JPS60132539A - 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, and more particularly to a pressure sensor for a blood pressure monitor.

(Background Art) In general, a pressure sensor, whether mechanical or electronic, converts the amount of displacement caused by applying pressure as a conversion output. For example, in a mechanical system, the extension tube expands when pressure is applied, and the extension of the tube is converted into the rotation angle of the gear. The converted output is the displacement length. On the other hand, in the electric type, the bellows expands due to pressure, which converts and outputs the displacement voltage of the differential transformer.Also, the tire flammable expands due to pressure, and when this tire flammable stretches, the slit changes depending on the situation. The change in the amount of light passing through the bridge is used as the converted output, and furthermore, the silicon tire phragm is displaced by pressure, this displacement causes a change in the strain resistance, and the output voltage of the bridge is used as the converted output.

Therefore, as changes in the pressure sensor over time, offset movement, displacement (inclination), elongation due to temperature, etc. must be taken into consideration. Unless excessive pressure or abnormal pressure that would displace the physical properties itself is applied, the change in the slope K will be small. Further, changes due to temperature also show a constant tendency as long as the physical properties do not change, so if correction is made on the display, the influence can be kept small. However, the cause of the offset movement is
This may occur if the distortion due to abnormal installation returns over time, or if the product is misaligned due to being dropped, etc.
The current situation is that it is difficult to suppress this as a factor.

Pressure sensors used in blood pressure monitors, etc., have a valve that opens to the atmosphere as a component, and the pressure sensors used in blood pressure monitors automatically adjust the pressure. I am using the method of importing after However, with manual pressurization, the above method cannot be used, and if the pressure drops fairly quickly after the power is turned on, assume that the pressure has not been released to the atmosphere, wait until the pressure stops dropping, and check the value. A method of using it as an offset value was considered. Therefore, there is a problem in devices that manually pressurize the cuff band that they cannot be used immediately in the above-mentioned state after the power is turned on.

In other words, if air remains in the cuff band, the offset value cannot be determined as a normal offset value until the pressure is released (until the rate of blood pressure drop falls below a certain level).

(Objective of the Invention) The present invention has been provided in view of the above-mentioned points, and provides a blood pressure monitor that can accurately measure blood pressure and can be used immediately with the power turned on.

(Disclosure of the Invention) Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. By the way, a microcomputer is used as an IC to control the entire operation of the blood pressure monitor, but it is
Those using O5 generally stop the operation in response to the "clock end" command, maintain only the oscillation of the external crystal oscillator, and then resume the original operation as an interrupt process after a certain period of time. has been adopted. Figure 1 shows a block diagram of the entire blood pressure monitor, where fl) is the cuff band wrapped around the upper arm of the body, and (3) is the cuff band (1).
It is a pressurized 16 ball that pressurizes the air inside. (4) is an exhaust valve. (5) is a pressure sensor that detects the pressure value in the cuff band full, and the output from this pressure sensor (5) is A/D converted by the A/D converter (6) and sent to the blood pressure determination circuit (7). It will be done. (2) is a sound sensor disposed inside the cuff band fil, and a filter circuit (9) that discriminates a predetermined frequency from the output signal from this sound sensor (2).
) is input to the combination discriminator (10), and the combination discriminator (10) discriminates between ]o and f. (8) is a display device. Now pressurize the cuff band (1) to a predetermined pressure using the 16 pressurizing bulbs (3), and then press the exhaust valve (4).
The air in the cuff band fl is gradually exhausted. and,
The first Korotkoff sound is taken as the systolic blood pressure value, and the blood pressure determination circuit (7) displays the pressure value at that time on the display (8) as the systolic blood pressure value. Furthermore, the air in the cuff band is exhausted, and the last Korotkoff sound at which the Korotkoff sound disappears is taken as the diastolic blood pressure value, and the pressure value at that time is displayed on the display (8) as the diastolic blood pressure value. This is the operating principle of blood pressure measurement.

(1 is an offset circuit that detects the pressure value in the cuff band fil after the power is turned off. (12) is a startup timer, and the offset circuit (1)
This is a circuit that instructs you to tilt the device and read the pressure and force values. By the way, since the blood pressure monitor is not a device that is used 24 hours a day, it remains in the off state for a longer time than when it is in the on state than when the power is turned on, but at this time the display (
8) etc. have stopped operating, but after a certain time, for example every 2 hours, the offset circuit (U) #? Perform only the pressure detection operation and read the pressure value. At this time, since the blood pressure monitor is not in use, it can be assumed that the pressure is in equilibrium with the atmospheric pressure, so this value is processed to be used as an offset value. The method is as follows.

