JPH0380494B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <<Field of the Invention>> The present invention relates to an electronic blood pressure monitor having a function of determining the presence or absence of congestion in the arm of a subject during blood pressure measurement.

<<Background of the Invention>> The applicant previously measured the blood pressure at the timing of the occurrence and disappearance of the Korotkoff sound as the maximum and minimum blood pressure (hereinafter referred to as the Korotkoff method).
The present invention also provides an electronic blood pressure monitor that measures the blood pressure at the peak timing of the pulse wave as the average blood pressure (hereinafter referred to as the oscillometric method).

By the way, when this type of electronic blood pressure monitor measures blood pressure continuously within a short period of time, congestion may often occur in the arm of the person being measured.

As described above, when the patient's arm becomes congested, peripheral vascular resistance increases and the state of Korotkoff sound generation changes, resulting in an increase in measurement errors.

As a result of intensive research to solve the above problem, the applicant has come to the following findings. In other words, if a state of congestion occurs in the subject's arm while measuring the maximum, minimum, and average blood pressure using the Korotkoff method and the oscillometric method, the results for the maximum and minimum blood pressures will differ from normal results, but the average blood pressure will Regarding this, there is almost no difference from normal conditions regardless of the presence or absence of congested blood. Therefore, the congested state of the arm can be determined conversely from the relationship between the systolic blood pressure and/or the diastolic blood pressure and the average blood pressure.

≪Object of the Invention≫ The object of the present invention is to provide an electronic blood pressure monitor using the Korotkoff method and the oscillometric method with a function to immediately detect when a state of congestion occurs in the arm of the subject during blood pressure measurement. An object of the present invention is to provide an electronic blood pressure monitor equipped with the following functions.

<<Structure and Effects of the Invention>> In order to achieve the above-mentioned objects, the present invention provides an electronic system that has means for detecting Korotkoff sounds and pulse waves, and measures systolic and diastolic blood pressure by the Korotkoff method and mean blood pressure by the oscillometric method. The sphygmomanometer is characterized by being provided with means for determining the presence or absence of a congested state in the arm from the measured systolic blood pressure and/or systolic blood pressure and the measured average blood pressure and outputting a determination output. .

According to this configuration, if a state of congestion occurs in the arm of the person to be measured during blood pressure measurement with this type of blood pressure monitor, it is possible to immediately notify the outside of the situation. The possibility of erroneous blood pressure measurement with a blood pressure monitor can be prevented.

<<Description of Embodiments>> FIG. 1 is a block diagram showing the electrical configuration of an electronic blood pressure monitor according to the present invention, FIG. 2 is a flowchart showing the configuration of a control program executed in the same blood pressure monitor, and FIG. are waveform diagrams showing the states of cuff pressure, pulse wave level, and Korotkoff sound level in normal times and in times of congestion, respectively.

In FIG. 1, a cuff 1 is wrapped around the arm of the person to be measured to tighten the arm, that is, it is pressurized by air from a pressurizing pump 2 through a rubber tube 3, and an exhaust valve 4 is opened. By doing so, the pressure can be reduced at a predetermined speed.

The pressure sensor 5 detects the air pressure inside the cuff 1 via the rubber tube 3 and converts it into an analog electrical signal. This cuff pressure signal is amplified via the amplifier 6 and then sent to two systems. One is directly taken into the CPU 13 via the A/D converter 12, and the other is passed through an amplifier 7 and a bandpass filter 8 in order to extract the pulse wave signal, and then sent to the A/D converter. Similarly, CPU13 via 12
be taken into account.

The Korotkoff sound sensor 9 is placed in close contact with the cuff 1 to detect the Korotkoff sound and convert it into an analog electrical signal. After the Korotkoff sound signal is extracted from this detection signal via the amplifier 10 and the bandpass filter 11, Similarly, it is taken into the CPU 13 via the A/D converter 12.

The display 14 displays systolic blood pressure (SYS), mean blood pressure (MEAN), and diastolic blood pressure (DIA).
In addition to the set of numerical display devices, an error display device (ERROR) according to the present invention is provided, and as will be described later, if measurement is started when the subject's arm is congested, this In addition to displaying the error message on the error display, the buzzer 1
5 is activated and a buzzer sounds to notify the state of stasis.

Next, the operation of the CPU 13 will be explained according to the flowchart of FIG. 2 while referring to the waveform diagram of FIG. 3.

In FIG. 2, in step (1), the CPU 13
A pressurizing command is issued to the pressurizing pump 2,
As a result, the pressurizing pump 2 is driven and air is sent into the cuff 1 through the rubber tube 3, so that the cuff wrapped around the arm of the person to be measured gradually tightens the arm.

