JP3178175B2 - Electronic sphygmomanometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic sphygmomanometer which devises a pressure adjusting method for correcting a difference in characteristics between individual instruments.

[0002]

2. Description of the Related Art Generally, in an electronic blood pressure monitor, a cuff is attached to an upper arm, a finger, or a wrist, the cuff is pressurized to a predetermined pressure by a pump or the like, and then the pump is stopped to reduce the pressure. In the process, the cuff pressure itself is detected by a pressure sensor or the like, and is converted into a digital signal by A / D conversion means.
The blood pressure is taken into the PU, and the blood pressure is measured based on cuff pressure, pulse wave information, K sound information, and the like. In this type of electronic sphygmomanometer, the detection of pressure is one of the most important ones. However, if attention is paid to individual instruments, the characteristics of a pressure detection unit including a pressure sensor, an A / D converter, and the like are constant However, even if the applied pressure (cuff pressure) is the same, the output of the pressure detection unit may be different, and even if the applied pressure is changed linearly, the output of the pressure detection unit does not always change linearly. . Therefore, it is necessary to adjust the sensitivity and linearity of the pressure detection unit for each instrument at the time of manufacture and before shipment. As shown in FIG. 2, the output characteristics of the A / D converter when a pressure from open to atmosphere (0 mmHg) to 280 mmHg is applied to any four electronic blood pressure monitors a,. The output N _{0 and} the output N ₂₈₀ when 280 mmHg are applied are different from each other. For this reason, as shown in FIG.
The difference ΔN between the applied pressure P and the output N ₀ of the A / D converter when ₀ mmHg is applied and the output N of the A / D converter at each applied pressure.
The characteristics of the above also differ in the distribution. That is, the sensitivity varies.

Conventionally, in order to correct this variation in sensitivity, the measured pressure P is determined by p = ΔN × g (g: sensitivity coefficient), and this coefficient g is set to a predetermined value, for example, 0.1. 1 and the output N ₀ of the A / D converter at ₀ mmHg.
280 mmHg and then apply N ₂₈₀
Is measured, and ΔN ₂₈₀ (= N ₀ −N ₂₈₀ ) is calculated. Further, a G value (temporary g value) is calculated from G = 280 / ΔN ₂₈₀ , and semi-fixed for adjusting the sensitivity of the A / D converter. Adjust the resistor. When the semi-fixed resistor is moved, N ₀ and N
₂₈₀ is measured, and ΔN ₂₈₀ and G are calculated, and G = g
Adjust the semi-fixed resistor until (0.1) is reached.

Further, an applied pressure is set to 0 mmH
The characteristic of the difference between the measured value (A / D converter output) p and the applied pressure P with respect to each applied pressure value P when changing from g to 280 mmHg, as shown in FIG. There is variation. In order to correct this linearity error, conventionally, correction data A, B, and C, which are representative standards, are set in advance. The data A, B, and C are, for example, as shown in FIG. 5, a plurality of predetermined applied pressures p1, p2, and p.
A1, B1, C1 for A3, A2, B2, C2,
A3, B3, and C3 are stored as point data. The correction data for each instrument is the data A, B,
Select and set one of C.

To set the correction data, first, pressure values p1, p2, and p3 are sequentially given to the gauge, linearity errors are measured at the respective pressure values, and data A, Compare and select which is closest to B or C. Then, the information of the selected data (A, B
Or C) the setting by the pattern cut board.

[0006]

In the above-described conventional method of adjusting the sensitivity of the pressure detecting portion of the electronic blood pressure monitor, it is necessary to repeat the adjustment using a semi-fixed resistor until the sensitivity is in an appropriate state. In addition to this, there is a problem that it takes time, and an error occurs at the time of adjustment because a person repeats the adjustment.

Further, the conventional electronic blood pressure monitor prepares a plurality of correction data for linearity correction, measures characteristics at the time of adjustment, selects correction data corresponding thereto, and
Since the information is set by the pattern cutting of the substrate, there is a problem that an error occurs because the correction value does not always coincide with a necessary correction value, and there is a problem that a work of pattern cutting of the substrate occurs. .

The present invention has been made in view of the above problems, and provides an electronic sphygmomanometer capable of accurately adjusting and correcting pressure without requiring time for pressure adjustment. The purpose is.

