JPH0655205B2 - Electronic blood pressure monitor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic sphygmomanometer.

2. Description of the Related Art The configuration of a conventional electronic sphygmomanometer is shown in FIG. 4 and the measuring principle will be described. First, the armband 1 is attached to the upper arm of the human body. At that time, the K sound sensor 7 built in the arm band 1 is aligned with the position of the artery of the upper arm of the human body. Next, the rubber ball 2 is fed into the arm band through the rubber tube and pressurized to a constant pressure. When the air supply by the rubber ball 2 is stopped, it is slightly discharged from the minute discharge valve built in the rubber ball,
The pressure in the arm band 1 gradually decreases. The pressure in the armband 1 is detected by the pressure detection circuit 4 connected to the rubber tube 3, and the output of the pressure detection circuit 4 is a digital signal which is input to the control unit 5. Further, when the pressure of the arm band 1 is the maximum value, the artery of the brachial artery is compressed and occludes blood. Therefore, the output of the K sound sensor 7 on the artery is a low frequency and low sound, but blood starts to flow as the pressure decreases. The Korotyukh sound appears in the output of the sound sensor 7, and when the pressure further decreases, the Korotyukh sound disappears.

Further, the output voltage of the K sound sensor is amplified by the amplifier circuit 8,
A filter circuit 9 detects a Korotow sound from the output voltage of the amplifier circuit 8. The output of the pressure detection circuit 4 when the output of the comparator 10 becomes high in the control unit 5 is converted into the maximum value by the comparator 10 which receives the output of the filter circuit 9 as an input to the control unit 5. The output of the pressure detecting circuit 4 when the blood pressure is set to high and then the comparator 10 becomes low is displayed on the display 7 as the minimum blood pressure.

Problems to be Solved by the Invention However, the above-described conventional configuration is inconvenient because the K sound sensor and the artery need to be aligned when the armband is worn. Also K
Since the sound sensor detects the Korotyuf sound, it sometimes malfunctions due to electrical noise or noise.

Therefore, the present invention can easily measure blood pressure without a microphone,
Moreover, the object is to provide a low-cost blood pressure monitor.

Means for Solving the Problems In order to solve the above problems, the present invention provides an arm band to be attached to an upper arm of a human body and a pressurizing for supplying air into the arm band until the upper arm of the human body is blocked. Means, a small discharge means for gradually exhausting and reducing the pressure, an instantaneous pressure detecting means for detecting the pressure in the arm band at regular intervals, and an exhaust pressure detecting means for detecting the exhaust pressure by the slight discharge means, First storage means for storing a pressure value when the rate at which the instantaneous pressure decreases during slight discharge begins to decrease, and the exhaust pressure and the instantaneous value after the rate at which the instantaneous pressure decreases during slight discharge begins to decrease The second storage means for storing the maximum value of the pressure difference as the loudness of the blood vessel sound generated during the minute discharge, and the value of the blood vessel sound that has been stored until now when the loudness of the blood vessel sound exceeds a certain value. 1 / K ₂ times, and the conversion means for converting the value of the blood vessel sound after that to 1 / K ₂ It is composed of a judging means for judging the blood pressure value from the change in the blood vessel sound and the pressure value stored in the first storage means, and a display means for displaying the blood pressure value.

Operation The present invention has the above-described configuration, does not require a K-sound sensor, does not require alignment, and reduces cost. Further, by detecting the loudness of the blood vessel sound as the difference between the exhaust pressure and the instantaneous pressure, it is possible to accurately detect the accurate blood pressure value regardless of the change in the exhaust speed.

In addition, the volume of blood vessel sound varies greatly from person to person, but when the volume of the blood vessel sound is above a certain level, it is detected by detecting the smallest person, and by reducing and storing it, all people can be measured accurately, Moreover, it can be configured with a small storage capacity.

Example Hereinafter, an example of the present invention will be described in detail with reference to FIGS. Reference numeral 1 is an armband worn on the upper arm of a human body, 2 is a rubber ball that functions as a pressurizing means and a minute discharging means, and this rubber ball 2
Insulates the rubber band 3 into the arm band and pressurizes it to a certain pressure.
A slight discharge valve (not shown) built in the rubber ball 2 is used to slightly discharge and gradually reduce the pressure.

Further, the pressure detection circuit 30 functions as an instantaneous pressure detection means and an exhaust pressure detection means, and inputs these detected pressures to the control unit 5. Here, unlike the 8-9-bit output of the pressure detection circuit that detects only the pressure value in the arm band in the conventional example, the pressure detection circuit 30 also detects a minute change in pressure due to blood vessel sound at the same time, so that the output is 12-. Use a high 16-bit resolution.

Next, a method of processing the instantaneous output signal detected by the control unit 5 will be described with reference to FIGS. 2 and 3. The period from the completion of pressurization to the completion of measurement is referred to as a measurement mode, and the period from the completion of exhaust to the exhaust mode.

