CN100346740C - Blood pressure measuring device based on radial artery pulse information - Google Patents

Abstract

The present invention provides a device for measuring arterial blood pressure using radial artery pulse information. The device comprises: an electrocardiogram signal acquisition module for acquiring electrocardiogram signals of a human body; a radial artery pulse signal acquisition module for acquiring radial artery pulse signals of a human body; a signal preprocessing module, which is electrically connected to the electrocardiogram signal acquisition module and the radial artery pulse signal acquisition module, and is used to preprocess the signals from the electrocardiogram signal acquisition module and the radial artery pulse signal acquisition module; a blood pressure measurement calibration module, which is used to provide calibration parameters for blood pressure measurement; and a microprocessor module, which is electrically connected to the signal preprocessing module and the blood pressure calibration module. The device can perform continuous, long-term, cuff-free, non-invasive continuous measurement of arterial blood pressure.

Description

Blood pressure measuring device based on radial artery pulse information

technical field

The invention relates to the field of blood pressure measurement, in particular to a non-invasive measuring device for continuously measuring arterial blood pressure, which can estimate the blood pressure value through time information extracted from radial artery pulse signals and electrocardiographic signals.

technical background

Measuring blood pressure is a basic method for understanding health conditions and observing conditions, especially for middle-aged and elderly people suffering from cardiovascular diseases.

There are two types of blood pressure measurement: invasive and non-invasive. Invasive measurement is a direct measurement method in which a catheter is inserted into the artery and the arterial pressure is measured through a transducer connected to a fluid column. This method needs to be operated by professional medical personnel, is expensive, and easily causes medical risks such as bacterial infection and blood loss.

Non-invasive measurement is an indirect measurement method. The method is safe, convenient and comfortable to use, and is currently a commonly used method for measuring blood pressure in hospitals. This method is also increasingly used at home by patients who require long-term monitoring of blood pressure. Due to the growing public awareness of high blood pressure as a serious health hazard and the importance of early diagnosis and treatment, the number of consumers using non-invasive blood pressure monitors continues to grow.

There are three main methods of non-invasive measurement: pulse sphygmomanometer, tone-determining sphygmomanometer, and photoplethysmography sphygmomanometer.

There are two measurement methods of the pulse sphygmomanometer, one is the auscultation method and the other is the oscillation method. The principle of auscultation is to collect Korotkoff sounds, and the whole device includes an inflatable and deflated cuff, a mercury manometer (electronic pressure sensors are also used in recent years) and a stethoscope. When measuring upper extremity blood pressure, expel the gas in the cuff first, then wrap the cuff around the upper arm flat and without folds, feel the pulse of the brachial artery, place the chest piece of the stethoscope there, turn on the mercury column switch, and when it passes through When the balloon with the live valve is inflated to the cuff, the mercury column or the watch hands will move immediately. When the mercury column rises to the preset value, the inflation will stop. Then, the balloon valve will be slightly opened to deflate slowly, and the mercury column will slowly When the mercury column or the pointer moves, you should observe the scale of the mercury column or the movement of the watch needle. If you hear the first sound of the brachial artery, the scale shown is the systolic blood pressure, referred to as the systolic blood pressure; when the mercury column drops to the point where the sound suddenly becomes weaker Or when you can't hear it, the scale indicates diastolic blood pressure, referred to as diastolic blood pressure. However, this method can only determine systolic and diastolic blood pressure and is not suitable for some patients with weak or inaudible 5th Korotkoff sound.

The oscillation method can make up for the above-mentioned shortcomings of the auscultation method, and blood pressure can also be measured for patients with weak Korotkoff sounds. When in use, wrap the cuff around the upper arm flat and without pleats, and inflate and deflate the cuff. Blood pressure values are determined by measuring the amplitude of pressure oscillations in the inflated cuff, which are caused by the constriction and dilation of arterial vessels. Values for systolic, mean and diastolic pressure can be obtained from monitoring the pressure in the cuff as the cuff is slowly deflated. The mean pressure corresponds to the pressure in the attenuation means of the cuff at the moment of the peak of the envelope. Systolic blood pressure is generally estimated as the pressure in the attenuating means of the cuff corresponding to the moment before the peak of the envelope at which the magnitude of the envelope is equal to a proportion of the peak magnitude. Diastolic pressure is generally estimated as the pressure in the attenuating means of the cuff at a time after the peak of the envelope corresponding to a time when the magnitude of the envelope is equal to a proportion of the peak magnitude. Using different scale values will affect the accuracy of blood pressure measurement.

