KR20100052608A - Measuring apparatus and method for pulse wave - Google Patents

Abstract

PURPOSE: A measuring apparatus and a method for a pulse wave are provided to obtain a diagnosis index by using the change of the pulse wave and pulse according to a pressure and a vessel diameter. CONSTITUTION: A measuring unit(100) holds a radial artery of a testee and measures the variation of a pressing unit for measuring pulse and pulse wave. A data collection unit(200) obtains the measured pulse wave and a variation signal and an operation unit(300) extracts data from the measured pulse wave and variation signal. A controller(400) controls the movement of the measuring unit. The controller transfers control information to the operation unit.

Description

Pulse wave measuring device and method {MEASURING APPARATUS AND METHOD FOR PULSE WAVE}

The present invention relates to a pulse wave measuring apparatus and method capable of extracting a new diagnostic index through the change of the pulse wave and pulse pressure according to the pressing force and blood vessel diameter.

Arterial stiffness is an important indicator of cardiovascular function.Echotracking is a non-invasive method of measuring vascular stiffness in the radial artery. There are two methods, the pulse wave measurement method based on the principle of tonometry.

The eco tracking method has a resolution of 1μm, which is about 1/100 of the ultrasound imaging equipment, but it is very expensive and practically difficult to use in clinical practice, while the equipment based on the tonometry measurement principle is easy to measure and relatively measuring equipment. Is widely used because of its low cost.

The principle of tonometry is that when the radial artery is supported by a rigid structure such as bone, when the pressure sensor placed on the radial artery is properly pressed, the elastic force of the vessel applied to the sensor vertical plane disappears and only the arterial pressure Is delivered to the sensor. A typical application of the radial artery pulse wave by the principle of tonometry is an evaluation of vascular stiffness through an augmentation index (AIx). In this case, a pen-type probe with a pressure sensor having high fidelity is generally used. By pressing the radial artery randomly through, the pulse wave at the maximum pulse wave size is obtained, and the aortic pulse wave is inferred therefrom.

However, while the radial artery pulse wave is easy to measure, even though the physiological and pathological causes of the subject are controlled, the radial artery pulse wave is differently measured by various factors such as the measurement position and the magnitude of the pressing force for measurement. Indeed, the oriental medical vein positions on the radial artery, chon, duct, and chuck are only about 12 to 15 mm apart from each other, but the hemodynamic characteristics such as the depth, diameter, and blood flow velocity of the radial artery have been reported to be different. In addition, a study on the difference in pulse wave form and augmentation index (AI) at these locations was performed, and as a result, there was a significant difference between the augmentation index according to the measurement position.

The technical problem to be solved by the present invention is to more accurately diagnose swelling and loss by measuring the pulse pressure and pulse pressure change relative to the pressure force and blood vessel diameter of the subject blood vessels.

In addition, the technical problem to be solved by the present invention is to change the pulse wave and pulse pressure according to the pressing force and the diameter of the blood vessel represents a physical characteristic of the blood vessel, thereby discovering a new diagnostic index.

Pulse wave measuring apparatus according to an aspect of the present invention is a measurement unit for measuring the displacement of the pressing unit for measuring the pulse wave and pulse wave by fixing the radial artery of the subject wrist so as not to move up and down, left and right, pulse wave and displacement measured by the measurement unit And a data acquisition unit for acquiring a signal, an operation unit for extracting information from pulse wave and displacement signals acquired by the data acquisition unit, and a control unit for controlling movement of the measurement unit and transferring control information to the operation unit.

The measuring unit of the pulse wave measuring apparatus according to the feature is provided with a vertically moving axis, the pressing portion moving up and down along the moving shaft, a motor unit connected to the moving shaft to adjust the position of the pressing portion, It is preferable that the pulse wave sensor is provided at the lower end of the pressing part to measure the pulse wave, and the laser displacement sensor is provided at the end side of the pressing part to measure the moving distance of the pressing part or the pulse wave sensor.

The laser displacement sensor of the pulse wave measuring apparatus according to the above characteristics is preferably provided at one end side of the pressing unit and may move in parallel with the ground.

