JPS6243536Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a pressure transmitter capable of extracting the pressure of one liquid as the pressure of another liquid in order to measure the pressure of a liquid.

[Conventional technology]

For example, when measuring lumbar puncture pressure (spinal fluid pressure), if the spinal fluid is directly introduced into a pressure measuring device, there is a risk of bacterial infection through the spinal fluid or infection due to the puncture site being exposed to the outside world. Therefore, pressure cannot be measured for a long period of time.

[Purpose of the invention] This invention is suitable for cases where it is inappropriate to introduce directly into a measuring device outside the body, such as biological fluids, or where the liquid to be measured is corrosive and cannot be directly introduced into a measuring device. The object of the present invention is to provide a pressure transmitter that enables the measurement of hydraulic pressure.

〔Example〕

An embodiment in which the present invention is applied to spinal fluid pressure measurement will be described below with reference to the drawings. In FIG. An indirect pressure transmitter 7 is connected by a tube connector 6 with a silicone tube inserted into the
is connected to the silicon tube 8. 9 is a pressure transducer connected by a polyethylene tube 10 and converts liquid pressure into an electrical signal; 11;
12 is an electric wire, 13 is a connector, 14 is a pressure indicator, and 15 is a recorder.

As shown in FIGS. 2 and 3, the pressure transmitter 7 includes two flat bags 17 made of a non-stretchable material such as polyethylene between hard shell-like metal or plastic shells 16. 18 is sandwiched between them. Spinal fluid is introduced into the first bag 17, and another liquid is sealed in the second bag, and both liquids do not mix bacteriologically, but pressure is transmitted. It is. The principle of this pressure transmission is 2.
This is because if the two bags are in plane contact with each other, the hydrostatic pressure in both bags is equal. That is, in general, when the contact is not a planar contact, the radius of curvature of the contact surface is R,
If the total tension of the contact surfaces of both bags is T, and the difference in the hydrostatic pressure of the liquid in both bags is dp, then dp=2T/R is given. Since R=∞ when there is plane contact, dp=0. Additionally, if the bag is made of an insulating material, both liquids will be electrically insulated and the risk of electric shock can be prevented.

FIG. 4 shows the characteristics of the pressure transmitter. The horizontal axis is
The internal volume of the second bag 18 is shown, and the vertical axis shows the reading of the pressure inside the bag 18 when the pressure P ₁ inside the first bag 17 is 200, 400, 600, 800, 1000 mmH ₂ O. . From this figure, it can be seen that the most desirable internal volume of the bag 18 is about 0.16 cc, and that even if this varies by about ±50%, there is little effect on the reading value. As long as the internal volumes of the bag 18, tube 10, and pressure transducer 9 do not change, and the shell 16 does not deform, the air inside the bag 18 is removed and 0.16 cc of liquid is sealed in the bag. The internal volume of 18 is 0.16cc
In this way, the most desirable measurement system can be constructed using a pre-filled bag. Note that the optimum internal volume of the bag 18 depends on the shape of the inner surface of the shell 16, that is, the internal volume of one side of the shell. On the other hand, an air vent tube 19 is integrally formed in the first bag 17, and its tip is opened to the outside air.

Next, how to use this device will be explained. First, the silicone tube 5 is inserted into the subarachnoid space of the spinal cord in the same manner as a normal lumbar puncture. After confirming that cerebrospinal fluid can be extracted from the silicone tube, connect the tube connector 6 to the pressure transmitter 7.
Connect with the bag 17. While holding the pressure transmitter with the air vent tube 19 facing up, confirm that spinal fluid has overflowed from here and that there is no air in the bag 17, and then tie the tube 19.

Silicon tubes 5, 8 and pressure transmitter 7
is buried on the subcutaneous fascia of the flank, 2 to 3 cm lateral to the midline. The tube 10 on the output side of the transmitter is advanced beyond the transmitter by passing over the subcutaneous fascia and pulled out to the outside of the skin at a point about 20 cm outside the midline. A rubber cap is attached to the tip of this tube. This rubber cap part is connected to the pressure transducer 9,
Affix it on the abdominal skin using adhesive tape. Electric wires 11, 1 are connected from the transducer 9 on the skin.
The pressure indicator 14 is connected to the pressure indicator 14 via the connector 13 by the cord No. 2, and measurement is performed. When the measurement is stopped and the patient leaves the bed, connect connector 1.
Attach/remove at step 3.

[Effect of idea]

As is clear from the above, according to the present invention, both fluids are isolated between the two bags, so in the case of biological fluids, there is no fear of bacterial infection from the outside world via the fluids. Furthermore, since the liquid to be measured does not directly touch the pressure indicator, it is electrically safe. Additionally, the pressure transducer can be located outside the body, which is advantageous from the standpoint of insulation.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing how the pressure of spinal fluid is measured using the pressure transmitter according to the present invention, Fig. 2 is an exploded perspective view showing the pressure transmitter, Fig. 3 is a sectional view of the same, and Fig. 4 is It is a figure showing the characteristic of a pressure transmitter. 1... Spinal cord, 2... Abdominal cavity, 3... Anterior abdomen, 4...
Posterior spine, 5...Silicon tube, 7...Liquid pressure transmitter, 8...Silicon tube, 9...Pressure transducer, 10...Polyethylene tube, 11, 12...Electric wire, 13...Connector, 1
4...pressure indicator, 15...recorder, 16...shell, 17,18...bag, 19...tube.

Claims (1)

[Scope of utility model registration request] A pair of hard shell-like shells have first and second pouch-like parts separated by two non-stretchable and flexible membranes, and a tube is connected to the first pouch-like part; A body fluid in a living body or the like is directly introduced into the bag as a liquid to be measured, and a tube that communicates the liquid sealed in the second bag-like part with the transducer is connected, so that the membrane surfaces of both bag-like parts are flat. A medical liquid pressure transmitter, characterized in that the pressure of the liquid in the first pouch-like part is transmitted to the pressure of the liquid in the second pouch-like part by contact.