JPS6287128A - 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 (a) Industrial Application Field This invention is based on the cuff pressure detected by a pulse wave sensor and the pulse wave amplitude extracted from the pulse wave component detected by the pulse wave sensor. This invention relates to an electronic finger sphygmomanometer for determining blood pressure.

(b) Conventional technology Electronic blood pressure monitors use a pressurizing means to pressurize a cuff attached around the finger, and in the subsequent pressure reduction process, the pulse wave amplitude is obtained from the pulse wave component detected by the pulse wave sensor. There are systems that determine blood pressure such as systolic blood pressure, mean blood pressure, and diastolic blood pressure based on this pulse wave amplitude and cuff pressure detected by a pressure sensor. In this type of electronic blood pressure monitor, there are various specific algorithms for determining blood pressure, but if the cuff pressure and pulse wave amplitude change over time as shown in FIG. The cuff pressure corresponding to the point exceeding systolic blood pressure sys is defined as systolic blood pressure sys, the cuff pressure corresponding to the point where the pulse wave amplitude is at its peak is defined as mean blood pressure MAP, and further, from these systolic blood pressure SYS and mean blood pressure MAP, (3MAP-3YS
)/2, the diastolic blood pressure DIA is calculated.

In this electronic blood pressure monitor, it is necessary to extract the peak point of pulse wave amplitude in order to determine the mean blood pressure and diastolic blood pressure.

Conventionally, the difference value between the maximum level and the minimum level of the pulse wave, which are derived in time order, has been obtained as the pulse wave amplitude. When these were arranged on the time axis (cuff pressure), the results were as shown in FIG. In addition, in order to detect the peak point of the pulse wave amplitude, if the change in pulse wave amplitude with respect to time changes from rising to falling, and the decline continues for a predetermined number of times (e.g. 3 times), then the peak point of the pulse wave amplitude up to that point is detected. The value was identified as the peak value.

(c) Problems to be Solved by the Invention When the pulse wave amplitude distribution becomes as shown in FIG. 6, it is possible to extract the peak point of the pulse wave amplitude using the above-described method. However, according to experiments conducted by the inventor of this application, in the finger electronic blood pressure monitor, the pulse wave amplitude changes depending on the breathing of the person being measured.
It was discovered that due to this influence, fluctuations occur as shown in FIG.

Ignoring this variation due to breathing, as in the conventional method, based on the distribution of pulse wave amplitude for each pulse wave, when the pulse wave amplitude changes from rising to falling and continues to fall a predetermined number of times, the maximum value up to that point is calculated. If you identify it as peak E, it will lead to misjudgment of the peak value point.
There was a problem in that there was a risk of obtaining erroneous measurement results.

In view of the above, an object of the present invention is to provide an electronic finger blood pressure monitor that can eliminate fluctuations in pulse wave amplitude caused by breathing, accurately capture the peak point of pulse wave amplitude, and perform highly accurate measurements. .

(d) Means and operation for solving the problems The electronic finger blood pressure monitor of the present invention, as shown schematically in FIG. A pressure means 2, a pressure reduction means 3 for reducing the pressure of the cuff, a pressure sensor 4 for detecting the pressure of the cuff, a pulse wave sensor 5 attached to the cuff for detecting pulse waves, and a pulse wave sensor 5 for detecting pulse waves detected by the pulse wave sensor. pulse wave amplitude extraction means 6 for time-sequentially extracting the pulse wave amplitudes of the pulse wave components that are extracted; moving average pulse wave amplitude calculating means 7 for calculating the moving average of the extracted pulse wave amplitudes; It comprises a blood pressure determining means 8 which determines the blood pressure based on the moving average pulse wave amplitude calculated by the calculating means and the cuff pressure which is the output of the pressure sensor.

In this electronic finger blood pressure monitor, the pulse wave amplitude extraction means first extracts the pulse wave amplitude of each pulse wave from the pulse wave component detected by the pulse wave sensor, and then moves the pulse wave amplitude of each pulse wave. The average is calculated by a moving average pulse wave amplitude calculation means. Then, blood pressure is determined based on the obtained moving average pulse wave amplitude and the cuff pressure that is the output of the pressure sensor. In this case, the peak value of the pulse wave amplitude used in blood pressure determination is specified by applying a predetermined method to the moving average pulse wave amplitude. Fluctuations in pulse wave amplitude due to breathing are removed by moving average processing of the pulse wave amplitude.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

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

On the front of the case of the main body 11, there are a display 14 for displaying systolic blood pressure, diastolic blood pressure, pulse rate, etc., a pressurization value setting device 15 for selecting a pressurization setting value, a clear key 16, and a start key 1.
7. A power key 18 is provided.

