JPS61193633A - 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] [Technical Field] The present invention relates to a blood pressure monitor that measures systolic blood pressure and mean blood pressure by a vibration method (oscillometric method) and calculates diastolic blood pressure from the systolic blood pressure and mean blood pressure. .

BACKGROUND TECHNOLOGY Conventionally, sphygmomanometers that measure blood pressure using the Liparot and Korotkoff methods have been proposed. In order to measure the diastolic blood pressure, it is necessary to wait until the Korotkoff sound disappears, which takes a long time to measure.
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On the other hand, a sphygmomanometer using a vibration method (oscillometric method) for determining a blood pressure value from a pulse wave component included in the pressure waveform of the intracuff pressure due to pulsation has been provided, for example, in Japanese Patent Application Laid-Open No. 59-1999.
It is known from the publication No.-181129.

This measures systolic blood pressure and mean blood pressure from changes in pulse wave components, and calculates diastolic blood pressure from these systolic blood pressure and mean blood pressure.Since diastolic blood pressure is determined when measuring mean blood pressure, blood pressure can be measured quickly. This has the effect of shortening the measurement time. However, in this case, the systolic blood pressure and mean blood pressure are measured by detecting fluctuations in the pulse wave component from the array of intra-cuff pressure data at the peak of the waveform corresponding to one heartbeat. Since the wave component is very small compared to the intra-cuff pressure, the variation in the intra-cuff pressure due to the pulse wave component is not clear, and the influence of noise is large, so there is a high possibility of measurement errors. In particular, when noise is mixed in, impulses with a large width and high frequency appear, which are also processed as pulse wave components, making it difficult to measure blood pressure accurately.
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[Purpose of the invention]

The present invention has been made in view of the above points, and its purpose is to provide a blood pressure monitor using a vibration method that is capable of accurate blood pressure measurement and is less affected by noise. .

[Disclosure of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5. Reference numeral 1 denotes a belt-shaped cuff that is wrapped around the upper arm of a human body, and is connected to the blood pressure monitor main body 2 through an air pipe 5&C. In the middle of the air pipe 5, a pressurizing pump 3 made of a rubber bead is provided which pumps air to the cuff 1 and pressurizes it.
The pressurizing pump 3 is equipped with an exhaust mechanism 4 that exhausts the air inside the cuff 1 to reduce the pressure. The pressure within the cuff 1 is detected by a pressure sensor 6, converted into a digital signal via an A/D converter 7, and then input to a sequence circuit 8 to measure blood pressure. The measurement results of the sequence circuit 8 are displayed on a display 9 made of a liquid crystal or the like provided on the top surface of the blood pressure monitor main body 2.

The sequence circuit 8 is composed of a microcomputer, and determines the systolic blood pressure and the mean blood pressure from the minute pressure vibration component of the internal pressure of the cuff 1, that is, the pulse wave component included in the pressure waveform of the internal pressure of the cuff 1 due to pulsation. The diastolic blood pressure is calculated from the systolic blood pressure and the average blood pressure.

3 and 4 are diagrams showing the blood pressure measurement principle of the blood pressure monitor of this embodiment, and as shown in FIG. 4, the waveform corresponding to one heartbeat of the pulse wave component included in the pressure waveform of the internal pressure Pn of the cuff 1. Find the area Sn of the pulse wave component waveform surface [Sn
In the sequence, the reading of the pressure Pn inside the cuff 1 at the first point when Sn/5n-1≧1.3 is the systolic blood pressure Ps. Let mean blood pressure pM. In general, if the systolic blood pressure P8 and the diastolic blood pressure pD are obtained, the mean blood pressure pM can be obtained from the relational expression pM = Immediate + (Ps - PD) /3, so the systolic blood pressure Ps and the mean blood pressure PM can be obtained as described above. If so, the diastolic blood pressure pD can be calculated from the following relational expression.

PD = (3PM - Ps ) /2 By the method described above, the diastolic blood pressure pD can be determined at the time when the mean blood pressure PM is determined.

Next, to explain the procedure for measuring blood pressure, after wrapping the cuff 1 around the upper arm of a human body, pressurize the pump 3 by hand to compress and inflate it to pump air into the cuff 1 so that the blood pressure exceeds the expected systolic pressure. Pressurizing the cuff 1 Next, operate the exhaust mechanism 4 to pressurize the cuff 1.
By gradually exhausting the air inside the cuff 1 at a constant speed, the internal pressure Pn of the cuff 1 is reduced at a constant speed as shown in FIG. 3 (&).

