JPS63220840A - Cuff structure of blood pressure measuring 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 <Industrial Application Field> The present invention relates to the structure of a finger cuff membrane that compresses a finger in a blood pressure measuring device that measures blood pressure with a finger.

<Prior Art> Photoplethysmography is a pulse wave detection method that utilizes the property that the amount of transmitted light when a peripheral site such as a fingertip is irradiated with light is inversely proportional to the amount of blood. A blood pressure measuring device that measures blood pressure with a finger generally utilizes this photoplethysmography method using a photoelectric element, and uses a rubber finger cuff membrane to compress the finger.

FIG. 6 shows the axial cross-sectional shape of the finger cuff membrane, and FIG. 7 shows a structure in which a part of the finger cuff membrane 101 is attached to the sensor main body 102. FIG. 8 shows a configuration for actually measuring blood pressure, in which a finger 103 is passed through the cylindrical finger cuff membrane 101, air is sent into the space between the finger cuff membrane 101 and the sensor part main body 102, The finger cuff membrane 101 is inflated inward. As a result, the finger 103 is compressed, and a blood vessel occlusion region 106 (hatched in the figure) is formed. A light emitting element 104 and a light receiving element 105 are arranged in the sensor part body 102 so as to face each other vertically in the figure with a finger cuff membrane 101 in between, and the light emitted from the light emitting element 104 passes through the blood vessels of the finger 103. and enters the light receiving element 105. Since the intensity of light incident on the light receiving element 105 changes according to the pulse wave, the light receiving element 1
05 outputs a pulse wave signal.

<Problems to be Solved by the Invention> As shown in FIGS. 6 and 7, the conventional finger cuff membrane 101 has a cylindrical shape with a constant diameter in the axial direction.

On the other hand, human fingers are thick at the base and taper toward the tip. Therefore, conventional finger cuff membranes need to stretch significantly in order to apply sufficient pressure to the narrow portion of the finger. However, since there is a limit to the elongation of the finger cuff membrane due to the material it is made of, there is a problem in that the thin parts of the fingers are not sufficiently compressed, and as a result, accurate measurements cannot be performed.

<Means for Solving the Problems> The present invention provides a finger cuff membrane that compresses a finger in a blood pressure measuring device that measures blood pressure with a finger based on photoplethysmography, etc., in which the inner cylinder has a tapered shape. The cuff structure of the blood pressure measuring device is characterized by being cylindrical.

<Function> The finger cuff membrane of the present invention has a tapered cylindrical shape, thereby uniformly compressing the portion of the finger to be measured.

<Example> Figure 1 shows the axial cross-sectional shape of the finger cuff membrane of this example.
The figure shows the side profile. The finger cuff membrane 2 has a cylindrical shape, and the shape of the inner cylinder 2a is tapered toward the right in FIG. The change in the diameter of the inner cylinder 2a in the axial direction is adapted to the shape of the finger, which gradually becomes thinner toward the fingertip.

FIG. 3 shows a state in which the finger cuff 1, which is constructed by attaching a finger cuff membrane 2 to a sensor main body 3, is worn on a finger when actually measuring blood pressure. In the figure, 4 is a finger.

5 is a light emitting element, and 6 is a light receiving element. Since the inner tube 2a of the finger cuff membrane 2 is tapered to follow the finger 4, the finger cuff 1 is shaped like the finger 4.
The gap between the finger 4 and the cuff membrane 2 is approximately constant over the entire measurement portion of the finger 4 when the finger 4 is attached to the body and no pressure is applied. Therefore, in the pressurized state, there is no need for the cuff membrane 2 to expand locally to a large extent, and the internal pressure of the finger cuff 1 is evenly applied to the finger 4.

FIG. 4 shows the configuration of a system for measuring blood pressure by photoplethysmography using the above-described cuff structure.

In the figure, 1 is a finger cuff, 5 is a light emitting element (light emitting diode), 6 is a light receiving element (phototransistor), 13 is a pneumatic circuit, 14 is a finger, 15 is a controller, 16 is a pressure sensor, and 17.19 is an amplifier. , 18 is a microcomputer, and 20 is a power supply.

21 is a display device.

The finger cuff 1 has an opening 11 formed therein.
A tube 1 for supplying pressure inside the finger cuff 1 to 1
2 are connected. Furthermore, the other end of the tube 12 is connected to a pneumatic circuit 13 for supplying pressure.

With the finger cuff 1 attached to the finger 14 of the person to be measured (for example, the ring finger of the left hand), the light emitting element 5 and the light receiving element 6 face each other across the blood pressure measurement point of the finger 14.

When pressure is supplied to the finger cuff 1, the digital artery in the finger 14 is percutaneously pressurized by this pressure (hereinafter referred to as cuff pressure). In the process of increasing the cuff pressure and then decreasing the pressure, the light emitted from the light emitting element 5 passes through the blood vessel of the finger 14 and enters the light receiving element 6. Changes in the received light are converted into electrical signals, and a photoplethysmogram signal is detected.

The drive of the light-emitting element 5 and the light-receiving element 6 and the rate of reduction of the cuff pressure are controlled by the controller 15.

The cuff pressure is detected by a pressure sensor (piezoelectric transducer) 16, and the detected pressure signal is input to the microcomputer 18 via an amplifier 17.

The photoplethysmogram signal is also input to the microcomputer 18 via an amplifier 19.

The microcomputer 18 performs waveform confirmation processing from the obtained pressure signal and photoplethysmogram signal, calculates the systolic blood pressure and the diastolic blood pressure, and displays the calculated systolic blood pressure and diastolic blood pressure on the display unit 21.

FIG. 5 shows the relationship between blood pressure values and pulse wave signals when blood pressure is measured using the finger cuff of this embodiment.

As is clear from this figure, the pulse wave signal rises at the systolic blood pressure value, and therefore the systolic blood pressure value can be accurately confirmed.

In the above-described embodiment, photoplethysmography was used as the blood pressure measurement method, but the present invention can also be applied to blood pressure measurement methods other than this method.

Furthermore, it goes without saying that other gases than air may be used as the pressure medium for the finger cuff 1.

<Effects of the Invention> As explained above, in the present invention, by forming the finger cuff membrane into a tapered cylindrical shape, the finger cuff membrane fits well with the finger when the finger cuff is attached to the finger, so that the finger cuff membrane fits well with the finger. The internal pressure is applied evenly and accurately to the finger, making it possible to accurately measure blood pressure.

[Brief explanation of drawings]

1 and 3 are diagrams showing a cross-sectional structure of an embodiment of the present invention, FIG. 2 is a diagram showing a side profile of an embodiment of the present invention, and FIG. 4 is a diagram showing the configuration of a blood pressure measurement system to which the present invention is applied. 5 is a diagram showing a waveform of a measurement result of a blood pressure measurement system to which the present invention is applied, and FIGS. 6, 7, and 8 are diagrams showing the structure of a conventional example. 1...Finger cuff 2...Finger cuff membrane 2a...Inner cylinder 3...Part of the sensor main body 4...Finger 5...Light emitting element 6...Light receiving element Patent applicant Sharp Corporation Agent Patent Attorney Nishi 1) New construction 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A cuff structure for a blood pressure measuring device in which an inner cylinder has a tapered cylindrical shape in a finger cuff membrane that presses a finger in a blood pressure measuring device that measures blood pressure with a finger based on photoplethysmography or the like.