[0009]

According to the electronic blood pressure monitor of the present invention, the cuff pressure is detected by the pressure detecting means in the process of attaching the cuff to the living body, pressurizing the cuff and depressurizing the cuff, and performing A / D conversion. obtain pressure information is converted into a digital signal by means in which to measure blood pressure using the pressure information, includes a writable nonvolatile storage means, in the nonvolatile storage means, a plurality of different predetermined respective application When the pressure value is given
Characteristics of the relationship between the applied pressure and the detected pressure difference.
Characteristic pattern, and store the applied pressure
Gives the relationship between the difference between the applied pressure and the detected pressure.
And select the closest characteristic pattern
Is used as pressure adjustment data .

In this electronic sphygmomanometer , a plurality of predetermined different applied pressures are used as pressure adjustment data unique to the instrument.
Of the difference between the detected pressure and the applied pressure when the force value is given
Memorize multiple characteristic patterns of relationships and store them in the instrument
The difference between the detected pressure and the applied pressure when each of the applied pressures is given
Obtain the relationship between the values and select the closest characteristic pattern.
The characteristic pattern may be stored in the nonvolatile storage means, using a pressure regulating This data during the measurement, which corrects a person for each instrument, there is no need to perform a pattern cut of the substrate.

[0011]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a block diagram showing a configuration of an electronic sphygmomanometer according to the present invention. This electronic sphygmomanometer includes a cuff 1, a pressure sensor 2, a pump 3, an exhaust valve 4, an A
/ D converter 5, CPU 6, storage unit 7, display 8
And a pipe 9.

The cuff 1 is attached to, for example, the upper arm, but may be attached to a wrist, a finger or the like depending on the type of the electronic sphygmomanometer. The pressure sensor 2 converts a pressure signal (cuff pressure) into an electric signal. The pump 3 pressurizes the cuff 1 through the pipe 9, and an automatic pressurizing pump, a manual pressurizing rubber ball, or the like is used. The exhaust valve 4 is a means for opening the pneumatic system such as the cuff 1 and the pipe 9 to the atmosphere, and an electromagnetic valve is used automatically and a manual exhaust valve is used manually. A / D
The converter 5 converts an analog electric signal from the pressure sensor 2 into a digital electric signal.

The CPU 6 has a function of separating a pulse wave component and a static pressure component from pressure information taken in from the A / D converter 5, and determines a systolic blood pressure and a diastolic blood pressure based on the obtained pulse wave data and cuff pressure data. It has a function of calculating, a function of controlling the pump 3, the exhaust valve 4, and the like, a control function of pressure sensitivity adjustment, and a control function of linearity correction. The storage unit 7 uses an EEPROM (electrically erasable PROM) and stores a set number of sensitivity coefficients, linearity correction values, and the like of the pressure detection unit. This storage unit 7 stores another P in place of the EEPROM.
A ROM may be used.

In this electronic sphygmomanometer, at the time of measurement, the cuff 1 is pressurized by the pump 3 to a predetermined pressure value, then evacuated slowly by the exhaust valve 4 and depressurized. The systolic blood pressure, the diastolic blood pressure and the like are determined using the pressure data and the pulse wave data. However, the blood pressure determination method itself is well known, and therefore, in the present invention, the blood pressure determination method is not particularly limited,
A well-known K-tone method may be adopted.

The cuff pressure P used in the blood pressure measurement is detected by the pressure sensor 2 as described above, and is taken into the CPU 6 as the output N of the A / D converter 5. In this case, the relationship between the applied pressure P and the output N of the A / D converter 5 is not constant due to the variation of the pressure sensor 2 of each instrument, as shown in FIG. Therefore, the applied pressure P and Δ
The characteristics of N = N ₀ −N also vary from instrument to instrument.

In this embodiment, each instrument is manufactured and subjected to an electrical test so that the same measured value p can be obtained for the same applied pressure P despite the above-mentioned variation. Performs the following processing. First,
As shown in FIG. 6, the exhaust valve 4 is opened (ST1), the cuff 1 is opened to the atmosphere, and the output N ₀ of the A / D converter 5 at that time.
(ST2). Next, the exhaust valve 4 is closed, the pump 4 is operated, and the applied pressure is set to 280 mmHg (ST
3) Obtain the output _N280 of the A / D converter at that time (ST
4). Next, ΔN ₂₈₀ = N ₀ −N ₂₈₀ is calculated (ST
5) Subsequently, a sensitivity coefficient g = 280 / ΔN ₂₈₀ is calculated (ST6). Then, the value of the sensitivity coefficient g is set and stored in the EEPROM 7 serving as a storage unit (ST7). The sensitivity coefficient g differs for each instrument.

