JP3586964B2 - Continuous injector - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a continuous infusion device for continuously injecting a predetermined amount of a drug solution into blood vessels, epidurals, bladders, and the like, and more particularly, to a drug solution stored under pressure in a balloon at a constant rate. The present invention relates to a continuous infusion device that can be infused into a patient for a long time.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a method for injecting a drug solution into a human body for a relatively long time, a syringe containing a drug solution is connected to an injection needle or a catheter, and the drug solution flows out manually, by a spring, or electrically. In the case of manual continuous infusion, the patient and the practitioner are restrained and fixed to the human body for a certain period of time, which causes great physical and mental pain. Even if an electric motor or a spring is used, it is necessary to secure a power source, install a syringe, and the like, and the behavior of the patient is limited. In order to solve such inconvenience, a small-sized and easy-to-handle chemical injector has been developed without restricting the actions of a patient or a practitioner. (JP-A-56-102252, JP-B-6-87895)
Each of these uses a contraction force of a balloon to inject a drug solution into a patient continuously for a long time little by little, and a balloon portion, a housing for accommodating the balloon portion, and a drug solution filled in the balloon. It consists of a drug solution outlet that flows into the human body via a human body attachment such as an injection needle.
[0003]
The continuous injector as described above has been provided with the following means for injecting the drug solution stored in the balloon continuously at a constant speed for a long time and little by little.
[0004]
The first means is to control the flow rate of the drug solution discharged from the balloon by providing a flow rate control unit such as a pipe having micro holes at the drug solution outlet. By appropriately changing the length of the pipe and the diameter of the fine holes, it is possible to cope with various set flow rates (JP-A-3-140163).
[0005]
The second means is to keep the injection pressure of the drug solution from the balloon filled with the drug solution constant.
[0006]
In order to keep the injection pressure constant, some balloons have improved properties. As an example, Japanese Patent Application Laid-Open No. 4-2360 is known, which discloses a balloon at the time of discharging a drug solution by forming a multilayer structure in which the inner cavity surface of a cylindrical body based on natural rubber is covered with a silicone resin film. The internal pressure of the liquid can be increased so that the drug solution can be injected at a substantially constant speed. In addition, a pretreatment of filling a balloon made of an untreated elastic material with a liquid or a gas to a predetermined amount or more, and then removing a part of the liquid or a gas and maintaining an inflated state of the balloon for one hour or more is performed. There is a method using a balloon which lacks a part of the energy elasticity from the stress of the primary elastic hysteresis curve (Japanese Patent Laid-Open No. 3-133460).
[0007]
On the other hand, there is a configuration in which the balloon can be inflated and contracted without receiving an action such as friction with the inner surface of the housing. This is because even if a balloon made of an improved material as described above is used, if the balloon is subjected to an action such as friction with the inner surface of the housing, the original inflation and deflation ability of the balloon is impaired, and the injection of a drug solution from the balloon is performed. This is because the pressure changes. As an example, Japanese Patent Application Laid-Open No. 4-67873 is known, and when filling a balloon with a liquid medicine, the balloon 3 is guided in the longitudinal direction (outside direction) together with the radial direction while being guided by the outer shaft having the inner shaft. (The axial direction of the shaft or the inner shaft). Also, the diameter of the housing is reduced so as to have a taper having substantially the same angle as the taper of the umbrella-shaped member fixed to the tip of the outer shaft. Bending during expansion can be prevented (FIG. 6). With such a configuration, the balloon can be inflated without being affected by friction with the inner surface of the housing when the liquid medicine is filled.