Most of the products currently on the market use auscultation or oscillation. However, since both methods need to inflate and deflate the cuff, it is difficult to perform frequent and continuous measurements. Also, the frequency of its measurements is limited by the time required to comfortably inflate the cuff and deflate the cuff while taking a measurement. Usually, a complete blood pressure measurement takes about 1 minute. In addition, the size of the cuff will also affect the blood pressure measurement results.

The basic principle of the tone measuring sphygmomanometer is: when the blood vessel is oppressed by external objects, the circumferential stress of the blood vessel wall is eliminated, and the internal pressure and external pressure of the blood vessel wall are equal at this time. By applying pressure to the artery, the artery is flattened. The pressure keeping the artery flattened is recorded. This pressure is measured by an array of pressure sensors placed on the surface arteries, from which the patient's blood pressure is calculated. However, the disadvantage of this method is that the cost of the sensor used is relatively high, and its measurement accuracy is easily affected by the measurement position, so it is not popular in the market.

Photoplethysmographic sphygmomanometers determine blood pressure based on the relationship between arterial blood pressure and the velocity of pulse wave transmission. When the blood pressure rises, the blood vessels dilate and the pulse wave transmission speed increases, otherwise, the pulse wave transmission speed slows down. When the sphygmomanometer is in use, the photoelectric sensor placed on the fingertip collects the signal of the light volume change. Currently, blood pressure monitors based on this technology are still under development.

Contents of the invention

Therefore, the present invention is made to solve the above-mentioned problems in the prior art, and its purpose is to provide a blood pressure measuring device capable of realizing continuous measurement and miniaturization.

In order to achieve the above object, according to the first aspect of the present invention, it provides a device for measuring arterial blood pressure using radial artery pulse information, the device comprising:

The electrocardiographic signal acquisition module is used to collect the electrocardiographic signal of the human body; the radial artery pulse signal acquisition module is used to collect the radial artery pulse signal of the human body; the signal preprocessing module is connected with the electrocardiographic signal acquisition module and the radial artery The arterial pulse signal acquisition module is electrically connected to preprocess the signals from the ECG signal acquisition module and the radial artery pulse signal acquisition module; the blood pressure measurement calibration module is used to provide calibration parameters for blood pressure measurement; and micro A processor module, which is electrically connected to the signal preprocessing module and the blood pressure calibration module, and is used to determine the blood pressure measurement formula according to the calibration parameters from the blood pressure measurement calibration module and the signal from the signal preprocessing module, and according to The determined blood pressure measurement formula and the signal from the signal preprocessing module calculate the blood pressure to obtain the blood pressure measurement result.

In the device according to the first aspect of the present invention, the ECG signal collection module includes a sensor for detecting the ECG signal, and the radial artery pulse signal collection module includes a sensor for detecting the radial artery pulse.

In an embodiment of the present invention, the sensor for detecting ECG signals includes two identical conductive electrodes, the sensor for detecting radial artery pulse is a mechanical sensor, and the mechanical sensor is preferably a displacement sensor or pressure sensor.

In addition, in the embodiment of the present invention, the signal pre-processing module further includes: a signal filtering circuit for filtering noise in the signal through a band-pass filter therein; and a signal amplifying circuit for amplifying the signal.

Also, in an embodiment of the present invention, the blood pressure measurement calibration module further includes: a standard sphygmomanometer, used to provide calibration parameters for blood pressure measurement; and an input device, used to input the calibration parameters provided by the standard sphygmomanometer to the signal processing module.

In addition, in the embodiment of the present invention, the device further includes a display device for displaying the blood pressure measurement result and a data transmission module for transmitting the blood pressure measurement result to the remote terminal. Furthermore, the device can also be placed in the casing of a wrist watch.

The device according to the present invention can be applied to small blood pressure measuring devices such as wrist watches, which is convenient for patients to wear for a long time, thereby realizing non-invasive, continuous and miniaturized blood pressure measurement. In addition, in some applications, the wireless data transmission module can also be used to wirelessly transmit the measured blood pressure value and the alarm signal to the abnormal blood pressure value to the professional medical staff in the distance, so that the medical staff can monitor the patient in real time. monitor.

Description of drawings

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. Through these descriptions, the above-mentioned objectives, advantages and features of the present invention will become more clear. In the accompanying drawings below:

Fig. 1 is a schematic block diagram of the structure of a blood pressure measuring device according to an embodiment of the present invention.

