JPS6137249A - Membrane type artificial lung sterilized by rays - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention incorporates a porous hollow fiber membrane of polyethylene acid,
This invention relates to a model artificial lung device sterilized with gamma rays.

[Prior art] As an artificial lung using a hollow fiber membrane, for example, US Pat.
No. 794488, JP-A-54-113001118,
Various proposals are already known, such as Japanese Patent Laid-Open No. 58-155882.

These artificial lungs use gas-permeable homogeneous hollow fiber membranes such as silicone or microporous hollow fiber membranes made of hydrophobic polymers such as polyolefin to bring gas and blood into contact through the hollow fiber membrane surface. This allows gas exchange to take place between them. The method of contact between gas and blood involves flowing blood into the hollow part of a hollow fiber membrane and flowing gas outside the hollow fiber membrane (internal perfusion method).
There are two methods: and, conversely, a method in which gas is allowed to flow through the hollow part of the hollow fiber membrane and blood is allowed to flow outside (external perfusion method).

An artificial lung using a homogeneous membrane is advantageous in extracorporeal blood circulation for a long time because there is no leakage of blood or the like. However, gas exchange performance is low because gas permeation occurs through dissolution and diffusion in the membrane.On the other hand, in oxygenators using porous membranes, gas permeates through the pores in the membrane in a volumetric flow. Therefore, the gas exchange performance is much better than that of a homogeneous membrane, especially in JP-A-52-1582.
The polyolefin-based microporous hollow fiber membranes disclosed in No. 7 and JP-A No. 57-813114 exhibit excellent functionality when applied to artificial lung devices due to the characteristic structure of their micropores. be done.

When using such an artificial lung device for gas exchange with the blood of a living body, it is important that it is sterilized and thoroughly cleaned in advance to prevent bacteria and disinfectants from entering the blood. It is essential to prevent this.

Conventionally, gas sterilization methods such as ethylene oxide gas or sterilization methods using solvents such as formalin have been adopted as sterilization treatment after manufacturing oxygenator devices, and the oxygenator lungs sterilized in this way are packaged. It was being shipped to treatment facilities such as hospitals. It is not desirable for the safety of the living body to have the drugs used for sterilization remaining inside the artificial lung device, especially in the blood flow path, so treatment facilities use sterile water to sterilize these drugs before use. It was necessary to thoroughly clean it so that no residue remained. Therefore, oxygenators that have been sterilized in this way cannot be used immediately and require large amounts of sterile cleaning water, which is one of the factors that hinders the efficient use of treatment equipment. was.

Conventionally, in addition to the above-mentioned sterilization methods, steam sterilization methods and sterilization methods using radiation such as gamma rays are known as methods for sterilizing medical devices. However, steam sterilization cannot be applied as a sterilization method for oxygenator devices containing porous hollow fiber membranes made of polyolefins such as polyethylene, which have poor heat resistance, because the hollow fiber membranes are deformed and destroyed by high temperatures. On the other hand, γ
The wire sterilization method enables sterilization through an extremely simple process, but steam sterilization is the best method for sterilizing an oxygenator device that has a hollow fiber membrane made of polyolefin, which is made up of many fine fibrils and has an extremely large internal surface area. As with the sterilization method, destruction of the shape of the micropores in the hollow fiber membrane or reduction in mechanical strength was expected, and this method was not considered to be an appropriate sterilization method.

[Problems to be Solved by the Invention] In view of the above circumstances, the inventors of the present invention have intensively investigated a sterilization method suitable for an oxygenator device incorporating a polyolefin porous hollow fiber membrane, and have surprisingly found the following. Artificial lung devices containing porous hollow fiber membranes made of polyethylene acid can be sterilized without damaging the hollow fiber membranes by limiting the amount of γ-ray irradiation within a specific range. I found out.

An object of the present invention is to provide an artificial lung device that has excellent oxygen uptake ability and carbon dioxide excretion ability, and that can be used immediately in treatment facilities without cleaning.

Another object of the present invention is to provide a novel sterilization method for an artificial lung device incorporating a porous hollow fiber membrane of polyethylene acid.

[Means for Solving the Problems] That is, the artificial lung device of the present invention incorporates a large number of hollow fiber membranes in the housing, and brings blood and oxygen-containing gas into contact through the hollow fiber membranes. An artificial lung for blood gas exchange, wherein the hollow fiber membrane is made of polyethylene and has a laminated structure in which micropores are interconnected from the inner wall surface to the outer wall surface of the hollow fiber membrane, and Artificial lung is 1.5~
It is characterized by being irradiated with 5.0 megarads of gamma rays.