[0008]
[Problems to be solved by the invention]
However, in the above structure, when the balloon is deflated, it may be affected by friction with the inner surface of the housing. There are various methods of carrying the continuous infusion device depending on the user, for example, after filling the medicinal solution according to the prescription of a doctor or the like, the device is attached to a part of the body or put in a pocket of a patient's clothes. Depending on the carrying method, even in the continuous injector of the publication, the umbrella-shaped member fixed to the outer shaft by the weight of the balloon containing the drug solution due to gravity is inscribed in the inner surface of the housing, and with the inner surface of the housing as the balloon contracts. Of the balloon may prevent uniform deflation of the balloon. As a result, if the injection pressure of the drug solution changes significantly due to the deflation of the balloon, it may be difficult to continuously inject the drug solution at a constant speed even if the above-described flow control unit including a pipe or the like is provided. The present invention has been made to solve such a problem, and provides a continuous injector capable of injecting a drug solution into a patient continuously at a constant speed for a long time with high accuracy by a means described below. Things.
[0009]
[Means for Solving the Problems]
As a result of various studies, the present inventors have achieved the above object by the fact that the configuration of the continuous injector includes means for constantly inflating and deflating the balloon in the longitudinal direction of the housing. That is, the continuous injector according to the present invention includes a balloon made of a rubber-like elastic material for storing a liquid under pressure, a drug solution inlet / outlet portion tightly fixed to one end of the balloon, and a closed end provided inside the balloon. A cylindrical member having an opening end portion tightly fixed to the other end of the balloon, a housing accommodating the balloon, and having one end to which the drug solution inlet / outlet portion is fixed, and a drug solution fixed to the housing. It comprises a rod-shaped shaft which is provided at a position facing the entrance / exit portion and is slidably mounted on the tubular member, and a chemical liquid outflow portion comprising a flow control tube connected to the chemical liquid inflow / outflow portion. is there.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
A feature of the present invention is that the balloon is inflated and deflated so as not to receive undesired effects from the outside. That is, it is important that the housing is provided with a rod-shaped shaft for guiding the inflation and deflation directions of the balloon.
[0011]
The rod-shaped shaft is provided at a position facing the liquid medicine inlet / outlet fixed to the housing. The distal end of the rod-shaped shaft has a closed end provided in the balloon, and the open end is provided in a cylindrical member tightly fixed to the balloon. The length of the rod-shaped shaft is preferably slightly shorter than the length of the cylindrical member. If the length of the rod-shaped shaft is longer than the cylindrical member, the closing portion of the cylindrical member that slides on the rod-shaped shaft as it is filled with the drug solution comes into contact with the tip of the rod-shaped shaft, and the inflation pressure of the balloon is applied to the tip of the rod-shaped shaft, The rod-shaped shaft may be bent or broken, which is not preferable. When the length of the rod-shaped shaft is slightly shorter than the length of the cylindrical member, the closed end of the cylindrical member does not come into contact with the tip of the rod-shaped shaft, and the open end of the cylindrical member has the root ( This is preferable because the rod-shaped shaft abuts around the position where the shaft is fixed to the housing, and the inflation pressure of the balloon is distributed to the housing.
[0012]
Further, in the present invention, the cylindrical member slides on the rod-shaped shaft accompanying the movement of the balloon, but since the relationship between the position and the amount of the drug solution remaining on the balloon is constant, a scale is provided on the rod-shaped shaft. Thus, the outflow amount of the chemical solution can be confirmed. Compared to the conventional case where a scale is provided on a housing for accommodating a balloon or an inner shaft provided inside the balloon, there is an advantage that it is very accurate and easily visible.
[0013]
A slight clearance is provided between the rod-shaped shaft and the cylindrical member so that the rod-shaped shaft can slide freely in the cylindrical member, and its width is preferably in the range of 0.5 to 9 mm. .
[0014]
Further, the rod-shaped shaft and the tubular member are preferably made of a synthetic resin such as polycarbonate, polyethylene, polypropylene, ABS and the like.
