JPS62183743A - Digital electronic hemomanometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to an electronic finger blood pressure monitor.

(b) Conventional technology In general, electronic finger blood pressure monitors use dental cuffs to press the finger.
A photoelectric pulse wave sensor attached to this dental cuff detects changes in arterial volume due to finger pressure, and a pressure sensor detects the pressure inside the cuff (hereinafter referred to as cuff pressure), and the cuff pressure is reduced during the cuff pressure reduction process. It is known that the blood pressure value and pulse rate are determined based on the pulse wave and cuff pressure obtained from the cuff.

As shown in FIG. 6, the pulse wave is generated gradually as the cuff pressure decreases, and after reaching a maximum amplitude value, the pulse wave attenuates.

At this time, the cuff pressure corresponding to around point 8 in Figure 6 (around the time when the pulse wave starts to occur) corresponds to the systolic blood pressure, and around point M (around the time when the maximum amplitude value of the pulse wave is observed). It has been clinically confirmed that the cuff pressure corresponding to the point D corresponds to the mean blood pressure, and the cuff pressure corresponding to the vicinity of point D (near the point at which pulse wave attenuation starts) corresponds to the diastolic blood pressure.

In the above-mentioned conventional digital finger blood pressure monitor, for the above-mentioned pulse wave, 8 points, M
points, etc., and determine the systolic blood pressure, etc. Therefore, in order to calculate the pulse wave amplitude value for each pulse wave (each cycle) and to accurately determine the pulse rate, it is necessary to accurately capture one cycle of the pulse wave. Ta. As a means for capturing one cycle of a pulse wave, that is, as a means for recognizing a pulse wave,
If the time differential of the pulse wave obtained by the pulse wave differentiator (hereinafter referred to as pulse wave differential) exceeds a predetermined threshold, it is assumed that a pulse wave has appeared, and the time of appearance of each pulse wave is A pulse wave recognition means has been adopted that recognizes one cycle of the pulse wave by understanding the pulse wave.

(c) Problems to be solved by the invention The problems with the above-mentioned conventional digital finger blood pressure monitor are shown in Figure 5 (
This will be explained below with reference to a) and FIG. 5(b).

Figure 5(a) shows the waveform of the pulse wave detected by the pulse wave sensor, and the left half is near point S in Figure 6, where the cuff pressure corresponds to the systolic blood pressure (hereinafter referred to as SYS). The right half shows the pulse waves around the midpoint of Figure 6, that is, the pulse waves before and after the time when the cuff pressure corresponds to the diastolic blood pressure (hereinafter referred to as DIA), with time taken on the horizontal axis. ing.

On the other hand, FIG. 5(b) shows the waveform of the pulse wave differential of the pulse wave shown in FIG. 5(a), and as in FIG.
The waveform of the pulse wave differential near ys is shown in the right half, and the waveform of the pulse wave differential near DIA is shown in the right half.

The pulse wave recognition means assumes that a pulse wave appears at the time when the level of the pulse wave differential exceeds a predetermined threshold Th, that is, at the time indicated by the small white circle in FIG. 5(b). The point at which this pulse wave originates is also indicated by a small white circle on the waveform shown in FIG. 5(a).

Regarding pulse waves near SYS, regardless of the size of the pulse wave of the subject, the waveform of the pulse wave is a simple pulse, and the difference in waveform between the pulse wave differentials corresponding to each pulse wave is small. The point in time when the level of the pulse wave differential exceeds the threshold value Th substantially corresponds to the point in time when the pulse wave appears, and it was possible to recognize one cycle of the pulse wave within a satisfactory range.

On the other hand, for a subject with a large pulse wave, the pulse wave near the DIA has a triangular waveform as shown in the right half of FIG. 5(a). Considerable differences occur in the pulse wave differential waveforms corresponding to each pulse wave near this DIA, and the point at which the pulse wave differential level exceeds the threshold may deviate from the time when the pulse wave appears. 5 (a), right half], it was sometimes impossible to accurately recognize one cycle of each pulse wave.

