JPH0316642Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an in-vivo pressure measuring device that measures in-vivo pressure, such as intracranial pressure and blood pressure, over a long period of time using a pressure sensor placed in the in-vivo.

[Summary of the idea]

The present invention relates to an in-vivo pressure measuring device that measures in-vivo pressure, such as intracranial pressure and blood pressure, over a long period of time using a pressure sensor placed in the in-vivo. A sensor for measuring in-vivo pressure, in which an indwelling strain gauge for pressure measurement is connected to a pressure indicating and measuring device, and one end of the inner cavity of a flexible cable is closed or opened to the outside air, and this sensor for measuring in-vivo pressure is encapsulated. a balloon having a lumen made of an elastic thin film;
a flexible communication tube having one end communicating with the inner lumen of the balloon; a fluid pressure supply means coupled to an opening at the other end of the communication tube for supplying fluid pressure to the inner lumen of the balloon through the communication tube; By providing a means for instructing the sensor, the sensor can be calibrated at any time, and the sensor can accurately measure internal pressure.

[Conventional technology]

Conventionally, various types of in-vivo pressure measuring devices have been proposed using in-vivo indwelling type sensors that measure the in-vivo pressure etc. by indwelling the sensor in the living body for a long period of time. A strain gauge is attached to the back of the membrane, and the strain gauge attached to this elastic metal membrane is placed in a small hollow container (balloon).
This balloon is connected to a flexible cable having a lumen, and this cable is led out of the living body and connected to the main body of the pressure measuring device to indicate the measured pressure. . Such pressure measuring devices whose internal cavity is open to the atmosphere at the outgoing part of the cable are called relative pressure sensors, and the in-vivo pressure is measured based on the difference between the sensor and the atmospheric pressure. The above-mentioned cable having a lumen whose outside the living body is closed is called an absolute pressure type sensor and is used for measuring absolute pressure. In general, most of these relative pressure type and absolute pressure type sensors cannot be calibrated during measurement, so zero-based calibration is performed by inflating the balloon while the sensor is inserted into the balloon. , sensors as shown in FIGS. 2A and 2B are known. FIG. 2A shows a side sectional view of the sensor during pressure measurement, and FIG. 2B shows a side sectional view of the sensor during zero base calibration. In FIGS. 2A and 2B, an elastic thin film balloon 5 is placed over the outside of the sensor 1 having a strain gauge attached to the back surface of an elastic metal film 9, and air pressure is applied to the balloon from the outside through the air passage 11 of the communication pipe 10. At the same time, the same air pressure is applied inside the sensor 1 through the cable lumen 12, and the pressure inside and outside the pressure receiving surface of the sensor 1 is balanced to create a zero point and perform calibration (Utility Application No. 59-76570). ), After performing zero base calibration by supplying air pressure to the inside and outside of the pressure receiving surface of the sensor 1 as shown in Fig. 2B, as shown in Fig. 2A, the internal pressure 15 of the living body is applied to the balloon 5 to adjust the internal pressure. It is designed to perform measurements.

[The problem that the idea aims to solve]

However, the above-mentioned prior art is applicable only to devices that measure relative pressure with the atmosphere (i.e., differential pressure with the atmospheric pressure) because the sensor 1 needs to be communicated with the lumen 12 of the cable 2 leading to the atmosphere. This method has the disadvantage that it cannot be applied to a measuring device that has a sensor that measures absolute pressure.

The present invention was developed in view of the above-mentioned drawbacks, and the purpose is to provide an in-vivo measuring device that can not only be calibrated when measuring absolute pressure, but also calibrated during measurement when measuring relative pressure. It is something.

[Means to solve the problem]

An example of the in-vivo measurement device of the present invention is shown in FIG. A sensor 1 for measuring internal pressure in a living body, which is connected to a measuring device 4 and has one end of a lumen 12 of a flexible cable 2 closed or open to the outside air;
A balloon 5 having an inner lumen 13 made of an elastic thin film enclosing this in-vivo pressure measurement sensor 1, a flexible communicating tube 6 whose one end communicates with the inner lumen 13 of the balloon 5, and a flexible communicating tube 6 at the other end of the communicating tube 6. It comprises a fluid pressure supply means 7 coupled to the opening for supplying fluid pressure to the lumen 13 of the balloon 5 through the communication tube 6, and means 8 for instructing the fluid pressure supply.

[Effect]

The in-vivo pressure measuring device of the present invention uses the value of the fluid supply pressure indicating means 8 which indicates the fluid pressure to be supplied to the sensor via the syringe 7 of the fluid pressure supply means, and the measuring device 4 which indicates the output of the sensor 1. By comparing the indicated pressure with the indicated pressure, it is possible to perform zero-base calibration at any time not only when measuring relative pressure but also when measuring absolute pressure.

〔Example〕

Hereinafter, the biological pressure measuring device of the present invention will be specifically explained using the embodiment shown in FIG.

