JPH0221844A - Hemandynamometer probe and blood pressure measuring device - Google Patents

Abstract

PURPOSE:To enable blood pressure measurement with high accuracy by connecting a projecting portion and a photo detecting portion by an elastic body at the time of optically detecting a volume pulse wave to be fitted to an arm of a measured person so that the distance between the projecting portion of the photo detecting portion is kept constant and the optical paths intersect each other. CONSTITUTION:As a projecting portion 1 and a photo detecting portion 2 of a probe 100 are fixed to a plate spring 3, the distance therebetween is kept constant regardless of the pressurization or decompression of an arm band and the optical axes thereof are kept in such a manner as to always intersect each other. Accordingly, in the photo detecting portion 2, the photo detecting intensity for the volume pulse wave is measured under the same conditions without considering the change of position and direction of the projecting portion 1 and the photo detecting portion 2, so that a signal concerning the accurate measurement of blood pressure can be outputted. In this arrangement, when a transparent sheet 40 is stuck at its outer frame 41 to the inside of an arm band 20 and the probe 100 is put therein, the probe 100 can be fitted to the arm only by winding the arm bend 20 round the arm.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a blood pressure monitor probe and a blood pressure measuring device, and more particularly to a blood pressure monitor probe for detecting volume pulse waves and a blood pressure measuring device in which the probe is connected with a cable. .

[Prior Art] Currently, there are various types of blood pressure measuring devices, but the term "sphygmomanometer" usually refers to a device that uses an auscultation method.

The auscultation method involves increasing the pressure inside the cuff until it is approximately 30 mmHg higher than the expected systolic blood pressure, then applying the stethoscope to the arm near the lower edge of the cuff or the inside of the cuff, and gradually increasing the pressure. The procedure involves auscultating Korotkoff sounds while reducing pressure, and in recent years, devices have appeared that automatically perform this series of processes.

By the way, when the subject to be measured is a child, the above-mentioned auscultation method may not be able to measure the subject. Furthermore, the current situation is that the technology for measuring blood pressure in children has not yet been established.

The reason for this is that Korotkoff sounds are very small in children. In other words, this occurs because Korotkoff sounds are not detected.

Therefore, it is necessary to measure blood pressure using another method, and it is known to apply the plethysmography method to one of these methods. Incidentally, the plethysmographic wave represents a change in the volume of a blood vessel caused by waves generated by heartbeats being transmitted through the arterial system.

Normally, the patient's fingertip is used to detect this volume pulse wave, and it is measured by sandwiching a pre-fixed light emitting part and light receiving part between the fingertips and detecting the intensity of the light received through the fingertip. Ta.

[Problems to be Solved by the Invention] However, when attempting to detect a volume pulse wave by simply attaching the light emitting section and the light receiving section to the patient's arm and wearing an arm cuff over them, the problem shown in Fig. 5 occurs. As shown in FIG. 3, there may occur cases where the optical path (or the light emitting axis) of the light projecting section 50 and the light receiving optical path of the light receiving section 51 do not intersect. Furthermore, even if the arm cuff 52 is rolled up with the optical axes of the light projecting section 50 and the light receiving section 51 intersecting, the arm itself has elasticity, and the pressure inside the cuff is It was also found that the distance between the light emitting part 50 and the light receiving part 51 is not fixed because it changes during measurement, and the state in which these optical axes intersect gradually changes to the state shown in Fig. 5. .

Therefore, it is conceivable to integrate the light emitting part and the light receiving part in advance with a member 53 that is slightly curved as shown in FIG. 6 so that their optical axes do not change. When the arm 52 is being pressurized, it is strongly pressed only in the direction of the arrow shown in the figure, making it impossible to pressurize the entire arm uniformly.

The present invention has been made in view of these problems, and provides a probe for detecting volume pulse waves that fits uniformly on the arm, and that the distance between the light emitting part and the light receiving part is constant, and that their optical axes always intersect. It is an object of the present invention to provide a blood pressure monitor probe and a blood pressure measuring device that make this possible.

[Means for Solving the Problem] In order to solve this problem, a blood pressure monitor probe and a blood pressure measuring device of the present invention are provided with the configurations shown below.

That is, this is a blood pressure monitor probe that optically detects a volume pulse wave for measuring blood pressure, and includes a light projecting section that irradiates light onto the blood vessels of a subject to be measured, and a light projecting section that receives the light emitted by the light projecting section. , a light receiving section that outputs a corresponding signal, and an elastic body that connects the light projecting section and the light receiving section.