If one cycle of the pulse wave is not accurately recognized, an accurate amplitude value of the pulse wave cannot be obtained, causing an inconvenience that errors occur in blood pressure measurement and pulse rate measurement. In addition, with digital finger blood pressure monitors that are configured to sound a buzzer or the like at the same time as the appearance of a pulse wave, the buzzer sounds at irregular intervals, which may cause the patient to be measured. However, there was an inconvenience in that patients were distrustful of electronic finger blood pressure monitors.

This invention was made in view of the above-mentioned disadvantages, and provides an electronic finger blood pressure monitor that accurately recognizes pulse waves, reduces errors in determining blood pressure and pulse rate, and does not cause distrust in the person being measured. The purpose is to provide

(d) Means for Solving the Problems The electronic finger blood pressure monitor of the present invention, as schematically shown in FIG. a pressurizing means 2, a depressurizing means 3 for reducing the pressure in the cafe, a pressure sensor 4 for detecting the pressure in the cafe, a pulse wave sensor 5 attached to the cuff 1 and detecting the pulse wave from the finger; Pulse wave differentiating means 6 that calculates the time differential of the pulse wave detected by the wave sensor 5; Pulse wave recognizing means 7 that recognizes the pulse wave when the maximum value of the output signal of the pulse wave differentiating means 6 is detected; A blood pressure determination means 8 is provided which responds to the pulse wave recognition means 7 and determines the blood pressure based on the pulse wave detected by the pulse wave sensor 5 and the cuff pressure detected by the pressure sensor 4.

(E) Effect The effect of this invention is shown again in FIGS. 5(a) and 5(b).
This will be explained below with reference to.

First, if we pay attention to the pulse wave differential near DIA in the right half of Figure 5 (bl), the pulse wave differential of each pulse wave has a maximum value as shown by the upper arrow in the figure. The points corresponding to the maxima are represented by small black circles on the pulse wave near DIA in the right half of Figure 5 (al).If you pay attention to these small black circles, you can see that the pulse wave is divided into almost exactly one cycle. It is confirmed that
If the appearance of the maximum value of the pulse wave differential is considered as the appearance of the next cycle of the pulse wave, the pulse wave can be accurately recognized even in the case of a subject who has obtained the pulse wave level.

The above pulse wave recognition method can also be applied to the pulse wave near sys [see the left half of Fig. 5 (a)], and the
The points represented by the small and medium black circles in Figure 5 (a), which correspond to the maximum values of the pulse wave differential indicated by the middle and downward arrows, indicate that each pulse wave is accurately divided into one period, and each pulse wave is accurate. will be recognized.

(F) Embodiment An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

FIG. 2 is an external perspective view of an electronic finger sphygmomanometer in which the present invention is implemented. has been done.

The case surface of the main body 11 is provided with a display 14 for displaying systolic blood pressure, diastolic blood pressure, etc., a pressurization value setter 15 for selecting a pressurization setting value, a clear key 16, a start key 17, and a power key 18. It is being

Further, a cuff rubber bag 19 having a cylindrical outer shape is stored in the case of the cuff storage portion 12. Although not shown, this cuff rubber bag 19 is provided with a pulse wave sensor for detecting finger pulse waves, an electric signal line connecting this pulse wave sensor and the main body ti, and an electric signal line connecting the cuff rubber bag 10 and the main body 11. The rubber tubes connecting the two are bundled and connected as a cord wire 13 between the two.

FIG. 3 shows a circuit block diagram of the electronic finger blood pressure monitor. In the figure, a pressurization value setting switch 15a, a clear switch 16a, a start switch 17a, and a power switch 18a correspond to the pressurization value setting device 15, clear key 16, start key 17, and power key 18, respectively.
It is designed to turn on when these keys are operated. The on/off signals and setting signals for each of these switches are C
It is designed to be input to PU20.

The motor drive circuit 21 receives instructions from the CPU 20.
The motor 22 of the pressurizing pump (pressurizing means) is turned on/off. By starting the motor 22, the cuff rubber bag 19 is pressurized.

Further, the rapid exhaust valve drive circuit 23 is configured to control opening and closing of the pulp (pressure reducing means) 24 based on commands from the CPU 20.

By driving the motor 22, air pressure is supplied to the cuff rubber bag 19 via the air tank 25, and the pressure in the cuff rubber bag 19 is converted into an electrical signal by the semiconductor pressure sensor 26, and then A/D converted via the amplifier circuit 27. The digital signal is converted into a digital signal by the device 28, and then taken into the CPU 20.

