JPS625173Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a body fluid processing circuit for treating body fluids such as blood and ascites.

BACKGROUND ART In devices that lead body fluids such as blood and ascites out of the body and process them, circuit devices for guiding the body fluids to the device and returning them back into the body are widely used. This circuit device is constructed by providing a pressure detection mechanism, a pressure adjustment mechanism, a bubble removal mechanism, a filtration mechanism, a sample collection or drug addition mechanism, etc. as necessary in addition to the tube body that serves as a flow path for body fluids. Among these mechanisms, a defoaming device called a drip chamber uses air in an air reservoir to remove bubbles and operate a pressure gauge. In conventional body fluid treatment, heparin is added to the body fluid to prevent coagulation (coagulation in the case of blood) or urokinase is added to the body fluid to dissolve clots, so even if the body fluid comes into contact with air, Since almost no coagulation occurred, it was not a problem to provide an air reservoir in the drip chamber.

However, in recent years, problems with the use of anticoagulants and the like have been pointed out to be an increase in the physiological burden on patients and an increased tendency for bleeding in patients (dialysis after surgery, dialysis for women during menstruation, etc.). It is increasingly said that reducing the amount or not using it is desirable. When treating body fluids by reducing or not using an anti-coagulant (hereinafter referred to as "reducing the amount"), since body fluids tend to coagulate when they come into contact with air, it is important to avoid areas where air exists, such as air reservoirs, in the circuit. should be strictly avoided. Therefore, in a pressure detection device using a drip chamber, body fluid comes into contact with air and blood clots occur. In addition, if air bubbles enter the circuit, they must be removed, but using a drip chamber equipped with an overmesh body, which has been conventionally used to remove air bubbles, will result in an overmesh body. Air bubbles may adhere to the surface and cause blood clots.

The present invention improves these shortcomings by housing fluid-tightly a body fluid flow tube made of a flexible material that expands and contracts under the pressure of the body fluid flowing inside, inside a container made of a non-flexible material. A pressure monitoring device is formed by forming a sealed chamber filled with fluid between the body fluid distribution pipe and the container, and a pressure gauge is attached to a conduit connected to the sealed chamber, and a body fluid inlet in the upper part. A defoaming device is directly connected in series with an air bubble removal pipe, a body fluid outlet at the bottom, and a mesh body whose surface is made of a material to which air bubbles do not adhere. This is a body fluid processing circuit.

The defoaming device used in the body fluid treatment circuit of this invention does not have air bubbles attached to the surface of the overmesh body, so there is no need to worry about blood clots.Therefore, even when body fluids are treated by reducing the amount of anti-coagulant, there is no blood clot and it can be used with confidence. can do.

A hydrophilic polymer having a receding contact angle with water of 45° or less, which is described in JP-A-50-683, is preferably used as a material for the overmesh body to which air bubbles do not adhere. Moreover, this polymer preferably has excellent biocompatibility.

Examples of such polymers include polymers of hydroxyethyl methacrylate, hydroxypropyl methacrylate, methoxyethyl acrylate, ethoxyethyl acrylate, and diacetone acrylamide. Furthermore, the above monomers and hydroxyethyl acrylate, hydroxypropyl acrylate, diethylene glycol (meth)
Acrylate, dimethylaminoethyl (meth)acrylate (and their quaternized salts), 2-hydroxy-3-(meth)acryloylpropyldimethylamine (and their quaternized salts), (meth)acrylic acid, (meth) ) acrylamide, methyl (meth)acrylamide, ethyl (meth)
Copolymers of acrylamide, propyl (meth)acrylamide, dimethyl (meth)acrylamide, vinylpyridine, vinylpyrrolidone, etc. with other hydrophobic monomers can also be used.

It is preferable to create a supermesh body by coating a conventional supermesh body with these polymers, but it is also possible to create a supermesh body using these polymers as materials. The most preferred hydrophilic polymers for coating the permesh are polymers prepared from hydroxyethyl acrylate, hydroxypropyl acrylate, vinylpyrrolidone, or acrylamides. Further, it is often effective to use a polymer of monomers containing a quaternary ammonium salt or a group that easily becomes a quaternary ammonium salt. This has the advantage that heparin can be immobilized.