FIG. 1 is a partial sectional view showing a preferred embodiment of the present invention. In the figure, 1 is a sensor for an in-vivo pressure measuring device having a strain gauge, and 2 is an inner cavity 12 through which a lead wire from the strain gauge of the pressure sensor 1 passes.
3 is a flexible cable having an electrical connector;
Reference numeral 4 denotes an in-vivo pressure measuring device main body having an amplifier and a pressure indicator 14, and the pressure indicator 14 has a zero adjustment mechanism and an amplifier gain adjustment mechanism inside. In this example, these 1 to 4 constitute an absolute pressure type sensor convenient for measuring absolute pressure. In other words,
The lumen 12 of the cable 2 is isolated from the atmosphere.

5 is a balloon made of an elastic thin film (silicon rubber, polyethylene, etc.) that envelops the entire pressure sensor 1 and has a lumen 13; 6 is a flexible communication tube (silicon rubber) that communicates with the lumen 13 of the elastic thin film balloon 5; (rubber or polyethylene, etc.), 7 is a syringe as a means for supplying fluid (air in this case) pressure, and 8 is a pressure gauge that indicates the relative pressure of the fluid pressure, and these 5 to 8 are parts that have been especially added according to the present invention. be.

The operation of the in-vivo pressure measuring device of the present invention in the above configuration will be explained.

The pressure sensor 1 surrounded by the balloon 5 is inserted into the living body together with the balloon 5 and left in place. When the thin film of the balloon 5 is passed through the strain gauge of the sensor 5 and internal pressure is applied, the internal pressure value is indicated to the pressure indicator 14 of the body 4 of the internal pressure measuring device. That is, when the inner shaft of the syringe 7 is removed and the communicating tube 6 is opened to the atmosphere, the relative pressure of the pressure gauge 8 connected to the communicating tube 6 shows "0",
The pressure indicator 14 of the body 4 of the body pressure measuring device indicates the body pressure. To perform calibration in this state, insert the inner shaft into the outer cylinder of the syringe 7 and insert the inner shaft into the inner cavity 1 of the balloon 5.
At this time, the pressure sensor 1 is receiving the in-vivo pressure, but at the same time the internal pressure of the lumen 13 of the balloon 5, that is, the pressure gauge 8
It is also subject to the internal pressure shown in . However, unless the internal pressure of the lumen 13 of the balloon 5 is raised to equal the internal pressure 15 of the living body, the internal pressure value of the pressure indicator 14 will not change. If the internal pressure 15 of the living body exceeds the internal pressure of the lumen 13 of the balloon 5 even slightly, the pressure value of the pressure indicator 14 of the main body 4 of the living body pressure measuring device increases. If the value obtained by converting the internal pressure value at the point at which the pressure value of the pressure indicator 14 starts to rise into relative pressure, that is, the value obtained by subtracting the atmospheric pressure at that time, and the indicated value of the pressure gauge 8 match, the pressure sensor 5 has been correctly calibrated. If there is a difference between these two values, the calibration has deviated. Therefore, increase or decrease the zero point adjustment mechanism or gain adjustment mechanism of the amplifier in the device main body 4 to adjust the instructions for both. Correct calibration can be achieved by adjusting the values so that they match.

Above, we have explained the case where the present invention is applied to an absolute pressure measuring device, but when it is applied to a relative pressure measuring device, that is, one in which the inner cavity 12 of the cable 2 is connected to the atmosphere, the calibration can be performed in exactly the same manner as described above. It can be performed. In this case, since the indication from the pressure indicator 14 is displayed as a relative pressure, it is not necessary to convert the internal pressure value as described above for the relative pressure indication from the pressure gauge 8, making direct comparison easier. It will be possible. It is also possible to use something other than air as the fluid.

[Effect of idea]

According to the present invention, the following remarkable effects can be obtained.

(a) It can be applied to any device that measures absolute pressure or pressure relative to the atmosphere.

(b) In either case, calibration can be performed at any time during measurement of intravital pressure, so there is no need to calibrate the measuring device before inserting it into the living body. Therefore, bacterial contamination due to pre-surgery calibration operations can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a preferred embodiment of the present invention, and FIG. 2 is a partial side sectional view of a conventional sensor. 1... Sensor, 2... Cable, 5... Balloon, 6... Communication tube, 7... Syringe (fluid pressure supply means), 8... Pressure gauge (means for indicating fluid supply pressure).

Claims (1)

[Claims for Utility Model Registration] An indwelling strain gauge for pressure measurement attached to one end of a flexible cable having a lumen is connected to a pressure indicating measuring device, and one end of the lumen of the flexible cable is connected to a pressure indicating measuring device. A sensor for measuring in-vivo pressure that is closed or open to the outside air; a balloon having a lumen made of an elastic thin film that encloses the sensor for measuring in-vivo pressure; and a flexible communication tube having one end communicating with the lumen of the balloon. a tube; fluid pressure supply means coupled to an opening at the other end of the communication tube for supplying fluid pressure to the inner lumen of the balloon through the communication tube; and means for indicating the fluid supply pressure. An in-vivo pressure measuring device characterized by: