoff sound delay time T _K signal is expressed by the time interval from the peak value of the ECG R wave to the arrival time of the Korotkoff sound (see Figure 1). The timing starts from the peak value of the R wave of the ECG. When the Korotkoff sound delay time of the set blood pressure is reached , output the starting point of the Korotkoff sound signal and subsequent waveforms.

In this example, the relationship curve T _K (P) between the Korotkoff sound delay time and blood pressure is stored in the computer, and the setting method is: describe the relationship between the Korotkoff sound delay time and blood pressure by several parameters and an equation The relationship curve T _K (P) of the known curve T _{K (P) is pre-stored in the equation parameters of the known curve T K} (P). When the real-time pressure of the cuff is greater than the systolic pressure, no Korotkoff sound signal is generated; when the cuff pressure is between the systolic pressure and When the diastolic pressure is between, the corresponding Korotkoff sound delay time is calculated according to the cuff pressure value and the equation parameter of the curve T _K (P); when the cuff pressure is less than the diastolic pressure, the Korotkoff sound delay time is constant, equal to Korotkoff sound delay time in diastolic pressure.

Claims (10)

1. The detection method of Korotkoff sound delay and pulse wave transit time blood pressure monitor is characterized in that: the signal generating device with computer as the central controller is set, and the respiration, electrocardiogram, The data output of pulse wave and Korotkoff sound signal is the corresponding analog signal of respiration, ECG, pulse wave and Korotkoff sound; A cuff pulse wave pressure generating device controlled by a computer is set to generate a simulated cuff pulse wave pressure signal; The data to be detected by the blood pressure monitor is set as a known quantity by the computer, according to the formula of the linear relationship between the pulse wave transit time and the arterial blood pressure BP: BP=a+b*PWTT, wherein: BP is the blood pressure value; a , b is the individual regression coefficient, PWTT is the pulse wave transit time; and according to the change of the Korotkoff sound delay time caused by the cuff pressure change when the blood pressure is constant, and the Korotkoff sound delay caused by the blood pressure change when the cuff pressure is constant Based on the principle that the time changes are the same in size and opposite in direction, determine the relative amplitude of various signals and the timing phase relationship between the signals, simulate the human body signal required for the detection process of the blood pressure monitor, and the pulse that conforms to the above formula and principle relationship The wave conduction time and Korotkoff sound delay time signals are input to the blood pressure monitor to check whether the detection result of the blood pressure monitor is consistent with the set data of the signal generating device. 2. The method according to claim 1, characterized in that: the signal generating device outputs the signal expressing the pulse wave transit time PWTT according to the following method: by controlling two signals expressing the pulse wave transit time in each cardiac cycle The time interval between the feature points is used to output the corresponding pulse wave transit time signal. It is known that the pulse wave transit time PWTT of the set blood pressure is determined by the following formula: PWTT=(BP-a)/b Among them: BP is the set blood pressure value; a and b are the set regression coefficients. 3. The method according to claim 2, characterized in that: the pulse wave transit time PWTT is expressed by the time interval from the peak value of the electrocardiographic R wave to the starting point of the pulse wave signal, and the timing starts from the output of the electrocardiographic R wave. When the pulse wave transit time of the blood pressure is determined, the pulse wave starting point and subsequent waveforms are output. 4. The method according to claim 1, characterized in that: comprising outputting a signal expressing the Korotkoff sound delay time TK according to the following method: In each cardiac cycle, the Korotkoff sound delay time is expressed by controlling the time interval from the fixed reference point to the Korotkoff sound arrival moment. The Korotkoff sound delay time TK is based on the set blood pressure value and the real-time pressure value in the cuff , and the relationship curve TK(P) between the Korotkoff sound delay time and blood pressure stored in the computer is obtained. 5. The method according to claim 4, characterized in that: the Korotkoff sound delay time TK signal is expressed by the time interval from the starting point of the cuff pulse wave or the peak value of the ECG R wave to the arrival moment of the Korotkoff sound, and is output by the cuff The starting point of the pulse wave or the peak value of the ECG R wave starts timing, and when the Korotkoff sound delay time of the set blood pressure is reached, the starting point and subsequent waveforms of the Korotkoff sound signal are output. 6. The method according to claim 4, characterized in that: the relationship curve TK(P) between the Korotkoff sound delay time and blood pressure is stored in the computer, and the setting method is: according to the preset blood pressure For systolic blood pressure and diastolic pressure, systolic blood pressure corresponds to the maximum value of Korotkoff sound delay, diastolic pressure corresponds to the minimum value of Korotkoff sound delay, and the curve is divided according to the pressure equal ratio to obtain the relationship curve between blood pressure and delay time, and store it in the microcontroller In , when the real-time pressure of the cuff is greater than the systolic pressure, no Korotkoff sound signal is generated. When the cuff pressure is between the systolic pressure and the diastolic pressure, look up the table in the relationship curve between the stored blood pressure and the delay time, and obtain the corresponding The delay time of the Korotkoff sound, when the cuff pressure is less than the diastolic pressure, the delay time of the Korotkoff sound is constant and equal to the delay time of the Korotkoff sound at the diastolic pressure. 7. The method according to any one of claims 1-6, characterized in that: it includes outputting the cuff pulse wave signal when the analog oscillometric method is used to measure blood pressure according to the following method: Inflate the cuff of the blood pressure monitor to be measured to be greater than the systolic pressure, and then gradually deflate and decompress. The signal generating device controls the cuff pulse wave generating device to generate an analog oscillometric blood pressure measurement according to the pressure change value of the cuff. The cuff pulse wave pressure signal, the change law is: when the cuff pressure drops from greater than the systolic pressure to less than the diastolic pressure, the pulse amplitude of the simulated cuff pulse wave increases gradually until the cuff pressure is equal to the mean pressure, The amplitude reaches a maximum, and then, as the cuff pressure decreases, the pulse amplitude gradually decreases. 8. The method according to any one of claims 1-6, characterized in that: the determination of the specific relationship of each signal by the computer includes the following content: the blood pressure signal BP is modulated by the respiratory signal to simulate the breathing When the blood pressure changes, the pulse wave propagation time changes accordingly; when the cuff pressure is between the systolic pressure and the diastolic pressure and remains basically constant, the Korotkoff sound delay time signal changes according to the delay time change rate of the cuff pressure to produce corresponding changes; The method of modulating the blood pressure signal by the breathing signal is as follows: in each cardiac cycle, detecting the amplitude of the breathing signal at this time, and then generating a blood pressure variation ΔBP proportional to the breathing amplitude. 9. The signal generator applying the method of any one of claims 1-8 is provided with a central control computer, characterized in that it is provided with a computer for storing ECG, pulse wave, respiration, and Korotkoff sound waveforms. The computer is connected to the analog signal output terminal of the human body through a digital/analog converter and an analog signal conditioning circuit; a cuff pulse wave pressure signal generating device controlled by a computer is also provided, and the cuff pulse wave pressure signal generating device is connected with the pressure Signal output connection. 10. The signal generator according to claim 9, characterized in that: the structure of the cuff pulse wave pressure signal generating device is: an air storage device is provided, and its input end is connected with an inflatable motor controlled by a single-chip microcomputer, and the output The end is connected with the cuff through an air circuit switch controlled by a single-chip microcomputer.

Images