Then, as shown in FIG. 3a, the cuff pressure, which is the output of the amplifier 6, rises relatively steeply from point _P0 to point _P1 . Next, in step (2), the CPU 13 gives a pressure reduction command to the exhaust valve 4, and the cuff 1
The air inside is gradually exhausted through the rubber tube 3 and exhaust valve 4, and the cuff pressure reaches P ₁ as shown in Figure 3a.
The pressure is gradually reduced from point P to point _P2 .

Next, during this pressure reduction process, when the Korotkoff sound that is the output of the bandpass filter 11 starts to be detected, the execution result of step (3) becomes YES.
Subsequently, step (4) is executed, and the cuff pressure at that point, which is the output of the amplifier 6, is stored in the register S as the systolic blood pressure.

Next, when the peak value of the pulse wave, which is the output of the bandpass filter 8, is detected while decompression is continued, the execution result of step (5) becomes YES, and the cuff pressure at that point is then taken as the average blood pressure. Stored in register M.

Furthermore, if the Korotkoff sound disappears while decompression continues, the execution result of step (7) becomes YES,
Subsequently, step (8) is executed and the cuff pressure at that time is stored in register D as the diastolic blood pressure.

Next, in step (9), each of the registers S,
According to the contents stored in M and D, the following calculations are performed: A=S-D B=M-D C=B/A, and register C stores the average blood pressure for the difference between the systolic blood pressure and the diastolic blood pressure. The value of the ratio of the difference between this and the diastolic blood pressure will be stored.

Here, as shown in Fig. 3c and d, when comparing the process from the onset to the end of the Korotkoff sounds in normal and congested conditions, the generation of Korotkoff sounds is slightly delayed during congested conditions compared to normal conditions; Also, Korotkoff sounds disappear more quickly.

On the other hand, if we look at the state from the start to the end of pulse wave detection, it is confirmed that the peak timing is almost the same in both normal and congested conditions, as shown in FIG. 3b.

Therefore, by measuring the systolic and diastolic blood pressures using the Korotkoff method and the mean blood pressure using the oscillometric method, the relationship between the maximum, minimum, and mean blood pressure values P _H , P _L , and P _M obtained during normal conditions and during congestion can be determined. The maximum, minimum and mean blood pressure values obtained P _H ′, P _L ′ and
This will cause a difference in the relationship between P and _M.

For example, if we simply compare the difference between the mean blood pressure and the diastolic blood pressure in normal conditions and in congested conditions, the difference between the two in normal conditions, P _M −P _L , and the difference in congested conditions, P _M −P _L ′. Then, the relationship (P _M −P _L )−(P _M −P _L ′)≧α can be obtained empirically. (α is a predetermined value) Furthermore, the following relationship can be empirically obtained not only by a simple difference but also by a ratio between three points.

(P _M −P _D )/(P _H −P _L )>γ (P _M −P _L ′)/(P _H ′−P _L ′)≦γ (γ is a predetermined value) Here, this example Now, the congestion state of the subject's arm is determined using the third ratio relationship.

In other words, if congestion occurs in the arm of the subject during measurement, the execution result of step (10) will be YES;
Next, step (11) is executed, whereby the display 14 displays the display "E" indicating a measurement error, and the buzzer 15 is activated to indicate that a state of congestion has occurred in the subject's arm. This will also be notified by an alarm sound.

Therefore, when such an error display or alarm sound is emitted, the measurer can know that an error has occurred in the measured value based on this, and in such a case, after the depressed value state is resolved, By re-measuring, it is possible to reliably obtain a more accurate measurement value.

Incidentally, if the determination result in step (10) is NO, it goes without saying that the maximum, minimum and average blood pressure values are displayed on the display 14 as before.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the electrical configuration of the electronic blood pressure monitor according to the present invention, Fig. 2 is a flowchart showing the configuration of the control program in the device, and Fig. 3 shows each measurement in normal and congested conditions. FIG. 7 is a waveform diagram showing that an error occurs in the value. 1... Cuff, 2... Pressure pump, 4... Exhaust valve, 5... Pressure sensor, 9... Korotkoff sound sensor, 13... CPU, 14... Display, 15...
buzzer.

Claims (1)

[Claims] 1. Having means for detecting Korotkoff sounds and pulse waves,
In an electronic sphygmomanometer that measures systolic and diastolic blood pressure by the Korotkoff method and mean blood pressure by an oscillometric method; the presence or absence of a congested state in the arm is determined from the measured systolic and/or diastolic blood pressure and the measured mean blood pressure. An electronic blood pressure monitor characterized by being provided with means for making a determination and issuing a determination output.