JPS61196936A - 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) Field of Industrial Application This invention relates to an electronic blood pressure monitor, particularly an electronic blood pressure monitor employing a vibration method.

“(B) Conventional technology” In electronic blood pressure monitors, a cuff is wrapped around the upper arm, and in the process of pressurizing the cuff to a predetermined value and then depressurizing it, the cuff pressure and the waveform of the pulse wave component contained in the cuff pressure are Based on information.

Some devices employ the so-called oscillatory method to determine mean blood pressure, systolic blood pressure, and diastolic blood pressure. This type of electronic blood pressure monitor
As shown in Figure 6(a), the DC component of the cuff pressure signal which is being depressurized by slow evacuation is detected, and the pulse wave component contained in this cuff pressure signal is extracted [Figure 6(b)]. For example, find the maximum pulse width for each beat of this pulse wave component, and use this maximum pulse width as a parameter to create a time series (or cuff pressure series).
Arrange in.

The envelope shown in FIG. 6(c) is obtained, and the blood pressure value is determined from this envelope and the cuff pressure DC. There are various algorithms for determining blood pressure.9 For example, the cuff pressure corresponding to the maximum value point of the parameter (envelope line) is the average blood pressure, and the cuff pressure on the high pressure side corresponding to the parameter corresponding to 50% of the maximum value point is the cuff pressure. Assume systolic blood pressure.

The cuff pressure on the low pressure side corresponding to the parameter corresponding to 70% of the maximum point is determined as the diastolic blood pressure.

In addition, there is a method in which the parameters are determined by dividing each fixed period, and the difference between the maximum and minimum values of the cuff pressure for each period is determined, and this is used as the pulse wave parameter for that period.

(c) Problems to be solved by the invention In the electronic blood pressure monitor that uses the vibration method described above, the time series of parameters in a normal case or the distribution corresponding to cuff pressure changes is the distribution shown in Figure 6 ((1)). Naruga.

For example, an abnormal distribution as shown in FIG. 6(d) may occur due to arm movement or the like. If such an abnormal distribution occurs and blood pressure is determined by applying a normal algorithm, there is a problem in that a large error will occur in the measurement results.

In view of the above, it is an object of the present invention to provide an electronic blood pressure monitor that does not cause measurement errors even when an abnormality occurs in the parameter distribution.

B) Means for Solving the Problems The electronic blood pressure monitor of the present invention, as schematically shown in FIG. , a force sensor 3 that detects the cuff pressure, a pulse wave parameter extraction means 4 that extracts parameters within a predetermined section of the pulse wave component included in the cuff pressure for each section, and a In an electronic sphygmomanometer including a blood pressure determining means 5 for determining blood pressure, a first determination is made in which the current parameter value is compared with the previous parameter value to determine whether the current parameter value is larger. means 6, a first difference calculation means 7 for calculating the difference between the current parameter value and the previous parameter value, and a second difference calculation means 7 for determining whether the first difference is greater than or equal to a predetermined value. a second difference calculation means 9 for calculating the difference value between the first parameter value and the second parameter value;
It is characteristically equipped with a third determining means 10 for determining whether or not the difference value is larger than the difference value by an equivalent value or more.

(E) Effect In this electronic blood pressure monitor, if the parameters extracted by the pulse wave parameter extraction means 4 have the distribution shown in FIG.
At time t(i), the current parameter value Hi and the parameter value H(i-1) at the previous time L(i-1) are compared by the first determining means 6, and H(i)>H. (i-1) If t' exists, there is a probability that the parameter value is increasing and is abnormal. Also, the difference value Ki=H(i)-H(i-
1) is calculated by the first difference calculation means 7, and 1 is added to this difference value.
is compared with a predetermined value by the second determining means 8. If the difference value is 1 or more than a predetermined value, it means that the rate of increase in the parameter value is large, and the probability that the current parameter value is abnormal becomes even higher.

However, the rate of increase in the parameters is greater at the 9th point even when the parameters are normal. Therefore, in addition, the puff meter value H (i-1) of the previous one and the parameter value H (i-2) of the second previous
2 = H(1-1) - H(1-2) is the second
The difference value calculation means 9 calculates the difference value, and the third determination means 10 compares whether the difference value 1 is considerably larger than the difference value 2. If K1>α・K2 (α: constant), it means that the parameter value has increased rapidly this time, and the first value of 1 or more
．． Second. If the third determining means outputs a positive result, the current parameter value is determined to be abnormal.

(f) Example Hereinafter, this invention will be explained in more detail with reference to Examples.