Further, according to the present invention, it is desirable that the elastic body is a plate spring.

Further, according to the present invention, it is desirable that a transparent bag-like sheet is fixed to the inside of the cuff, and the blood pressure monitor probe of the present invention is housed within this bag-like sheet.

[Function] In the configuration of the present invention, by connecting the light emitting part and the light receiving part with an elastic body, it fits well on the arm of the person to be measured, and the distance between the light emitting part and the light receiving part and their optical path can be adjusted. Can be held in an intersecting manner.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Explanation of blood pressure monitor probe (Fig. 1, Fig. 7)> Fig. 1 (
Figure a) is a top view of the pulse wave detection probe 100 in the example, and figure (b) is a cross-sectional view taken along line A-A'.

In the figure, reference numeral 1 denotes a light projecting section, in which a near-infrared generating element was used in the example. Reference numeral 2 denotes a light receiving section that receives the near infrared rays and generates a signal with a current level corresponding to the intensity of the received light.

The light projecting section 1 and the light receiving section 2 were fixed to both ends of the leaf spring 3 with transparent molded plastic members 4 and 5, respectively. Reference numeral 6 denotes a cable in which a signal line for driving the light emitter 1 is stored, and 7 is a cable in which a signal line for transmitting the current level signal outputted by the light receiver 2 is stored. Connected to the measuring device body.

Although the explanation may be confusing, in this embodiment, a stainless steel strip with a thickness of 0.08 mm is used for the plate spring 3 to enable the light emitting part 1 and the light receiving part 2 to emit and receive light. , a hole was made in the leaf spring 3 corresponding to the center position of each.

In the embodiment, the light emitting section 1 and the light receiving section 2 are entirely mounted on the leaf spring 3, but if they are fixed to a part of the leaf spring 3, it is not necessarily necessary to make a hole.

Moreover, when both the light projecting part 1 and the light receiving part 2 are made sufficiently thin, it is also possible to fix them to the lower side of the leaf spring 3. In this case, it is no longer necessary to make holes in the leaf spring 3.

FIG. 7 shows an example of an overview of a blood pressure measuring device equipped with a pulse wave detection probe 100 having such a structure.

In the figure, 20 is a wristband, 70 is a blood pressure measuring device main body,
71 is a power-on switch, 72 is a switch that supports starting measurement, and 73 is a display section that displays measurement results. Additionally, inside the blood pressure measuring device main body 70, there is a known pump that pumps air into the cuff to pressurize it.
It is composed of a CPU, etc. that performs control processing.

Explanation of blood pressure measurement state (FIGS. 2 and 3)> FIG. 2(a) shows a state in which blood pressure is actually measured using the probe 100 of the above-described embodiment.

In the embodiment, as shown in the figure, a probe 100 is placed on the menoid artery 22 (or ulnar artery) of the wrist of the person to be measured, and this is covered with a cuff 20 for measurement.

In the figure, 21 is a tube that is an air conveyance path from a pump in a blood pressure measuring device (not shown).

Further, a cross-sectional view of the vicinity of the probe 100 in this state or in a state where the cuff 2o is pressurized is shown in FIG. 2(b).

As shown in the figure, in the embodiment, the light emitting part 1 and the light receiving part 2 of the probe 10o are fixed to the leaf spring, so the distance between them is constant regardless of whether the cuff is pressurized or decompressed. The optical axes are also maintained to intersect at all times. Therefore, the light receiving section 2 measures the received light intensity corresponding to the volume pulse wave under the same conditions without considering changes in the position and orientation of the light projecting section 1 and the light receiving section 2, thereby obtaining accurate blood pressure. A signal related to measurement will be output.

Note that while the probe 100 is actually fixed to the patient's arm, it is necessary to cover it with the cuff 20. Therefore,
In order to save this effort, for example, as shown in Figure 3,
A transparent sheet 40 is placed inside the arm cuff 20 with its outer frame 41.
If the structure is such that the probe of the embodiment is placed inside the probe, the probe 100 can be fitted to the arm simply by wrapping the arm cuff 20 around the arm.

Principle of blood pressure measurement (Figure 4) Next, the principle of blood pressure measurement in the above configuration will be explained.

Incidentally, a blood pressure measurement method applying the plethysmography method is well known.