Almost any water-soluble monomer can be conveniently used to form a coating with a receding contact angle to water of 45° or less by graft polymerization. Note that the temperature at which the receding contact angle with respect to water is measured is 25°C.

The inner surface of the supermesh body can be coated with a hydrophilic polymer having a receding contact angle of 45° or less with respect to water by, for example, a graft polymerization method or a coating method. The graft polymerization method is r
This is a method in which active points such as radicals are generated on the inner surface of a supermesh body using radiation, electron beams, ozone, etc., and a hydrophilic polymer monomer is brought into contact with the active points and polymerized to form a coating. Generation of active sites is carried out in the presence or absence of the monomer. The coating method is a method in which a hydrophilic polymer is synthesized in advance, this solution or latex is applied to the inner surface of a supermesh body, and the solvent is evaporated to form a coating of the hydrophilic polymer. In the solution coating method, in order to improve adhesion, the inner surface of the overmesh body is treated with chromium sulfate and sodium chloride.
It may be preferable to perform pretreatment such as naphthalene treatment or ultraviolet treatment. In terms of workability in forming the coating, the above-mentioned melting method is most preferred, but in consideration of the properties of the resulting coating, the grafting method is preferred.
Improvements in bubble adhesion and affinity with biological cells in the hypermesh body can be achieved sufficiently even if the inner surface coating with hydrophilic polymer is extremely thin, so taking physical properties into consideration, the coating thickness is set to 0.1. mm or less is preferable. A thickness of the order of 10 mμ is particularly suitable.
In order for such a thin coating layer to be stable, when using a coating method, the hydrophilic polymer must be
It is required to have a molecular weight of 10,000 or more, preferably 30,000 or more, and be water-insoluble.

Next, the present invention will be explained with reference to the drawings.

Fig. 1 shows an embodiment of a defoaming device used in a body fluid treatment device of the present invention, in which the defoaming device 1 has an inlet 3 for body fluid and an outlet 5 for bubbles at an upper portion 2, and has an outlet 4 for body fluid at a lower portion. A mesh body 6 is attached inside 8 of the defoaming device 1,
The surface of the overmesh body is coated with the above-mentioned polymer (e.g., polyhydroxyethyl methacrylate). The pore size of the mesh of the overmesh body 6 must be large enough to prevent air bubbles present in the body fluid from passing through, while at the same time preventing red blood cells of blood from passing through or being damaged.
When the amount of anticoagulant is reduced, the degassing device 8 is filled with body fluid (e.g., blood), there is no air in the air reservoir, and physiological saline is filled at the tip 9 of the air bubble extraction tube 5. When air bubbles enter the degassing device 8, which has a large cross-sectional area, from the narrow body fluid inlet 3, the flow velocity becomes small according to Bernoulli's theorem,
Most of the air bubbles do not flow down with the body fluid, but gather in the upper part 2 of the degassing device 1, and can be removed by opening the clamp 7 of the air bubble removal tube 5.
The air bubbles that flow down together with the blood are prevented from passing through by the mesh body 6 and are taken out to the outside through the upper part 2 without adhering to the mesh body 6.
The liquid rises to the surface and is taken out through the extraction pipe 5.

FIG. 2 shows another embodiment used in the body fluid treatment circuit of the present invention, in which the upper part 2 of the defoaming device 1 is sloped to make it easier for air bubbles to escape from the extraction tube 5.

FIG. 3 is an example of a body fluid processing circuit according to the present invention, which includes a defoaming device and a pressure monitoring device. This pressure monitoring device consists of a container 10 and a pressure gauge 15. Inside the container 10, there is a body fluid flow pipe 11, at least a part of which is made of a flexible material. It communicates with an inlet 13 (blood dialyzed by an artificial kidney is introduced into this inlet) and an outlet pipe 16 for body fluids. A closed chamber 12 formed between the container 10 and the body fluid flow pipe 11 is filled with a compressible or non-compressible fluid such as air, physiological saline, or glucose. A conduit 14 is provided in the sealed chamber 12.
is provided and communicates with the pressure gauge 15.

