JPH03111058A - Liquid chemical injector - Google Patents

Abstract

PURPOSE:To inject a required and exact volume of a liquid chemical by providing a pipeline constituting a liquid chemical flow passage from a reservoir for storing the liquid chemical to a liquid chemical injecting section and a liquid feed pump provided near the front end of the pipeline and forming the pipeline in such a manner that the diameter on the upstream side thereof with the liquid feed pump as a boundary is larger than the diameter on the downstream side. CONSTITUTION:The entire part of the liquid chemical injector is embedded into the body and the front end of a catheter 50 is inserted into a blood vessel 60. A CPU 18 operates a driving circuit 19 and a bimorph diaphragm 34 of the liquid feed pump 30 is oscillated vertically when an operation command is applied to a reservoir unit 10. The liquid chemical flowing from the reservoir unit 10 into the catheter 20 is discharged to be catheter 50 and is injected into the blood vessel 60. Since the catheter 50 is short, the compression rate of the liquid chemical based on the blood pressure from the blood vessel 60 is extremely slight; in addition, the catheter >=0 has the large diameter and, therefore, the tube friction therein decreases and the pressure loss decreases. The required and exact volume of the liquid chemical is, therefore, injected into the blood vessel 60 by driving of the chemical feed pump 30.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a liquid drug injection device for injecting a liquid drug into a living body.

[Prior Art] Conventionally, as a drug injection device for injecting a drug into a living body, for example, Japanese Patent Application No. 63-164867 and Japanese Patent Application No. 63-28
No. 0491, Patent Application No. 1-56996, Special Publication No. 1973-3
There is a type that can be implanted in the body, as shown in No. 0719.

When injecting medicinal solutions such as antidiuretic hormone or insulin using such a medicinal solution injection device, approximately 1~
It requires precise injection in a minute amount of 10 nl/g+in.

[Problems to be Solved by the Invention] However, in the conventional chemical injection device as disclosed in Japanese Patent Publication No. 51-30719, all of the chemical liquid put into the device is injected as is, and therefore only the required amount is injected. The chemical solution must be added in advance, making measuring difficult and troublesome.

In addition, even if the correct amount of drug solution is put into the device, there is a pressure loss in the flow path from the device to the injection site, and there is also the influence of external pressure (blood pressure) from the injection site, so in the end, the correct amount of drug solution cannot be filled. The reality is that injection is difficult.

This invention was made in view of the above circumstances,
The purpose is to provide a highly reliable drug injection device that can inject a necessary and accurate amount of drug.

[Means for Solving the Problems] The present invention provides a reservoir for storing a chemical liquid, a conduit forming a medical liquid flow path from the reservoir to a medical liquid injection site, and a wave transmitting system provided at or near the tip of the conduit. A pump is provided, and the diameter of the upstream side of the pipe line is larger than that of the downstream side with the wave sending pump as a boundary.

[Effects] Since the chemical liquid flow path from the wave sending pump to the chemical liquid injection site is short, the amount of chemical liquid compression based on the pressure from the chemical liquid injection site is very small. Moreover, since the chemical liquid flow path from the reservoir to the wave pump has a large diameter, the pipe friction there (inversely proportional to the pipe diameter) is reduced, and the pressure loss is reduced.

[Example] Hereinafter, a first example of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a reservoir unit for storing a medicinal solution, and an inlet of a wave pump 30 is connected to this reservoir unit 10 via an inlet catheter 20. An outleft catheter 50 is connected to the outlet of the wave pump 30.

These reservoir units 10. Inlet catheter 2
0. Wave pump 30. and outleft catheter 5
0 constitutes an implantable drug infusion device, and the tip of the catheter 50 is inserted into a drug injection site, such as a blood vessel.

That is, the catheter 20.50 is connected to the reservoir unit 1.
This is a conduit that forms a medicinal solution flow path from zero to the medicinal solution injection site, and a wave pump 30 is provided at or near the tip of this conduit. In the conduit, the catheter 20 on the upstream side of the wave pump 30 is made larger in diameter than the catheter 50 on the downstream side.

The internal configuration is shown in Figure 2.

The reservoir unit 10 has a built-in reservoir 11, and the reservoir 11 is communicated with an opening 12 on the top surface of the unit. The reservoir 11 is a polymeric bag whose volume changes depending on the amount of the medicinal solution stored therein.

Then, the opening 12 is closed with a polymeric septum 13 that can be punctured by an injection needle and has self-sealing properties, and a metal needle stopper 14 is installed below the septum 13 inside the opening 12 to prevent internal damage. has been established.