FIG. 2 is a block diagram of an electronic blood pressure monitor in which the present invention is implemented. In the figure, a cuff 11 is a rubber bag that is wrapped around the arm, and is connected to an exhaust valve 15 and a pressure pump 14, which constitute a pressure system 12, through a rubber tube 15. Further, the pressure sensor 16 is also connected to the cuff 11 by the rubber tube 15.
communicated with.

Converts cuff pressure into an electrical signal. The output end of the pressure sensor 16 is connected to the input end of the amplifier 17, and the output electrical signal of the pressure sensor 16, that is, the cuff pressure signal.

The amplifier 17 amplifies the direct current. The output terminal of the amplifier 17 is A
It is connected to one end of the input of the /D converter 18 and also to the input end of the bandpass filter 19 . The output end of the A/D converter 18 is connected to the CPU 20, and the output of the amplifier 17 and the output of the bandpass filter 19 are converted into digital signals by the A/D converter 18, and then input to the CPU 19.

The CPU 20 executes predetermined processing according to a built-in program, has a function of extracting parameters (level difference between maximum value and minimum value) for each fixed time interval (window), and extracts systolic blood pressure from the cuff pressure and the parameters.

It has a function of determining blood pressure values such as diastolic blood pressure, and the determined blood pressure values are displayed on the display unit 11. In addition to the above-mentioned general functions, the CPU 10 also has a parameter value correction function.

Further, when the measurement start key 9 (not shown) is operated, the CPU 20 starts the operation of the pressurizing pump 14 in response to a command a.
When the cuff 11 is pressurized, the exhaust amount of the exhaust valve 13 is controlled by commands. In addition, the cuff pressure from the amplifier 17 and the pulse wave component from the bandpass filter 19 are controlled by commands c and d.
is read at a predetermined sampling period.

The following will refer to the control flow diagram shown in FIG.

The overall operation of the electronic sphygmomanometer according to the embodiment will be explained. .

When a measurement start key (not shown) is pressed to start operation, the pressurizing pump 14 starts operating according to command a [step ST (hereinafter abbreviated as ST) 1], and the cuff is pumped until the cuff pressure reaches sufficient for measurement. 11 is pressurized (Si2"). When the cuff pressure reaches a predetermined cuff pressure, the operation of the pressurizing pump 14 is stopped (ST!), and the exhaust valve 13 is opened by a command. Exhaust at a slow speed and start depressurizing (Si
4). Then, initial settings for parameter calculation are performed, such as clearing counters for calculating each parameter and registers for storing the maximum and minimum cuff pressure values (Si5).
.

Next, parameters are calculated in Si2. This parameter calculation is performed for each predetermined time interval (window).

The maximum and minimum values of the cuff pressure that are sampled finely within that section are determined, and the difference between them is determined as the parameter value for that section. Through this calculation process, the uncorrected parameter H(i) shown in FIG. 3 is obtained.

If there is an abnormality in this calculated parameter H(i).

The parameters are corrected in Sr1. This correction is the most characteristic feature of the present invention, and details will be described later.

After the correction process, the parameter value H(i
) and the maximum parameter value Hmax up to that point (5T8), if H(i)>Hmax.

Set the current parameter H(i) to the new parameter maximum value H
5T9), and determine the cuff pressure corresponding to that point as the mean blood pressure 5T10).

The cuff pressure corresponding to the maximum parameter value Hmax, for example, 4, is determined as the systolic blood pressure (ST11).

Next, it is determined whether the current parameter value Hi has become 70% or less of the maximum parameter [Hmaz] (ST12). At the stage where the parameter is increasing, this judgment is No. 9 section counter i is +1 (ST13)
, Return to ST 6, calculate parameters for the 9th section (Si2), and perform parameter correction (Sr1)
. After that, the parameter value turns from rising to falling, and H(i
) (The processes of ST6 to ST13 are repeated until the value reaches 70% of Hmax.

Eventually, the parameter H(i) reaches 70% of Hmax.

If it becomes even smaller than this, the determination at 5T12 is YES, and the cuff pressure corresponding to this point is determined to be the diastolic blood pressure (ST14), followed by the determined average.

The maximum and minimum blood pressure values are displayed on the display 11 (ST1
5) The exhaust valve 13 is set to rapid exhaust (ST16) and the measurement ends.

Next, details of the parameter correction process of Sr1 will be explained with reference to the flowchart of FIG.

When entering the parameter correction subroutine, first 5T71
Then, the current parameter value Hi and the previous parameter value H (
1-1), and it is determined whether the current parameter value Hi is larger than the previous parameter value H(i-1) (first determining means). If H(i)>H(1-1), the parameter is increasing as shown in FIG. As shown in R(i) in Figure 3, if there is an abnormal and rapid increase, the judgment of 5T71 is YES.
At T72, 1 is calculated as the difference value between the current parameter value H(i) and the immediately previous parameter @IH(it) (first difference value calculation means).