Furthermore, the LED drive circuit 29 drives a light emitting element 30 attached to the cuff rubber bag 19 in response to a command from the CPU 20, while a signal received by the light receiving element 31 is transmitted through a filter 32 and an amplifier circuit 33. , A/D converter 28
The data is digitally converted and then taken into the CPU 20. Light emitting element 30 and light receiving element 31
A pulse wave sensor is configured.

Display data from the CPU 20 is displayed on a display (LCD) 14 via an LCD drive circuit 34. In addition, in order to recognize each pulse wave and notify errors, etc., the buzzer drive circuit 35 receives a command from the CPU 20.
The buzzer 36 is driven through the process. In addition, 37 is a slow exhaust valve (one-pressure means).

The CPU 20 executes various functions according to the programs in the flowcharts described later, and each of the above-mentioned component circuits
Under the control of 20, blood pressure measurement operation is executed.

Next, the operation of the digital finger blood pressure monitor according to this example will be described in the fourth section.
This will be explained below with reference to the figures.

The right hand side of FIG. 4 shows a blood pressure determination routine for determining 5YS-DIA and pulse rate. When the power switch 18a is turned on, input/output and display are first initialized (step (hereinafter referred to as ST) 1).
It waits at Sr1 until the start switch 17a is turned on.

In Sr1, when the subject inserts a finger (for example, the index finger of the left hand) into the cuff rubber bag 19 and turns on the start switch 17a, the process proceeds to the next Sr3, where the CPU 20 gives a command to the motor drive circuit 21, and the motor 22 starts driving. the cuff rubber bag 19 until the set value selected with the pressurization value setting switch 15a
Pressurize. When the cuff rubber bag 19 is pressurized to a set value, the motor 22 is stopped and slow exhaustion is started from the slow exhaust valve 37 (Sr1).

Following the processing, the systolic blood pressure is determined (Sr5), then the mean blood pressure is determined (Sr6), and the diastolic blood pressure is determined based on the systolic blood pressure and the mean blood pressure (Sr1).
, and the pulse rate is determined (Sr8). Note that there are various algorithms for calculating the systolic blood pressure, mean blood pressure, and diastolic blood pressure. For example, the systolic blood pressure is defined as the cuff pressure at the time when the pulse wave amplitude value of the pulse wave detected by the pulse wave sensor exceeds a predetermined level, and the cuff pressure at the maximum pulse wave amplitude value is defined as the average blood pressure. The diastolic blood pressure is calculated from the blood pressure by (3 x mean blood pressure - systolic blood pressure)/2. However, in this invention, since the blood pressure determination process is not the main part, detailed explanation thereof will be omitted.

- The systolic blood pressure etc. determined in Sr5 to Sr8 are displayed on the display 14 (Sr9), and then the CPU 20 gives a command to the rapid exhaust valve drive circuit 23, opens the valve 24, and rapidly exhausts the cuff rubber bag 19. 5TIO) and end the blood pressure measurement.

The right hand portion of FIG. 4 is a pulse wave recognition routine that is processed in parallel with the blood pressure determination routine. This pulse wave recognition routine starts with the initialization (STI) of the blood pressure determination routine, and is repeatedly executed during execution of the blood pressure determination routine.

In 5T11, the latest pulse wave level
i and the previously sampled pulse wave level X1-1
The difference value (XiXi-1) between the xt and xt is calculated as a pulse wave differential and compared with the cutoff value xt.

If xi On the other hand, x1
If ~X1-1 is greater than or equal to xt, the process advances to 5T12 to perform pulse wave recognition processing, which will be described later. In addition, the above 5TII
Then, the sampled pulse wave level (xiXi-1)
Although this is defined as the pulse wave differential level, the means for obtaining the pulse wave differential is not limited to this.

