JP3608984B2 - Chemical solution continuous infusion device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chemical solution continuous infusion device used for anesthesia for postoperative pain, administration of analgesics and administration of anticancer agents.
[0002]
[Prior art]
Administration of the drug solution into the body is performed via a catheter placed in the body or via a needle punctured into a vein or the like, and infusion is performed at a constant rate in order to keep the concentration constant. Is called. Devices that are connected to catheters and needles to continuously inject a drug solution into the body can be broadly divided into mechanical types and disposable types.
[0003]
Most of the disposable types are devices (Japanese Patent Laid-Open No. 6-296688) for injecting a chemical solution into a rubber balloon and injecting the chemical solution using the contraction force of the balloon as a driving force. Generally, the instrument is composed of a chemical solution inlet and a balloon, a housing that covers the balloon at the chemical solution outlet, a tube for liquid feeding, and a flow rate control tube. When using a chemical solution continuous infusion device, the balloon is first expanded by injecting the chemical solution into the balloon from the chemical solution inlet. The expanded balloon pressurizes the chemical solution in an attempt to contract due to the elastic force of the material, and this becomes a driving force for feeding the chemical solution. The flow rate is adjusted by a flow rate control tube. When the drug solution filled in the balloon is exhausted, the balloon returns to the shape before the drug solution is injected, the contraction force is lost, and the liquid feeding is finished. Since the disposable type is compact, portable and inexpensive, it is more popular than the mechanical type and is often used. However, there has been a problem that a transient increase in the chemical injection rate occurs just before the end of the injection.
[0004]
An apparatus (Japanese Patent Laid-Open No. 7-194701) in which a constant load spring is attached to a gasket and a chemical liquid is injected by the extension force of the spring for the purpose of suppressing a temporary increase in the injection speed just before the end of the chemical liquid injection is also known. ing. When a constant load spring is used, there is no increase in the chemical injection rate just before the end of the chemical, but the size of the tool increases, so the portability decreases, and the disposal process after use because the spring is metal. Was troublesome. Other injection devices using negative pressure have been developed for the same purpose. Although the transient rise of the chemical solution injection flow rate just before the end of the chemical solution injection was suppressed, the extra pressure was required to provide the negative pressure generating mechanism, and the portability was not good.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a compact chemical solution continuous infusion device in which a transient increase in flow rate does not occur just before the end of chemical solution administration.
[0006]
[Means for Solving the Problems]
That is, the present invention is slidable in a chemical solution continuous infusion device having a chemical solution injection port, a balloon, and a chemical solution outlet, filling the balloon with a chemical solution, expanding and deforming the balloon, and using the contraction force of the balloon as the driving force of the liquid supply The chemical liquid continuous infusion device is characterized in that the feeding of the chemical liquid filled in a state expanded from the shape of the balloon before the chemical liquid injection is completed by the inner cylinder . Moreover, it is a chemical | medical solution continuous injection | pouring apparatus with which the balloon raw material is expanded beyond the yield point when liquid supply of a chemical | medical solution is complete | finished.
[0007]
The flow rate of the chemical solution is determined according to Hagen-Poiseuille's law, and the flow rate of the liquid flowing through the circular tube is determined by the viscosity of the flowing liquid, the diameter of the tube, and the pressure difference. In the case of a balloon type chemical solution continuous infusion device, the main variable factor involved in the flow rate change is a pressure change, and the contraction force of the balloon changes depending on the remaining amount of the chemical solution. In other words, the main cause of the change in the flow velocity is that the stress-strain curve of the material is not constant in the balloon use range. The stress-strain curve of the balloon material varies depending on the type of material, but it is generally steep up to the first inflection point (yield point), then gradually rises from there and then steep again from the next inflection point (break point). And breaks. In the conventional drug solution continuous infusion device using a balloon as a driving force, the balloon shape before filling with the drug solution and at the end of the administration is not stressed and distorted. Therefore, the first inflection point is included in the use range of the balloon. For this reason, when the drug solution in the balloon decreases at a constant speed and the strain decreases, the pressure of the balloon rapidly changes in the vicinity of the inflection point, so that the flow rate changes. According to the present invention, since the liquid delivery is completed in a state where it is expanded from the vicinity of the inflection point (yield point) of the stress-strain curve of the balloon in which the chemical liquid flow rate starts to rise, there is no temporary increase in the chemical liquid. If the material to be inserted into the balloon in order to finish the delivery of the balloon in the expanded state is a part that is conventionally provided outside the balloon (chemical solution inlet, chemical solution outlet, etc.), it is compact without taking up any special space. Can be.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