[Preferred Mode for Carrying Out the Invention] The oxygenator of the present invention includes a large number of hollow fiber membranes disposed within a housing that forms the main body of the oxygenator, and the inside thereof has a blood flow path and a gas flow path. It is divided into: The housing is provided with at least an inlet and an outlet for blood, and an inlet and an outlet for oxygen-containing gas. The artificial lung device of the present invention may be of either the internal perfusion method or the external perfusion method described above, and there are various types of arrangement of the hollow fiber membranes in the housing. The arrangement mode is not particularly limited. As the housing and the fixing member for fixing the hollow fiber membrane in the housing, various materials can be used as long as they do not undergo significant deterioration due to irradiation with gamma rays and do not generate eluates. For example, as a housing material, Polystyrene, polycarbonate, etc. can be used for the fixing member, and polyurethane, epoxy resin, etc. can be used for the fixing member.

The hollow fiber membrane used in the oxygenator of the present invention is a porous membrane made of polyethylene, and has a laminated structure in which micropores are interconnected from the inner wall surface to the outer wall surface of the hollow fiber membrane. The one disclosed in Japanese Unexamined Patent Publication No. 57-Ei8114 is suitable. This polyethylene hollow fiber membrane has a porosity of 30 to 80% by volume, and the micropores are (1) microfibrils arranged in the fiber length direction and the...
These are strip-shaped micropores formed by nodules connected at almost right angles to the microfibrils, and (2) the average thickness & average length of the microfibrils is dw=0.02~ 0.3 μ, μ=0.5 to 3.0−.

(3) The average length IK of the knot in the fiber length direction is 0.1 to 1.0μ, and (4) the average convergence & of the strip-like micropores is Sa I
9 is dv/d+, l=0.3~5, jv/
It is specified by the relationship dv = 3 to 50-. Furthermore, the bubble point of the hollow fiber membrane in ethanol is 1-20Kg/C112
It is preferable that the value falls within the range of .

The artificial lung device of the present invention has a device main body configured as described above, and after washing with sterile water or the like if desired, γ
It is subjected to a sterilization process using a wire. In order to prevent re-contamination after sterilization, sterilization using γ-rays is preferably carried out after packaging the product in a polyethylene film or the like for shipping. The conditions for sterilization treatment with gamma rays are as follows:
This is carried out by irradiating gamma rays using a gamma ray irradiation source such as 60co at a temperature around room temperature. The irradiation atmosphere is
It does not particularly affect the sterilization process, and irradiation in the air may be sufficient. The optimum amount of γ-ray irradiation varies somewhat depending on the material of the housing forming the main body of the oxygenator, but the appropriate value is 1.5 to 5.0 megarads, preferably about 2.5 megarads.

If the γ-ray irradiation dose is less than 1.5 megarads, the sterilization process by γ-ray irradiation is insufficient, and if the γ-ray irradiation dose exceeds 5.0 megarads, the inside of the oxygenator This is not suitable because the hollow fiber membrane of polyethylene acid disposed in the membrane deteriorates, resulting in a decrease in mechanical strength, etc.

Polypropylene acid membranes are also known as porous hollow fiber membranes having a similar structure to the polyethylene acid hollow fiber membranes that can be used in oxygenator devices. However, in cases where polypropylene acid hollow fiber membranes are used, it is inappropriate to use gamma ray irradiation for sterilization because the polypropylene hollow fiber membranes deteriorate under normal conditions.

[Effects of the Invention] According to the present invention, the sterilized product has excellent oxygen uptake ability and carbon dioxide excretion ability, and can be used immediately in treatment facilities without cleaning before use. A processed artificial lung device is provided, and its practical value is extremely high.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 2 and Comparative Example 1.2 Polyethylene microporous hollow fiber membrane disclosed in the above-mentioned JP-A-57-Ei8114 or polypropylene microporous hollow fiber membrane 2000 having a substantially similar microporous structure
An artificial lung device having a structure in which 0 tubes were bundled together in a cylindrical polycarbonate acid housing and fixed at both ends using polyurethane as a sealing resin was fabricated. In air at a temperature near room temperature, the total irradiation dose to this artificial lung device was 2.5.4, respectively, using gamma rays at a radiation source of 6°C.
．． 5 and 8.0 megarads were irradiated. The irradiation results are summarized in Table 1.

When the irradiation dose exceeded 5 megarads, the mechanical strength of the hollow fiber membrane was significant, and leaks caused by the hollow fiber membrane occurred frequently, making it unusable as an oxygenator. On the other hand, in the case of using a polypropylene acid hollow fiber membrane, there were many leaks caused by the hollow fiber membrane even at a total irradiation dose of 2.5 megarads.

Claims (1)

[Claims] 1) An artificial lung that includes a large number of porous hollow fiber membranes in a housing and performs blood gas exchange by bringing blood into contact with oxygen-containing gas through the hollow fiber membranes, wherein the hollow fiber membranes is made of polyethylene and has a laminated structure in which micropores are interconnected from the inner wall surface to the outer wall surface of the hollow fiber membrane, and the oxygenator is irradiated with gamma rays of 1.5 to 5.0 megarads. An artificial lung characterized by being made of artificial lungs.