JPH05253198A - Pulse wave measuring system - Google Patents

Abstract

PURPOSE:To drastically decrease the errors of an index indicating the shape characteristics of the first or second differential waveform of pulse waves. CONSTITUTION:The pulse waves detected by a pulse wave sensor part 1 is differentiated once or twice by a differential processing section 2. The area of the region lower than the base line of the waveforms is calculated in an area calculating section 5. The height of the peak of the waveforms is detected in a peak detecting section 6 simultaneously therewith and the ratio of the height of the second peak of the waveforms obtd. in such a manner to the area of the region lower than the base line is computed by an index computing section 7, by which the index having the decreased errors is obtd. The errors of the index are further decreased by adopting the constitution to limit the calculating range of the area to the regions including the second, third and fourth peaks of the waveforms. Further, the index capable of dealing with special cases is obtd. by adopting the constitution to subtract the area of the region upper than the base line of the peak existing upper than the base line from the area of the region lower than the base line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse wave measuring device used for health condition management, diagnosis, etc. in a health care room, a medical institution or a general household.

[0002]

2. Description of the Related Art Conventionally, as a pulse wave measuring device of this type,
The output of the pulse sensor unit that detects an increase or decrease in blood volume at the distal end of the body such as a fingertip or an earlobe is differentiated twice, and the height of the first peak of the waveform (distance from the baseline) obtained by this is calculated. There is known a structure in which the ratio of the heights of the second, third and fourth peaks to the value obtained by addition and subtraction processing is calculated to obtain an index showing the characteristics of the waveform (for example, Japanese Patent Laid-Open No. 57-93036). Bulletin).

FIG. 6 shows a specific example of the index calculation method of this pulse wave measuring apparatus. In FIG. 6, reference numeral 11 is a curve showing an example of a waveform obtained by differentiating the output of the pulse sensor unit twice.
Reference numeral 2 indicates a position where the height of the waveform 11 is 0, that is, a base line. Further, in FIG. 6, the height of the first peak 11a in the waveform 11 is a, the heights of the second, third, and fourth peaks 11b, 11c, and 11d are b, respectively.
c and d, and X as an index X representing the characteristics of this waveform
= (-B + c + d) / a is written (November 1985)
13 date correction) has been made.

[0004]

However, the index X obtained by the configuration of the above-mentioned conventional pulse wave measuring apparatus is calculated based on the heights a to d of the peaks 11a to 11d after the second differentiation. Therefore, there is a problem that the variation error must be extremely large. That is, while the pulse wave itself is a human waveform that tends to fluctuate,
This is a method of differentiating twice to detect a slight change in the inclination of the original waveform as the heights a to d of the peaks 11a to 11d, so that the third and fourth peaks 11c having relatively small values are detected. In particular, the heights c and d of 11d, 11d are prone to fluctuation errors, and electrical detection errors are also likely to occur. The errors generated here are directly reflected in the index X.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a pulse wave measuring apparatus capable of minimizing the error in the index indicating the characteristic of the waveform.

[0006]

In order to solve the above-mentioned problems, the first means of the present invention is to differentiate the output of a pulse wave sensor unit for detecting an increase or decrease in blood volume once or twice in a differentiation processing unit. , Based on the waveform obtained by this, the area calculation unit calculates the area of the region below the base line, the peak detection unit detects the peak height of the waveform, and the exponent calculation unit calculates this area. , And the ratio to the height of the second peak of the waveform is calculated to obtain an index representing the characteristics of the waveform.

The second means of the present invention is the same as the first means, wherein the area calculation range is set to the second, third and fourth peaks of the waveform for the purpose of reducing the error of the exponent. The configuration is limited to the area including the area.

Further, the third means of the present invention is based on the first aspect.
In the method of (1), when at least one of the second, third, and fourth peaks of the waveform is located above the baseline, the peak can be used for an index that can be applied to a special waveform. The area of the region above the baseline is subtracted from the area of the region below the baseline.

[0009]

With the first means, the index calculation method is based on the shape of the entire waveform, as compared with the conventional method which uses the height of the waveform as a reference because a specific point is taken out and measurement error is likely to occur. By changing to the method based on the area of the waveform, it is possible to greatly reduce the error of the index,
In addition, it becomes possible to accurately represent the characteristics of the waveform.