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, and an electric signal line connecting this pulse wave sensor and the main body 11 and the cuff rubber bag 19 and the main body 11 are provided. 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 pump motor 22 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 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, which is 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 according to a command from the CPU 20.
On the other hand, a signal received by the light receiving element 31 is digitally converted by an A/D converter 28 via a filter 32 and an amplifier circuit 33, and is also taken into the CPU 20. The light emitting element 30 and the light receiving element 31 constitute a pulse wave sensor.

Display data from the CPU 20 is displayed on a display (LCD) 14 via an LCD drive circuit 34. Further, a buzzer 36 is driven by a command from the CPU 20 via a buzzer drive circuit 35. Note that 37 is a slow exhaust valve.

The CPU 20 executes various functions according to the programs in the flowcharts described later, and each of the above-mentioned component circuits is
Blood pressure measurement operation is executed under the control of U20.

Next, referring to the flowcharts shown in FIGS. 4 and 5,
The functions of the CPU 20 and the operation of the digital finger blood pressure monitor will be explained.

Overall Operation> First, the overall operation of the finger electronic blood pressure monitor will be described with reference to the flowchart in FIG.

When the power switch 18a is turned on, operation starts,
All display patterns on the display (LCD) 14 are displayed [step ST (hereinafter referred to as ST) 1], and then the display 1
All display patterns No. 4 are turned off, and it is checked whether the display 14 is operating normally. (Sr1). Subsequently, a ready mark (9) is displayed on the display 14 (S
r3). The measurer who sees this ready mark knows that the measurement preparation has been completed, inserts a finger, for example, the index finger of the left hand, into the cuff rubber bag 19, and switches the start switch I7a.
Turn on. By turning on the start switch 17a, the determination of Sr1 becomes YES, and then the ready mark is turned off (Sr5). Then, proceed to pressure treatment.

Specifically, in the pressurizing process, first, the light emitting element 30 is turned on (5T6), the pulp 24 is closed (Sr7), and the pump driving motor 22 is turned on (Sr1).

As a result, the cuff rubber bag 19 is pressurized via the air tank 25. Then, pressurization continues until the current pressure reaches the pressurization set value set by the pressurization value setting device 15, and when the cuff pressure reaches the pressurization set value (Sr9), the motor 22 is turned off and the 5TIO ), end pressurization. Thereafter, the air pressure in the cuff rubber bag 19 is gradually exhausted through the slow exhaust valve 37, and measurement processing begins.

When starting the measurement process, first, a pulse wave stability check is performed (STII), and then points where the pulse wave amplitude exceeds a predetermined threshold value are extracted [in another process, each pulse wave output from the pulse wave sensor is The pulse wave amplitudes of the wave components are each extracted (pulse wave amplitude extraction means)] and the corresponding cuff pressure is determined to be the systolic blood pressure (ST12).

Next, at 5T13, the pulse wave amplitude (this pulse wave amplitude is a moving average pulse wave amplitude) is sequentially checked, the peak point of the pulse wave amplitude is extracted, the corresponding cuff pressure is set as the average blood pressure, and the diastolic blood pressure is (3×mean blood pressure−systolic blood pressure)/2 is calculated to calculate the diastolic blood pressure (blood pressure determining means). This process is important to the present invention and will be described in detail later.

When the measurement is completed, the motor 22 is turned off (ST14).
, the pulp 24 is opened (ST15), and the cuff rubber bag 19 is rapidly evacuated. When the current cuff pressure becomes 2On+m11g or less (ST16), the light emitting element 30 stops emitting light.
TI7), it returns to Sr3 again and waits for the next measurement.

<Mean Blood Pressure Determination, Diastolic Blood Pressure Calculation> Next, the details of the average blood pressure determination and diastolic blood pressure calculation in 5T13 will be explained with reference to the flowchart of FIG. 5.

When the operation enters the process of 5T13, which is not shown in FIG.
In step 11, set AMP-sx and Cuff-y to 0, and set A
Let M P -c be 2. Here, AMP-■ is a storage area for calculating the moving average of five pulse wave amplitudes, and is an area for storing the sum of five pulse wave amplitudes.
−, is 1On+mf1g from the peak point of pulse wave amplitude later
This is an area for memorizing low cuff pressures.

Further, A M P -c is a counter for counting a predetermined value when the pulse wave amplitude continuously decreases, for example.

Following 5T21, the timer T- is set to 1.5 seconds (Sr22). This timer T-, 1.5 seconds means that if 1.5 seconds or more elapses from one pulse wave to the next,
This is to determine that there is an error because the interval is too long.