Further, in the reservoir unit 10, the reservoir 11 communicates with a base 15 which is a wave transmission port, and one end of the catheter 20 is connected to the base 15.

Furthermore, the reservoir unit 10 has a coil 16 that also serves as an energy transmission section and a signal transmission/reception section at a position surrounding the septum 13 of the opening 12, and a battery 17 at the bottom. CPU (Central Processing Unit)18. and a drive circuit 19.

The coil 16 receives a magnetic field emitted from a coil outside the body and induces an electromotive force, and the battery 17 is charged by the electromotive force.

The CPU 1g uses the battery 17 as an operating power source and the coil 1
6 is used to transmit and receive signals with an external control section (not shown), thereby controlling the wave pump 30 via a drive circuit 19 which also uses a battery 17 as an operating power source.

The catheter 20 has a length that allows the catheter 5o to sufficiently reach the drug solution injection part, and also includes a built-in lead tI21 that electrically connects the drive circuit 19 of the reservoir unit 10 and the wave pump 30.

The wave pump 30 is connected to the catheter 50 as well as the catheter 2o.
It has a flow path 31 that forms a part of the chemical liquid flow path, and an inlet check valve 32 and an outlet check valve 33 are installed at both ends of the flow path 31.
are provided for each.

In other words, the medical solution is made to flow in one direction from the catheter 20 side to the catheter 50 side.

In addition, the upper surface of the flow path 31 of the wave pump 30 is bimorph.
It is composed of diaphragm 34, and its bimorph
The upper surface of the diaphragm 34 is watertight but has a breathable filter 3
5 to the outside of the wave pump 3°.

The bimorph diaphragm 34 is a bimorph vibrator coated with an insulating film, and has the property of being bent vertically alternately as shown in FIGS. 4 and 5 by applying an alternating current voltage Vc as shown in FIG. have. Note that in order to reduce the operating resistance of this bimorph diaphragm 34, ventilation with the outside is ensured as described above.

The control circuit is shown in FIG.

The coil 16 has two functions as an energy transmission section and a signal transmission/reception section, and a battery 17 is charged by the electromotive force induced in the energy transmission section, and the voltage of the battery 17 is used as a signal transmission/reception section.

CPU18. The drive circuit 19 operates. When injecting the chemical liquid, the drive circuit 19
A drive signal of a predetermined voltage and a predetermined frequency is supplied from the drive circuit.

Next, the operation in the above configuration will be explained.

First, as shown in FIG. 7, the entire medical fluid injector is implanted in the body, and in this state, the tip of the catheter 50 is inserted into the medical fluid injector, for example, a blood vessel 60.

When an operation command is given to the reservoir unit 10 from the outside, the CPU 18 operates the drive circuit 19. Then, driving power is supplied to the bimorph diaphragm 34 of the wave pump 30, and the bimorph diaphragm 34 vibrates in the vertical direction.

When the bimorph diaphragm 34 vibrates, the flow path 31
The volume of is expanded and compressed repeatedly. At this time, the medicinal liquid flowing into the catheter 20 from the reservoir unit 10 is sucked into the same flow path 31 based on the volume change of the flow path 31, and the sucked medicinal liquid is also sucked into the catheter 20 based on the volume change of the flow path 31. 50.

The medicinal liquid discharged into the catheter 50 is
0 into the blood vessel 60.

Here, since the medical fluid flow path from the wave pump 30 to the blood vessel 60, that is, the catheter 50, is short, the amount of medical fluid compression based on the pressure (blood pressure) from the blood vessel 60 is very small.

Moreover, since the drug fluid flow path from the reservoir unit 10 to the wave pump 30, that is, the catheter 20, has a large diameter,
There, the pipe friction (inversely proportional to the pipe diameter) becomes smaller, and the pressure loss becomes smaller.

Therefore, by driving the wave pump 30, a necessary and accurate amount of the medical solution can be injected into the blood vessel 60.

Furthermore, since the pressure loss across the catheter is reduced, the required lift of the wave pump 30 can be reduced. This leads to miniaturization of the wave pump 30, which has the advantage of reducing the degree of invasion within the body.

In the above embodiment, the bimorph diaphragm 34 was used in the wave pump 30, but the eighth
As shown in the figure, an insulating diaphragm 36 may be provided and the vibration of a laminated piezoelectric element 37 may be applied to the insulating diaphragm 36.

The insulating diaphragm 36 is a thin plate of metal or the like covered with an insulating coating.

