JPS63153042A - 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 The configuration of a conventional electronic blood pressure monitor is shown in FIG. 5, and its measurement principle will be explained. First, the cuff 26 is attached to the upper arm of a human body. At this time, the microphone 27 built into the arm cuff 1 is aligned with the artery of the upper arm of the human body. Next, the rubber bulb 28 blows air into the cuff through the rubber tube 29 to pressurize it. When the air supply by the rubber bulb 28 is stopped, a small amount of air is discharged from the micro-exhaust valve built into the rubber bulb.
The pressure within the cuff gradually decreases. Further, the pressure inside the cuff 26 is detected by a pressure sensor 30 connected to the rubber tube 29,
The output of the pressure sensor 3o is converted into a digital signal by an A/D converter 31, and becomes an input to the control section 32. Also, when the pressure inside the cuff 28 is high, the brachial artery is compressed and blood is blocked, so the output of the microphone 27 on the artery is a low frequency.
As the pressure decreases, blood begins to flow and Korotkoff sounds appear in the output of the microphone 27, and as the pressure decreases further, the Korotkoff sounds disappear. Further, the output voltage of the microphone 2 is amplified by an amplifier circuit 34, and the output voltage of the amplifier circuit 34 is inputted to a filter circuit 36 to detect the Korotkoff sound.

The output of the filter circuit 35 is compared by a comparator 36 and used as an input to the control unit 32, and the output of the Mu/D converter 31 when the output of the comparator 36 first becomes high is set as the systolic blood pressure in the control unit 32. , Mu/D converter 3 when high was detected last.
The number 1 is displayed on the display 33 as the diastolic blood pressure.

Problems to be Solved by the Invention However, the conventional configuration described above requires alignment between the microphone and the artery when wearing the cuff, which is inconvenient. Additionally, since Korotkoff sounds are detected using a microphone, electrical noise or noise could cause malfunctions.

Therefore, the present invention allows blood pressure to be easily measured without a microphone.
Moreover, the aim is to provide a low-cost blood pressure monitor.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides an arm cuff to be worn on the upper arm of a human body, and a pressurizing means for supplying air to the arm cuff to pressurize the upper arm of the human body until blood ischemia is achieved. , a slight evacuation means for gradually evacuation, a pressure detection means for detecting the pressure within the cuff at a constant sampling period, a conversion means for converting the output of the pressure detection means into a digital pressure signal, a first detecting means for detecting a starting point of pressure vibrations occurring in synchronization with a pulse, a second detecting means for detecting an end point of the pressure vibrations, and a first detecting means for calculating an instantaneous value of the pressure vibrations. a second detection means for detecting the maximum value of the instantaneous value of the pressure vibration as the magnitude of the pressure vibration generated during micro-evacuation;
storage means for storing the magnitude of the pressure oscillation and the pressure at the starting point of the pressure oscillation; determining means for determining a blood pressure value from the magnitude of the pressure oscillation and the pressure at the origin of the pressure oscillation; and a display for displaying the blood pressure value. It is composed of means.

Operation The present invention, with the above-mentioned configuration, is microphoneless and does not require positioning, resulting in cost reduction. In addition, in addition to easily detecting the magnitude of blood vessel noise as a pressure oscillation component, in order to eliminate the influence of changes in pumping speed, the change in pressure drop straight line during minute evacuation is detected as a pressure oscillation component. , Accurate blood pressure values can be obtained regardless of pumping speed.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 to 4. First, the arm cuff 1 is attached to the upper arm of a human body. At this time, unlike the conventional example, there is no microphone, so alignment with the artery is not necessary. Next, the rubber bulb 2 blows air into the cuff through the rubber tube 3 and pressurizes it to a constant pressure. This period is called pressurization mode. Next, it is slightly discharged through the fine discharge valve built into the rubber bulb 2.
Gradually reduce the pressure. That is, the rubber ball 2 functions as a pressurizing means and a fine evacuation means. The pressure inside the cuff 1 is detected by a pressure detection means (hereinafter referred to as a pressure sensor) 4 connected to a rubber tube 3, and the output of the pressure sensor 4 is detected by a conversion means (hereinafter referred to as a Mu/D converter) 5. It is converted into a digital pressure signal and becomes an input to the control section 6. Said Mu/D
The transducer 5 is a conventional system that detects only the pressure value inside the arm cuff.
Unlike the D converter 31, the one with high resolution ((11ssH
g or more).

Next, a method of processing the detected digital pressure signal in the control section 6 will be explained with reference to FIGS. 2 to 4.

The period from the completion of pressurization to the completion of measurement is called the measurement mode, and the period from then until the completion of evacuation is called the exhaust mode (
Figure 3).

In the measurement mode, data acquisition is first started (step 8). First, the pressure p immediately after the start is captured (step 9) and stored as initial data (step 10). The pressure p2 after the next sampling time is captured (step 11) and stored (step 12). Next, initial settings are performed (step 13), 1 is incremented (step 14), and pressure measurement after the next sampling time is performed (step 15). Next, the pressure vibration component q
, is obtained by calculating equation (2) (step 16).

Here, 1 indicates the i-th sampling after the start of measurement, p is the instantaneous value of the current pressure, P, l.

TM is the pressure at the rising point of the current Nth beat vibration and N
It shows the value of 1 at the rising point of the beat (see Figure 3.4).