Subsequently, at 5T73, the difference [K1 is set to a predetermined value X (X-Q, 5~
1 mHf) or more (second determining means).

If the difference value is 1 or more than the predetermined value X, it means that the current parameter has increased significantly compared to the previous time. H in Figure 3
If there is an abnormal and sudden increase like in (i), then the JST
If the judgment in 73 is YES, then in 5T74, the previous parameter [H(i-1) and the second previous parameter value H(i-
z) difference [K2 is calculated (second difference value calculation means).

Then, at 5T75, it is determined whether 2=0 or not. Here, if 2=0, that is, H(i-1) −H(i-2
), the minimum unit yt- of (i) is 2 and 5
If 2≠0 at 5T75, the process immediately moves to 5T77. In 5T76, y is entered as 2.

This is because in the case of K2-00, it is impossible to determine 5T77. In 5T77, it is determined whether or not the difference value 1 is greater than 3 times the difference value 2 (third determining means). If the difference value 1 is also large (6 times the difference value 2), it means that the parameter has suddenly increased this time. 3 used here
The multiple value of 3 is determined empirically, and other appropriate constants may be selected depending on the case. In the judgment of 1≧X in 5T75.

Even in normal cases, parameters may change at a steep slope, so in this 5T77, the difference value is further compared with 2, and the parameter changes not only at a steep slope.

It has been detected that the price has suddenly started to rise. H(i
) If there is an abnormal and sudden increase in the
The judgment is ygs.

In the above manner, 5T71's °"H(i))H(i-
t), 5T75 ex1 ≧
At 78, 2 is added to the parameter value H(i) to obtain the corrected H(i) [H(i)' in FIG. 3]. and.

Return is made from this sub-μm line.

Further, if any of the determinations of 5T71, 5T73 and 5T77 is NO, the process returns without correction.

In the above embodiment, when the parameter value H(i) is abnormal, a correction calculation is performed in 5T78, but the abnormality notification may be made without performing this calculation.

Further, in the above embodiment, a case has been described in which parameters are determined for each fixed time interval (window), but the present invention can of course also be applied to a method in which parameters are determined using one pulse wave pulse as one interval.

(G) Effects of the Invention According to the present invention, when an abnormality occurs in pulse wave waveform information due to arm movement, etc., this abnormality is detected, so it is possible to prevent measurement errors caused by abnormal waveforms. .

In addition, in a device that performs correction calculations based on abnormality detection, substantially accurate measurements can be made even when an abnormality occurs in the pulse waveform.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a schematic configuration of the present invention. FIG. 2 is a block diagram of an electronic blood pressure monitor in which the present invention is implemented, and FIG. 3 is a control flow diagram of the electronic blood pressure monitor. FIG. 4 is a control flow diagram showing the parameter correction routine of the control flow in more detail, and FIG. 3 is a diagram showing an example of parameter distribution for explaining the operation of the electronic blood pressure monitor.
FIGS. 6(a), 6(b), 6(c), and 6(d) are time charts for explaining the principle of an electronic blood pressure monitor employing the sampling method. 1: Cuff, 2: Pressure system, 3: Pressure sensor. 4: Pulse wave parameter extraction means, 5: Blood pressure determination means,
6: first determination, separate means; 7: first difference calculation means;
8: Second discrimination means. Figure 3 1. 7) Figure 3 Figure 6 II Yosakugin IW'1

Claims (2)

[Claims] (1) A cuff, a pressure system connected to the cuff to pressurize or depressurize the cuff, a pressure sensor that detects the cuff pressure, and a parameter that detects the parameters within a predetermined interval of the pulse wave component included in the cuff pressure. Pulse wave parameter extraction means for extracting for each section;
In an electronic blood pressure monitor including a blood pressure determining means for determining blood pressure based on the cuff pressure and pulse wave parameters, the current parameter value is compared with the previous parameter value, and the current parameter value is larger. a first determining means for determining whether or not the parameter value is the same; a first difference calculating means for calculating the difference value between the current parameter value and the previous parameter value; a second determining means for determining whether or not the first difference value is present; a second difference calculating means for calculating a difference value between the parameter value one time before and the parameter value two times before; A third step that determines whether the difference value is greater than the second difference value by an equivalent value or more.
determining means, wherein if the outputs of the first, second, and third determining means are all positive, the current parameter value is determined to be abnormal. (2) If the outputs of the first, second, and third determining means are positive, in response to this, the second difference value is added to the previous parameter, and the current correction parameter is The electronic sphygmomanometer according to claim 1, wherein the value is a value.