The laser displacement sensor of the pulse wave measuring apparatus according to the above characteristics may further include a reflector at a position spaced apart from the lower portion of the laser displacement sensor by a predetermined distance.

The pulse wave measuring method according to another aspect of the present invention comprises the steps of placing the subject's wrist on the wrist rest, the pulse wave sensor of the pulse wave sensor and the laser displacement sensor provided at one end of the pressing portion by moving the pressing portion to contact the subject's wrist Step, storing the initial pulse wave signal and the displacement signal measured by the pulse wave sensor and the laser displacement sensor in the data acquisition unit, the pulse wave sensor provided in the pressing unit is pressed by increasing 10 to 20 steps on the subject's wrist And storing the pulse wave signal and the displacement signal measured by the pulse wave sensor and the laser displacement sensor in the data acquisition unit in increments of 10 to 20 steps, and calculating the average of the pulse wave signals and the displacement signal stored in the data acquisition unit. Calculating, including the pulse pressure for each step number, the pressing force, and the moving distance of the pressing unit. Deriving a relationship between the pulse wave parameters included therein, and estimating a blood vessel diameter when the pulse displacement is greater than 1.5 mm to 4.5 mm and no pulse wave is detected.

According to the pulse wave measuring method according to the above feature, when the moving distance of the laser displacement sensor is less than 1.5 mm to 4.5 mm, or the pulse wave is detected, the pulse wave sensor is returned to the step of increasing the pressure on the subject's wrist by 10 to 20 steps. It is preferred to further comprise a step.

According to this feature of the invention,

The present invention has the effect of diagnosing more accurate ups and downs by measuring the pulse wave and pulse pressure change compared to the pressing force and blood vessel diameter.

The present invention has the effect of discovering new diagnostic indicators from the change in pulse wave and pulse pressure according to the pressing force and the diameter of the blood vessel.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail as follows.

1 is a block diagram showing a pulse wave measuring apparatus according to an embodiment of the present invention.

As shown in FIG. 1, an embodiment of the present invention includes a measurement unit 100, a data acquisition unit 200, an operation unit 300, and a control unit 400.

Here, the measuring unit 100 is fixed to the wrist cradle 160 so as not to move the radial artery of the subject's wrist up, down, left and right, and measure the pulse wave and displacement while pressing the skin on the radial artery, the measuring unit 100 The measured pulse wave and the displacement signal are acquired by the data acquisition unit 200. In FIG. 1, the measurement surface is shown in place of the subject's wrist.

In addition, the calculation unit 300 extracts information from the pulse wave and the displacement signal obtained by the data acquisition unit 200.

The controller 400 controls the movement of the measurement unit 100 and transmits control information to the calculation unit 100.

In this case, the measuring unit 100 includes a moving shaft 110, a pressurizing unit 120, a motor unit 130, a pulse wave sensor 140, and a laser displacement sensor 150. 100 includes a moving shaft 110 formed vertically, and is provided at right angles to the moving shaft 110 to form a pressing unit 120 moving up and down along the moving shaft 110.

In addition, the motor unit 130 is connected to the moving shaft 110 to adjust the position of the pressing unit 120, the pulse wave sensor 140 for measuring the pulse wave at the lower end of the pressing unit 120, and The pressing unit 120 includes a laser displacement sensor 150 provided at one end side of the pressing unit 120 to measure a moving distance of the pressing unit 120 or the pulse wave sensor 140. At this time, the laser displacement sensor 150 is provided on one end side of the pressing portion, but moves to the left and right. In addition, the wrist rest 160 is fixed to fix the subject's wrist, which is a reflector of the laser displacement sensor, and further includes a reflector (not shown) fixed at a position spaced a predetermined distance from the lower end of the laser displacement sensor.

Referring to the embodiment of the present invention provided as described above in detail.