[0015]
The housing prevents the balloon from being damaged by touching an external sharp object, and seals the chemical so that the chemical does not splash outside if the balloon leaks due to a defect such as a pinhole in the balloon itself. Perform the function of
[0016]
The shape of the housing is not particularly limited in the present invention, and an appropriate shape such as a cylindrical shape, a spherical shape, and a prism shape may be adopted. The dimensions are selected according to the dimensions when the balloon is inflated. It is preferable to select the inner diameter of the housing such that there is a slight clearance between the inflated balloon and the inner surface of the housing when the filling of the drug solution is completed (when the balloon is fully inflated). This is to prevent the balloon from rubbing against the inner surface of the housing to prevent uniform inflation and deflation. The housing is preferably made of a transparent material so that the state of injection of the chemical solution can be visually observed from the outside, and examples thereof include synthetic resins such as polyvinyl chloride, polypropylene, and polycarbonate. The housing is sealed in a sealed state so that the drug solution does not leak to the outside even if the balloon is damaged.However, if the inside is completely airtight, the air inside the balloon will be filled as the drug solution is injected into the balloon. Is compressed and the pressure in the housing is increased, so that there is a disadvantage that the liquid medicine cannot be injected to a certain degree or more. Therefore, it is preferable to form an air vent opening at an appropriate position in the housing, and to provide a water-repellent air-permeable filter through which air passes but does not pass a chemical solution. The material of the water-repellent ventilation filter is preferably an acid-resistant synthetic fiber bundle obtained by performing a water-repellent treatment, and examples thereof include polyester and polytetrafluoroethylene.
[0017]
The balloon has a cylindrical or spherical shape, and one end is provided at a drug solution inlet / outlet, and the other end is provided at the open end of a cylindrical member having a closed end provided inside the balloon by a sealing means such as an O-ring. Liquid tightly fixed.
[0018]
The balloon is preferably made of a high-toughness material which has high elasticity and is not easily damaged by an external action. Silicone rubber, butyl rubber, nitrile butadiene rubber, poly-1.4-butadiene rubber, polyisoprene (natural rubber) Or a synthetic rubber), polyurethane, butadiene styrene copolymer, etc., whose length, outer diameter, and wall thickness can be appropriately selected according to the amount of the drug solution injected into the patient and the injection time.
[0019]
By filling the balloon with a drug solution, a cylindrical balloon has a structure that can be inflated both in the radial direction and in the longitudinal direction. The contraction force of the balloon when the medicinal solution is stored is preferably a pressure of 100 to 1000 mmHg, and a human vein is about 60 mmHg. The reason why the above pressure range is preferable is that when the contraction force is 100 mmHg or less, it is difficult to control the injection speed, and when the contraction force is 1000 mmHg or more, it is difficult to inject the drug solution into the balloon by a syringe or the like with human power. It is. However, the pressure range is not limited as long as the injection rate can be controlled and the drug solution can be injected into the balloon.
[0020]
The drug solution entry / exit portion tightly fixed to the balloon is a portion serving as a passage for inflow or outflow of the drug solution into the balloon. The chemical liquid inlet / outlet portion is constituted by a Y-shaped tube or the like having a different outflow portion and inflow portion, and is preferably made of a synthetic resin such as polyolefin, polyvinyl chloride, or polycarbonate.
[0021]
At the tip of the inflow portion, a medical fluid inflow plug that can flow a medical fluid into the balloon using a syringe or the like may be provided. Further, the luer taper shape may be adopted so that the inflow portion is fitted or screwed into the end of the syringe of the syringe so that the liquid medicine can be injected in a liquid-tight manner.
[0022]
Further, it is preferable to provide a check valve at the inflow portion, which allows only the flow of the chemical solution in the inflow direction. As the check valve, a duckbill type valve, an umbrella valve, a flap valve, a povet valve, a ball valve, and the like can be used. These valve materials include fluororesin, nylon, polyolefin, polyvinyl chloride, polycarbonate, and silicone resin. And the like. It is also preferable to provide a filter for removing minute substances in the chemical solution. As the filter, a mesh filter or a membrane filter made of a woven fabric, a nonwoven fabric, or the like can be suitably used.
[0023]
On the other hand, a tube for controlling the flow rate of the chemical solution is connected to the tip of the outflow portion. The tube may have micropores, and the chemical solution injection speed may be set by utilizing the increase or decrease in resistance by changing the inner diameter or length of the micropores. The shape of the micropores is not particularly limited as long as it is uniform over the entire length of the micropores. As a material of the tube, synthetic resins such as polyolefin, polyvinyl chloride, polyacetal, polyester, polyamide resin, polyurethane, polystyrene, and polycarbonate can be used, but are not limited thereto.