As shown in FIG. 9, the laminated piezoelectric element 37 receives an AC voltage V
It expands and contracts in the vertical direction by adding c, and is in contact with the insulating diaphragm 36 via a hemispherical member 38 attached to the upper part.

That is, when the laminated piezoelectric element 37 expands and contracts in the vertical direction,
The insulating diaphragm 36 vibrates, and the volume of the flow path 31 expands and compresses repeatedly. At this time, the medical solution flowing into the catheter 2o from the reservoir unit 10 is sucked into the same flow path 31 based on the volume change of the flow path 31, and the sucked medical solution is also sucked into the catheter 2o based on the volume change of the flow path 31. 5
o is discharged.

In this case, there is an advantage that the injection pressure can be increased by employing the laminated piezoelectric element 37. However, since the laminated piezoelectric element 37 has a longer lifespan than the bimorph resonator, the wave pump 30
It has the advantage of a longer service life.

Further, as an example of reuse of the laminated piezoelectric element 37, there is one shown in FIG. 1.

Here, the vibration of the laminated piezoelectric element 37 is transmitted to the insulating diaphragm 34 in a magnified state by a lever 39.

According to this configuration, since the displacement of the insulating diaphragm 36 becomes large, there is an advantage that the setting range of the injection amount is expanded.

On the other hand, as shown in FIG. 11, a configuration may be adopted in which a pressing member 40 made of a magnetostrictive material is provided in place of the laminated piezoelectric element 37, and a coil 41 is wound around the pressing member 40.

Coil 41 is connected to drive circuit 19 via lead wire 21 .

As shown in FIG. 12, the pressing member 40 expands and contracts in the vertical direction when an alternating current voltage Vc is applied to a coil 41 and a magnetic flux that alternately changes direction is applied from the coil 41. It is in contact with the insulating diaphragm 36 via its shape.

A second embodiment of the invention will be described with reference to FIG.

Here, the medicinal fluid flow path is configured only by a catheter 20, and a wave pump 70 is provided at the tip of the catheter 20.

A double lumen catheter having a first flow path 71a and a second flow path 71b is employed as the catheter 20, and these flow paths 71a.

71b is communicated with the flow path 72 of the wave pump 70.

Here, the flow path 71a of the catheter 20 and the flow path 72 of the wave pump 70 are conduits that form a drug fluid flow path from the reservoir unit 10 to the drug solution injection site, and the distal end of this conduit directly connects to the wave pump 70. It has become. In the pipe, the flow path 7 on the upstream side bordering the wave pump 70
1a has a larger diameter than the flow path 72 on the downstream side.

The wave pump 70 has an inlet check valve 73 in the flow path 71a of the catheter 20, and a nozzle 7 at the end of the flow path 72.
It has 4.

Note that the structure of the inlet check valve 73 and its surroundings is the same as that of the 14th
The structure of the flow path 72 and its surrounding area is shown enlarged in FIG.

The flow path 72 is a hollow part of a cylindrical piezoelectric element 75,
The inner peripheral surface of the hollow part, that is, the part that comes into contact with the liquid, is covered with an insulating coating.

The piezoelectric element 75 has a property of alternately expanding and contracting in the radial direction by applying an alternating current voltage Vc, as shown in FIG.

The flow path 71b of the catheter 20 is connected at its proximal end to a subcutaneous boat 77 via a connecting tube 76. This subcutaneous boat 77 has an open lower lower part 8, in which a septum 79 made of a polymeric material that can be inserted with an injection needle and has a self-sealing property is provided.

The proximal end of the flow path 71b is closed by a sealing member 80.

Note that the configuration of the base end portion of the flow path 71b and its surrounding area is shown in an enlarged manner in FIG. 17.

The other configurations are the same as in the first embodiment.

Explain the action.

In the case of this embodiment, the nozzle 74 of the wave pump 70 is used by directly implanting it in a drug injector, for example, a blood vessel.

When an operation command is given to the reservoir unit 10 from the outside, the CPU 18 operates the drive circuit 19. Then, driving power is supplied to the piezoelectric element 75 of the wave pump 70, and the piezoelectric element 75 expands and contracts in the radial direction.

When the piezoelectric element 75 expands and contracts, the volume of the flow path 72 repeats expansion and compression. At this time, the medicinal solution flowing from the reservoir unit 10 into the flow path 71a of the catheter 20 enters the flow path 71a.
The medicinal solution is sucked into the flow path 72 based on the change in volume of the flow path 72, and the sucked chemical solution is discharged from the nozzle 74 based on the change in the volume of the flow path 72 as well.

The medicinal liquid discharged from the nozzle 74 is injected into the blood vessel.