First, the moving shaft 110 of the measuring unit 100 is formed in the form of a screw vertically provided. In an embodiment of the present invention, when the moving shaft 110 of the screw model is rotated one step, one step is about 0.064 mm, but not limited thereto, and the moving shaft 110 is perpendicular to the moving shaft 110. Forming the pressing portion 120 to move up and down along the pressing portion 120 one side is fastened to the moving shaft 110, the other end is combined with the pulse wave sensor 140 for measuring the pulse wave, pulse wave sensor At the other end side of the pressing unit 120 at the same position as the 140, the light receiving unit and the light emitting unit are provided with a laser displacement sensor 150 measuring a moving distance of the pressing unit 120 or the pulse wave sensor 140 toward the lower direction. .

In addition, the movement of the moving shaft 110 provided in the screw model to the left and right, to control the direction of the moving shaft 110 to move up and down the pressing unit 120 fastened to the moving shaft 110 or the moving shaft 110 In order to assist the rotation of the motor unit 130 is provided by connecting to the moving shaft (110).

Although the pulse wave sensor 140 may use any sensor for measuring pulse wave, the pulse wave sensor 140 used in the embodiment of the present invention adopts a smaller sensor of the radial artery.

Description of the characteristics of the laser displacement sensor 150 will be described later in the drawings.

The data acquisition unit 200 collects the stable pulse wave signal and the displacement signal measured by the pulse wave sensor 140 and the laser displacement sensor 150 for 5 to 15 seconds, A / D converts them, and transmits them to the calculation unit 300. In this case, the pulse wave signal refers to a pulse wave detected by the subject's wrist, and the displacement signal is a pressing unit coupled to the moving shaft 110 measured using the laser displacement sensor 150 having the light receiving unit and the light emitting unit facing downward. It means a vertical movement distance signal of 120.

In addition, by observing the displacement measured by the laser displacement sensor 150 and the shape of the pulse wave measured at the displacement, the diameter change of the radial artery can be estimated, and further, the diameter and elasticity of the radial artery can be used. have.

The calculation unit 300 calculates an average displacement, an average pulse wave, a pressing force, and a pulse pressure by using the pulse wave signal and the displacement signal transmitted from the data acquisition unit, and the average displacement is an average of the output values of the laser displacement sensor for 5 to 15 seconds. The average pulse wave is calculated by averaging the bits of N generated for 5 to 15 seconds, and the pressing force is calculated by averaging the pressures of the start point (shrink start point) and the end point (diastolic end point) of the average pulse wave. Let it be the difference between the maximum value and the minimum value of the average pulse wave.

In addition, the operation unit 300 stores the moving part displacement, average pulse wave, pressing force, and pulse pressure information for each motor step number used for moving the pressing unit 120 input from the control unit 400 and determines whether the data is stable. Here, the determination of whether the signal is stable means that the signal is determined to be stable when the variation of the laser displacement sensor is within a certain value for a predetermined time, and that the signal is unstable in other cases.

In addition, the calculation unit 300 determines a step in which the correlation coefficient between the average pulse wave of the pressing step having the maximum pulse pressure and the average pulse wave of the remaining pressing step is equal to or greater than a predetermined threshold value, and among these steps, the minimum pressing step is the start point of the vessel wall pressing, and these steps are performed. The maximum pressurization step is determined at the time of vascular occlusion, and the diameter of the blood vessel can be estimated by the difference between the displacement at the start of vessel wall compression and the displacement of the vessel occlusion according to the determined displacement signal. 120) The displacement of the pressure unit 120 from the displacement to the time of vascular occlusion is set as the X-axis value, and the information such as pulse pressure as the Y-axis value is reconstructed.

The control unit 400 moves down the pressing unit 120 by a predetermined step from the initial position until it is determined that the contact unit 300 is in contact with the skin. When the control unit 300 determines that the acquisition signal is stable, the control unit 400 descends by the predetermined step. The position is maintained until the stability of the next acquired signal is determined. In addition, when the falling stop is determined by the calculation unit 300, the pressing unit 120 may move to the initial position of measurement without further lowering.

2 is a graph showing the relationship between the number of moving steps during no load and the laser displacement sensor output of the pulse wave measuring apparatus according to the embodiment of the present invention.