[0024]
A clamp, a three-way cock, or the like may be provided in the middle of the tube as a passage opening / closing member for opening / closing the passage as needed. In short, any material may be used as long as it allows or blocks the flow of the chemical solution flowing in the tube.
[0025]
A connecting device is provided at the other end of the tube, and a venous needle or the like is connected to the human body through the connecting device. The connector may be provided with a check valve for preventing the chemical solution from flowing backward due to venous pressure or the like.
[0026]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of one embodiment of a continuous injector. FIG. 2 is an enlarged cross-sectional view of the balloon portion of the continuous infusion device shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view of the balloon portion showing a state in which the continuous infusion device shown in FIG.
[0027]
As shown in FIG. 1, the continuous injector according to the present invention comprises a balloon portion A and a drug solution outlet portion B.
[0028]
The balloon portion A is a portion that accommodates the drug solution and a driving portion that moves the drug solution to an injection point of a human body. As shown in FIG. 2, the balloon portion A has a balloon 1, a drug solution inflow portion 2 tightly fixed to one end of the balloon 1, and a closed end 3a provided inside the balloon. A cylindrical member 3 tightly fixed to the other end of the housing, a housing 4 that accommodates the balloon 1, and the medical solution inlet / outlet 2 fixed to one end, and a position facing the medical solution inlet / outlet 2 fixed to the housing 4. A rod-shaped shaft 5 is provided inside and is housed in the tubular member 3.
[0029]
The balloon 1 has a tubular shape, one end of which is a drug solution inlet / outlet 2, and the other end of which is provided with O-rings 6, 6 ′ on an open end 3 b of a tubular member 3 having a closed end 3 a provided inside the balloon 1. It is tightly fixed in a liquid-tight manner by such a sealing means. The O-rings 6 and 6 ′ may be provided with annular grooves at each of the chemical liquid inlet / outlet portion 2 and the opening end 3 b of the tubular member 3, and fitted into the annular grooves.
[0030]
The balloon 1 is preferably made of a high-toughness material which has high elasticity and is not easily damaged by an external action. Further, a transparent or translucent material is preferable so that the state of the drug solution filled in the balloon can be seen from the outside. As such a material, silicone rubber or the like is preferable. However, the present embodiment is not particularly limited.
[0031]
The balloon 1 can be of various sizes depending on the amount of the drug solution injected into the patient, the injection time, and the like, and is not particularly limited. The thickness is 0.1 to 5 mm, and the length is 3 to 30 cm.
[0032]
The housing 4 for storing the balloon 1 prevents the balloon 1 from being damaged by touching an external sharp object, and is provided outside when a leak occurs from the balloon 1 due to a defect such as a pinhole of the balloon 1 itself. It functions to seal the chemical so that the chemical does not scatter. However, if the inside is completely airtight, the inside air is compressed as the liquid medicine is injected into the balloon 1, the pressure inside the housing 4 increases, and the liquid medicine cannot be injected to a certain degree or more. Occurs. Therefore, it is preferable to provide a water-repellent ventilation filter 7 that allows gas (air) outside the housing 4 to flow and does not allow liquid (chemical liquid) to pass through. Examples of the material of the water-repellent ventilation filter 7 include polyester and polytetrafluoroethylene.
[0033]
The housing 4 has a cylindrical shape, and its size is selected according to the size of the balloon 1 when inflated. It is preferable to provide a slight clearance between the balloon 1 and the housing inner surface 4 'when the filling of the balloon 1 with the drug solution is completed (when the balloon 1 is inflated to the maximum), and the balloon surface closest to the housing inner surface 4' and the housing inner surface thereof It is preferable that the clearance with 4 ′ is in the range of 2 to 10 mm. If it is less than 2 mm, depending on the carrying method, the surface of the closest balloon hangs down due to its own weight and comes into contact with the inner surface 4 ′ of the housing, which may cause friction with the inner surface 4 ′ of the housing when the balloon 1 is contracted. If it exceeds 10 mm, the housing 4 is unnecessarily large in a portable continuous injector which is originally desired to be small in size. However, it is not limited to such a numerical range as long as the balloon 1 and the housing inner surface 4 'do not come into contact with each other regardless of how the continuous injector is carried. The housing 1 is preferably made of a transparent material so that the state of injection of the drug solution can be visually observed from the outside, and is preferably made of a synthetic resin such as polyvinyl chloride, polypropylene, or polycarbonate.