Fig. 2 is a flowchart of a method for measuring blood pressure according to an embodiment of the present invention;

Fig. 3 is the flow chart of concretely realizing the calibration process shown in Fig. 2;

FIG. 4 is a flow chart for implementing the process of determining the time interval in the measurement process shown in FIG. 2 .

Fig. 5 is a flow chart for implementing the process of determining the blood pressure shown in Fig. 2 .

Fig. 6 (a) is the exterior view of the wrist watch adopting the device of the present invention according to one embodiment of the present invention;

6(b) is a sectional view of the wrist watch shown in FIG. 6(a) along the X axis.

Detailed ways

The beating of the heart produces rhythmic pulsation in the walls of arteries throughout the body, and this pulsation is called a pulse. The superficial artery is usually used to check the pulse, and the most commonly used site is the radial artery at the wrist on the side of the thumb. In Chinese medicine, pulse characteristics such as strength, depth, rhythm, and waveform are often used as diagnostic information. In an embodiment of the present invention, we use the waveform of the pulse intensity detected by the mechanical sensor and the ECG signal to determine the blood pressure.

Fig. 1 is a schematic block diagram of the structure of a blood pressure measuring device according to an embodiment of the present invention. As shown in Figure 1, this blood pressure measurement device includes: ECG signal acquisition module 1, radial artery pulse signal acquisition module 2, signal preprocessing module 3, microprocessor module 4 and blood pressure calibration module, wherein the blood pressure calibration module is composed of standard The sphygmomanometer 8 and the keyboard input device 7 are composed.

The radial artery pulse signal acquisition module 2 collects the radial artery pulse wave of the human body and converts it into an electrical signal. The converted waveform is shown in FIG. 1 , where the horizontal axis represents time and the vertical axis represents voltage. The electrocardiographic signal acquisition module 1 utilizes such as traditional PQRST method to acquire electrocardiographic pulse signals. FIG. 1 shows the waveform of the R-wave pulse collected by it, wherein R represents the top point of the R-wave pulse. The signal preprocessing module 3 preprocesses the electrocardiographic signal and the radial artery pulse signal from the electrocardiographic signal acquisition module 1 and the radial artery pulse signal acquisition module 2 respectively. Specifically, the signal preprocessing module 3 uses the band-pass filter and the signal amplifier (not shown in the figure) to process the ECG signal and the radial artery pulse signal respectively. For the ECG signal, its band-pass frequency 0.5-40Hz, the magnification is 2000. For the radial artery pulse signal, the band-pass frequency is 0.5-15Hz, and the amplification factor is 1000. The filtered and amplified signal is input to the microprocessor module 4 . The microprocessor module 4 first performs analog-to-digital conversion on the input signal, and then performs vertex detection on the above two signals and calculates the time interval between corresponding vertices in the two signals. Afterwards, the microprocessor 4 can calculate the blood pressure value in real time according to the calculated time interval and the calibration parameters provided by the blood pressure measurement calibration module. The specific calculation method will be described in detail later. In addition, in this embodiment, the blood pressure measurement device further includes a wireless data transmission module 6 and a display device 5 . The display 5 can be used to display the output real-time blood pressure value. The wireless data transmission module can transmit the obtained blood pressure value to the remote terminal, so as to facilitate the medical staff to monitor the patient's health remotely and in real time.

For those skilled in the art, since the implementation circuits of the above modules are already known in the prior art, these module circuits can be made very easily by reading a large number of existing reference documents. Therefore, the implementation of these module circuits will not be further described in this specification.

Fig. 2 is a flowchart of a method for measuring blood pressure according to an embodiment of the present invention. As shown in FIG. 2 , generally speaking, the method mainly includes three processes, namely: a calibration process, a process of determining the pulse wave transit time (ie, the time interval), and a process of calculating blood pressure measurement results. These three steps will be described in detail below.

