JPS5828563Y2 - indirect continuous blood pressure measurement device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an indirect continuous blood pressure measuring device that can continuously measure blood pressure by indirect means.

As is well known, conventional general blood pressure measuring devices are
For example, when external pressure is applied to an artery in the arm, if the pressure exceeds the systolic blood pressure, there will be no blood flow in this artery, and if the pressure is between the systolic and diastolic blood pressures, a blood flow sound detector attached to this artery will detect blood flow. If a flowing sound is detected and the pressurized pressure is lower than the diastolic blood pressure, the blood flow sound will not occur or will be extremely weak even if blood flow is present. This is a device that continuously measures one side.

However, in the above-mentioned blood pressure measuring device, only one of the systolic and diastolic blood pressures can be measured continuously, and the requirement for measuring both the systolic and diastolic blood pressures at the same time cannot be satisfied. I couldn't.

Furthermore, not only the simultaneous measurement of maximum and diastolic blood pressure, but also the recording of all fluctuations in blood pressure waveforms has a wide range of medical uses, and although such a blood pressure measuring device has been desired, there is no device that meets this demand. I couldn't find it.

Therefore, the creator of this invention proposed a device that measures systolic blood pressure, diastolic blood pressure, and all fluctuations in the blood pressure waveform.

(The details will be described later) However, this device has a problem in how to concretely configure a part of its configuration in order to obtain high measurement accuracy.

This idea was made in view of the above circumstances, and consists of a rigid chamber filled with fluid with an insertion hole for a part to be measured such as a finger, and a blood vessel blood pressure at the part to be measured such as a finger inserted into the insertion hole. A detection circuit that detects a change in volume that fluctuates with pulsating changes, a comparison circuit that receives the signal from the detection circuit, compares it with a predetermined reference value, and outputs a positive or negative signal; It includes a control circuit that outputs a control signal based on an output signal, and a volume control operation unit that increases or decreases the pressure of the fluid so that the volume becomes a predetermined constant volume based on the output signal from the control circuit. The present invention is based on an indirect continuous blood pressure measuring device in which the volume is controlled to a predetermined constant volume by the volume control operation section and the pressure of the fluid at that time is measured as blood pressure.

The object of this invention is to provide a device that can accurately detect the volume and accurately measure blood pressure.

This idea will be explained in detail below.

First, the principle of blood pressure measurement using the device of this invention will be explained.The device of this invention measures blood pressure using a volume compensation method.

Blood pressure measurement using the volume compensation method involves applying external pressure to blood vessels from outside the body, keeping the pulsating intravascular volume constant, balancing the external pressure with the intravascular pressure, that is, blood pressure, and measuring the external pressure while maintaining this state. This system measures blood pressure continuously.

This blood pressure measurement method is based on the following findings.

That is, the external pressure P is adjusted so that the intravascular volume V (which changes sequentially when no external pressure Pc is applied) always matches the intravascular volume Vo when the blood vessel wall is in an unloaded state (natural state).
If c is controlled, the controlled external pressure Pc always matches the intravascular pressure pb.

Therefore, by controlling the external pressure Pc as described above,
By measuring c, intravascular pressure pb, that is, blood pressure, can be continuously measured.

In this case, when the intravascular volume change △■ is measured while applying the mean external pressure Pc, △V shows the maximum value (△VM) at the time when PC (mean external pressure) = pb (mean intravascular pressure); The mean intravascular volume ■ corresponds to Vo.

Therefore, in this state, the external pressure △
When Pc is applied, the total external pressure Pc (=Pc±△pb) is always balanced with the intravascular pressure Pb (=Pb±ΔPb), and the blood vessel is maintained at the initial internal volume Vo, and by measuring the external pressure Pc, Intravascular pressure pb, ie blood pressure, can be measured continuously.

This invention will be explained below with reference to the drawings.

First, an outline of the continuous blood pressure measuring device will be explained with reference to FIG.

In the figure, reference numeral 1 denotes a rigid chamber formed of a rigid body, and this chamber 1 is provided with a finger insertion hole 2, into which a finger 3 (part to be measured) is inserted.