[0034]
A rod-shaped shaft 5, which is a feature of the present invention, is provided in the housing 4 at a position facing the liquid medicine outlet 2 fixed to the housing 4, and the tip of the rod-shaped shaft 5 is provided inside the cylindrical member 3. Have been.
[0035]
The length of the rod-shaped shaft 5 is preferably slightly shorter (2 to 50 mm) than the length of the tubular member 3. When the length of the rod-shaped shaft 5 is longer than the cylindrical member 3, the closed end 3a of the cylindrical member 3 slid in the longitudinal direction C at the time of filling the liquid medicine comes into contact with the tip of the rod-shaped shaft, and Since the inflation pressure of the balloon 1 is applied, the rod-shaped shaft 5 may be bent or broken, which is not preferable. If the length of the rod-shaped shaft is about slightly shorter (2 to 50 mm) than the length of the cylindrical member 3, the closed portion 3a of the cylindrical member 3 does not come into contact with the tip of the rod-shaped shaft, and The inflating pressure of the balloon 1 is applied around the base of the rod-shaped shaft 5 (the position where the rod-shaped shaft is fixed to the housing 1) at the opening end 3b, and the inflating pressure of the balloon 1 is dispersed to the housing 4, which is preferable.
[0036]
Further, the cylindrical member 3 slides on the rod-shaped shaft 5 accompanying the movement of the balloon 1, and a scale is provided on the rod-shaped shaft 5 because the relationship between the position and the amount of the chemical solution remaining in the balloon 1 is constant. Thus, the outflow amount of the chemical solution can be confirmed.
[0037]
It is preferable to provide a clearance between 0.5 mm and 9 mm between the rod 3 and the cylindrical member 5 so that the rod 3 can slide on the cylindrical member 5. If a clearance larger than 9 mm is provided, the housing will be slightly displaced in the radial direction D due to the clearance when the liquid medicine is completely filled (when the balloon is inflated to the maximum), and additionally, the balloon 1 will sag due to its own weight. It is not preferable because the balloon surface closest to the inner surface 4 'may come into contact with the inner surface 4' of the housing. However, the degree of sagging of the balloon 1 due to its own weight depends on the material of the balloon, and is not particularly limited to this range unless the balloon surface and the housing inner surface 4 'come into contact with each other.
[0038]
The chemical liquid inlet / outlet part 2 is formed of a Y-shaped pipe having an inflow part 2a and an outflow part 2b branched, and is preferably made of a hard synthetic resin such as polycarbonate.
[0039]
As shown in FIGS. 4 and 5, the inflow passage 2a is composed of a stationary disk 8, a polyolefin duckbill check valve 9, a sealing means 10, and a luer tapered adapter 11 in this order from the balloon 1. I have. The check valve 9 of the duckbill type has a structure in which the closed end of the valve has a shape like a platypus beak, and allows the inflow of the drug solution into the balloon 1 but blocks the flow in the reverse direction. . The fixed disk 8 supports the substrate of the check valve 9 and has a passage through which the chemical solution flows into the balloon 1, and an opening is formed in the middle of the passage to join the passage of the outflow portion 2b. ing. The substrate of the check valve 8 is sandwiched between the fixed disk 8 and the adapter 11, but it is preferable to provide an O-ring as a sealing means 10 between the check valve 9 and the adapter 11. The adapter 11 is a substantially cylindrical connecting tool whose inner surface is formed in a tapered shape. A screw 12 for connecting a syringe for injecting a drug solution into the balloon 1 is formed on the outer periphery of the end of the adapter 11. As shown in FIG. 5, the syringe 17 of the syringe is fitted to the tapered inner peripheral surface of the adapter 11, connected to the adapter 11 by screwing, and injecting the drug solution into the balloon 1.
