JPS61255636A - 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 compresses an artery with a cuff, detects pulse wave amplitude in the process of changing cuff pressure, and uses this pulse wave amplitude to determine blood pressure. Regarding electronic blood pressure monitors.

(B) Prior Art Electronic blood pressure monitors that are generally well known are of the so-called arm type, in which an arm cuff is wrapped around the upper arm to compress the artery.

However, arm-type electronic blood pressure monitors are relatively large and inconvenient to carry, and when wearing an arm cuff, the arm cuff must be rolled up, which is cumbersome. The company has already filed a separate application for an electronic finger blood pressure monitor that uses pressure.

This electronic finger sphygmomanometer detects the amplitude of a pulse wave signal to measure blood pressure, and determines blood pressure from changes in the pulse wave amplitude and cuff pressure. To detect the pulse wave amplitude, extract the pulse wave from the pulse wave component output of the pulse wave sensor, calculate the difference between the maximum value and the minimum value of the pulse wave component for each pulse wave, and calculate this difference value. This is done by measuring the pulse wave amplitude.

In this case, the pulse wave component a (t
) is shown in FIG. 5(A), and this pulse wave component a
In order to detect the pulse wave from (t), as shown in FIG. When a t exceeds the threshold level TH (in the negative direction in the figure), it is determined that there is a pulse wave,
The period from this pulse wave presence to the next pulse wave presence is defined as one beat, and the difference value between the maximum value and the minimum value of the pulse wave components in this interval is defined as the pulse wave amplitude.

(c) Problems to be solved by the invention In the above-mentioned electronic finger blood pressure monitor, if the threshold level TH is set to a low value to detect one pulse wave, there is a problem that noise will be picked up, so it cannot be made too small. However, if the threshold level TH is large, in the case of a person with a small pulse wave amplitude or a person whose pulse wave changes gradually, the differential value will not exceed the threshold level and the pulse wave will not be detected, so the amplitude of each pulse wave j When Aj is illustrated, it becomes as shown in FIG. 5(C), and a sufficient number of data could not be obtained, making it impossible to accurately measure blood pressure.

In view of the above, this invention makes it possible to obtain the necessary data even when the pulse wave amplitude is small, which is often seen in women, or when the pulse wave is smooth, which is seen in people with blood vessel abnormalities.
The purpose of the present invention is to provide an electronic blood pressure monitor that can perform accurate measurements.

(d) Means and operation for solving the problems As shown in FIG. 1, the electronic blood pressure monitor of the present invention includes a cuff 1 that compresses the artery of the subject, and a system that pressurizes or depressurizes the inside of the cuff. a pressure system 2; a cuff pressure sensor 3 that detects cuff pressure;
A pulse wave sensor 4 detects a pulse wave component during the process of cuff pressure change; a pulse wave presence/absence determining means 5 determines the presence or absence of a pulse wave based on the output of the pulse wave sensor; While the presence is being determined, the first pulse wave amplitude detection means 6 which sets the difference value between the maximum value and the minimum value of the output of the pulse wave sensor for each pulse wave as the pulse wave amplitude value, and the pulse wave presence/absence determining means A second pulse wave amplitude detecting means 7 that sets the pulse wave amplitude to the difference value between the maximum value and the minimum value of the output of the pulse wave sensor at each fixed time period while the presence of a pulse wave is not determined.
and the cuff pressure from the cuff pressure sensor and the first and second
and a blood pressure determining means 8 for determining blood pressure based on the pulse wave amplitude detected by the pulse wave amplitude detecting means.

In this electronic blood pressure monitor, when a pulse wave is detected by the pulse wave presence determination means, the pulse wave amplitude is detected for each pulse wave by the first pulse wave amplitude detection means, and conversely, the pulse wave amplitude is detected by the pulse wave presence determination means. If the wave is not detected, the second pulse wave amplitude detection means detects the pulse wave amplitude at regular intervals, and the pulse wave amplitude data necessary for blood pressure determination is obtained from the data obtained by the double door wave amplitude detection means. .

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

FIG. 2 is a schematic block diagram of an electronic finger blood pressure monitor in which the present invention is implemented.

