JPS59139239A - Blood pressure measuring device - 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] Technical fields> The present invention relates to a blood pressure measuring device.

<Prior Art> For blood pressure measurement, an indirect blood pressure measurement method called the Korotkoff method is generally used. That is, the upper arm is pressurized to a certain pressure with a cuff, and the systolic and diastolic blood pressure values are read based on the pressure at the time when the fricative sound (Korotkoff sound) of the blood vessels and blood that occurs during the decompression or pressurization process occurs and disappears. be.

The blood pressure measuring device measures the blood pressure mentioned above mechanically and electronically. A microphone is placed in the cuff, the Korotkoff sound generated during the cuff pressure change process is collected by the microphone, and the Korotkoff sound obtained is electrically transmitted. cuff pressure values at the time of Korotkoff sound generation and disappearance.

By the way, in the blood pressure measuring device, after the detection of the Korotkoff sound, the subsequent Korotkoff sound is not detected during a predetermined Korotkoff sound extinction determination period C time, the number of pulse sounds generated, the amount of decrease in the internal cuff pressure, etc.). In this case, it was determined that the Korotkoff sound had disappeared, and the pressure at which the last detected Korotkoff sound was detected was taken as the lowest pressure (or systolic blood pressure).

Therefore, if the generation of Korotkoff sounds ceases due to the auscultation gap (the time interval between the continuous generation time of Korotkoff sounds and the time of the next continuous generation of Korotkoff sounds), even though Korotkoff sounds still occur later, the previous Korotkoff The pressure at the time the sound is generated is taken as the diastolic blood pressure (or systolic blood pressure), and a large error may occur in the measurement of the diastolic blood pressure value (or systolic blood pressure value).

<Object of the Invention> In view of the above-mentioned matters, the present invention provides a blood pressure measuring device that changes the attenuation judgment time of Korotkoff sounds according to the measurement pressure, accurately judges the disappearance of Korotkoff sounds, and does not confuse them with the auscultation gap. The purpose is to provide

<Example> The inventive structure will be described with reference to the drawings.

Usually, it is said that the systolic blood pressure value and the diastolic blood pressure value form a ratio of 11 nia. Therefore, in the blood pressure measuring device of this embodiment, the diastolic blood pressure value is predicted from the systolic blood pressure value that is first determined in the process of reducing the pressure from a constant pressure, and the Korotkoff sound disappears before and after the pressure is reduced to the predicted diastolic blood pressure value. I tried changing the viewing time.

FIG. 1 shows a block diagram of the blood pressure measuring device of this embodiment.

In the figure, A is a Korotkoff sound detection section, and B is a pressure detection section. In the Korotkoff sound detection section A, there is a microphone 1. An amplifier 2 and a filter 3 are provided.

That is, the microphone 1 is a part that detects Korotkoff sounds and noises and converts them into electrical signals, and is generally installed inside a wristband. Further, the electrical signals of the Korotkoff sound and noise detected by the microphone 1 are sent to the next stage amplifier 2,
Subsequently, the waveform is shaped by the filter 3 to distinguish the Korotkoff sound electrical signal from other noise electrical signals. Further, a pressure section 4 is provided in the pressure detection section B, and the pressure value of the pressure reducer 5 that executes pressure reduction after being pressurized to a constant pressure (for example, 250 Hg) by the pressure section 4 is determined by the piezoelectric transducer 6. is converted into piezoelectric material.

In this way, when the Korotkoff sound is generated in the filter 3, the pressure value i of the piezoelectric converter 6 is inputted to the A/D converter (analog-to-digital converter) 78 and becomes digital m.

Subsequently, the Korotkoff sound generation norrhus and 'cuff r daily pressure values are determined by the Δ/D converter 7 and the microcomputer 8 (with built-in LSI) connected to the A/D converter 7.
is input. This microcomputer 8 is a part that determines the systolic blood pressure value and diastolic blood pressure value based on the measured cuff seat pressure when the Korotkoff sound occurs, and a predetermined program (program corresponding to the flowchart described later) is stored in 11-. 1-node O-only memory ROM that stores
, registers A, r, BR, and Cr for temporarily storing data of cuff pressure values, a timer T1, a random access memory RAM, and a central processing unit CPU for controlling them (not shown in the figure). . The timer T (';! time) is timed, but when the microcomputer 8 and the generation pulse of the Kokorotkoff sound are inputted, the time measurement is stopped by the CPU.

The systolic blood pressure value determined by the microcomputer 8,
The diastolic blood pressure value is displayed on the display section 9 (liquid crystal display).

Continuing on, the processing operation of the microcomputer 8 will be explained using a flowchart (FIG. 2).

First, after pressurizing to a certain pressure, the system moves to a depressurization process and starts measuring blood pressure (SO Ste-knob).

After starting the measurement, the first generation of Korotkoff sounds is detected (s+ step).

” 2nd S1 step 1st [1 Korotkov 1;?
When the occurrence of the cuff pressure is detected, the cuff pressure value at that time is entered into the register Ar, and the pressure value is displayed on the display section 9 as the systolic blood pressure value. Further, using the above-mentioned systolic blood pressure value, an assumed diastolic blood pressure value is calculated according to the following formula.