Next, A M P -sx is A M P -r + A
M P -z + A MP "' 3 + A M
It is determined whether P -4+ A M P -5 or more (Sr23). This determination is made by comparing the sum of the five pulse wave amplitudes with the magnitude relationship of the pulse wave amplitudes already stored in AMP- and 4X. Here AMP-A
M P -z, A M P -:I, A M P -
4. AMP-s is an area for storing the five latest pulse wave amplitudes from the current time. To calculate the moving average from 5 pieces of pulse wave amplitude data before the current time, use A M
P −r + A M P −z+・・・・・・+AM
P-, is further divided by 5, but AMP-MXO
Since both are divided by 5, the comparative judgment omits dividing both by 5. Initially, AMP-Mx is O, and AMP-, +...+AMP-5 are also O, so the decision is YES, and then moves to 5T24.
A M for this time's AMP-, +...+AMP-s
P-sx, and also the third cuff pressure CufC.
uff-3 (AiAMP-2,...,AM
Corresponding to P-s, the corresponding cuff pressure is also Cuff-+,
Cuff-z, Cuff-*, Cuff-a.

It is stored in Cuff-5. Also to Cuff-o, C
Cuff-7) is stored in the mean blood pressure MAP, and further Cuff-7 is stored in the mean blood pressure MAP.
Cuff pressure at the time of current pulse wave detection from Cuff-0 to lQmmHg
Remember the reduced cuff pressure. This cuff pressure is the cuff pressure at a point 10 mmHg lower than the peak point. Also, AMp
- Store 2 in c.

Next, the process moves to 5T25, symbol 9 is displayed, a beeping sound is sounded for 200 milliseconds, and the current cuff pressure Cuff-0 is displayed on the diastolic blood pressure display section.

Subsequently, it is determined whether the clear switch 16a is turned on (Sr26). Normally, if the clear switch 16a is not turned on, this determination is No, and it is further determined whether the timer buzzer T-11LI2 is O or not (
Sr27). If the timer buzzer set to 200 milliseconds does not time up, wait for 200 milliseconds, and when the timer buzzer times up, turn off symbol 9 (5T28) and display the current cuff pressure Cuff-p.
5T29)
Further, it is determined whether or not the timer T-I has timed up and become 0 (Sr30). At this point, if the cuff pressure reaches 20 mm and 11 g or the timer T-, times up and no pulse wave arrives for 1.5 seconds, it is assumed that an error has occurred, and the process moves to 5T43, where H is set to O and Er
A message is displayed, a beep sound is produced for 2 seconds to notify that there is an error, and the process moves to 5T14 to begin exhaust processing.

On the other hand, at 5T29, the cuff pressure Cuff-p was 2Qmmt1g
If the following is not true and the timer T-1 is not 0, that is, 1.5 seconds have not elapsed, the rear switch 16a is not turned on (Sr31), and the AM
If P (pulse wave flag) is O (S732), A
5 until MP-F becomes 1, that is, until AMP-F becomes 1 due to the pulse wave check progressing in another interrupt process.
The processes from T29 to 5T32 are repeated. If the timer T-, does not time up further until the temperature falls below 20 mmHg, and if AMP-I becomes 1 within 1.5 seconds, that is, if the pulse wave amplitude is detected, after setting AMP-F to O at 5T33, (Hg + (150-T-,)) /2 is set as a new Hll, processing for pulse rate detection is performed, and 5T2
Return to 2.

Note that when the clear switch 16a is turned on while the processes 5T29 to 5T32 are being repeated, the determination in 5T31 becomes YES, the storage area H3 is set to 0, and the systolic blood pressure display section is completely turned off (5742). , and then emit a beeping sound for 1 second (Sr41), and then press 5 in Figure 4.
Jump to T14 and begin exhaust processing.

While the pulse wave amplitude detected this time is larger than the previous one, 5T
23 becomes YES and the above-mentioned processing proceeds, but when the pulse wave amplitude passes the peak point and begins to decline, 5T23
The determination becomes NO, and then 1 is subtracted from AMP-0 and stored in a new AMP-0 (Sr34).

Since 2 is already set in AMP-c,
This time, 1 will be stored in AMP-c. Therefore, the determination of ``AMP-c≧0'' at Sr15 is YES, the process jumps to 5T25, and the same process as the previous time proceeds.