1. Calibration process:

As shown at 210 in FIG. 2 , the purpose of the calibration process is to provide calibration parameters for subsequent blood pressure measurements. Its operation is realized by measuring the diastolic and systolic blood pressure using the standard sphygmomanometer 8 shown in FIG. 1 . In the embodiment of the present invention, the above-mentioned two blood pressure values are input through the keyboard 7 and transmitted to the microprocessor of the blood pressure measuring device by means of infrared to determine the constants of the regression equation. Figure 3 shows the detailed steps of the calibration process. As shown in Figure 3, at first, in steps 310 and 320, the systolic pressure and the diastolic pressure are input into the microprocessor 4 of the blood pressure measurement device respectively, as previously mentioned, these two blood pressure values as calibration parameters are determined by The standard sphygmomanometer 8 measures and is input to the microprocessor 4 through an input device such as a keyboard. Then, in step 330, the time interval between the reference points on the ECG signal and the pulse wave signal during calibration is determined by the microprocessor 4 (see FIG. 1 ) (the detailed steps will be given in FIG. 4 ). Here, it is assumed that the blood pressure values used in the calibration process are SBP1_cal, SBP2_cal, DBP1_cal and DBP2_cal respectively (that is, two measurements are performed using the standard sphygmomanometer 8, two blood pressures are measured each time, and SBP1_cal represents the systolic blood pressure measured for the first time , DBP1_cal represents the diastolic blood pressure measured for the first time, and so on), and the time intervals corresponding to the above two blood pressure measurements are PTT1_cal and PTT2_cal respectively. In addition, it is assumed that the constants corresponding to the systolic blood pressure regression equation are αs and βs, The constants corresponding to the diastolic pressure regression equation are αd and βd, then the blood pressure can be expressed as:

SBP1_cal=αs×PTT1_cal+βs

SBP2_cal=αs×PTT2_cal+βs

DBP1_cal=αd×PTT1_cal+βd

DBP2_cal=αs×PTT2_cal+βd

In this way, according to the above relational expression, in step 340, the constants αs and βs and αd and βd of the regression equation can be calculated. Then, in step 350, these determined constants are stored in the memory of the microprocessor for use in subsequent blood pressure measurement calculations.

2. The process of determining the pulse wave transit time:

As shown in step 220 in FIG. 2 , this process is used to determine parameter values (time interval or pulse wave transit time) in the actual blood pressure measurement process. Fig. 4 illustrates the steps of how to calculate the time interval or the pulse wave transit time for determining the blood pressure from the radial artery pulse and the ECG signal. As shown in FIG. 4, first, in step 410, the peak point of the R-wave signal in the electrocardiogram waveform is detected and the time position at this time is recorded. Then, in step 420, a tangent at a peak point with a slope of zero in the pulse wave waveform is detected. Next, in step 430, the tangent at the point t _s with the largest slope in the pulse wave waveform is detected. Then, in step 440, determine the peak point according to the intersection point of the above two tangent lines and record the time position t _ps at this time. The peak point found in this way has stronger robustness and is more suitable for calculating the pulse wave transfer speed. Next, in step 450, the pulse wave transmission velocity is calculated, that is, the time interval between the peak value of the R-wave signal of the electrocardiogram and the corresponding peak point t _ps of the pulse wave signal. The corresponding pulse wave refers to the radial artery pulse wave that appears immediately after the R-shaped wave signal on the ECG. Finally, in step 460, the average value of the above-mentioned time interval is calculated. The reason why the average value is used is that the process of determining the above parameters will be disturbed by many factors, resulting in a decrease in measurement accuracy. In this embodiment, it is suggested that the patient should obtain at least 10 seconds of measurement data for averaging when performing blood pressure measurement. The averaged parameter values are input to step 230 in FIG. 2 for calculating blood pressure or to step 330 in FIG. 3 for calibrating the device.

3. The process of calculating blood pressure measurement results

As shown in step 230 in FIG. 2, the process uses the regression constants and parameter values (time interval or pulse wave transit time) determined in steps 210 and 220 to calculate systolic and diastolic blood pressure, respectively. Specifically, in this process, the microprocessor 4 substitutes the average value of the time interval (or pulse wave transit time) measured in the actual blood pressure measurement process into the regression equation determined in step 210, thereby calculating the actual blood pressure value. Figure 5 shows the specific implementation steps of this process.

As shown in FIG. 5, step 510 is used to calculate the systolic blood pressure through the constants of the regression equation stored in the memory of the microprocessor 4, and its calculation formula is as follows:

Systolic blood pressure = αs × PTT_ave + βs

Wherein αs and βs are calculated in step 340 of the calibration process shown in FIG. 3 , and PTT_ave is an average time interval as shown in FIG. 4 .