In the measurement mode, first determine the initial value (step 1
1) The instantaneous pressure signal P _i during the slight discharge is detected at regular intervals (steps 12 and 13). Next, from the measured instantaneous pressure signal Pi, the previous value P _i-1, and the last _- previous value P _i-2 , P _i-1 -Pi
It is judged whether or not the change value of is smaller than the change value of P _i-2 −P _i-1 by k1 or more (step 14). DP
₁ is calculated (steps 15 and 16). Then, the process returns to step 12 and is repeated. When step 14 is satisfied, P _i-1
Is stored as the pressure value P _N when the blood vessel sound is generated. At the same time i-
1 is stored as M _N (step 17). Then N ≧ 2
Of time, the exhaust pressure DP _N per step _{DP N = (P N-1} -P
_N ) / ( _MN - _MN-1 ) is calculated (step 18).
Next, the instantaneous pressure signal Pi is measured (steps 19 and 2).
0). Next, the instantaneous value of the pressure change corresponding to the volume of the blood vessel sound
DQ _i is calculated as DQ _i = P _i −P _N + D P _N × (i−M _n ) (step 21). Next, it is judged whether DQ _i has reached the maximum value, and the process returns to step 19 and is repeated until it reaches the maximum value (step 2
2). If step 22 is satisfied, the volume Q _{N of the} blood vessel sound
_Is stored as Q _N = (DQ _iMAX / k ₂ ) (step 2
3).

Next, it is determined whether Q _N exceeds the allowable value Q _{M of the} memory (step 24). When Q _N > Q _M , k ₂ is doubled (step 25). Next, the Q _N stored so far is divided by 2 and stored again (step 26). Then 1 for N
Is added (step 27). If Q _N Q _M , proceed to step 27. Next, the maximum value of Q _N is determined, and when it does not reach the maximum value, the process returns to step 12 and the blood vessel sound is detected again (step 28). When the maximum value of Q _N is detected in step 28, it is judged in the blood pressure determination process whether or not the minimum blood pressure has been reached. If not satisfied, the process returns to step 12 and the blood vessel sound is detected again (step 29). Next, when the minimum blood pressure is determined in step 29, the maximum blood pressure is determined and displayed as a blood pressure value.

EFFECTS OF THE INVENTION As described above, according to the present invention, the K-sound sensor is not required and the alignment is not required, and the K-sound sensor, the amplification circuit, the filter circuit and the comparator are not required, and the cost is reduced. To be done.

In addition, the loudness of the blood vessel sound can be easily detected as the increase value of the pressure value and can be detected without the influence of the exhaust velocity, so that the accurate blood pressure can be measured. Moreover, by correcting the loudness of the blood vessel sound with the maximum value, it is possible to provide an electronic sphygmomanometer capable of accurately measuring blood pressure by anyone.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronic sphygmomanometer according to an embodiment of the present invention, FIG. 2 is a waveform diagram showing a loudness of blood vessel sound from a pressure value of the present invention, and FIG. FIG. 4 is a flowchart showing the control, and FIG. 4 is a block diagram showing the configuration of the conventional electronic blood pressure monitor. 1 ... arm band, 2 ... rubber ball (pressurizing means, slightly discharging means), 5
...... Control unit, 30 ...... Pressure detection circuit (instantaneous pressure detection means, exhaust pressure detection means).

Claims (2)

[Claims] 1. An arm band to be attached to the upper arm of a human body, a pressurizing means for supplying air into the arm band to pressurize the upper arm of the human body until ischemia, and a minute discharge means for gradually exhausting and reducing the pressure. The instantaneous pressure detecting means for detecting the pressure in the arm band at regular intervals, the exhaust pressure detecting means for detecting the exhaust pressure by the minute discharge means, and the rate at which the instantaneous pressure decreases during the minute discharge decrease. First storage means for storing the pressure value at the time of starting, and the maximum value of the difference between the exhaust pressure and the instantaneous pressure is generated during the minute discharge after the rate at which the instantaneous pressure decreases during the minute discharge begins to decrease. Second storage means for storing as the loudness of blood vessel sound, and when the loudness of the blood vessel sound exceeds a certain value, the value of the blood vessel sound that has been stored so far is converted to 1 / K ₂ times, and the blood vessel sound after that. Is also 1 /
An electronic sphygmomanometer including a conversion unit for converting into K ₂ , a determination unit for determining a blood pressure value from the change in the blood vessel sound and the pressure value stored in the first storage unit, and a display unit for displaying the blood pressure value. . 2. The determination means sets the pressure when the loudness of the blood vessel sound increases with the decrease of the instantaneous pressure in the arm band and becomes a predetermined ratio or more of the maximum value of the blood vessel sound, as the systolic blood pressure, and 2. The electronic device according to claim 1, wherein the blood pressure value is determined with the pressure when the pressure in the arm band decreases as the pressure decreases and falls below a predetermined ratio of the maximum value of the blood vessel sound as the minimum blood pressure. Sphygmomanometer.