JPS6214830A - 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] Industrial applications The present invention relates to an electronic blood pressure monitor.

2. Description of the Related Art A conventional electronic blood pressure monitor will be described with reference to FIG. In Figure 3, 1 is a wristband, 2 is a rubber ball, 3 is a rubber tube, and 4
is a microphone, 5 is a pressure sensor, 6 is an A/D converter,
7 is a central processing unit (hereinafter referred to as "CPU"), 8 is a display, 9 is an amplifier circuit, 10 is a filter circuit, and 11 is a comparator.

When measuring blood pressure, the arm cuff 1 is first worn on the upper arm of the human body. At this time, the microphone 4 built into the cuff 1 is aligned with the artery of the upper arm of the human body. Next, air is blown into the cuff using the rubber bulb 2 through the rubber tube 3 to pressurize it to a constant pressure. When the air supply by the rubber bulb 2 is stopped, a small amount of air is discharged from the micro-exhaust valve built into the rubber bulb 2, and the pressure inside the cuff 1 gradually decreases.

Further, the pressure within the cuff 1 is detected by a pressure sensor 5 connected to the rubber tube 3, and the output of the pressure sensor 5 is converted into a digital signal by an A/D converter 6, which becomes an input to the CPU 7. Furthermore, when the pressure of the arm cuff 1 is at its maximum value, the brachial artery is compressed and blood is ischemic, so the output of the microphone 4 on the artery is a low frequency and only a low sound is detected, but as the pressure decreases, the surface begins to flow. , a Korotkoff sound appears in the output of the microphone 4, and when the pressure further decreases, the Korotkoff sound disappears. Further, the output voltage of the microphone 4 is amplified by an amplifier circuit 9, and the filter circuit 1
Korotkoff sound is detected at 0. The Korotkoff sound is digitally converted by a comparator 11 that receives the output of the filter circuit 10 and is input to the CPU 7, and the output of the A/D converter 6 when the output of the comparator 11 becomes high level in the CPU 7. is set as the systolic blood pressure, and then the output of the A/D converter 6 when the output of the comparator 11 becomes low level is set as the diastolic blood pressure, and is displayed on the display 8.

Problems to be Solved by the Invention However, the conventional configuration described above requires alignment of the microphone 4 with the artery when wearing the cuff, which is inconvenient. Furthermore, since Korotkoff sounds are detected by the microphone 4, malfunctions may occur due to electrical noise or noise.

The present invention solves the above-mentioned conventional problems, and aims to provide an electronic blood pressure monitor that can easily measure blood pressure without a microphone and is inexpensive.

Means for Solving the Problems In order to solve the above-mentioned problems, the electronic blood pressure monitor of the present invention includes a cuff that is attached to the upper arm of a human body, and a device that blows air into the cuff to bring the upper arm of the human body to a predetermined pressure. a micro-evacuation means for gradually ejecting blood after it is pressurized and ischemic blood; a pressure detection means for detecting the pressure within the cuff; a conversion means for converting the output of the pressure detection means into a digital pressure signal; a pressure value storage means for storing a pressure value when the signal starts to increase during micro-evacuation; and a time from when the digital pressure signal starts to increase during micro-evacuation until it returns to the pressure value at the time when the digital pressure signal starts to increase. A blood pressure value determining means for storing an integral value as the magnitude of a blood vessel sound generated during microextraction, a maximum value detecting means for detecting the maximum value of the blood vessel sound, and a blood pressure value determined from the magnitude of the blood vessel sound and its maximum value. The blood pressure value determination means for determining the blood pressure value and the display means for displaying the determined blood pressure value are configured.

Effects According to the above configuration, since the microphone is eliminated, alignment is not required, and the circuit configuration is also simplified, resulting in cost reduction. Furthermore, since blood vessel sounds are detected as time-integrated values of pressure change values, the influence of variations in individual pressure digital signals can be suppressed and accurate pressure change values can be detected.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a configuration diagram of an electronic blood pressure monitor according to an embodiment of the present invention, in which 21 is a cuff, 22 is a pressurizing rubber bulb, 23 is a rubber tube,
24 is a pressure sensor, 25 is an A/D converter, 26 is a CP
U127 is a display.