As described above, when the sensitivity coefficient g is set and shipped, when the user's blood pressure is measured, the measured cuff pressure P is obtained from the measured cuff pressure P = ΔN × g. Here, ΔN = N ₀ −N, where N ₀ is the output of the A / D converter 5 when open to the atmosphere, and N is the output of the A / D converter 5 when the measured pressure P is applied. Further, the relationship between the applied pressure P and the measured value p is not constant as shown in FIG. 4, and the measured cuff pressure p has a linearity error. Moreover, the linearity error also varies among the instruments. In this embodiment, in order to correct the linearity error, the following processing is performed at the same stage as the setting of the above-described sensitivity coefficient g, that is, at the time of production. First, a plurality of different application pressures p1, p2, and p3 preset by a program are sequentially applied at an applied pressure of 0 to 280 mmHg (ST11, ST13, ST15), and linearity errors D1, D2, D3 at each applied pressure are applied. Is calculated (ST1).
2, ST14, ST16). And this linearity error D
It is selected which of 1, D2, and D3 is closer to data A, data B, or data C in FIG. 5 (ST17), and if the selected data, for example, data B is the closest, data B
1. EEP using data B2 and data B3 as correction data
The setting is stored in the ROM 7 (ST18).

When the linearity error correction data B1, B2, and B3 are set as described above and shipped, the correction value Δp at the time of the measurement value p at the time of measuring the blood pressure of the user is:

[0019]

(Equation 1)

[0020] And with p + Δp,
The measured value p corrected for the linearity error is obtained. Further, as another embodiment of correcting the linearity error, each of p1, p2,
The values of the linearity errors D1, D2, and D3 obtained by applying p3 may be set and stored in the EEPROM 7. In the method of selecting the data closest to the data A, B, and C, even if the data can be selected as close as possible, there is a difference from the actually required correction value and some errors are generated. Is not required, and the accuracy is improved.

As another embodiment of the correction of the linearity error, if the pressure values p1, p2, and p3 are set at equal intervals, if only the interval values are set, each applied pressure value is programmed in advance. , It is possible to reduce the program amount and the ROM size, which contributes to cost reduction.

[0022]

Effects of the Invention According to the invention, comprising a nonvolatile memory means, in the nonvolatile storage means, and pressure adjustment data
The plurality of predetermined different applied pressure values
Characteristics of the relationship between the applied pressure and the detected pressure difference.
Characteristic pattern, and store the applied pressure
Gives the relationship between the difference between the applied pressure and the detected pressure.
And select the closest characteristic pattern
Since the is for preset memory allows for automatic reduction of the adjustment, thereby improving the productivity. In the adjustment work, the repetitive work is eliminated, and the number of steps and cost can be reduced. There is no human adjustment error, and the accuracy can be improved. Necessary linearity correction data itself can be set, errors due to data selection are eliminated, and accuracy can be improved. There is no need to determine a case where the linearity correction data does not match the preset linearity correction data as a defect, thereby improving the production yield and reducing costs.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic sphygmomanometer according to the present invention.

FIG. 2 shows an applied pressure value of an electronic sphygmomanometer and A / D of a pressure sensor.
It is a figure showing the relation with conversion output.

FIG. 3 is a characteristic diagram illustrating a variation in sensitivity of a pressure detection unit of the electronic sphygmomanometer.

FIG. 4 is a characteristic diagram illustrating a variation in an error in linearity of a pressure detection unit of the electronic sphygmomanometer.

FIG. 5 is a characteristic diagram illustrating correction of a linearity error of a pressure detection unit of the electronic sphygmomanometer.

FIG. 6 is a flowchart showing a process of setting a sensitivity coefficient in the electronic blood pressure monitor of the embodiment.

FIG. 7 is a flowchart showing a process of setting correction data for a linearity error in the electronic blood pressure monitor of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cuff 2 Pressure sensor 3 Pump 4 Exhaust valve 5 A / D converter 6 CPU 7 Storage part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 5/02-5/0295

Claims (1)

(57) [Claims] In a process of attaching a cuff to a living body, pressurizing and depressing the cuff, the cuff pressure is detected by a pressure detecting means, and converted into a digital signal by an A / D converting means to obtain pressure information. An electronic sphygmomanometer for measuring blood pressure using pressure information, comprising writable nonvolatile storage means, and applying a plurality of predetermined different applied pressure values to the nonvolatile storage means.
The relationship between the applied pressure and the detected pressure difference
The characteristic pattern of the number is memorized,
The relationship between the difference between the applied pressure and the detected pressure when a pressure is applied
And select the closest characteristic pattern,
An electronic sphygmomanometer characterized by using turns as pressure adjustment data .