Here, the flow of the chemical solution in the nozzle 74 follows a downward gradient of pressure during discharge, so there is little loss; however, during suction, the flow goes against the upward gradient of pressure, and the resulting flow separation due to backflow causes a very large loss. Therefore, backflow from the nozzle 74 during suction is small and can be ignored relative to the amount of liquid suctioned from the catheter 20.

In this way, since the wave pump 70 is located at the tip of the medical fluid flow path, the amount of medical fluid compression based on the pressure (blood pressure) from the blood vessels is very small. In addition, the medical solution flow path from the reservoir unit 10 to the wave pump 70, that is, the catheter 20
Since the flow path 71a has a large diameter, the pipe friction there (inversely proportional to the pipe diameter) is small, and the pressure loss is small.

Therefore, by driving the wave pump 70, a necessary and accurate amount of the medical solution can be injected into the blood vessel.

Furthermore, since the catheter 50 shown in the first embodiment is not provided, a small-diameter portion of the catheter is not required, and therefore, the channel diameter (the diameter of the catheter 20) can be increased over the entire length, and the flow channel resistance can be further reduced. . Therefore, the required head of the wave pump 70 can be small. It becomes very difficult to understand.

This leads to miniaturization of the wave pump 70, which has the advantage of reducing the degree of invasion within the body.

Note that in this second embodiment, the piezoelectric element 75 is
A piezoelectric element 81 as shown in the figure may be used instead.

The piezoelectric element 81 has a cylindrical shape with a hollow portion serving as a flow path 72, and its tip is constricted into a nozzle shape. The piezoelectric element 81, like the piezoelectric element 75, has a property of alternately expanding and contracting in the radial direction when an alternating current voltage Vc is applied.

On the other hand, instead of the piezoelectric element 75, a piezoelectric element 91 shown in FIG. 19 may be employed.

The piezoelectric element 91 has a cylindrical shape with a hollow portion serving as a flow path 72, and has a plurality of electrodes 91a along its outer peripheral surface and in the axial direction.
, 91 b, 91 c, and 91 d, and has a common electrode 91 e on the inner peripheral surface forming the flow path 72 .

Then, the CPU 93 and the drive circuit 94 are connected to the battery 92.
are connected to each other, and the output of the drive circuit 94 is sequentially applied to each of the electrodes by a control circuit 95 that responds to commands from the CPU 93.

Note that the battery 92. CPU93. The drive circuit 94 includes the battery 17. of the first embodiment. It corresponds to the CPU 18° drive circuit 19.

That is, the radial expansion and contraction of the piezoelectric element 94 is made to slide in the axial direction, thereby generating a traveling wave in the flow path 72 toward the distal end, thereby injecting the chemical solution.

In this case, the presence of traveling waves has the advantage that backflow from the drug solution injection site can be reliably prevented.

[Effects of the Invention] As described above, according to the present invention, there is provided a reservoir for storing a medicinal solution, a conduit extending from the reservoir to a medicinal solution injection site without forming a medicinal solution flow path, and a distal end of the conduit or its vicinity. The diameter of the upstream side of the pipeline is larger than that of the downstream side from the wave pump, so it is highly reliable and can inject the necessary and accurate amount of chemical solution. It is possible to provide a chemical liquid injector with the following characteristics.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a first embodiment of the present invention, FIG. 2 is a diagram showing the internal configuration of the same embodiment, and FIGS. 3 to 5 are respectively the configurations of the bimorph diaphragm in the same embodiment. FIG. 6 is a block diagram of the control circuit of the embodiment, FIG. 7 is a perspective view showing how the embodiment is used, and FIG.
12 to 12 are diagrams each showing the configuration of a modified example of the wave sending pump in the same embodiment, and FIG.
Figures 14 and 15 are diagrams showing the configuration of the embodiment.
3 is an enlarged view of the configuration of the main parts in FIG. 3, FIG. 16 is a view showing the structure of the piezoelectric element in the same example, FIG. 18
This figure and FIG. 19 are diagrams each showing a configuration of a modified example of the same embodiment. DESCRIPTION OF SYMBOLS 10... Reservoir unit, 20... Inlet catheter, 30... Transmission pump, 50... Outlet catheter.

Claims (1)

[Claims] A reservoir for storing a chemical solution, a conduit forming a medicinal solution flow path from the reservoir to a medicinal solution injection site, and a wave pump provided at or near the tip of the conduit, and the wave pump is used as a boundary to A chemical liquid injector characterized in that the upstream side of the conduit has a larger diameter than the downstream side.