The body fluid passing through the body fluid flow pipe 11 expands or contracts the body fluid flow pipe 11 according to its pressure, and the pressure of the fluid in the sealed chamber 12 changes according to the change in volume, so the fluid pressure in the closed room 12 changes. can be detected. Therefore, the fluid of the pressure detection mechanism and the body fluid do not come into direct contact with each other, and even when air is used as the fluid, the body fluid and the air do not come into contact with each other. Pressure gauge 15
Although various types of pressure transducers can be used, a pressure transducer that converts pressure electrically is preferably used. Further, in order to transmit pressure accurately, it is better to make the conduit 14 as short as possible. In the unlikely event that a leak occurs in the body fluid flow pipe 11, physiological saline or glucose solution are safer than air as the fluid in the sealed chamber 12, and liquid is an incompressible fluid. It is more preferable because it is excellent as a pressure transmission means. The material for the body fluid flow tube 11 may be one in which at least a part of the material is made of a flexible material, as long as it has enough flexibility to be sensitive to the pressure of the body fluid passing through the tube, such as silicone, silicone, etc.
Various materials such as polyurethane, soft vinyl chloride, natural or synthetic rubber can be used. The non-flexible material for the container 10 only needs to be rigid enough not to absorb changes in the pressure of the fluid within the sealed chamber, and various plastic materials such as polypropylene, polyethylene, hard vinyl chloride, polycarbonate, etc., or metals can be used. . The body fluid flow pipe 11 is made of a flexible material and utilizes the expansion and contraction of the flexible material, so it is desirable to use it in an area where the flow body fluid exhibits positive pressure or slight reduced pressure. If the degree of decompression of the circulating body fluid becomes large, the flexible material portion will collapse to a large extent, resulting in the closure of the flow path, which is undesirable. Therefore, a circuit in which a pressure monitoring device and a defoaming device are connected in series as shown in FIG. 3 is particularly useful as a circuit for treating body fluids in the positive pressure and mildly reduced pressure ranges.

In the body fluid treatment apparatus of the present invention, it is preferable to provide the defoaming device after the pressure monitoring device, as shown in FIG. 3, but it can also be provided in front of the pressure monitoring device.

As described above, the body fluid treatment circuit of the present invention is particularly effective when treating body fluids with a reduced amount of anticoagulant, and is useful for hemodialysis circuits, oversized artificial kidney circuits, ascites treatment circuits, and other body fluid treatment circuits. It is useful for circuits.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a defoaming device used in the body fluid processing circuit of the present invention, and FIG. 2 is a longitudinal sectional view showing another example of the defoaming device used in the bodily fluid processing circuit of the present invention. FIG. 3 shows a longitudinal sectional view of a body fluid treatment circuit in which a defoaming device and a pressure monitoring device are provided in series. 1... Defoaming device, 2... Upper part of the defoaming device, 3...
...body fluid inlet, 4...body fluid outlet, 5...bubble outlet tube, 6...overmesh body, 7...clamp.

Claims (1)

[Scope of utility model registration request] A body fluid distribution tube made of a flexible material that expands and contracts under the pressure of the body fluid flowing inside is fluid-tightly housed in a container made of a non-flexible material, and fluid is created between the body fluid distribution tube and the container. a pressure monitoring device formed by forming a sealed chamber filled with air and a pressure gauge attached to a conduit connected to the sealed chamber, a body fluid inlet and a bubble outlet in the upper part, and a body fluid outlet in the lower part. What is claimed is: 1. A body fluid processing circuit, characterized in that a defoaming device is connected in series, the defoaming device having a mesh body whose surface is made of a material to which air bubbles do not adhere.