[0040]
On the other hand, a tube 13 having fine holes for controlling the flow rate of the chemical solution is inserted into the outflow portion 2b and adhesively connected thereto.
[0041]
1 is a tube 13 for controlling the flow rate of the chemical solution discharged from the balloon via the outflow portion 2b, a clamp 14 provided for opening and closing a flow path in the middle of the tube 13, and an outflow portion. It consists of a luer tapered connector 15 provided on the opposite end of the tube 13 connected to 2b.
[0042]
The tube 13 has a circular fine hole, and the chemical solution injection speed can be set by using the increase and decrease of the resistance caused by changing the inner diameter and length of the fine hole. The micropores preferably have an inner diameter of 30 to 500 μm and a length of 1 to 100 cm. If the inner diameter is less than 30 μm, the flow of the chemical solution may be stopped due to the mixing of air in the chemical solution. In addition, a chemical solution in which refuse floats or easily solidifies may block micropores. If the inner diameter exceeds 500 μm, it may be difficult to control the flow rate of the chemical solution. However, the shape of the fine holes may be uniform over the entire length of the fine holes, and is not limited to a circular shape. In order to control the flow rate in the tube having the micropores, a length of at least 1 cm is required. However, in this embodiment, since the clamp 14 and the luer taper-like connecting device 15 are provided, the total length of the tube is Requires a minimum of 5 cm.
[0043]
The outer shape of the tube 13 varies depending on the material and the diameter of the micropores. Generally, when the inner diameter of the tube is small, the ratio of the outer diameter to the inner diameter is large, so that the influence of the temperature of the outside air does not reach the inside of the tube. Is preferred.
[0044]
The material of the tube 13 is not particularly limited, but is made of a flexible synthetic resin having high flexibility so as not to bend in any use mode of a patient, for example, made of a soft vinyl chloride resin. Tubes are preferred.
[0045]
A detachable vein needle 16 or the like is connected to the luer taper-like connecting device 15 as a human body mounting device. The connector may be provided with a check valve for preventing the chemical solution from flowing backward due to venous pressure or the like.
[0046]
Next, a method of using the continuous injector according to the present invention will be described with reference to FIGS.
[0047]
To inject the drug solution into the balloon 1, a syringe 17 of a syringe is inserted into the adapter 11 of the inflow portion 2a, the syringe 17 is fitted to the inner surface of the tapered adapter 11, and the two are connected by screwing. At this time, it is necessary to stop the clamp 14 so that the chemical solution does not flow into the human body.
[0048]
As the balloon 1 is filled with the drug solution, the balloon 1 expands in the radial direction D together with the longitudinal direction C while sliding the cylindrical member 3 in the shape of a rod 5. At this time, since the cylindrical member 3 is guided by the rod-shaped shaft 5, the position of the balloon 1 does not deviate from the center regardless of the direction of the continuous injector, and the balloon 1 is placed on the inner surface 4 'of the housing. The contact can be expanded without being affected by friction or the like. At this time, the air existing in the housing 4 is expelled to the outside of the housing 4 through the water-repellent filter 7. When the liquid medicine is filled to a certain extent, the cylindrical member 3 comes into contact with the vicinity of the root of the rod-shaped shaft 5, the progress of the balloon 1 in the longitudinal direction C is restricted, and the balloon 1 expands only in the radial direction D. When the filling of the chemical is completed, the balloon 1 is fixed at a predetermined position while leaving a slight clearance between the balloon 1 and the inner surface 4 'of the housing.