When the pulse wave amplitude starts to decrease in the next stage and the second pulse wave amplitude is obtained, the judgment of 5T23 becomes No again, AMP-c-1 is processed in Sr14, and a new AMP-C
is memorized. At this point, since A M P-c is 1, the newly stored AMP-c becomes 0, and 5T
The determination in step 35 is still YES, and the process jumps to 5T25, and the series of processes from 5T25 to ST33 is continued in the same manner as the previous time and the time before the previous time. Then, it returns to 5T22 again, and after starting to fall at 5T23, the third moving average value also becomes NO, and in this case, -1 for Sr14.
will be counted in AMP-C, so 5T3
The judgment of 5 was No, and it was 5T36 for the first time in this third time.
, and here further “Cuff-0≧Cuff-7
The current cuff pressure Cuff-0 is set 10 mmf (g) lower than the peak point cuff pressure.
Determine whether it is larger than f−y. If the cuff pressure Cuff-0 at the time of current pulse wave detection is larger, the maximum value of the pulse wave amplitude up to that point is not determined as the peak value yet, and the process moves to 5T25 to perform the same processing as the previous time. For example, even though the pulse wave cycle is very fast and all three pulse wave detections show a downward trend, it is dangerous to conclude that this is the true peak point when the cuff pressure hardly decreases. Yes, the process will be like this.

However, when Cuff-o becomes smaller than Cuff-y at 5T36, it means that the cuff pressure itself has dropped considerably after three pulse wave amplitude detections, and following judgment No at 5T36, at that point at 5T37. The cuff pressure corresponding to the peak value of the pulse wave amplitude up to that point is determined as the mean blood pressure MAP,
The diastolic blood pressure CIA is calculated from the mean blood pressure MAP and the systolic blood pressure sys using the following formula.

Then, this diastolic blood pressure DIA is displayed on the diastolic blood pressure display section (Sr37).

After that, divide 6000 by H3 and store it in H, 5T38), and if this H8 is 200 or more (Sr39),
Or check whether it is 40 or less (Sr40), and if 1 step < YES, x color processing (Sr4
3) However, if H6 is less than 200 or more than 40,
Since the pulse rate was within the normal range, it made a strange beeping sound (Sr41) and moved to STI 4 to perform exhaust processing.

(f) Effects of the Invention According to this invention, when determining blood pressure based on pulse wave amplitude and cuff pressure, a moving average pulse wave amplitude is calculated, and a peak value is detected for this moving average pulse wave amplitude. Because it performs processing, even if the pulse wave amplitude of each pulse wave fluctuates due to breathing, that fluctuation is alleviated by the moving average, making it possible to identify the correct peak value and achieve high accuracy. Blood pressure measurements can be taken.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a schematic configuration of the present invention, FIG. 2 is an external perspective view of an electronic finger blood pressure monitor in which the present invention is implemented, and FIG.
The figure is a circuit block diagram of an electronic blood pressure monitor for peer use, and Figure 4 is:
FIG. 5 is a flow chart showing the average blood pressure determination and diastolic blood pressure calculation routine in more detail in the overall flow, and FIG. FIG. 7, a diagram showing pulse wave amplitude changes, is a diagram for explaining pulse wave amplitude fluctuations due to breathing. 1: Cuff, 2: Pressurizing means, 3: Applanation stage, 4: Pressure sensor, 5: Pulse wave sensor, 6: Pulse wave amplitude extraction means, 7: Moving average pulse wave amplitude calculation means, 8: Blood pressure determination means. Patent applicant Tateishi Electric Co., Ltd. Agent
Patent Attorney Shigeru Nakamura Figure 1, District 6, Figure 7 Procedure Ne TIT Correction 1 ((spontaneous) 1. Indication of the case 1985 Patent Application No. 229443 2 Name of the invention Electronic finger blood pressure monitor 3, Amendment Relationship with the case of a person who does
94) Tateishi Electric Co., Ltd. Representative Takao Tateishi 4, Agent ■600 Address 6 Kakihonmachi, Gojo-dori Omiya Higashiiri-ru, Shimogyo-ku, Kyoto-shi, subject of correction 1 screen/tsu to °- 3 C, l-” 7.1ili Correct contents Figure 2 of the drawing is corrected as shown in the attached sheet. 8. List of attached documents ([) Drawing C Figure 2] One or more copies

Claims (1)

[Claims] (1) A cuff for compressing a finger, a pressurizing means for pressurizing the cuff, a depressurizing means for depressurizing the cuff, a pressure sensor for detecting the pressure of the cuff, and a pressure sensor attached to the cuff for detecting pulse waves. A pulse wave sensor for detecting a pulse wave, a pulse wave amplitude extraction means for time-sequentially extracting the pulse wave amplitude of a pulse wave component detected by the pulse wave sensor, and a moving average pulse wave for calculating a moving average of the extracted pulse wave amplitudes. A finger electronic device comprising a wave amplitude calculation means, and a blood pressure determination means for determining blood pressure based on the moving average pulse wave amplitude calculated by the moving average pulse wave amplitude calculation means and the cuff pressure that is the output of the pressure sensor. Sphygmomanometer.