JPH0580972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in biological pressure sensors, and particularly to a capillary pressure gauge suitable for assembling a pressure chip to the distal end of a capillary (catheter).

[Prior Art] As shown in Fig. 2, a conventional capillary pressure gauge is a flexible resin capillary tube whose end face is closed and a pressure-receiving port is provided on the side surface that extends to a predetermined size from the end face. (catheter) 4 tip, a pedestal 2 inserted into the tip of the thin tube 4 facing the pressure receiving port, and a pressure chip 1 equipped with a sensing diaphragm mounted on the pedestal 2 via an insulating film 8; It has a structure consisting of at least one signal line 3 connected to the pressure chip 1, and a protective film 5 having insulation and elasticity provided between the pressure receiving port and the pressure chip 1. (Tokuko Akira
(Refer to Publication No. 59-21495) For this reason, for example, when inserted into a small blood vessel in a living body, or when a bending force is applied to the tubule, the resin tubule deforms and compresses or stretches the silicone rubber protective membrane. That force can distort the diaphragm, producing an output that is unrelated to actual in-vivo pressure. Furthermore, since the pressure chip is surrounded by resin, it takes some time for the temperature to stabilize after insertion into a living body due to the insulating properties of the resin.

[Problem that the invention seeks to solve]

Conventionally, there was a drawback that pressure measurement accuracy could not be obtained due to deformation of the tubules in areas of the body where the pressure was low, or areas that had to pass through very thin blood vessels to reach the area.

An object of the present invention is to provide a capillary pressure gauge that does not deform even when bending force is applied, and that is capable of measuring pressure in a living body with high precision in a short time using a capillary tube with good thermal conductivity. be.

[Means for solving problems]

In order to achieve the above object, the present invention provides a capillary tip portion whose end face is closed and a pressure receiving port is provided on the side surface, a pressure chip inserted into the capillary tip portion opposite to the pressure receiving port, and the pressure chip and the pressure receiving port. In a capillary pressure gauge that detects the pressure inside a living body through the protective film, the capillary tip has a curved surface at the tip and an inset part into which the capillary is inserted at the rear end. The pressure chip is formed of a metal cap having a pressure chip, and a metal pedestal on which a pressure chip is mounted is fixed in a hollow hole of the metal cap.

[Effect]

According to the present invention, pressure such as blood pressure in the living body is applied to the pressure chip via the insulating film provided at the pressure receiving port of the capillary pressure gauge and output as an electrical signal. Even if bending stress is applied to the tip of the thin tube to which the pressure chip is attached, the metal cap has high rigidity and no strain is transmitted to the pressure chip. The distal end of the metal cap is curved and rounded, and a flexible thin tube is connected to the rear end for easy insertion into a living body. In addition, it has high thermal conductivity and external temperature is quickly transmitted to the pressure chip.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the tip of a thin tube (a tubular instrument called a catheter) 4 whose end face is closed and a pressure-receiving port is provided on the side that protrudes to a predetermined size from the end face, and the thin tube facing the pressure-receiving port. A pedestal 2 made of stainless steel or an insulating material inserted into the tip of the thin tube 4;
A pressure chip 1 equipped with a sensing diaphragm mounted on this pedestal 2 via an insulating film 8, and at least one pressure chip 1 connected to the gold wire of this pressure chip 1, fixed to the pedestal 2, and protected with epoxy resin 6. The above usually consists of five signal lines 3 and a protective film 5 made of silicone rubber or the like having insulation and elasticity provided between the pressure receiving port and the pressure chip 1, and the protective film 5 is inserted into a living body. In a capillary pressure gauge that detects pressure through a capillary tube and connects to an external connector (not shown), the capillary tip of the capillary tube 4 is formed with a metal cap 7, which is cylindrical and has a rounded tip surface. The processed curved surface 9 and
Fitting part 1 with an outer diameter into which a thin tube 4 can be inserted at the rear end side
0 and is configured to connect flexible thin tubes 4 made of various materials and structures to provide rigidity at the tip.

In the unlikely event that a pulling force is applied to the metal cap 7 and the thin tube 4, the thin tube 4 will be pulled and deformed in a direction in which its outer diameter will shrink, and the fitting portion 10 will be further crimped and the metal cap 7 and The thin tube 4 never separates.

To show the specific structure of this embodiment, the thin tube 4 is made of vinyl chloride with an outer diameter of 1.6 mm, and the tip of the thin tube has an outer diameter of 1.8 mm.
A stainless steel metal cap 7 with a length of 8 mm and a length of 8 mm is attached, and both are fixed with epoxy adhesive. The metal cap 7 has a cylindrical shape with a rounded end surface 9, and the surface is smoothed by electrolytic polishing so as not to injure the living body. A hollow hole with an inner diameter of 1.2 mm is provided inside the metal cap 7, and a stainless steel pedestal 2 and a silicon semiconductor pressure chip 1 are fixed therein. The metal cap 7 has a major axis.
A 3.5mm oval pressure receiving port is provided with its center located 4mm from the tip. The upper surface and periphery of the pressure chip 1 installed inside this pressure receiving port is filled with a protective film 5 made of silicone rubber to perform pressure sealing. It also serves to prevent fragments from entering blood vessels, etc. even if they break. Pressure such as blood pressure is applied to the pressure chip 1 through the protective film 5 and output as an electrical signal. When stress is applied to the tip of the thin tube 4 to which the pressure chip 1 is attached, since the metal cap 7 has high rigidity, the strain is not transmitted to the pressure chip 4, making it possible to accurately measure pressure. Furthermore, since it has high thermal conductivity, the external temperature, that is, the temperature of the living body, is quickly transmitted to the pressure chip 1, so that the drift of the zero point due to temperature changes can be reduced. In particular, if the thin tube 4 is made of metal, its insertion into the living body is restricted, but by making only the tip of the thin tube made of metal and making the rest of the thin tube flexible, it can be easily inserted into the living body, and the above-mentioned effects can be achieved. Together with this, the accuracy of pressure measurement is improved. On the other hand, the material of the thin tube 1 fitted into the fitting part 10 of the metal cap 7 for connection can be freely selected, and its uses as a sensor can be widened and expanded.

〔Effect of the invention〕

By forming the tip of a thin tube with a metal cap, fixing a metal pedestal on which a pressure chip is mounted in the hollow part, and connecting a flexible thin tube, it becomes easier to insert the tube into a narrow blood vessel, and at the same time It can prevent the effects of distortion caused by external forces, and has a quick response to temperature changes, allowing for accurate measurement of pressure within a living body. On the other hand, the material and structure of the thin tube connected to the metal cap can be freely selected, expanding the range of uses.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG.
The figure is a sectional view showing a conventional technique. 1... Pressure chip, 4... Thin tube (catheter),
5...Protective film, 7...Metal cap.

Claims (1)

[Claims] 1. A capillary tip whose end face is closed and a pressure receiving port is provided on the side, a pressure chip inserted into the capillary tip facing the pressure receiving port, and a pressure chip provided between the pressure chip and the pressure receiving port. A capillary type pressure gauge comprising a protective film and detecting pressure within a living body through the protective film, the capillary tip end portion of which is a metal cap having a curved surface at the distal end and an inset portion into which the capillary tube is inserted at the rear end. What is claimed is: 1. A capillary type pressure gauge characterized in that a metal pedestal on which the pressure chip is mounted is fixed to a hollow hole of the metal cap.