In FIG. 2, the cuff 11 is made of a rubber bag and has a cylindrical shape that allows a finger to be inserted into the cuff 11.
1 is attached with a pulse wave sensor 12, and the pulse wave signal detected by the pulse wave sensor 12 is sent to an MPU (microprocessor unit) 15 via an amplifier 13 and an A/D converter 14.
It is now being incorporated into the

Further, the cuff 11 is connected to a pressure sensor 17 through a rubber tube 16, and also to an air buffer 18, and further connected to a slow exhaust valve 19 and a rapid exhaust valve 20. Also,
The air buffer 18 is connected to a pressurizing pump 21 via a check valve 22 . This pressurizing pump 21 includes a motor (air buffer 18, quick exhaust valve 19,
A pressure system is composed of a rapid exhaust valve 20, a pressurizing pump 21, etc.).

The cuff pressure detected by the pressure sensor 17 is amplified by an amplifier 23, and is taken into the MPU 15 via the A/D converter 14.

The MPU 15 has a built-in memory for storing programs and calculated values, and also has a function of importing pulse wave data and cuff pressure data by switching from the A/D converter 14, a function of turning the pressurizing pump 21 ON10F, and a function of rapid evacuation. Valve 20 0N10
FF function, a function to determine the presence or absence of a pulse wave from the output of the pulse wave sensor 12 after the start of operation, a function to detect the pulse wave/amplitude of each pulse wave on the condition of the presence of a pulse wave, a function on the condition of pulse wave heat. For a certain period of time (
For example: A function to detect pulse wave amplitude every 1.5 seconds), a function to determine blood pressure values such as systolic blood pressure (SYS) and diastolic blood pressure (DIA) from cuff pressure and both pulse wave amplitude data, etc. We are prepared.

Further, the determined blood pressure value, that is, the systolic blood pressure (SYS), etc., is output from the MPU 15 and displayed on the display 24, and a notification sound is generated by the buzzer 25 according to a command from the MPU 15.
More output is now available.

Next, the operation of the electronic blood pressure monitor of the above embodiment will be explained with reference to the control flow diagram shown in FIG.

Before starting the measurement, the measurer inserts his or her index finger into the shaft of the cuff 11 and turns on a power switch (not shown) attached to the MPU 15. This starts the operation, and first, in step ST (hereinafter referred to as ST) 1, all display segments of all digits on the display 24 are lit for 1.5 seconds (5T2).
, then open the rapid exhaust valve 20 < (Sr3) and,
The rapid exhaust mark 8 on the display 24 flashes (Sr4).

Next, it is determined whether the cuff pressure is O or not, and if it is not O, the cuff pressure is O.
Wait until (Sr1). When the cuff pressure becomes O,
Exhaust mark 8 is turned off (5T6), ready mark 9
lights up (Sr1). This lets the measurer know that preparation is complete.

Here, when the start switch also attached to the MPU 15 is turned on, the determination of Sr1 becomes YES and the ready mark 9 disappears (Sr9).

Subsequently, an LED (not shown) indicating that measurement is in progress lights up (5TIO), and the rapid exhaust valve 20 is closed (STI).
1) The cuff 11 is pressurized to the set value (ST12
). The set value here is 2 times higher than the patient's systolic blood pressure.
This refers to the pressurization target value that is set to a higher value by 0 to 30 mmHg. When the pressure is increased to the set value, the pressure pump 21 is set to 0FFL,
It is determined whether the current pressurization is re-pressurization (5T13), and if it is the first pressurization, the process moves to 5T15 and slow exhaustion by the slow exhaust valve 19 is started. However, since the baseline of the pulse wave is not stable immediately after the end of pressurization, it is determined whether or not the baseline has stabilized (ST16), and the process waits until the baseline becomes stable. If the baseline is not stable and the cuff pressure is 40
If it falls below n+mHg (STo 17), it is difficult to determine whether repressurization has already been performed (5T1B), and if repressurization corresponds to the first time, the set value + 3QmmHg
as the new set value (S719), the repressurization mark blinks (Sr20), returns to 5T12, repressurizes to the set value, and when pressurized to the reset value, this time 5T1
The judgment of “Repressurization process” in step 3 is YES, and the repressurization mark? is turned off (ST14).