The second means can reduce the error of the exponent, and the third means can deal with a special waveform in which the peak is located above the base line.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the pulse wave measuring device of the present invention will be described below with reference to the drawings. FIG. 1 is a block configuration diagram of a pulse wave measuring device according to an embodiment of the present invention, FIG. 2 is an external perspective view of the pulse wave measuring device, and FIG. 3 is a diagram for explaining an index calculation method of the pulse wave measuring device. It is a figure.

As shown in FIGS. 1 to 3, the pulse wave measuring device includes a pulse sensor unit 1 for detecting an increase or decrease in blood volume at a fingertip,
Differentiation processing unit 2 for differentiating the output signal of the pulse sensor unit 1 twice
An area calculation unit 5 for calculating the area of a region below the base line 4 of the waveform 3 output from the differentiation processing unit 2; and peak detection for detecting the height L of the second peak 3b of the waveform 3. The area below the base line 4 of the waveform 3 obtained by the area 6, the area calculator 5, and the peak detector 6 (the shaded area in FIG. 3)
From the area A1 of the second peak 3b to the height L of the second peak 3b, and an exponent calculator 7 for calculating an exponent X1 = A1 / L, which is characteristic of the waveform 3, and a display 8 including a liquid crystal display device. Has been done. Here, the display unit 8 displays the output waveform 3 obtained by the differentiation processing unit 2 and the index X obtained by the index calculation unit 7.
1 can be displayed. Further, in FIG. 3, 3a
3d are the 1st-4th peaks in the waveform 3.

Next, the operation of this pulse wave measuring apparatus will be described. The pulse wave signal obtained in the pulse wave sensor unit 1 is differentiated twice in the differentiation processing unit 2, and is displayed as an image on the display unit 8 as a waveform 3 of a so-called acceleration pulse wave.

On the other hand, the data of the waveform 3 obtained in the differential processing unit 2 is guided to the area calculation unit 5 and the peak detection unit 6, and the area A1 of the region below the base line 4 of the waveform 3 is calculated. The height L of the second peak 3b of the waveform 3 is detected. Then, the ratio of the area A1 to the height L is calculated by the index calculation unit 7 and displayed on the display unit 8 as the index X1.

At this time, the waveform 3 of the acceleration pulse wave obtained by the differentiation processing unit 2 is obtained by differentiating the original pulse wave waveform twice, and the heights of the respective peaks 3a to 3d of the waveform 3 are the original. It represents the rate of change of the slope in the waveform. Therefore, the waveform of the original pulse wave slightly fluctuates,
The peak 3a of the waveform 3 of the acceleration pulse wave which is the second differentiation
The height of 3d changes sensitively and greatly.

Therefore, in the case of the index X calculated by the conventional index calculation method as shown in FIG. 6, the values of the heights c and d of the third and fourth peaks 11c and 11d are the second peak. Since the absolute value itself is smaller than the value of the height b of 11b, it is inevitable that the electrical detection error becomes large and the ratio of the fluctuation error of the waveform 11 becomes relatively large.

However, the purpose of the index obtained here is to quantify the characteristics of the waveform of the acceleration pulse wave, and the maximum characteristic of this acceleration pulse wave waveform is the height L of the second peak 3b. In consideration of the above, each peak 3a-
It is not necessary to pay attention to the height of 3d (particularly the heights of the third and fourth peaks 3c and 3d), as long as the characteristic of the waveform is exhibited. Therefore, in the present invention, as shown in FIG. 3, the ratio of the area A1 of the region below the baseline 4 of the waveform 3 to the height L of the second peak 3b is used as an index as a value representing the characteristics of the entire waveform. Chose as. In this case, since the feature indicated by the heights of the third and fourth peaks 3c and 3d having a large error is treated as the area of the peak, the variation error of the original waveform is averaged and is relatively small. At the same time, it is possible to realize a pulse wave measuring device with a small detection error and an extremely small index error as a whole.

FIG. 4 is a diagram for explaining the exponential calculation method of the pulse wave measuring device according to another embodiment of the present invention. Although this embodiment has the same structure as that of the above embodiment,
By the area calculation unit 5, the area below the base line 4 is
The area A2 is calculated by adding while limiting to the third and fourth peaks 3b to 3d.