■The pressure collected in a state that is not in actual use is the O offset value.

■If the values read continuously (at certain intervals) do not change, use them as offset values. this is,
This is because if it is done only once, there is a risk that data such as when air in an abnormal state remains will be taken in.

(2) If the value is negative compared to the previous value in the state (2) above, it is set as the offset value at that point. This is because the atmospheric pressure will never become more negative than the initially set value, and in this case, it can be considered that the sensor is offset.

FIG. 2 shows a specific example of one embodiment, in which the systolic blood pressure and diastolic blood pressure are measured by pressurizing the first cuff band f1+ and then gradually evacuating it as described above. be. The horizontal axis represents time and the vertical axis represents pressure. At specified time intervals, the offset value is read at points ■, ■, ■, and 0 points in the diagram.In the case of 0 points, of course, the pressure value will be read during the measurement (
Even if you try to read the atmospheric pressure of 0 = x Ht, you can only read the pressure at the 0 point. but,
As shown in FIG. 3, if the power is on, the pressure measurement routine is entered and the offset value is not read. Therefore, with this method, there is no need to worry about taking in the distant date as an offset value. However, the specified time is an interval longer than the time required for normal measurement (approximately 2 hours).
It is said that Furthermore, by performing measurement two or more times in a row and using the value that is the same as or lower than the previous value as the correction value (offset value), the correction value can be calculated accurately. That is, as shown in FIG. 3, when the power is off,
When the above-mentioned specified time has elapsed, the pressure value in the cuff band full from which the air has completely escaped is read, and this is done twice in a row, and it is determined whether the pressure value is the same as or lower than the previous time or the time before the previous time, The read pressure value when it is the same or lower is the correction value (
offset value). This is controlled by the offset circuit (river) mentioned above. During actual measurement, the pressure inside the cuff band +11 is read and subtracted using both this read pressure value and the correction value (offset value). Then, normal blood pressure measurement begins.

FIG. 4 shows another embodiment of the measurement method, in which the power is on during blood pressure measurement, and when the user turns off the power after the measurement is completed (point [F]), the startup timer (I2 )
Start. Then, by reading the pressure value in the cuff band (1) at point [F] after a certain period of time (specified time) from point [F] and using it as a correction value (offset value), the pressure is sufficiently exhausted. , the pressure that is in equilibrium with the atmospheric pressure can be used as the correction value. FIG. 5 is a flow diagram of this embodiment. In Fig. 5, the pressure value in the start timer (the cuff band f1 after the country starts and the specified time has elapsed) is detected from the moment the power is turned off, and its configuration and operation are as shown in Fig. 3. It is almost the same as the case.

(Effects of the Invention) As described above, the present invention provides a blood pressure monitor in which an offset circuit is provided to detect the pressure value inside the cuff and the band when the measurement power source is turned off, and the pressure value is used as the offset value. Therefore, when measuring the applied pressure with the pressure sensor of a blood pressure monitor, in order to detect the offset value (detector output used for correction as atmospheric pressure of OXJH), the pressure must be measured with the power turned off. In order to read the data, it is possible to read the pressure in the cuff band after it has been sufficiently released. Therefore, that pressure value can be read as an offset value, and the blood pressure value can be determined without any error. This is effective because it sometimes eliminates the need to judge offset values and can be used immediately.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a blood pressure monitor according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of the same as the above, Fig. 3 is a flow diagram of the same as the above, Fig. 4 is an explanation of another embodiment of the same as the above, Fig. 1 , FIG. 5 is a diagram 70- of the same as above. (1) shows the cuff band, and (II) shows the offset circuit. Agent Patent Attorney Ishi 1) Choshichi

Claims (1)

[Claims] +11 In a blood pressure monitor that communicates the pressure within the cuff band with the atmosphere and exhausts it, and detects the pressure value within the cuff band, the pressure value within the cuff band when the measurement power source is turned off. 1. A blood pressure monitor comprising an offset circuit for detecting the pressure value, the pressure value being used as the offset value. (2) The blood pressure monitor according to claim 1, wherein the pressure value within the cuff band is detected at regular intervals. (3) The sphygmomanometer according to claim 1, wherein the pressure value within the cuff band is detected after a certain period of time has elapsed since the measurement power was turned off. (4) The pressure value within the cuff band is detected multiple times in succession, and if the value is the same as or lower than the previous measured value, the detected value is used as the offset value. The blood pressure monitor described in Section 2.