[0049]
When the prescribed amount of the drug solution has been filled, the syringe 17 is withdrawn from the adapter 11, and the continuous injector is attached to a part of the patient's body or inserted into a pocket of clothing according to the patient's convenience, depending on the injection point of the patient. Be carried. After that, it is connected to the venous needle 16 or the like via the connector 15, and after performing a predetermined operation such as priming, the medical solution is injected into the patient's body. When the injection of the drug solution into the patient's body is started, the balloon 1 starts to contract, and the cylindrical member 3 slides in the direction opposite to the direction C while being guided by the rod-shaped shaft 5. At this time, regardless of the direction of the continuous injector, the position of the balloon 1 does not deviate from the center of the housing 4 and the balloon 1 contracts without contact with the inner surface 4 ′ of the housing without being affected by friction or the like. can do.
[0050]
【The invention's effect】
As is apparent from the above, in the continuous infusion device of the present invention, the tubular member is always provided inside the tubular member and installed in the housing when the balloon is inflated or deflated by any portable method. Since the balloon is guided by the rod-shaped shaft 5, the position of the balloon does not deviate from the center, and therefore, the balloon does not receive an action such as friction with the inner surface of the housing. Further, by providing a clearance between the balloon and the inner surface of the housing that have been fully inflated when the liquid medicine is completely filled, the balloon can be caused by a slight displacement in the radial direction of the balloon due to the clearance between the rod-shaped shaft and the cylindrical member. Since the contact between the inner surface of the housing and the balloon closest to the inner surface of the housing at the time of completion of the filling of the liquid medicine does not cause the contact between the balloon and the inner surface of the housing which may occur due to the weight of the balloon, the balloon may be subjected to friction with the inner surface of the housing. It can be shrunk without. Therefore, it is possible to inject the drug solution into the patient continuously at a constant speed for a long time with little accuracy, regardless of the state, without causing a change in the balloon internal pressure due to uneven inflation and deflation. .
[Brief description of the drawings]
FIG. 1 is a plan view showing an embodiment of a continuous injector according to the present invention.
FIG. 2 is an enlarged sectional view of a balloon portion of the continuous injector shown in FIG.
FIG. 3 is an enlarged cross-sectional view of a balloon portion showing a state when the continuous infusion device shown in FIG. 1 is filled with a drug solution.
FIG. 4 is an explanatory view when injecting the drug solution in the syringe into the balloon, showing the state in which the syringe and the balloon are not connected.
FIG. 5 is an explanatory diagram when a drug solution is filled into the balloon from the syringe shown in FIG. 4;
FIG. 6 is an enlarged cross-sectional view of a balloon portion showing a state when a medical solution is filled in a conventional continuous injector.
[Explanation of symbols]
1. balloon
2a. Inflow channel
2b. Outflow tract
3. Tubular member
3a. Closed end
3b. Open end
4. housing
4 '. Inner surface of housing
5. Rod-shaped shaft
6. O-ring
7. Water repellent filter
8. Fixed disk
9. Check valve
10. adapter
11. Fitting
12. screw
13. tube
14． Clamp
15. Fitting
16. Venous needle
17． Syringe

Claims (4)

(A) a balloon made of a rubber-like elastic material for containing a liquid under pressure;
(B) a drug solution inlet / outlet portion closely fixed to one end of the balloon;
(C) a tubular member having a closed end provided inside the balloon and having an open end closely fixed to the other end of the balloon;
(D) a housing that houses the balloon and has the drug solution inlet / outlet fixed at one end; and (e) a housing that is provided at a position facing the drug solution inlet / outlet portion fixed to the housing and slides on the cylindrical member. A rod-shaped shaft that is freely mounted,
And (f) a continuous injector comprising a drug solution outlet comprising a tube for flow control connected to the drug solution inlet / outlet. The continuous injection device according to claim 1, wherein a clearance between the cylindrical member and the rod-shaped shaft is in a range of 0.5 to 9 mm. The continuous injector according to any one of claims 1 to 2, wherein a clearance between the inner surface of the housing and the balloon which comes closest to the inner surface of the housing when the filling of the drug solution is completed is in a range of 2 to 10 mm. The continuous drug solution injector according to any one of claims 1 to 3, wherein a scale is provided on the rod-shaped shaft for visually checking a charged amount of the drug solution.

Images