FIG. 4(a) shows the visual pressure waveform ΔP corresponding to the heartbeat (time T), and FIG. 4(b) shows the waveform of the volume pulse wave ΔV measured with the probe 100 of the embodiment. As shown in the figure, these waveforms are very similar, and moreover, when this external pressure (pressure inside the cuff) is applied, the amplitude of the intravascular volume pulse wave Δ■ changes as the pressure changes over time. I found out that it does. It was also found that the pressure within the cuff corresponding to this maximum amplitude point and the average blood pressure value matched extremely well, and the pressure within the cuff corresponding to the point where the pulse wave disappeared coincided with the systolic blood pressure. In the illustrated case, the maximum value of each waveform is set to "1".

Further, the diastolic blood pressure value is calculated by using the detected volume pulse wave waveform and the blood pressure pulse wave waveform.

A specific calculation example will be explained below.

In FIGS. 4(a) and 4(b), waveform constants αp and αV of the average values of the waveforms are defined as follows.

a p = (Pan - Pad) / (Pas
-Pad)av = (Vm -Vd) / (
Vs - Vd) Here, since the waveforms of ΔV and ΔP are considered similar, αp=α■, and the diastolic blood pressure value Pad to be obtained is calculated by using αV obtained from the volume pulse wave instead of αp, Pad= Pa
It is obtained as m -av/ (1-av) · (Pas-Pam).

As explained above, if the probe of this embodiment is used, the distance between the light emitting part and the light receiving part is kept constant, and their optical axes are always held to intersect, so blood pressure can be measured with high precision. It becomes possible to perform measurements.

In the embodiment, the light emitting part 1 and the light receiving part 2 are connected by a plate, but it may be rod-shaped as long as it has the same elastic force. However, since this may give a sense of discomfort to the person being measured, a plate spring is considered to be optimal.

[Effects of the Invention] As explained above, according to the present invention, the distance between the light receiving part and the light emitting part is kept constant with a simple structure, and the light emitting and receiving parts are maintained so that their axes of light always intersect. This makes it possible to measure blood pressure with high precision.

Furthermore, by connecting the light projecting section and the light receiving section with a leaf spring, it is possible to avoid giving a sense of discomfort to the person to be measured.

By fixing a transparent bag-like sheet to the inside of the cuff and inserting the probe of the present invention into this sheet, it becomes possible to easily attach the probe to the part to be measured of the person to be measured.

[Brief explanation of the drawing]

FIG. 1(a) is a top view of the probe in the example, FIG. 1(b) is a sectional view of the probe in the example, and FIG. 2(a) is the top view of the probe in the example.
) is a diagram showing a state in which the probe of the embodiment is attached to an arm, and FIG. 2(b) is a diagram showing a cross section of the probe in a state in which the probe is attached to an arm. Figure 3 is a diagram showing an example of fixing the probe to the arm cuff in the example, Figure 4 (a) is a diagram showing the invasive blood pressure waveform, and Figure 4 (b) is the volume detected with the probe in the example. A diagram showing a pulse wave waveform. Figure 5 is a sectional view showing a state in which the light emitter and the light receiver are worn on the arm without an elastic connector between them. Figure 6 is a diagram showing the connection between the light emitter and the light receiver. FIG. 7 is a cross-sectional view showing a state in which the devices are connected by a rigid connection member, and FIG. 7 is an external perspective view of a blood pressure measuring device equipped with a pulse wave detection probe according to an embodiment. In the figure, 1... Light emitting part, 2... Light receiving part, 3... Leaf spring, 4 and 5... Molded plastic member, 6 to 8
... Cable, 20 ... Bracelet, 21 ... Tube, 40 ... Transparent sheet, 70 ... Blood pressure measuring device, 7
DESCRIPTION OF SYMBOLS 1...Power supply switch, 72...Switch for supporting the start of measurement, 73...Display unit, 100...Probe. Figure 1 (0) Figure 1 (b) Figure 2 Figure 2 (b) Figure 5 Figure 6

Claims (4)

[Claims] (1) A sphygmomanometer probe that optically detects a volume pulse wave for blood pressure measurement, which includes a light projecting section that irradiates light onto the blood vessels of a person to be measured, and a light receiving section that receives the light irradiated by the light projecting section. A blood pressure monitor probe comprising: a light receiving section that outputs a corresponding signal; and an elastic body that connects the light projecting section and the light receiving section. (2) The blood pressure monitor probe according to claim 1, wherein the elastic body is a plate spring. (3) The sphygmomanometer probe according to claim 1, wherein a transparent bag-like sheet is fixed to the inside of the cuff, and the blood pressure monitor probe is fixed within the bag-like sheet. (4) A blood pressure measuring device to which the blood pressure monitor probe according to any one of claims 1 to 3 is connected.