If the pressure has already been repressurized once and this is the second time, the judgment in 5T1B is No, the LED is turned off (5T31), and then the rapid exhaust valve 20 is opened to temporarily exhaust the air. . When the baseline becomes stable by the time the cuff pressure decreases to the set value of 40 mm+Hg, the determination at 5T16 becomes YES, and the subsequent processing moves to measurement of the amplitude of each pulse wave. That is, let the pulse number j for finding the amplitude of the pulse wave be O, Sr21),
Furthermore, the sample counter i within one beat is set to 1,
Let the pulse number j=1, the maximum value x wax of the pulse wave level be 0, and the minimum value x + aLn be x sup (Sr22
).

Here x sup is pulse wave level X! is the upper limit that can be taken.

Subsequently, at 5T23, it is determined whether the cuff pressure is greater than 20 mmHg. If less than 20IIIHg, 5
731, turns off the LED, returns to Sr3, opens the rapid exhaust valve 20, turns on the exhaust mark (Sr4), and waits for exhaust, but under normal conditions, the judgment of 5T23 is YES, and then the pulse wave The data Xi is read (Sr24), the difference value between the previous pulse wave data X1-1 and the current pulse wave data Xi is determined, and it is determined whether this difference value has become larger than a predetermined value x2 (Sr25). This determination is made in order to determine that the pulse wave is one beat at a point where the pulse wave level changes rapidly. In other words, Xl-1-Xi indicates the output of the pulse wave sensor 12, that is, the differential value of the pulse wave level, and it is checked whether this differential value "i-1"i is larger than the threshold level Xt. The larger size is 5T25.
The determination becomes YES, which means that a pulse wave has been detected.

If the determination of 5T25 is NO, move on to the next 5T32,
Determine whether pulse number j is not updated for 1.5 seconds,
If it has been updated, then compare the current pulse wave data X with the maximum pulse wave value xIIIax (Sr33
), and if xi>xmax, the current pulse wave data X is updated and stored as a new pulse wave maximum value x max (Sr34). Conversely, if X, ≦x max, 5
Skip T34 and move to 5T35. At 5T35, the current pulse wave data Xi and the pulse wave minimum value x min are compared in magnitude.

Then, if )Hi<xmin, the current pulse wave data X is updated and stored as the new minimum pulse wave value xmin (
Sr36), conversely, if Xi ≧x min, 5T
36 and moves to ST3'7.

From 5T33 to 5T36, the maximum value of pulse wave data X11aX
When the update of s minimum value x min is completed, the counter i is incremented by +1 in 5T37 and the process returns to 5T23.
Thereafter, Sr12~ until x, -, -Xi >x.
5T37.5T23 to 5T25 are repeated, and the pulse wave maximum value x max and minimum value x min are updated to 1.5 under the condition that Xl-IXi, which corresponds to the differential value, does not exceed the threshold level Xt. The maximum pulse wave value x max and minimum value x min in the second interval are determined. This x
max and xmin are later used in 5T27 to calculate the pulse wave amplitude Aj in the 1.5 second interval.

When it is determined at 5T25 that Xl-1-Xi is greater than or equal to the predetermined value X2, the buzzer 25 is sounded at 5T26 to notify that a pulse wave has been extracted, that is, that a pulse wave is present. Then, the pulse wave maximum value x max
and the pulse wave minimum value x min, that is, the pulse wave amplitude Aj is determined (Sr27). Pulse number j is 1 at 5T32
．． If it has not been updated for 5 seconds, it is equivalently treated as one beat has passed, and the buzzer 25 does not sound, but the pulse wave amplitude Aj is determined (sT27).

The obtained pulse wave amplitude Aj is stored in the memory within the MPU 15.

The detection operation of this pulse wave amplitude Aj will be supplementarily explained with reference to FIG. 4.

The pulse wave data Xi detected at 5T24 in the above flow, that is, the output of the pulse wave sensor 12 is shown continuously in a time series as shown in FIG. 4(A). In addition, Xl-1"i at 5T25 is the change in the pulse wave level when shifted by one sampling period, so it is a differential value, and
25, this differential value xi-1-Xi is compared with the threshold level Xt shown in FIG. 4(B). Then, as shown in FIG. 4(C), Xl-I Xi 〉X
In the period other than t, the pulse wave amplitude Aj is calculated at 1.5 second intervals (Sr32, ST27), and Xi-+Xt
> During the period of Xt, the pulse wave amplitude A for each pulse wave (1 beat)
j is calculated (Sr25.5T26.5T27).