In the case immediately after the start of the measurement, P)1-1 t''N -f is the first data immediately after the start of the measurement, and pHI''N is the second data. For the second beat or later, p, -11”If
-1 is the data of the rise point of the pressure vibration one beat before, PN,
Ti is the data of the rising point of this pressure oscillation.

Next, store the local maximum value of qi (step 17.18
), determine whether ql is greater than or equal to the value (i-T,) 39 multiplied by the time from the rising point TN of the current pressure vibration to the present (step 19), and if it is large, return to step 14 and step 19). Repeat the process up to 19. If it is small, the detection of the maximum value of the current pressure vibration is completed, and it is determined whether the current pressure vibration magnitude QN is larger than a certain judgment level ΔQ (step 20); if it is not larger,
The current pressure oscillation value is canceled and the current instantaneous pressure value is stored as the new pressure rise point (step 21), and the process returns to step 14 and repeats the process up to step 21. As described above, the magnitude QN of the pressure vibration and the pressure PN at the rising point are detected as shown in FIGS. 3 and 4.

Next, determine whether Q)l has reached the maximum value (step 22), if not, increment N (step 23), and repeat steps 14 to 23 until the maximum value of QN is determined. repeat. When the maximum value of Q8 is determined (QNI!1ax), the pressure value PM at the first Qi, which is the detection level determined by kIQNm, is taken as the systolic blood pressure, and the pressure value PM at the first Q when it is less than k2Qmax is determined. The pressure values P and l are determined to be the diastolic blood pressure (step 24). If the conditions are not met and the blood pressure cannot be determined, steps 14 to 24 are repeated.

Display the determined blood pressure value on the display 7 (step 25)
.

Effects of the Invention As described above, according to the present invention, a microphone is not required and positioning is not required. Also, microphone and amplifier circuit.

Filter circuits and comparators are not required, resulting in lower costs.

Another object of the present invention is to provide an electronic sphygmomanometer that can easily detect the magnitude of blood vessel sounds as a vibration component of the pressure value, and can detect blood pressure accurately by correcting it without being affected by the pumping speed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an electronic blood pressure monitor according to an embodiment of the present invention, FIG. 2 is a flowchart showing control of the electronic blood pressure monitor, and FIG.
FIG. 4 is an explanatory diagram of the method of detecting the oscillation component of pressure according to the present invention, and FIG. 6 is a configuration diagram of a conventional electronic blood pressure monitor. 1... Bracelet, 2... Rubber ball (pressurizing means, micro evacuation means), 4... Pressure sensor (pressure detection means), 5...・Mu/D converter (conversion means), 6.
...Control unit, 7...Display device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure L J 2nd
Figure Pressure (PJ-4-In No. 4 Figure 1 Level 7i1 Period Figure 5

Claims (5)

[Claims] (1) An arm cuff to be attached to the upper arm of a human body, a pressurizing means for supplying air to the arm cuff and pressurizing the upper arm of the human body until blood ischemia, a micro evacuation means for gradually discharging air, and an air cuff inside the arm cuff. pressure detection means for detecting the pressure of the pressure at a constant sampling period; conversion means for converting the pressure of the pressure detection means into a digital pressure signal; and detection means for detecting the origin of pressure vibrations that occur in synchronization with the pulse during microevacuation a first detection means; a second detection means for detecting the end point of the pressure vibration; a first calculation means for calculating the instantaneous value of the pressure vibration; a third detection means for detecting the magnitude of the pressure vibration generated during evacuation in a range from a starting point to an end point of the pressure vibration; and a storage means for storing the magnitude of the pressure vibration and the pressure at the starting point of the pressure vibration. An electronic sphygmomanometer comprising: determining means for determining a blood pressure value from the magnitude of the pressure vibration and the pressure at the starting point of the pressure vibration; and a display means for displaying the blood pressure value. (2) The first detection means detects a difference between the current pressure and an extension line of a pressure drop straight line that connects the starting point of the previous pressure oscillation and a point that is the sampling period before the current point. 2. The electronic sphygmomanometer according to claim 1, wherein when the above occurs, a point that is just the sampling period before the current point is detected as the starting point of the pressure oscillation. (3) The second detection means detects the predetermined value at the time from the origin of the current pressure oscillation to the present time on an extension line of the pressure drop straight line formed by connecting the origin of the previous pressure oscillation and the origin of the current pressure oscillation. 2. The electronic blood pressure monitor according to claim 1, wherein the electronic blood pressure monitor is configured to detect the current moment as the end point of the pressure oscillation when the instantaneous value of the pressure at the current moment becomes smaller than the value obtained by adding the value multiplied by . (4) The first calculating means calculates the difference between the current pressure and an extension line of a pressure drop straight line connecting the starting point of the previous pressure oscillation and the starting point of the current pressure oscillation, and The electronic blood pressure monitor according to claim 1, which is configured to obtain an instantaneous value of vibration. (5) The determining means determines that the pressure at which the magnitude of the pressure oscillations increases as the pressure within the cuff decreases and becomes equal to or higher than a first predetermined ratio of the maximum value of the pressure oscillations is the systolic blood pressure; Claim 1: The blood pressure value is determined by using the pressure when the pressure in the cuff decreases and becomes equal to or less than a second predetermined ratio of the maximum value of the pressure vibration as the diastolic blood pressure. The electronic blood pressure monitor described.