JPS58149731A - Non-observing type hemomanometer apparatus - 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 The present application relates to a non-invasive blood pressure measuring device, and more specifically,
The present invention relates to a device that calculates the difference between in-cuff pulse waves, detects its peak value, and measures systolic blood pressure and diastolic blood pressure.

Blood pressure measurement is generally divided into two types: a viewpoint method and a non-invasive method.

The viewpoint method is one in which blood pressure and its fluctuations are measured directly by cutting the blood vessel or inserting a needle into the blood vessel and leading it to a pressure gauge. Specifically, a catheter (hollow tube) or sensor filled with liquid is inserted into the measurement site, blood pressure and its fluctuations are guided to a pressure transducer placed outside the body, and the output signal of the transducer is amplified. Record and display.

However, blood pressure measurement using this method involves directly inserting a needle or the like into a blood vessel, which places a burden on the patient and does not allow easy measurement of blood pressure.

Therefore, except in special cases, non-invasive methods of measuring blood pressure indirectly from outside the body are widely used.

Currently, the most common indirect method is called the auscultation method, which is performed according to the following steps.

First, a cuff (compression band) is wrapped around the upper arm, and after increasing the internal pressure of the cuff with a pressure pump, the pressure is gradually reduced while
Place a stethoscope over the elbow artery and auscultate. When the internal cuff pressure matches the systolic blood pressure value, a Korotkoff sound occurs in synchronization with the heartbeat (the blood flow passing through the artery under the cuff collides with stationary arterial blood on the distal side). The systolic blood pressure and diastolic blood pressure are measured by listening to the sound that vibrates the blood vessel wall and confirming that the Korotkoff sound disappears when the cuff internal pressure matches the diastolic blood pressure value.

Furthermore, the electric blood pressure monitors currently in use apply the principle of the auscultation method described above, and the Korotkoff sounds are collected with a microphone and, after discrimination and confirmation, are displayed on a meter or the like.

However, what is particularly difficult about this blood pressure monitor is:
This means that the machine must perform the confirmation and judgment of Korotkoff sounds, which are the standard for determining systolic and diastolic blood pressure values, which is normally performed by humans.

In order to determine the maximum and diastolic blood pressure values, it is necessary to confirm and judge the appearance or disappearance of Korotkoff sounds, but since the volume is very weak, it is difficult to determine whether the Korotkoff sounds appear or disappear. They are susceptible to skin friction noise, making blood pressure measurement difficult.

The present invention was developed to eliminate such defects in conventional blood pressure monitors, and uses a completely different principle from the previous ones, that is, it calculates the difference between cuff pulse waves, detects its peak value, and measures the systolic blood pressure. and devised a method for measuring diastolic blood pressure.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a configuration diagram showing an embodiment of a blood pressure monitor according to the present invention. In the illustration, sensors (4) (including microphones, pressure transducers, optical sensors, etc.) are drawn out from the cuff (1) via a hollow tube (6).

A pump (2) supplies fluid to and pressurizes the cuff. In the output of the sensor, the cuff internal pressure component is amplified by a DC amplifier (5), and the cuff internal pulse wave component is amplified by an AC amplifier (7). The output of the AC amplifier is sent as is, and the output of the DC amplifier is sent to the arithmetic processing circuit (8) via the A/D converter (6).
(a microcomputer is used in the embodiment). In the illustrated embodiment, a timer (10) and a memory (9) are provided around the microcomputer. These functions and actions will be described later.

In the illustrated embodiment, the sensor is made hollow so that the cuff is not limited to the upper arm as in conventional auscultation methods (for example, the cuff can be wrapped around a finger). The tube (3) is pulled out of the cuff, and the hollow tube, the cuff, and the hollow tube (12) connecting the cuff and the pump are filled with liquid having the same specific gravity as blood, and the sensor is placed at the same height as the heart. It is configured so that it can be installed. however,
In the present invention, there is no problem even if the sensor is built into the cuff and the measurement is carried out by wrapping the cuff around the upper arm as in the conventional case.

Now, when fluid is supplied and pressurized to the cuff with a pump, the pressure inside the cuff increases, and the internal pressure of the cuff gradually increases as shown in Figure 2 (a). Although the cuff internal pressure waveform shown in Figure 2 (b) is more accurately the cuff internal pressure waveform, it is shown as a straight line for simplicity.

Next, the cuff pulse waveform increases sequentially, and the cuff pressure at this time gradually decreases after reaching a certain peak value (the mean blood pressure (BP)). The result is as shown in Fig. 2 (c). In the figure, the peak value of the pressure corresponds to the systolic blood pressure (BP), and the negative peak value corresponds to the diastolic blood pressure ax (BPmin).