The chamber 1 is filled with a fluid 4 such as water.

5 in the figure is a finger volume detection circuit (finger plethysmograph), which is a circuit that detects pulse waves and blood volume (intravascular volume per unit) in the finger vascular bed accompanying changes in blood flow flowing in from the finger artery.

This detection is performed by a charging pulse wave method, which will be described later, and the detection results are recorded.

The volume pulse wave signal output from the finger volume detection circuit 5 is sent to a comparison circuit 6.

The comparison circuit 6 compares the volume pulse wave signal with a voltage set in advance as a reference value, and outputs a positive signal if the voltage is higher than the reference value, and a negative signal if it is lower.

These positive and negative output signals are sent to a compensation circuit (control circuit) 7 consisting of a proportional circuit, a differentiating circuit, an integrating circuit, etc. to improve the control performance of the finger volume control operation, and are used to drive the operating section via a switch 8. The signal is sent to the amplifier 9 for use.

Switch 8 servo-controls the finger volume per unit to a constant value, that is, servo-controls the intravascular volume per unit to a constant value to measure blood pressure (switch 8.
ON) or detect only finger volume changes (finger plethysmograph) corresponding to intravascular volume changes (Switch 8
．． 0FF).

The operation unit driving amplifier 9 receives the above signal and sends an output signal to the finger volume control operation unit 10.

The finger volume control operation section 10 pressurizes the fluid 4 in accordance with the command from the comparison circuit 6 if the signal is positive, and depressurizes the fluid 4 if the signal is negative.

To measure blood pressure with this device, first switch 8
is opened, and a reference generation signal, which can be arbitrarily varied and set, is applied from a signal generator (not shown) to the finger volume control operation unit 10 to increase or decrease the pressure of the fluid 4, and the extravascular pressure is arbitrarily varied and set.

In this way, the finger volume detection circuit 5 detects the pulse wave signal superimposed on the intravascular volume signal.

Here, the average value of the volume signal at the time when the amplitude of the pulse wave component superimposed on the volume signal becomes maximum is the servo target value, and the pressure of the fluid 4 at this time, that is, the external pressure, is set as the servo initial pressure.

Thereafter, the switch 8 is closed and the finger volume control operation unit 10 is operated based on the volume pulse wave signal obtained from the detection circuit 5.

That is, the comparison circuit 6 converts the volume pulse wave signal into the servo target value (
Based on the comparison result, the finger volume control operation unit 10 increases or decreases the pressure of the fluid 4, and finally makes the intravascular volume coincide with the servo target value.

At this time, the external pressure change required to clamp to the target value by volume control always matches the intravascular change, so by measuring the external pressure, that is, the pressure of the fluid 4, the intravascular pressure, that is, the blood pressure, is continuously measured. be able to.

The second figure shows an embodiment of this invention, and the same parts as in FIG. 1 are given the same reference numerals.

In the figure, 6a is a variable resistor provided to set the reference voltage (servo target value), and 6b is a display for displaying the voltage before sending the signal output from the comparison circuit 6 to the control circuit 7. It is a meter for use, and is switched and connected by a changeover switch 6C.

In addition, 7a in the figure is an integrating circuit that performs an integral operation,
7b is a differentiation circuit that performs a differentiation operation.

The rigid chamber 1 is made of a light shielding material.

A screw 1a is formed on the outer periphery of one end of the rigid chamber 1, and a lid 12 is screwed onto the screw 1a.

A base end of a finger insertion member 11 formed of a thin film with no rigidity is attached between the lid body 12 and the chamber (2), and a cover 13 is further held between the fingers.

This cover 13 has a circular hole in the center so that a finger can be inserted, and has many cuts, and is colored black to block light.

A measurement hole 16 for measuring the internal pressure of the fluid 4 is provided in the upper wall 15 of the chamber 1, and the measured internal pressure is automatically recorded by a recorder.

In addition, a bubble removal hole 1 is provided near the other end of the chamber upper wall 15.
7 is provided so that air bubbles sealed when the fluid 4 is sealed can be removed.