The drug solution is first injected into the balloon from the drug solution inlet. When the drug solution is injected, the balloon expands. Thereafter, an inner cylinder or the like equipped with a chemical solution inlet is inserted into the balloon to obtain an excluded volume. The drug solution is sent from the inside of the balloon through the drug solution outlet. At the end of drug administration, the balloon is deformed by the volume of the cylinder inserted therein.
[0009]
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows an automatic chemical solution injection device according to the present invention. The device is slidable and liquid-tightly fixed to the balloon (1), the housing (4) to which the balloon (1) is mounted, the balloon gripping tool (2) to which the lid (5) is connected, and the balloon gripping tool (2). An inner cylinder (3), a lid (5), and a liquid feeding tube (6). The inner cylinder (3) has a chemical solution inlet (7) and a chemical solution outlet (8) connected to the liquid feeding tube (6). The chemical solution injection port (7) can be connected to a syringe and has a one-way valve (9). The inner cylinder (3) has an O-ring (10) for sliding in a liquid-tight manner with the balloon gripping tool (2). The balloon (1) is preferably made of silicone rubber or isoprene rubber. The balloon (1) is preferably cylindrical or bathtub-shaped in order to expand evenly. The embodiment of FIG. 1 is cylindrical. The balloon (1) may be formed into a tubular shape by extrusion, and then welded on one side, may be formed by dipping, or may be formed by compression molding or the like. The balloon gripping tool (2) and the lid (3) are desirably formed by injection molding. The balloon gripping tool (2) is preferably designed in the shape of a rib or a bamboo shoot to connect the balloon (1). The connection between the balloon (1) and the balloon gripping tool (2) may be performed by bonding the connecting surface, or may be tightened from the outside of the balloon (1) with a balloon stopper (11) such as a tie band.
[0010]
The housing (4) is preferably molded by blow molding, but may be injection molding or the like. It is desirable to be transparent so that the state of the balloon can be confirmed. In addition, it is desirable to print a scale or the like in order to check the remaining amount of the chemical in the balloon. The liquid feeding tube (6) is preferably thick so as to have excellent kink resistance. Furthermore, it is desirable to be transparent so that air bubbles and the like can be confirmed, and the material used is preferably polyvinyl chloride, polyurethane or the like. Next, a method of using the present invention will be described with reference to FIG. The drug solution is injected and filled into the balloon (1) by connecting a syringe or the like to the drug solution injection port (7). Next, the inner cylinder (3) is pushed and fixed to the balloon gripping tool (2). The chemical liquid is fed through the chemical liquid outlet (8) and the liquid feeding tube (6) by the contraction force of the balloon (1). The balloon (1) ends the liquid supply in the expanded state by the volume into which the inner cylinder (3) has been inserted.
[0011]
[0012]
FIG. 2 shows the result of comparing the change over time of the flow rate of the present invention with that of the conventional chemical solution continuous injector. The experiment was performed with the liquid injected into the balloon 2 (16) of the present invention and with the liquid not injected. The experimental system was kept at 37 ° C. The flow rate was measured with an ultrasonic blood flow meter. As shown in FIG. 2 , in one embodiment according to the present invention, the flow rate is substantially constant until the end of administration, and an increase in the flow rate just before the end of liquid feeding, which has been a problem in the past, is suppressed.
[0013]
【The invention's effect】
As is clear from the above, the chemical solution continuous infusion device of the present invention that terminates the delivery of the chemical solution in a state expanded from the shape of the balloon before the chemical solution injection is a change in the flow rate immediately before the end of the liquid delivery, which has been a problem until now. Suppress. Since there is no increase in the flow rate just before the end of liquid feeding, the set flow rate can be secured even with a small amount of chemical solution filling.
[Brief description of the drawings]
FIG. 1 shows an embodiment of the present invention. This shows that the medicinal solution administration is finished before the balloon returns to the initial state by sliding the inner cylinder.
FIG. 2 shows the change in flow rate over time between the present invention and a conventional continuous injector.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Balloon 2 Balloon gripping tool 3 Inner cylinder 4 Housing 5 Lid 6 Liquid feeding tube 7 Chemical liquid inlet 8 Chemical liquid outlet 9 One-way valve 10 O-ring 11 Balloon stopper

Claims (2)

In a chemical liquid continuous infusion device that has a chemical liquid injection port, a balloon, a chemical liquid outlet, fills the balloon with a chemical liquid, expands and deforms the balloon, and uses the contraction force of the balloon as the driving force of the liquid supply , A chemical solution continuous infusion device characterized in that the feeding of a chemical solution filled in a state expanded from the shape of a balloon before the chemical solution is injected is finished. 2. The chemical solution continuous infusion device according to claim 1, wherein the balloon material is expanded beyond the yield point when the delivery of the chemical solution is completed.

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