Figure 2 is a laser displacement sensor as shown in the graph shown by repeating the experiment three times each with a white solid, a black solid, and the human skin as a reflector to confirm that the characteristic change according to the type of reflector is insignificant. It can be seen that the sensor has little characteristic change depending on the type of reflector.

The laser displacement sensor used is + 5V when the reflector is 5mm closer to the reference position (L = 25mm), -5V is output and saturates to -5V and 5mm further away from the reference position (L = 35mm) even when approaching further. The output has a characteristic of saturating to + 5V when it is further away.

The position of the reflector was tested using this property after fixing the position of the displacement sensor output to + 5V at positive saturation, that is, the distance L between the object and the displacement sensor was 35mm. The output value was moved in units of 20 steps and until the output of the laser displacement sensor was saturated with a positive value.

3 is a graph showing the relationship between the number of pressure steps under load and the laser displacement sensor output and the average pulse wave at each step of the pulse wave measuring apparatus according to the embodiment of the present invention.

3 shows an example in which the output signal of the laser displacement sensor and the pulse wave is lowered by 10 to 20 steps and measured and stored at a predetermined interval, but the blood vessels are completely blocked until the pulse wave is no longer observed.

Moreover, the average waveform of the pulse wave measured in each position of a press part is shown together. The output voltage of the laser displacement sensor uses a stable average value for 5 to 15 seconds.

Looking in detail in FIG. 3, it can be seen that the laser displacement sensor output voltage with respect to the step number increase has a non-linear characteristic unlike in the no-load state. This is due to the repulsive force of vascular support structures such as the radial bone, which occurs after the radial artery is occluded, unlike at no load.

In addition, it can be seen that the shape of the pulse wave changes according to the number of pressing steps, and in particular, the pulse pressure change corresponding to the difference between the pulse wave baseline and the systolic pressure and the diastolic pressure is prominent.

Figure 4a is a graph showing the pulse wave baseline according to the number of pressing steps of the pulse wave measuring apparatus according to an embodiment of the present invention, Figure 4b is a graph showing the pulse pressure according to the pressing step number of the pulse wave measuring apparatus according to an embodiment of the present invention. .

As shown in FIGS. 4A and 4B, the change in the baseline and the pulse pressure of the pulse wave average waveform according to the increase in the number of steps of the pressurization unit is represented as a voltage value, and when the pulse wave sensor output characteristic curve with respect to pressure is obtained, the pressure value is also represented. You can correct it.

The pulse wave baseline was taken as the mean value of the systolic start point and the diastolic end point on the pulse wave signal. It can be seen that the pulse wave baseline increases with a slight nonlinearity as the number of steps used to lower the pressure part increases, which is the pressure on the skin contact surface of the pressurized part, that is, the pressure on the skin above the radial artery. This shows an increase in the number.

On the other hand, it can be seen that the pulse pressure has a form similar to the Gaussian function that increases and decreases again as the number of steps of the pressurizing part increases. By combining the values, the change in pulse pressure according to the pressing force can be observed.

5 is a graph showing the change in pulse pressure with respect to the pressing force according to an embodiment of the present invention.

As shown in FIG. 5, the maximum pulse pressure of FIG. 4B is when the number of pressurization steps is 70 and the applied pressure on the pulse wave sensor output is 0.32 V. From this point, the contact area between the blood vessel and the pulse wave sensor was maximum. Can be inferred.

6 is a graph showing a change in pulse pressure with respect to the moving distance of the pressing unit according to an embodiment of the present invention.

As shown in Fig. 6, when comparing the average pulse wave at the point of time when the pulse pressure is maximum, that is, the representative waveform and the average pulse wave at the remaining step number or the moving distance, the number of steps is 40 or the moving distance is 2.54 mm before the fifth measurement. The average waveform after the ninth measurement with 90 steps or 0.20 mm travel was different from the representative waveform. From this, it can be inferred that the average pulse wave of the fourth measurement in which no pulse wave was observed but the first pulse wave was observed was measured in the undercompressed state without the change in the diameter of the blood vessel by pressure.

In the tenth and eleventh measurements in which the pulse wave of the representative waveform and other forms were observed, the increase in the moving distance decreases rapidly, and it is estimated that the measurement was performed in the overcompressed state in which the blood vessel was sufficiently occluded.