A drainage hole 19 is provided in the lower wall 18 of the chamber for draining the fluid 4 filled in the chamber 1.
Furthermore, finger rests 20, 20 are provided on the inner wall surface of the lower wall of the chamber for resting the inserted fingers.

Furthermore, a light source attachment hole 21 is formed in the center of the upper wall 15, and after attaching a red light emitting element 22 to this hole 21, the toe to be measured is irradiated with light of 600 to 7QQnm. The amount of transmitted light is measured by a charging element 23 (light receiving element) fixed at a position facing the hole 21.

Note that the light source mounting hole 21. Red light emitting element 22, photoelectric element 23
The photoplethysmogram detection device 24 is configured by the following.

This photoplethysmogram detection device 24 constitutes a part of the finger volume detection circuit 5, and detects the pulse wave and the blood volume (intravascular volume per unit) in the finger vascular bed by photoplethysmography. be.

That is, it is known that hemoglobin contained in blood (red blood cells) has a strong absorption band in the visible light region.

Therefore, by utilizing such specificity in the visible light region of the absorption spectrum of blood, the above detection can be performed by detecting the amount of transmitted light accompanying changes in blood volume.

Thus, since the transmitted light increases or decreases with the change in blood volume during the above procedure, the volume pulse wave and the blood volume in the finger vascular bed are measured by the AC bridge of the finger volume detection circuit 5 connected to the photoplethysmogram detection device 24. It will be detected.

Note that the photoplethysmogram detection device 24 can be moved laterally (in this case, the charging element 23 is not fixed to the finger insertion member 11).

), it is possible to detect the finger plethysmogram at each part of the finger and the blood volume in the finger vascular bed.

A fixing plate 25 is provided at the tip of the finger insertion member 11,
This fixed plate 25 is supported by support strips 26.

Further, at the rear of the fixed plate 25, a buffer material (filter) 27 made of aluminum or the like and formed into a mesh shape is interposed.

Further, one end of a bellows 28 is fixed to the other end of the chamber 1 so that the inside communicates with the inside of the chamber 1 via a buffer material 27, and the other end of the bellows 28 is fixed to the other end of the bellows 28 so as to close the opening. A diaphragm 29 is fixed to.

At the rear of the diaphragm 29, a force compensation spring 30 is attached to a rear cover 31.
An interlocking member 32 is interposed so as to be in contact with the vibration plate 29 through the spring 30, and the interlocking member 32 is connected to a vibration generator 41.

The vibration generator 41 has a magnet 34 mounted on a yoke 33 whose cross section is approximately [shaped] as shown in the third figure.
An annular drive coil 35 is disposed at the tip of the magnet 34, and a frame 37 having an opening 36 is formed in the yoke 33, and mounting screws 38, 38 are attached to one end of the leaf spring 39, 39. Attach this plate spring 39.
The other end of the vibration table 40 is attached to the side wall of a vibration table 40 which is installed in the opening 36 of the frame 37 so as to be retractable.

In this configuration, the bellows 28, the diaphragm 29, the spring 30, the interlocking member 32, and the vibration generator 41 constitute the finger volume control operation section 10.

In this finger volume control operation unit 10, the drive coil 3
5 vibrates the vibration table 40 based on the positive and negative signals output from the comparator circuit 6.

Since the tip of the vibrating table 40 is connected to the interlocking member 32, the vibration of the vibrating table 40 is transmitted to the interlocking member 32, vibrating the diaphragm 29 and causing the bellows 28 to expand and contract.

Therefore, at this time, the fluid 4 filled in the chamber 1 and the bellows 28 is pressurized or depressurized.

Thus, in this device, after setting the servo target value by operating the switch 8 as described above, the finger volume control operation unit 10 is operated based on the output of the detection circuit 5, and the fluid 4 is pressurized and depressurized to set the servo target value. The blood pressure is measured by keeping the intravascular volume constant and measuring the pressure of the fluid 4 through the measurement hole 16 in this state.

