JPH032246Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an indirect continuous blood pressure measuring device that can continuously measure blood pressure.

(Prior Art) As a prior art of the present invention, a continuous arterial blood pressure measurement method using a volume compensation method invented by Kenichi Yamakoshi is known (Japanese Patent Laid-Open No. 156325/1983). The volume compensation method, which is the premise of this blood pressure measurement method, adds external pressure (cuff pressure) to blood pressure from outside the body and sets the average cuff pressure at which the pulsating blood vessel wall has the maximum amplitude. This method instantly equilibrates the external pressure and intravascular pressure, that is, blood vessels, and continuously extracts the cuff pressure as blood pressure by keeping it constant.

Therefore, in measuring blood pressure using this volume compensation method, the two most important issues are to detect that the blood vessels are in an unloaded state and to maintain this state.

(Problems to be solved by the invention) However, although the above-mentioned method for continuous blood pressure measurement using the volume compensation method works in principle, there were various problems in commercializing it, so it has not been practical in practice. It has not yet been put into practical use.

In other words, one problem is that the finger segment to be examined, more specifically, is inserted into the cuff, and the pressure is controlled by the internal pressure of the fluid-filled measurement chamber built into the compression cuff. Since the thickness of fingers differs from person to person, the load conditions applied to the internal pressure of the measurement chamber are different for each person.
As a result, the range of objects that can be measured is restricted, such as the inability to measure blood pressure or the inability to perform accurate measurements, resulting in problems that cannot be put to practical use.

To explain in more detail, in the above conventional technology,
The pressurization of the fluid sealed in the chamber is controlled by controlling the stroke motion of the plunger of the diaphragm actuator; in other words, changes in fluid volume are converted into changes in cuff pressure to adjust the external pressure of the subject's finger. It is something.

However, as mentioned above, there are individual differences in the fingers to be tested, so the load conditions will vary accordingly.However, since the stroke length of the plunger is within a certain range, depending on the load conditions, there may be a range that cannot be measured. , a situation occurred in which the maximum cuff pressure state could not be measured.

In this way, the conventional technology has been completed in principle, but there are various problems in commercializing it, one of which is the above-mentioned problem of restricting the measurement range of the object to be measured. It was hot.

In order to best implement the volume compensation method described above, the present invention limits the blood pressure measurement range by making blood pressure measurement possible regardless of the volume change that is the load condition of the subject's body. The object of the present invention is to provide an indirect continuous blood pressure measuring device that can be used over a wide range of areas and is practical.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a position detector on a reciprocating pressurizing body that pressurizes and depressurizes the enclosed fluid, and detects the position according to the object to be measured. The starting point of the pressurizing body can be controlled to a constant position by means of a device.

(Function) As described above, in the present invention, the starting point of the reciprocating pressurizing body, more specifically the plunger of the diaphragm actuator, can be positioned according to the object to be measured, so the initial setting As a result, the starting point of the plunger remains constant without being affected by changes in the volume of the object to be measured, and the object to be measured can be adequately measured within the stroke range of the plunger.

Therefore, since the plunger can be operated regardless of the load condition of the object to be measured, the measurement range of the object to be measured is not restricted.

Moreover, since the object to be measured can be measured within the operating range of the plunger, the cuff pressure applied to the object to be measured can be measured with high accuracy in response to the object to be measured.

(Example) Hereinafter, embodiments of the present invention will be described according to an example shown in the drawings.

FIG. 1 is a block diagram showing the principle of an indirect continuous blood pressure measuring device for carrying out the present invention. In the figure, 1 is a cuff with an annular inner wall; In this embodiment, external pressure is applied to the finger 2, and the inner peripheral wall of the chamber 3 attached to the inner wall thereof is made of an elastic thin film and has a structure that is pressed onto the outer periphery of the finger 2.

Furthermore, a liquid 5 such as water is supplied to the inside of the cuff 1 through a tube 4, and this liquid 5 is pressurized by a linear pump 6 and a vibrator 7. The cuff pressure applied percutaneously pressurizes the artery within the finger 2. This cuff pressure is then detected by a pressure sensor 8 communicating with the tube 4 and output as an electrical signal.

On the other hand, between the finger 2 and the inner walls 3, 3 of the cuff 1,
Light emitting diode 9a attached to the front and back of finger 2
A phototransistor 9b is interposed so as to face each other, and the light emitted from the light emitting diode 9a passes through the finger 2 and is received by the phototransistor 9b, and the amount of light received corresponds to the volume of the blood vessel. Incidentally, during the measurement, the finger is actually measured by covering the finger with a light shielding means such as a black cloth in order to prevent the light emitted from the light emitting element from leaking to the outside.

Based on the volume signal obtained from the optical sensor consisting of the light emitting diode 9a and phototransistor 9b as described above, an average cuff pressure is set such that the pulse wave component of the volume signal (volume pulse wave signal) is maximized, and then If the change ΔPc is superimposed on the average cuff pressure so that the volume pulse wave signal Sg becomes zero (that is, the volume of the blood vessel is constant), then the cuff pressure Pc (=+ΔPc) at this time changes from time to time. It is equal to the blood pressure.