At this time, as is clear from FIG. 4, the internal pressure Pn of the cuff 1 includes a minute pressure vibration component that appears with pulsation, that is, a pulse wave component.

The processing operation in the sequence circuit 8 will be explained below based on the flowchart shown in FIG. The processing operation of the sequence circuit 8 includes measuring the area Sn of the pulse wave component waveform (step 8).
1 to S4), systolic blood pressure Ps determination (step 5s-8γ)
, mean blood pressure pM determination (step S.

* S's Sll * Ss ), diastolic blood pressure pD calculation (
The blood pressure measurement starts from the time when the cafe starts depressurizing. First, in order to extract the waveform corresponding to one heartbeat of the pulse wave component, the pressure Pvn at the valley is determined by setting the point at which the pressure Pn inside the cafe starts to rise from the falling state as the valley (steps 81 to 5s). Valley pressure P
The straight line connecting the previously determined valley pressure P is man
Since this is a straight line of descent of the cuff 1 internal pressure that does not include the Vfi-1 pulse wave component, the area Sn of the portion surrounded by this straight line and the cuff 1 internal pressure Pn waveform is measured (step 84).

The A/D converter 7 is of high resolution and converts the pressure value Pn at each point in time of the internal pressure Pn of the cuff 1 into a digital signal at high speed, and the sequence circuit 8 converts the output signal of the A/D converter 7 into a digital signal. - Add each pressure value Pa during the heartbeat to find the area between the cuff 1 internal pressure Pn waveform and the predetermined level, and from this area, calculate the trough pressure P.
The area Sn is measured by subtracting the area between a straight n-1 line connecting and pvn and a predetermined level. This area Sn is the area Sn of the pulse wave component waveform, and is considered to represent the energy due to pulsation. Therefore, the blood pressure value can be determined from the data of the area Sn of the pulse wave component waveform using the vibration method. This is possible. At this time, if the systolic blood pressure Pg has not been determined, the area Sn of the pulse wave component waveform measured this time
By comparing the previously measured area Sn-, Sn/Sn-
2" 3, the previous trough pressure pvnL is displayed on the display 9 as the systolic blood pressure Pg, and the process returns to step S1 to obtain the next trough pressure (step 5s-8).
. When the processes of steps 81 to S4 are performed in the same manner as last time, the systolic blood pressure Ps has already been determined, so the area Sn of the pulse wave component waveform measured this time is compared with the area Sn- measured last time (step Ss). As shown in FIG. 3(b), after the systolic blood pressure Ps is determined, the area Sn of the pulse wave component waveform continues to increase, and since S,<Sn, the process returns to step S1. After repeating steps 81 to Ss and S,
Sa diagram (as shown in bl, the area of the pulse wave component waveform Stmi
Since it reaches the maximum and then starts to decrease, 5n-8>
When reaching Sn, the previous trough pressure pvn-8 is set as the average blood pressure (steps Ss, Ss). Once the mean blood pressure pM is determined, the above-mentioned relational expression PD = (3PM-P
s)/2, the diastolic blood pressure value pD is calculated and displayed on the display 9, and the measurement is ended (Stellab 5so). As described above, since the blood pressure value is measured from the data of the area Sn of the pulse wave component waveform, fluctuations in the pulse wave component become clearer than when measuring from the data of the intracuff pressure at the peak of the pulse wave component waveform. Thus, the systolic blood pressure and mean blood pressure can be determined reliably, and the diastolic blood pressure value pD can be determined with high accuracy. Furthermore, even if an impulse appears superimposed on the cuff 1 internal pressure Pn waveform due to noise, the area of the pulse wave component waveform is Sn It has little effect on the data (there is no possibility of measurement errors due to noise contamination).