The assumed diastolic blood pressure value obtained as a result of the calculation is input into the register Br. Then, set the internal timer T (S
2 steps).

At step S2, the provision of information regarding the systolic blood pressure value has ended. The following is the processing procedure regarding the diastolic blood pressure value.

In the next step S3, the process proceeds to either step (a) or (b) below depending on the second or subsequent generation of Korotkoff sounds.

(,) When a Korotkoff sound occurs, the pressure value of the cuff pressure at the time when the Korotkoff sound occurs is manually entered into the register Ar, and the pressure value is displayed on the display section 9 as the diastolic blood pressure value. Then, timer r is reset (step S4).

Feed back to S3 step again.

(b) When the generation of the Korotkoff sound stops The pressure value of the cuff pressure (decompression process pressure value) at the time when the generation of the Korotkoff sound stops is manually entered in the register Cr (SS step), and the pressure value of the decompression process is entered in the register Cr. The assumed diastolic blood pressure value (entered into register Br) calculated in step S2 is compared (step S6).

In step S6, if the decompression process pressure value≧the assumed diastolic blood pressure value, the Korotkoff sound extinction determination time is set to 6 seconds, and the blood pressure measurement is ended when the timer T measures 6 seconds or more. Then, if the timer T finishes counting less than 6 seconds, the feedbank is again returned to step S3 (step S7).

Similarly, in 86 Stesov, if the decompression process pressure value is the assumed diastolic blood pressure value, the Korotkoff sound disappearance determination time is set to 3 seconds, and the blood pressure measurement is ended when the timer T measures 3 seconds or more.

If the timer T finishes counting for less than 3 seconds, feedback is sent back to step S3 (sg step).

When the measurement is completed (step S9), the patient's systolic blood pressure value (obtained in step S2) and diastolic blood pressure value (obtained in step S2) and diastolic blood pressure value (inputted into register Cr in the order of SS step → S6 step → S1 step → S9 step) are input. (or the decompression process pressure value input into the register Cr when the process progresses from S5 step to S6 step to S8 step to SO step) is grasped.

As described above, a difference was set in the Korotkoff sound disappearance determination time by comparing the assumed diastolic blood pressure value calculated from the systolic blood pressure value and the decompression process pressure value.

In other words, in this example, the Korotkoff sound extinction determination time at a pressure lower than the assumed minimum + ffi baroin in the decompression process is set to the standard 3 seconds, whereas in the decompression process, the pressure equal to or higher than the assumed diastolic blood pressure value is set as 3 seconds. The Korotkoff sound extinction determination time was doubled to 6 seconds.

This is because when the cuff pressure drops, there is a greater possibility that an auscultation gap will occur when the pressure is high, and when the cuff pressure drops, there is a greater possibility that an auscultation gap will occur when the pressure is low. This is based on the theoretical basis that the auscultation gap is small, and the assumed minimum +(+tl4r-i) was used as a basis for determining the level of pressure that contributes to the occurrence of an auscultation gap.

In addition, the Korotkoff sound disappearance determination time when the pressure is lower than the assumed diastolic blood pressure value in the depressurization process described in "2" may be other standard 2 seconds, 4 seconds, or 5 seconds.

Also, the ratio of the systolic blood pressure value to the diastolic blood pressure value (11 in the above example)
(near) may be determined by other accurate values determined by clinical medicine.

Furthermore, in the above embodiment, a blood pressure measuring device was described that measures blood pressure during cuff pressure reduction, which first determines the systolic blood pressure value, but of course, blood pressure is measured during cuff pressure increase, which first determines the diastolic blood pressure value. The same process can be performed in the blood pressure measuring device that measures the blood pressure. In that case, calculate the assumed systolic blood pressure value using the formula below.

Effects> As described above, the present invention provides a blood pressure measuring device that measures two blood pressure values, systolic blood pressure value and diastolic blood pressure value, by the generation or disappearance of Korotkoff sounds during the cuff pressure reduction or pressurization process. In this method, since a time period is provided to recognize the disappearance of the Korotkoff sounds, which is suitable for the measured pressure, the auscultation gap is never considered to be the disappearance of the Korotkoff sounds, and accuracy in blood pressure measurement can be expected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the blood pressure measuring device of the present invention, and FIG.
The figure is a flowchart showing the operation of the judgment section 3g of the blood pressure measuring device of the present invention. Δ...Korotkoff sound detection section, B...Pressure detection section, 7
...A/D converter, 8...microcomputer,
9...Display section. Agent Patent attorney Aihiko Fukushi (and 2 others) Figure 1

Claims (1)

[Scope of Claims] 1. In a blood pressure measuring device that measures two blood pressure values, systolic blood pressure value and diastolic blood pressure value, by the generation or disappearance of Korotkoff sounds during the process of reducing or increasing cuff pressure, There is a calculation means for calculating another blood pressure (iM) based on the previously determined blood pressure value, and a comparison means for comparing the pressure at the time of decompression or pressurization with the blood pressure value assumedly calculated by the calculation means, and two different , a setting means for setting the time required to determine that the Korotkoff sound has disappeared, and a determining means for determining whether the Korotkoff sound has disappeared using the time of either of the setting means based on the output of the comparison result of the comparison means. A blood pressure measuring device characterized by comprising: