JPS6392332A - Hemomanometer - Google Patents

Abstract

(57) [Abstract] 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 is a non-invasive method of compressing the measurement site with a cuff.
This invention relates to a sphygmomanometer for measuring blood pressure, and relates to a sphygmomanometer that maintains a constant rate of reduction of the internal pressure of the cuff during blood pressure measurement.

<Prior Art> Conventionally, cuff compression type blood pressure monitors have been equipped with a pressure reduction device using a check valve, and the internal pressure of the cuff has been reduced by the pressure reduction valve.

The internal volume of the cuff when wrapped varies depending on the thickness of the area to be measured, as shown in FIG.

The rate of decompression of the internal pressure of the cuff was constant. The horizontal axis of the figure represents time Tk, and the vertical axis of the figure represents the internal pressure P of the cuff.

Changes in the rate of decompression of the internal pressure of the cuff are particularly noticeable when the internal volume of the cuff is small, and in this case, a situation may arise in which blood pressure measurement is performed when the rate of decompression is drastically changing.

Therefore, errors in measured values may become large.

<Object of the Invention> In view of the above circumstances, the present invention aims to improve the accuracy of measured values by increasing the rate of reduction of the cuff internal pressure at a constant rate in a blood pressure monitor that measures blood pressure when the cuff internal pressure is reduced. With the goal.

<Example> Hereinafter, an uninvented configuration will be explained with reference to the drawings.

FIG. 1 is a block diagram of a pressure reducing device for a blood pressure monitor according to an embodiment of the present invention.

In the figure, l is a cuff for compressing a measurement target site such as a peripheral site such as a fingertip.

And said cuff 1! A cylinder 3 and a pressure sensor 4 are connected to each other via a tube body 2.

The cylinder 3 is provided with a guard to adjust the internal pressure of the cuff 1, and the internal pressure of the cuff 1 changes as the internal volume of the cylinder 3 changes.

Then, when the internal pressure of the cuff 1 decreases, the systolic blood pressure and diastolic blood pressure are measured based on the photoplethysmogram signal detected from the blood vessel at the measurement site compressed by the cuff 1.

In this embodiment, the internal pressure control of the cuff 1 during blood pressure measurement is carried out as follows.

When pressurizing, the piston shaft 5 that changes the internal volume of the cylinder 8 is moved in the direction of the arrow, and the pressure medium in the cylinder 3 is pumped into the cuff 1.

Continuing with this, during depressurization to measure blood pressure, the controller 6 controls the actuator 7E while referring to the output signal 1 of the pressure detector 4 so that the rate of decompression of the internal pressure of the cuff remains constant. Send the signal m and move the arrow B of the piston shaft 5
Adjust the speed of movement in the direction.

Therefore, according to the unexamined example, the decrease curve of the internal pressure of the cuff eye is as shown in FIG. 2. In the figure, the horizontal axis is 'time Ti
The vertical axis P represents the internal pressure of the cuff 1. As shown in the figure, the decreasing rate (gradient) of the internal pressure of the cuff I is constant.

FIG. 3 is an internal block diagram of the controller 6, and in FIG. 1, 8 represents a central processing unit CPU.

The CPU 8 receives and receives pressure data from the pressure sensor 475.

Then, the CPU 8 determines the pressure to be adjusted based on the pressure cadence, and outputs a signal mf to the actuator 7 so that the pressure is set to the determined pressure.

The above-mentioned matters are accomplished as follows.

The speed at which the internal pressure of the cuff 1 is reduced is stored in the memory 9 and is expressed as hkK.

If the pressure value k P 1 obtained from the pressure data is expressed as follows, where t is the unit time. However, P2. Ps, ・”, Pn-I, P
n is the adjustment pressure value.

Therefore, the CPU 8 uses the memory 9 to execute the calculation of the following formula.

P2=jK+P.

P3 = tK + P2 P n = t K + P n-1 That is, by inputting the pressure data Pl, it is determined whether to set the internal pressure 1b of the cuff l to a certain pressure value, and the pressure value l is set to a certain pressure value. A corresponding signal m is output.

Note that the output signal of the photoplethysmographic signal detector IO of the blood vessel at the site to be measured is input to the CPUg&; The internal pressure of the cuff when the signal disappears is taken as the diastolic blood pressure, and this is stored in the memory 91 and displayed on the display.]
Display as 1. As blood pressure information, in addition to the systolic blood pressure and diastolic blood pressure, the average blood pressure when the amplitude of the photoplethysmogram signal reaches its maximum and the cardiac index can also be measured and displayed.

The unimplemented example is suitable when the part to be measured is a finger or the like and the volume of the cuff is very small.

FIG. 4 is a block diagram of a pressure reducing device for a blood pressure monitor according to another embodiment of the present invention.

The configuration of FIG. 4 (therefore, parts similar to those in FIG. 1 are given the same reference numerals).

In this embodiment, pressure medium is introduced into the cuff.

Further, in order to cause the pressure medium to flow out of the cuff l, a shaft 1a and an actuator 14 are provided to +r. The operation is similar to the previous embodiment.

This embodiment is improved in that the span of the shaft 13 is about % of that of the previous embodiment, so it can be made smaller and has excellent airtightness.

In the two embodiments described above, in the first embodiment, the cylinder 3. Pressurization and depressurization can be carried out by the piston shaft 5 and the actuator 7, and in the second embodiment, by the bellows 12, the shaft 13, and the actuator 14.
The cost is lower than that in which pressurization and depressurization are performed using separate parts.

<Effects> As described above, according to the present invention, there is provided a device for non-invasively measuring blood pressure by compressing the area to be measured with a cuff, which maintains a constant rate of decrease in the internal pressure of the cuff during blood pressure measurement. This prevents the blood pressure measurement from being performed when the rate of decompression is at its highest, allowing accurate measurements to be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a pressure reducing device for a blood pressure monitor according to Embodiment 1 of the present invention, FIG. 2 is a diagram showing changes in the rate of cuff pressure reduction by the device, and FIG. 3 is a diagram of a controller of the blood pressure monitor. FIG. 4 is a block diagram of an internal block diagram of a pressure reducing device for a blood pressure monitor according to an embodiment of the music of the present invention, and FIG. 5 is a diagram showing changes in cuff pressure reduction speed due to a conventional blood pressure monitor. l...Cuff, 3...Cylinder, 4...Pressure detector. 5... Piston shaft, 6... Controller, 7...
Actuator, 12... bellows - 13... 1l
L14...actuator. Agent: Patent attorney Takeshi Sugiyama (and 1 other person) Figure 2

Claims (1)

[Scope of Claims] 1. A device for non-invasively measuring blood pressure by compressing the area to be measured with a cuff, which is provided with means for keeping the rate of reduction of the internal pressure of the cuff constant during blood pressure measurement. Characteristic blood pressure monitor.