Next, another embodiment of the present invention will be described based on FIGS. 6 and 7. As shown in Fig. 6, the pressure inside the cuff 1 at the rise of the waveform corresponding to one heartbeat of the pulse wave component is taken as the base pressure, and the systolic blood pressure and the average It determines the blood pressure and calculates the diastolic blood pressure value from the systolic blood pressure and mean blood pressure.The processing operation of the sequence circuit 8 in blood pressure measurement will be explained below based on the flowchart of the Kr diagram. The processing operations of the sequence circuit 8 include measuring the area Sn of the pulse wave component waveform (steps 81 to Ss), determining the systolic blood pressure P8 (steps 86 to Ss), and determining the mean blood pressure PM (step S'
s Sto s,, Sto ), diastolic blood pressure pD calculation (
It consists of a STELAB 511) and starts measuring blood pressure from the moment the cafe starts depressurizing. First, in order to extract the waveform corresponding to one heartbeat of the pulse wave component, the rising point of the pulse wave component waveform when the cuff 1 internal pressure Pn starts to rise while it is falling is defined as a trough, and the pressure at this trough is the reference pressure. It is stored as PVn (step 81 to SS). Next, the reference pressure pvn and the cuff 1 internal pressure Pn at each time point are sequentially compared, and Pn-Py
H": If 0, the wave height value (Pn - Pvn) based on the reference pressure pvn is calculated and added sequentially, and the waveform area Sn in the range equal to or higher than the reference pressure pvn is measured (step S4-85). .

As is clear from FIG. 6, the area Sn is the area surrounded by the cuff 1 internal pressure Pn curve and the reference pressure Pvn level, and is the area Sn of the pulse wave component waveform. Thereafter, step 5a is performed based on the data of the area Sn of the pulse wave component waveform.
Perform the processing of Ns.

The systolic blood pressure Ps and the diastolic blood pressure pD are determined and displayed on the display 9. Since the steps 86 to S11 are the same as steps S to S1° in the processing operation of the above-described embodiment,
Explanation will be omitted. As described above, the area Sn of the pulse wave component waveform
Since the blood pressure value is measured from the data, fluctuations in the pulse wave component become clear, the systolic blood pressure and the mean blood pressure can be reliably determined, and the diastolic blood pressure value pD can be determined with high accuracy. Further, noise has little influence on the area Sn of the pulse wave component waveform, and no measurement errors are caused by the mixing of noise.

〔Effect of the invention〕

As described above, the present invention includes a cuff that is worn on the human body, a pressure sensor that detects the pressure inside the cuff, an A/D converter that converts an analog signal from the pressure sensor into a digital signal, and the A/D converter that converts an analog signal from the pressure sensor into a digital signal. /D converter output signal is obtained, the area of the waveform corresponding to one heartbeat of the pulse wave component included in the cuff intra-cuff pressure is measured, and the systolic blood pressure value and the mean blood pressure value are determined from this area. It consists of a one-step circuit that calculates the diastolic blood pressure value from the high blood pressure value and the average blood pressure value, and a display that displays the results obtained from the one-step circuit, so the pressure inside the cuff at the peak of the pulse wave component waveform is Compared to the case where the blood pressure value is measured from the data, fluctuations in the pulse wave component become clearer, the systolic blood pressure and the mean blood pressure can be reliably determined, and the diastolic blood pressure value can be determined with high accuracy. Furthermore, even if noise is mixed in, the effect of the noise on the area data of the pulse wave component waveform is small (and there is also the effect that measurement errors will not be caused by the noise mixed in).

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is a block circuit diagram of the same as above, Fig. 3 (g), cb) is a characteristic diagram showing the measurement principle of the same as above, and Fig. 4 is a diagram of Fig. 3 ( Partial enlarged view of a), No. 5
This figure is a flowchart of an embodiment of the present invention, FIG. 6 is a characteristic diagram showing the measurement principle of another embodiment of the present invention, and FIG. 7 is a flowchart of the same. 1... Cuff, 6... Pressure sensor, ? -A/D converter, 8...v-ken circuit, 9-...display device.

Claims (2)

[Claims] (1) A cuff to be attached to a human body, a pressure sensor that detects the pressure inside the cuff, an A/D converter that converts an analog signal from the pressure sensor into a digital signal, and the A/D converter that converts an analog signal from the pressure sensor into a digital signal.
Obtain the output signal of the converter, measure the area of the waveform corresponding to one heartbeat of the pulse wave component included in the intracuff pressure, determine the systolic blood pressure value and the mean blood pressure value from this area, and determine the systolic blood pressure value. A sphygmomanometer comprising: a sequence circuit that calculates a diastolic blood pressure value from an average blood pressure value; and a display that displays the results obtained by the sequence circuit. (2) The sequence circuit uses the cuff internal pressure at the rise of the waveform corresponding to one heartbeat of the pulse wave component as a reference pressure, and determines the systolic blood pressure value and the average blood pressure value from the area of the waveform within the range above the reference pressure. The sphygmomanometer according to claim 1, further comprising calculating a diastolic blood pressure value from the systolic blood pressure value and the average blood pressure value.