When measuring blood pressure, the arm cuff 21 is first worn on the upper arm of the human body. At this time, unlike conventional devices, there is no microphone, so alignment with the artery is not necessary. Next, air is blown into the arm cuff 21 through the rubber tube 23 using the rubber bulb 22, pressurized to a constant pressure, and exhausted through the micro-exhaust valve to gradually lower the pressure. Further, the pressure inside the cuff 21 is detected by a pressure force sensor 24 connected to the rubber tube 23, and the output of the pressure sensor 24 is A.
It is converted into a digital signal by the /D converter 25 and sent to the CPU 26.
becomes the input.

The A/D converter 25 differs from the 8-9 bit A/D converter 6 in the conventional example shown in FIG. 3, which detects only the pressure value within the cuff 1, in that it detects even minute changes in pressure due to blood vessel sounds. For simultaneous detection, one with high resolution of 12 to 15 bits is used.

Next, a method of processing the pressure digital signal detected by the CPU 26 will be explained with reference to the flowchart shown in FIG. First, the initial values of i and N are set to i=o and N=1 (step ■). Next, the pressure @ No. P during slight evacuation is detected at regular intervals (step ■■). Next, compare the pressure signal P・ measured next with the previous value PH−1,
When the measured value becomes large, proceed to the next step (step ■). The pressure P before it starts to increase.

-1 is stored as the pressure PN when the blood vessel sound occurs,
At the same time, the initial value of the time integral value Qs of pressure is set to zero (step ■). While the pressure (a Q P is greater than PN,
The pressure change value (P, -PN) is added to the pressure time integral value Q (steps ① to ①).

- When the pressure signal P becomes smaller than PN, the process advances to the next step and stores Q as the pressure change value when the blood vessel sound occurs (step [phase]). Next, while QN is increasing, the ON maximum value detection means detects the maximum value QN of Q.
When HAX is updated and QN starts to decrease, Q remains fixed and when QN becomes 70% or less of QNHAX NHAX, QNHAX is determined as the maximum value (Step ◎@). Next, compare with QN by the detection level determined by QNHAX and pressure value,
The pressures PN at the matching points are determined to be the highest surface pressure and the lowest surface pressure (step 0). Then, the determined blood pressure value is displayed on the display 8.
(Step 0).

Effects of the Invention As described above, according to the present invention, there is no need for a microphone and no need for alignment with the artery.

Furthermore, a microphone, amplifier circuit, filter circuit, and comparator are not required, and costs can be reduced. Furthermore, since blood vessel sounds are detected as time-integrated values of pressure change values, accurate pressure change values can be detected without being affected by variations in individual pressure digital signals, and thus accurate blood pressure values can be detected.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electronic blood pressure monitor according to an embodiment of the present invention, FIG. 2 is a flow chart of a blood pressure detection method using the same electronic blood pressure monitor, and FIG. 3 is a block diagram of a conventional electronic blood pressure monitor. 21... Bracelet, 22... Rubber ball for pressurization, 23...
Rubber tube, 24...Pressure sensor, 25...A/D converter, 26...CPU127...Display agent Yoshihiro Morimoto Figure 1 22--1 Pressure, use 23-D'A Figure 2

Claims (1)

[Claims] 1. An arm cuff to be attached to the upper arm of a human body, a micro-exhaust means for supplying air to the arm cuff to pressurize the upper arm of the human body to a predetermined pressure, and then gradually discharge the blood after it is discharged, and the pressure inside the arm cuff. a pressure detection means for detecting the pressure, a conversion means for converting the output of the pressure detection means into a digital pressure signal, and a pressure value storage means for storing a pressure value when the digital pressure signal starts to increase during slight evacuation. , a blood vessel sound value storage means for storing a time integral value from when the digital pressure signal starts to increase during micro evacuation until it returns to the pressure value at the time when the digital pressure signal starts increasing as the magnitude of the blood vessel sound generated during micro evacuation; and a maximum value detection means for detecting the maximum value of the blood vessel sound, a blood pressure value determination means for determining a blood pressure value from the magnitude of the blood vessel sound and its maximum value, and a display means for displaying the determined blood pressure value. Electronic blood pressure monitor.