Therefore, the diameter of the vessel is approximated to 2.34 mm, which is the difference between the movement distance of 2.54 mm and the movement distance of 0.20 mm, and the pulse wave shape compared to the movement distance measured between these two measurements can be defined as the pulse wave shape according to the degree of vascular occlusion.

7 is a photograph showing an ultrasound B mode image of the lower radial artery of the pulse wave measurement site according to an exemplary embodiment of the present invention.

7 is a diameter of the radial artery located under the pulse wave measurement site of the same subject in order to verify the diameter of the blood vessel obtained in FIG. A thin metal was wound around the pulse wave measurement site to identify the location on the ultrasound B mode image. On the other hand, because the vascular diameter may be measured differently by pulsation, the ultrasound image was stopped by the diastolic device and the output of the photo-plethysmograph (PPG) sensor attached to the left index finger was used to monitor whether the subject was in the diastolic state.

The radial artery was about 2.8 mm (0.28 cm) deep from the skin, and the radial artery was about 2.4 mm (0.24 cm) in diameter. As a result, it can be seen that the estimated radial artery diameter of 2.34 mm in FIG. 6 is almost the same as the actual radial artery diameter.

Therefore, the embodiment of the present invention can not only measure the moving distance and pulse wave of the pressing unit through the laser displacement sensor, but also extract the pressing force and pulse pressure information from the pulse wave signal while quantitatively pressing the skin on the radial artery through the moving axis. In addition, the diameter and occlusion of blood vessels can be estimated based on the timing of pulse wave shape change.

8 is a flowchart illustrating a pulse wave measuring method according to an exemplary embodiment of the present invention.

As shown in FIG. 8, first, the subject's wrist is placed on the wrist rest and positioned below the pulse wave sensor and the laser displacement sensor (S810). At this time, the pulse wave sensor and the laser sensor is attached to one end of the pressing unit coupled to the moving shaft, the subject's wrist should be located at the bottom of the pulse wave sensor, so that the subject's wrist is located at the bottom of the pulse wave sensor without moving up, down, left and right Can be fixed using the wrist rest.

Subsequently, the pulse wave sensor among the pulse wave sensor and the laser displacement sensor attached to the pressing unit is in contact with the subject's wrist (S820).

Subsequently, the initial pulse wave signal and the displacement signal measured by the pulse wave sensor and the laser displacement sensor are stored in the data acquisition unit (S830). At this time, the initial pulse wave signal and the displacement signal stored in the data acquisition unit are stored by A / D conversion.

Subsequently, the pulse wave sensor provided in the pressing unit increases and presses the subject's wrist by 10 steps (S840). At this time, the pressing portion is coupled to the screw-shaped moving shaft, and if the screw-shaped moving shaft rotates once, it is one step and the vertical movement of the pressing portion is possible by the rotation of the moving shaft. In addition, the number of steps of the pulse wave sensor may vary depending on the interval of one step.

Subsequently, the pressing unit increases the pulse wave signal and the displacement signal measured by the pulse wave sensor and the laser displacement sensor in increments of 10 to 20 steps (S850).

Subsequently, the displacement average, the pulse wave average, the pressing force, and the pulse pressure are calculated by the calculator using the pulse wave signal and the displacement signal stored in the data acquisition unit (S860). At this time, the operation unit may know the information about the number of pressing steps, pressing force, moving distance, and pulse pressure of the pressing unit.

Subsequently, the calculation unit derives a relationship between pulse wave parameters including pulse pressures for the number of steps of the pressing unit, the pressing force, and the movement distance (S870).

Finally, if the moving distance of the laser displacement sensor is greater than 3mm, and the pulse wave is not detected, the calculating unit estimates the blood vessel diameter (S880).

At this time, if the moving distance of the laser displacement sensor is less than 3mm, or if the pulse wave is detected, the pulse wave sensor is repeated in the step of increasing the pressure on the subject's wrist by 10 to 20 steps.

While the present invention has been particularly shown and described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of course, this is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the equivalents as well as the claims to be described later.

1 is a block diagram showing a pulse wave measuring apparatus according to an embodiment of the present invention.

2 is a graph showing the relationship between the number of moving steps during no load and the laser displacement sensor output of the pulse wave measuring apparatus according to the embodiment of the present invention.

3 is a graph showing the relationship between the number of pressure steps under load and the laser displacement sensor output and the average pulse wave at each step of the pulse wave measuring apparatus according to the embodiment of the present invention.

4A is a graph illustrating pulse wave baselines of pulse wave variation characteristics according to the number of pressing steps of the pulse wave measuring apparatus according to an exemplary embodiment of the present invention.

Figure 4b is a graph showing the pulse pressure change characteristics according to the number of pressing steps of the pulse wave measuring apparatus according to an embodiment of the present invention.

5 is a graph showing the change in pulse pressure with respect to the pressing force according to an embodiment of the present invention.

6 is a graph showing a change in pulse pressure with respect to the moving distance of the pressing unit according to an embodiment of the present invention.

7 is a photograph showing an ultrasound B mode image of the lower radial artery of the pulse wave measurement site according to an exemplary embodiment of the present invention.

8 is a flowchart illustrating a pulse wave measuring method according to an exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: measuring unit 110: moving axis

120: pressurization unit 130: motor unit

140: pulse wave sensor 150: laser displacement sensor

160: wrist rest 200: data acquisition unit

300: operation unit 400: control unit

Claims (6)

Measuring unit for measuring the displacement of the pressing portion for measuring the pulse wave and pulse wave by fixing the radial artery of the subject wrist to move up, down, left and right, A data acquisition unit for acquiring pulse wave and displacement signals measured by the measurement unit; An operation unit which extracts information from pulse wave and displacement signals obtained by the data acquisition unit, and Pulse wave measuring device configured to control the movement of the measuring unit and to transmit the control information to the operation unit. According to claim 1, The measuring unit is a vertically formed moving shaft, A pressing part which is provided at right angles to the moving shaft and moves up and down along the moving shaft, A motor unit connected to the moving shaft to adjust a position of the pressing unit; A pulse wave sensor provided at a lower end of the pressing part to measure a pulse wave; A pulse wave measuring apparatus comprising a laser displacement sensor provided at one end side of the pressing unit and measuring a moving distance of the pressing unit or the pulse wave sensor. 3. The method of claim 2, The laser displacement sensor is provided on one end side of the pressing portion, the pulse wave measuring device to move in parallel with the ground. 3. The method of claim 2, The laser displacement sensor is fixed to an arbitrary position along the axis of the pressing portion, the pulse wave measuring apparatus further comprises a reflector parallel to the pulse wave measuring surface at a position spaced a predetermined distance away from the laser displacement sensor. Placing the subject's wrist under the pulse wave sensor, Moving the pressurizing unit to contact the pulse wave sensor of the pulse wave sensor and the laser displacement sensor provided at one end of the pressurizing unit with the subject's wrist; Storing the initial pulse wave signal and the displacement signal measured by the pulse wave sensor and the laser displacement sensor in a data acquisition unit; The pulse wave sensor provided in the pressing unit is pressurized in increments of 10 to 20 steps on the subject's wrist, Storing the pulse wave signal and the displacement signal measured by the pulse wave sensor and the laser displacement sensor in the data acquisition unit in increments of 10 to 20 steps. Calculating an average of a pulse wave signal and a displacement signal stored in the data acquisition unit by a calculation unit; Deriving a relationship of pulse wave parameters including pulse pressure for each of the number of steps, pressing force, and moving distance of the pressing unit in the calculating unit, and The pulse wave measuring method comprising the step of estimating the blood vessel diameter if the movement distance of the laser displacement sensor is greater than 1.5mm to 4.5mm, and at the same time the pulse wave is not detected. The method of claim 5, The pulse wave further comprises the step of repeating the step of returning to pressurizing the pulse wave sensor in increments of 10 to 20 steps to the subject's wrist when the movement distance of the laser displacement sensor is less than 1.5mm to 4.5mm, or the pulse wave is detected How to measure.

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