In the next 5T12, X i X i of said 5TII
-1 is equal to the maximum value xtz. At 5T13, the process waits until the next pulse wave level data Xj is obtained, and when Xj is obtained, the process proceeds to 5T14, where the previously sampled pulse wave value xJ-I (Xj when proceeding from ST12 to 5T13)
-1 is X in 5TII) and the difference (xj
"=-+)" is determined to be positive or negative. If X, -Xj-, is negative, it is assumed that the pulse wave differential has started to decrease after taking the maximum value, and the process proceeds to 5T17, where the pulse wave recognition flag is set. stand up,
The appearance of the pulse wave is determined by the systolic blood pressure determination process (S) of the blood pressure determination routine.
r5), the average blood pressure determination process (Sr6), and the pulse rate determination process (Sr8). At this time, although not shown in FIG. 4, the CPU 20 gives a command to the buzzer drive circuit 35, and the buzzer 36 rings briefly once to notify the subject that the pulse wave has been recognized. When 5T17 is executed, the pulse wave recognition process is temporarily terminated.

On the other hand, if it is determined in 5T14 that Xj-Xj- is positive or zero, it is determined that the pulse wave differential level is increasing, and the process proceeds to 5T15, where the magnitude of Xj-xj-1 and xj2 is compared.・Be judged. If it is determined in 5T15 that Xj"j-1 is greater than xj2, the process advances to 5T16, updates Xj-Xj-, to xt2, returns to 5T13, and returns
j If it is determined that Xj-1 is less than or equal to xt, directly return to 5T13 without updating xj2,
The above processes 5T13 to 5T16 are repeated until the pulse wave differential level takes the maximum value and starts decreasing, and the time when the pulse wave appears is recognized.

Note that the external appearance, circuit configuration, blood pressure determination procedure, etc. of the digital finger blood pressure monitor of the present invention are not limited to those of the above embodiments, and the design can be changed as appropriate.

(G) Effects of the Invention The electronic finger blood pressure monitor of the present invention includes a cuff for compressing a finger, a pressurizing means for pressurizing the cuff to a predetermined set value, and a depressurizer for reducing the pressure of the cuff. a pressure sensor for detecting the pressure of the cuff; a pulse wave sensor attached to the cuff for detecting the pulse wave from the finger; and a pulse wave sensor for calculating the time differential of the pulse wave detected by the pulse wave sensor. a pulse wave differentiating means, a pulse wave recognizing means for recognizing the appearance of a pulse wave when the maximum value of the output signal of the pulse wave differentiating means is detected, and a pulse wave detected by the pulse wave sensor in response to the pulse wave recognizing means. Since it is equipped with a blood pressure determining means that determines blood pressure based on the pulse wave and the cuff pressure detected by the pressure sensor, the pulse wave can be accurately recognized regardless of the size of the pulse wave of the subject. However, it has the advantage of being able to accurately measure systolic blood pressure, diastolic blood pressure, and pulse rate.

In addition, if the system is configured to sound a buzzer or the like at the same time as pulse wave recognition, each pulse wave can be accurately recognized even if the pulse wave of the subject is large. ,
It also has the advantage that the buzzer does not ring at irregular intervals, which eliminates the subject's distrust of the digital finger blood pressure monitor.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a schematic configuration of the present invention, FIG. 2 is an external perspective view of an electronic finger blood pressure monitor according to an embodiment of the present invention, and FIG. A circuit block diagram, FIG. 4 is a flow diagram explaining the operation of the electronic blood pressure monitor for equal authority,
FIG. 5 is a diagram illustrating the problems of the prior art and details of the present invention. FIG. 6 is a diagram showing the time-differentiated waveform of the pulse wave shown in FIG. Sensor, 5: Pulse wave sensor, 6: Pulse wave differentiating means, 7: Pulse wave recognition means, 8: Blood pressure determining means. Patent applicant Tateishi Electric Co., Ltd. Agent
Patent Attorney Shigeru Nakamura Figure 1 Figure 4 Figure 8 A/] → No. 6

Claims (1)

[Claims] (1) A cuff for compressing a finger, a pressurizing means for pressurizing the cuff to a predetermined set value, a depressurizing means for reducing the pressure of the cuff, and a pressure sensor for detecting the pressure of the cuff, A pulse wave sensor attached to the cuff and detecting the pulse wave from the finger, a pulse wave differentiating means for calculating the time differential of the pulse wave detected by the pulse wave sensor, and an output signal of the pulse wave differentiating means. pulse wave recognition means that recognizes the appearance of a pulse wave when the maximum value of and blood pressure determining means for determining blood pressure based on the above.