This allows blood pressure measurement to be carried out continuously and automatically.

In FIG. 1, 16 is a comparator and 17 is a comparator.
Ac separator, 18 is a phase compensator, 19 is a gain adjustment, 20, 21 is a driver, 22 is a comparator, 2
3 is an integrator, 24 is an amplifier, 15 is a control section, 26
indicates a display section, and explanations of their operations will be omitted.

Based on the above continuous blood pressure measuring device, this embodiment is equipped with a potentiometer 10 as a position detector as shown in FIG. The potentiometer 10 is connected to the plunger 13 of the actuator 11 via a connecting rod 14.
Note that 15 indicates a control section.

In the indirect continuous blood pressure measuring device configured as described above, when measuring blood pressure, first insert the finger 2 into the cuff 1 as shown in FIGS. 1 and 2, and drive the linear pump 6. The liquid 5 flows through the tube 4 into the chamber 3 forming the inner circumferential wall of the cuff 1 and pressurizes the finger 2.

However, at this time, the load condition of the finger 2 is read while the pressure sensor 8 detects the cuff pressure based on the flow rate of the liquid 5, and the starting point of the plunger 13 is set to the optimal state for the potentiometer 10 while being controlled by the control unit 15. Determine the position.

That is, the potentiometer 10 controls the positioning of the starting point of the plunger 13 to the optimum position.

This optimum state position is achieved by reading the load state using the pressure sensor 8 and controlling the plunger 13 to the maximum stroke range by operating the potentiometer 10 using the controller 15. .

After the starting point of the plunger 13 is initially set by the potentiometer 10 in this way, when the actuator 11 is driven, the plunger 1
3 will operate from the initially set position, so the maximum stroke length will be obtained,
Therefore, measurements can be made without affecting the load conditions of the object to be measured.

In this way, the starting position of the plunger 13 can be determined by operating the potentiometer 10, which is a position detector, while reading with the pressure sensor 8, depending on the object 2 to be measured.
This allows measurement to be performed in an optimal state regardless of load conditions such as the thickness of the object 2 to be measured.

In the above embodiment, a potentiometer is used as a position detector, but the type thereof is not limited in any way; it may also be a sensor using a differential transformer, magnetism, light, etc. do not have. Therefore, the means for interlocking the position detector and the plunger is not critical, as long as the position detector can control the positioning of the plunger in accordance with the object to be measured.

In addition, although the plunger 13 is used in this embodiment as a reciprocating pressurizing body that pressurizes and depressurizes the sealed fluid, it is by no means limited to this.
In short, any means for increasing or decreasing the pressure of the fluid sealed in the chamber may be used, and the actuator and other configurations are not limited to the embodiments. Furthermore, the object to be measured is not limited to a finger, but may also be an arm or the like. Furthermore, the structure of the measuring device itself is by no means limited to that shown in FIG.

(Effects) As described above, when measuring an object to be measured, the present invention allows the starting position of the pressurizing body to be controlled in advance using a position detector according to the object to be measured, so that the pressurizing body is optimally positioned. Since the initial setting is within the range in which the device operates under normal conditions, measurements can be made within the maximum range regardless of the load conditions caused by the thickness of the object to be measured.

Therefore, the present invention eliminates the narrow restriction on the measurement range of the object to be measured in the past, and makes it possible to measure in the optimal condition depending on the object to be measured, so the measurement range is no longer restricted. Therefore, it is possible to measure with high accuracy and over a wide range without being unable to measure or making optimal measurement difficult, and this has the special effect of solving the limitations of the measurement range that were a problem in the past. It was done.

Furthermore, the above-mentioned great practical effects were obtained with an extremely simple configuration that included a position detector.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the principle of an indirect continuous blood pressure measuring device. FIG. 2 is a partially cutaway schematic diagram of a drive unit that controls cuff pressure. 8... Pressure sensor, 10... Potentiometer, 12... Diaphragm, 13... Plunger.

Claims (1)

[Claims for Utility Model Registration] 1. A cuff to which an object to be measured such as a finger is attached, and a fluid sealed in the cuff that is pressurized or depressurized to the object to be measured, and that this pressure becomes the same as the blood pressure of the object to be measured. In an indirect continuous blood pressure measurement device that continuously measures blood pressure by using a pressure sensor, a position detector is provided on a reciprocating pressurizing body that pressurizes and depressurizes the enclosed fluid. An indirect continuous blood pressure measuring device characterized in that it is configured so that the starting point of the pressurizing body can be controlled to a constant position. 2. The indirect continuous blood pressure measuring device according to claim 1, wherein the pressurizing body is a plunger. 3. The indirect continuous blood pressure measuring device according to claim 1, wherein the position detector is a potentiometer.