Step 520 is used to calculate the diastolic pressure through the constants of the regression equation stored in the memory of the microprocessor 4, and its calculation formula is as follows:

Diastolic blood pressure == αd×PTT_ave+βd

Wherein αd and βd are also calculated in step 340 of the calibration process shown in FIG. 3 , and PTT_ave is the average time interval shown in FIG. 4 .

After the calculation is completed, the resulting data can be further processed in step 240 , that is, if the blood pressure value exceeds the normal standard, an alarm message will be given, as shown in step 250 . If further measurements are required, steps 220, 230, 240 and 250 will be recalled in step 260 to repeat the process described above.

Fig. 6(a) is an appearance view of a wrist watch using the device of the present invention according to an embodiment of the present invention. As shown in Figure 6 (a), a rectangular liquid crystal display device 630 is placed on the front of the watch case 610, covered with a watch glass 620, as shown in the upper part of Figure 6 (a), a device for detecting electrocardiographic signals The electrodes 640 are placed on the lower portion of the front surface of the watch and are recessed. Fig. 6(b) is a cross-sectional view of the wrist watch shown in Fig. 6(a) along the X axis. As shown in FIG. 6(b), the back case 650 of the watch is made of conductive material, which is used as another electrode for detecting electrocardiographic signals. At the same time, a displacement diaphragm is also placed on the back casing of the watch as a radial artery pulse signal sensor to detect the intensity of the radial artery pulse. The wrist watch device is small, portable and capable of continuous blood pressure measurement of a patient.

It should be noted that the above descriptions of the specific implementation modes and examples of the present invention are only exemplary, and those of ordinary skill in the art can understand that the equivalent technical means or alternative means of each step of the method described in the present invention can be used to implement the present invention. invention. But these changes and modifications that do not deviate from the idea of the present invention all fall within the scope of the present invention defined by the claims of the present invention.

Claims (11)

1. device that utilizes radial pulse information to measure arteriotony comprises:

The ecg signal acquiring module, the electrocardiosignal that is used to gather human body;

The radial pulse signal acquisition module is used to gather the radial pulse signal of human body;

Signal pre-processing module, it is electrically connected with described ecg signal acquiring module and described radial pulse signal acquisition module, is used for the signal from described ecg signal acquiring module and described radial pulse signal acquisition module is carried out pretreatment;

The blood pressure measurement calibration module is used to provide the calibration parameter of blood pressure measurement; And

Microprocessor module, it is electrically connected with described signal pre-processing module and described blood pressure calibration module, be used for according to determining the blood pressure measurement formula, and blood pressure calculated to obtain blood pressure measurement according to the blood pressure measurement formula of being determined and from the signal of described signal pre-processing module from the calibration parameter of described blood pressure measurement calibration module and the signal of described signal pre-processing module.

2. device according to claim 1 is characterized in that, described ecg signal acquiring module comprises the pick off that is used to detect electrocardiosignal.

3. device according to claim 2 is characterized in that, the described pick off that is used to detect electrocardiosignal comprises two identical conducting electrodes.

4. device according to claim 1 is characterized in that, described radial pulse signal acquisition module comprises the pick off that is used to detect radial pulse.

5. device according to claim 4 is characterized in that, the described pick off that is used to detect radial pulse is a mechanical pick-up device.

6. device according to claim 5 is characterized in that described mechanical pick-up device comprises displacement transducer, pressure transducer and acceleration transducer.

7. device according to claim 1 is characterized in that, described signal pre-processing module further comprises:

Signal filter circuit, the band filter that is used for by wherein filters the noise of signal; And

The signal amplification circuit that is used for amplifying signal.

8. device according to claim 1 is characterized in that, described blood pressure measurement calibration module further comprises:

Standard-sphygmomanometer is used to blood pressure measurement that calibration parameter is provided, i.e. the standard blood pressure readings; And

Input equipment is used for the calibration parameter that described standard-sphygmomanometer provides is inputed to described signal processing module.

9. device according to claim 1 is characterized in that also comprising display device that is used for the display of blood pressure measurement result and the data transmission module that is used for blood pressure measurement is transferred to remote terminal.

10. device according to claim 9, it is characterized in that described data transmission module comprises a wireless data transfer module that is built in the described blood pressure measuring device, utilize this wireless data transfer module blood pressure measurement can be sent to wireless data transfer module in the user short range, this module can be transferred to computer to do further processing by microprocessor with data.

11. device according to claim 1 is characterized in that, described device is placed in the middle of the shell of wrist formula wrist-watch.

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