Therefore, the pulse wave amplitude Aj data can be obtained not only during the period in which the pulse wave is detected in Fig. 4 (B), but also equivalent pulse wave amplitude Aj during other periods, which is necessary for blood pressure measurement. A lot of data can be obtained.

Following the calculation of pulse wave amplitude Aj at 5T27, blood pressure determination processing is performed using this pulse wave amplitude Aj as a parameter (Sr28
). There are various algorithms for determining blood pressure, but for example, the cuff pressure at the point when the pulse wave starts to appear is the systolic blood pressure ps
vs, and the cuff pressure at the time when the pulse wave amplitude (difference value) is maximum is the mean blood pressure P□, and the diastolic blood pressure PDIA
PM! A, 4=PDIA + (Psvs Pn+
A) Calculated from the formula: /3.

and 5T22 until the diastolic pressure P DIA is determined.
Return to 5T22, add 1 to the pulse number j, and then repeat the above process to calculate the pulse wave amplitude Aj (maximum value x + wax and minimum value x winO difference value) for each pulse wave,
Continue blood pressure determination processing.

When the systolic blood pressure and diastolic blood pressure determination process is completed (Sr2
9), these blood pressure values are displayed on the display 24 (Sr3
0), then turn off the LED S731), Sr1
Then, the rapid exhaust valve 20 is operated and the measurement operation is completed.

(f) Effects of the invention According to this invention, even when pulse wave detection cannot be partially performed,
During that period, the pulse wave amplitude is determined using a pseudo pulse wave at regular intervals, so even if the pulse wave amplitude is small or the pulse wave is gentle, the predetermined pulse wave amplitude data can be obtained. Accurate blood pressure measurement can be performed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of the present invention, FIG. 2 is a block diagram of an electronic finger blood pressure monitor in which the present invention is implemented, and FIG.
4 is a flowchart for explaining the operation of the electronic blood pressure monitor for equal authority, FIG. 4 is a time chart for explaining the operation of the electronic blood pressure monitor for equal authority, and FIG. The pulse wave component waveform, Figure 4 (B) is the differential waveform of the same pulse wave component, Figure 4 (C
) is a diagram showing the extracted pulse wave amplitude, and FIG. 5 is a time chart for explaining the conventional example.
5(B) is a differential waveform of the same pulse wave component, and FIG. 5(C) is a diagram showing the extracted pulse wave amplitude. 1: Cuff, 2: Pressure system, 3: Cuff pressure sensor, 4: Pulse wave sensor, 5: Pulse wave presence/absence determination means, 6: First pulse wave amplitude detection means, 7: Second pulse wave amplitude detection means , 8: Blood pressure determination means. Patent applicant Tateishi Electric Co., Ltd. Agent
Patent Attorney Shigeru Nakamura Figure 1, Ward 2'! J4 figure

Claims (1)

[Claims] (1) A cuff that compresses the artery of the subject, a pressure system that pressurizes or depressurizes the inside of the cuff, a cuff pressure sensor that detects the pressure of the cuff, and a pulse wave component that detects the pulse wave component during the process of changing the cuff pressure. A pulse wave sensor for detecting a pulse wave, a pulse wave presence/absence determining means for determining the presence or absence of a pulse wave based on the pulse wave sensor output, and a pulse wave for each pulse wave while the pulse wave presence/absence determining means determines the presence of a pulse wave. A first pulse wave amplitude detection means takes the difference value between the maximum value and the minimum value of the sensor output as a pulse wave amplitude value, and the pulse wave detection means detects the pulse wave at a certain time interval while the pulse wave presence determination means does not determine the presence of a pulse wave. a second pulse wave amplitude detection means for determining the difference between the maximum value and the minimum value of the wave sensor output as a pulse wave amplitude value; and cuff pressure from the cuff pressure sensor and the first and second pulse wave amplitude detection means. An electronic sphygmomanometer comprising a blood pressure determination means for determining blood pressure based on pulse wave amplitude and pulse wave amplitude.