By the way, in this device, when performing measurement, the pressure of the fluid 4 is increased and decreased by the bellows 28, and vibrations of the fluid 4 are buffered by the buffer material 27.
8 is prevented from being deformed and the entire chamber 1 is prevented from causing resonance.

Therefore, in this device, the above-mentioned disadvantages are prevented and the pressure of the fluid is appropriately increased and decreased by the bellows 28, so that blood pressure can be measured with high measurement accuracy.

Furthermore, the pressure applied to the fluid 4 in the bellows 28 is transmitted to the fluid 4 filling the interior front of the chamber 1, bypassing the fixed plate 25, so that dynamic pressure is not directly applied to the finger tip. Therefore, there is no danger that the finger insertion member and the finger inserted into the chamber 1 will come off to the outside.

Furthermore, if the vibration table 40 is configured to display the movement stroke, the absolute amount of finger volume change can be measured by the product of this stroke and the area where the vibration plate 29 contacts the fluid 4. .

The finger volume control operation unit 10 is fixed to a base 42 with bolts, and a support base 43.43 placed on this base 42
The chamber 1 and the vibration generator 41 are supported by.

Furthermore, a hand fixing base 44 is provided on the base 42,
This is to fix the hand so that the finger 3 inserted into the finger insertion hole 2 does not move.

It should be noted that the structure and shape of the vibration generator 41, which includes the magnet 34, the vibration table 40, etc., are not limited to the above embodiment, and can of course be modified as appropriate without departing from the gist of this invention. .

As is clear from the above description, this invention is a continuous blood pressure measuring device using a volume compensation method, in which an insertion member for inserting a body part to be measured, such as a finger, is provided in a rigid chamber, and the rigid chamber is covered with a light shielding material. A photoplethysmogram detection device consisting of a light emitting element and a light receiving element constituting a part of the detection circuit is disposed in the same rigid chamber, and the charging pulse wave detection device detects a volume pulse wave of a finger or the like. It is characterized by detection.

Therefore, the light shielding material can reliably block external light, so the photoplethysmogram detection device can reliably detect the volume pulse wave of a finger, etc., and the accuracy of blood pressure measurement measured by the indirect continuous blood pressure measurement device. can be raised.

Further, since the insertion member such as a finger is attached to the rigid body chamber, the fluid does not come into direct contact with the finger, so that measurement can be performed without wetting the part to be measured such as the finger.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a continuous blood pressure measuring device, FIG. 2 is a circuit diagram showing an embodiment of the invention, a sectional view of a chamber and a vibration generator, and FIG. 3 is a sectional view of the vibration generator. 1...Chamber, 2...Finger insertion hole, 3
...Finger, 4...Fluid, 5...
Finger volume detection circuit, 6... Comparison circuit, 7...
... Compensation circuit (control circuit), 10 ... Finger volume control operation section, 22 ... Light emitting element, 23 ...
- Photoelectric element (light receiving element), 24...Photoplethysmogram detection device.

Claims (1)

[Scope of utility model registration request] A rigid chamber filled with fluid is provided with an insertion hole for a measurement target site such as a finger, and detects changes in volume that vary with blood pressure pulsation changes in blood vessels at the measurement target site such as a finger inserted into the insertion hole. a detection circuit that receives the signal from the detection circuit, compares it with a predetermined reference value, and outputs a positive or negative signal, and a control circuit that outputs a control signal based on the output signal from the comparison circuit. , a volume control operation unit that increases or decreases the pressure of the fluid so that the volume becomes a predetermined constant volume based on an output signal from the control circuit, and the volume control operation unit controls the volume. In an indirect continuous blood pressure measuring device that controls the volume to a predetermined constant volume and measures the pressure of the fluid at that time as blood pressure, an insertion member for inserting a part to be measured such as a finger into the rigid chamber. , the rigid chamber is formed of a light shielding material, and a photoplethysmogram detection device comprising a light emitting element and a light receiving element constituting a part of the detection circuit is disposed within the rigid chamber. indirect continuous blood pressure measurement device.