According to this configuration, the peaks 3e to 3g after the fifth peak, which tends to have a larger error, are ignored, and thus the error of the index X2 = A2 / L can be further reduced. ..

FIG. 5 is a diagram for explaining still another exponential calculation method of the present invention, which shows an acceleration pulse wave waveform 9 of a person who has a very good blood circulation. In this case, a third peak, which is rare, is shown. It has been observed that 9c rises above baseline 4. In this embodiment, the area calculation unit 5 determines the area B of the region above the base line 4 of the third peak 9c.
Is subtracted from the area A3 of the area below the base line 4 to obtain the index X
3 = (A3-B) / L is calculated.

Thus, the index X3 is calculated in consideration of the area B of the region above the base line 4, so that the characteristic of the special acceleration pulse wave waveform of a person with good blood circulation can be emphasized. ..

In the above embodiment, the case where the acceleration pulse wave waveform is obtained by performing the second differentiation as the waveform processing in the differentiating section 2 has been described, but the case where the velocity pulse wave waveform is obtained by the first differentiation is explained. Can likewise show the characteristics of the waveform. In the pulse wave measuring device shown in FIG. 2, the pulse wave sensor unit 3 is shown built in the device. However, the pulse wave sensor unit is configured separately from the device body, and is connected to the device body by a cord. Obviously, it doesn't matter.

[0023]

As is apparent from the above description, according to the pulse wave measuring apparatus of the present invention, the area of the region below the base line of the waveform obtained by the area calculating section and the waveform detected by the peak detecting section are determined. Since the ratio to the height of the second peak is calculated as an exponent in the exponent calculation unit, it is possible to calculate an accurate exponent having a small error and well representing the shape characteristic of the waveform. ..

Further, by configuring the area below the base line calculated by the area calculation unit to be the area including the second, third, and fourth peaks, it is possible to provide an index calculation method with a smaller error. Furthermore, by adopting a configuration in which the area of the region above the baseline of the peak located above the baseline of the second, third, and fourth peaks is subtracted from the area of the region below the baseline, The pulse wave measuring device having a high practical effect can be provided because the shape feature of the special waveform can be further emphasized to be indexed.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a pulse wave measuring device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an appearance of the entire pulse wave measuring device.

FIG. 3 is a diagram of an acceleration pulse wave waveform for explaining an index calculation method in the pulse wave measuring device.

FIG. 4 is a diagram of an acceleration pulse wave waveform for explaining an index calculation method of a pulse wave measuring device according to another embodiment of the present invention.

FIG. 5 is a diagram of an acceleration pulse wave waveform for explaining an index calculation method of the pulse wave measuring device according to another embodiment of the present invention.

FIG. 6 is a diagram of an acceleration pulse wave waveform for explaining an index calculation method of a conventional pulse wave measuring device.

[Explanation of symbols]

 1 Pulse Wave Sensor Section 2 Differentiation Processing Section 3, 9 Waveform (Acceleration Pulse Waveform) 4 Baseline 5 Area Calculation Section 6 Peak Detection Section 7 Index Calculation Section 8 Display Section

Claims (3)

[Claims] 1. A pulse wave sensor unit for detecting an increase or decrease in blood volume at the distal end of the body such as a fingertip or an earlobe, and a differential processing unit for applying differential processing once or twice to the output of the pulse wave sensor unit. , An area calculation unit that calculates the area of a region below the base line of the waveform obtained by the differential processing, a peak detection unit that detects the height of the peak of the waveform from the base line, output data of the area calculation unit, and the peak A pulse wave measuring device comprising: an exponent calculation unit that calculates an index from the ratio of the second peak of the waveform obtained from the detection unit. 2. The pulse wave measuring device according to claim 1, wherein the area calculation range by the area calculation unit is limited to a region including the second, third and fourth peaks of the waveform. 3. The area of a region above a baseline of at least one of the second, third and fourth peaks of the waveform obtained by the differential processing when the peak is located above the baseline. The pulse wave measuring device according to claim 1, further comprising an area calculation unit that subtracts from the area of a region below the base line.