The microcomputer recognizes whether the arterial wave is correctly detected, calculates the difference in waveform energy, recognizes the two peak points of the difference as the blood pressure value, and stores the pressure value at the peak point in memory (9). It has a program that controls other controls. Note that the timer (10) is for setting the measurement interval.

The reason why systolic blood pressure can be measured by measuring the peak of the difference in arterial waves is as follows.

Diagram 3 (a) shows that the pump (2) is used to pump the blood vessels (1) inside the cuff (1).
11), the blood flow (triangular wave) collides with the tube wall (the shaded area in the figure), and the shock wave passes through the fluid in the cuff and the hollow tube (3) to the sensor. (4).

Figure 6 (b) shows the state when the pump pressurization is stopped and as the applied pressure decreases, the crushed blood vessel gradually expands and blood begins to flow.At this time, the cuff internal pressure and the pressure inside the blood vessels are equal. The blood vessel vibrates in the shaded area, that is, the entire inside of the cuff.
A pressure pulse wave is generated that can be clearly distinguished from the shock wave in (a). The upper point of Fang 2 (b) corresponds to this,
In Figure 2 (c), this corresponds to the positive peak value of the difference.

Figure 4 shows the actual measured value of systolic blood pressure (SEP) by the device of the present invention in comparison with the conventional indirect method (RIvA-ROCICI method). The number of samples is 30° in mm Hg. It can be seen from the figure that the actual measured values of the two coincide well.

The reason why the peak value of the difference corresponds to the diastolic blood pressure value is based on actual measurements. Figure j/-5 shows the actual measured value of diastolic blood pressure (DBP) by the device of the present invention compared to the conventional indirect method (RIVA-ROO).
A comparison with the OI method) is shown below. Number of samples is 30, unit is mmH
It is g. As can be seen from the figure, the measured values of diastolic blood pressure by the device of the present invention are in good agreement with the values obtained by the conventional method.

The configuration and measurement principles of the blood pressure measuring device according to the present invention have been described in detail above, and the configuration provides the following unique effects.

That is, unlike the conventional method of measuring blood pressure by detecting Korotkoff sounds, the present invention only requires observing the intracuff pressure and arterial wave, which can be easily detected with a sensor, so the measurement conditions are relaxed, and therefore the measurement is easy. It is easy to use and is less affected by noise, so the measurement accuracy is high.

Moreover, since data processing is performed using a computer, blood pressure can be measured and monitored over a long period of time. For example, it has become possible to measure blood pressure intermittently during sleep by controlling a timer and pump, and its uses have expanded significantly compared to conventional ones.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention. Figure 1 is a configuration diagram of a measurement circuit, Figure 2 is an explanatory diagram of an observed blood pressure waveform modeled, and Figure 3 is an illustration of blood pressure measurement according to the present invention. Figures explaining the principle, Figure 4 and Figure 5, are graphs comparing the measured values of the device of the present invention and the conventional method. [Explanation of symbols of main parts] F 7 −−−−−−−−−−−−−−−
−−−−−−−−−−−−−−−−−−−i pump
−−−−−−−−−−−−−−−−−−−−−−−−−−
−−−−−−−−−2 Hollow tube −1−−−−−−−−−
−−−−−−−−−−−−−−−−−−−m−−−3 sensor −−−−−−−−−−−−−−−−−−−
----------m----4DC amplifier -------
−−−−−−−−−−−−−−−−−−−−−−−−−
---= 5A/D converter ---------
−−−−−−−−−−−−−−−−−−−−6 AC amplifier
−−−−−111−−−・7 Arithmetic processing circuit −−−−−
−−−−−−−−−−−−−−−−−−−−−−−−−
-= 8O Figure 4 AP R1νA-ROCCI

Claims (1)

[Claims] 1. A cuff (1), a pump (2) that supplies and pressurizes fluid to the cuff, a sensor (4) installed in the cuff or in a hollow tube (3) communicating with the cuff, and a sensor (4) for the sensor. A DC amplifier (5) that amplifies the cuff internal pressure component of the output signal, an AC amplifier (7) that amplifies the cuff internal pulse wave component, and the DC
An A/D converter (6) connected to the amplifier, the output of the converter and the output of the AC amplifier (7) are used as manual data to calculate the difference in arterial waves, and detect the positive and negative peak values thereof. A non-invasive blood pressure measuring device comprising an arithmetic processing circuit (8) that detects the cuff internal pressure corresponding to the peak value.