JPS60215369A - Artificial lung equipped with degassing mechanism - 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 [Technical Field] The present invention relates to an oxygenator using a microporous hollow fiber membrane, and more particularly to an oxygenator equipped with a gas venting mechanism.

[Prior Art] Conventionally, oxygenators using hollow fiber membranes include those using homogeneous membranes such as silicone resin membranes, and 1, for example, JP-A-54
Two types are known that use a porous material made of a hydrophobic material such as polypropylene, typified by No. 180098.

An oxygenator using a homogeneous membrane is considered advantageous for long-term extracorporeal circulation because there is no risk of leakage of blood, etc. However, gas exchange through a homogeneous membrane is carried out by a mechanism in which gas dissolves and diffuses into the membrane and permeates through the membrane.
．． 1IilI itself has a large resistance, and its gas exchange performance is considerably lower than that of porous membranes.Even when using a silicone membrane with good gas permeability, the membrane must be thick to maintain its strength as a hollow fiber membrane. As a result, the gas exchange performance is inferior to that of porous membranes. On the other hand, in the case of a porous membrane, the gas exchange performance is better than that of a homogeneous membrane because gas permeates through the pores in a volumetric flow.

The blood perfusion method in an oxygenator that uses a porous hollow fiber membrane made of polymer involves flowing oxygen-containing gas into the inner space of the hollow fiber membrane, and flowing blood into the outer space. There is a hollow fiber external perfusion type, in which the blood is brought into contact with a gas containing oxygen, and the blood is exchanged with the gas, and the other is the hollow fiber external perfusion type, in which the blood is passed through the internal space of the hollow fiber membrane, and the external space is filled with a gas containing oxygen. There are two types: a hollow fiber external perfusion type and a hollow fiber external perfusion type. In the case of the hollow fiber internal perfusion type, the blood flowing inside the hollow fiber membrane forms a laminar flow, so the inner diameter of the hollow fiber must be made quite small in order to achieve sufficient gas exchange. . However, even if the inner diameter of the hollow fiber is reduced, as long as the blood flows laminarly, the oxygen uptake capacity will not be dramatically improved, and clocking (a phenomenon in which the hollow fiber is blocked by blood coagulation) will occur frequently. Requires quite high pressure to flow.

On the other hand, when an external perfusion system is adopted for an oxygenator using a porous hollow fiber membrane made of polymer, if the balance between the gas side pressure and the blood side pressure is disrupted for some reason, Although blood does not enter inside the porous hollow fiber membrane, gas may enter the blood flow path outside the porous hollow fiber membrane, creating fine bubbles along the hollow fiber filtration membrane. be. The fact that such bubbles are discharged from the contact chamber of the oxygenator together with the blood poses a safety problem, even if degassing is performed outside the contact chamber. In addition, if these bubbles remain attached to the hollow fiber filtration membrane for a long period of time, blood clots may occur along the hollow fiber filtration membrane, and furthermore, the bubbles may prevent blood from coming into contact with fresh gas containing oxygen. It was found that blood gas exchange gradually decreased, perhaps because of this.

[Object of the Invention] An object of the present invention is to solve the above-mentioned problems and to provide an artificial lung device equipped with means for removing fine air bubbles generated along the outside of the hollow fiber filtration membrane in the contact chamber by a simple means. It is about providing.

[Configuration of the Invention] In other words, the oxygenator of the present invention comprises: a large number of porous hollow fiber membranes made of polymer; a gas flow path for flowing gas containing oxygen into the internal space of the hollow fiber membrane; In an artificial lung device having a contact chamber equipped with a blood flow path for flowing blood into the external space of the hollow fiber membrane, connected to the gas flow path,
The present invention is characterized in that a circuit equipped with a pressure reducing means is attached to the gas flow path outside the contact chamber.

[Optimum Mode for Carrying Out the Invention] Hereinafter, the artificial lung device of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of one embodiment of the artificial lung device of the present invention.

The artificial lung device of the present invention basically comprises a contact chamber 1 , an external blood flow path 2 , an external gas flow path 3 , and a pressure reduction circuit 5 having a pressure reduction device 4 .

Inside the contact chamber 1, there are a large number of porous hollow fiber membranes made of polymers, a gas flow path for flowing oxygen-containing gas into the inner space of the hollow fiber membranes, and a gas flow path for flowing oxygen-containing gas into the outer space of the hollow fiber membranes. A blood flow path is provided for the flow of blood, and the blood and oxygen-containing gas come into contact with each other through a porous hollow fiber membrane, gas exchange occurs between the blood, and carbon dioxide from the blood is removed. At the same time, oxygen is supplied. Specifically, blood gas exchange is performed according to the following flow. That is, the blood on which gas exchange is carried out is transferred from the external blood flow path 2 to the blood population 6 of the contact chamber l.
The blood is supplied into the contact chamber 1 through the contact chamber 1, flows through the blood flow path in the contact chamber 1, undergoes gas exchange via the porous hollow fiber membrane, and then flows from the blood outlet lower of the contact chamber 1 to the external blood flow path 2. be discharged.

On the other hand, the gas containing oxygen is transferred from the external gas flow path 3 to the contact chamber l.
The gas is supplied into the contact chamber 1 through the gas port 8 in the contact chamber 1, flows through the gas flow path in the contact chamber 1 and inside the porous hollow fiber membrane, and after gas exchange with the blood, is supplied to the outside from the gas outlet 9 of the contact chamber 1. The gas is discharged to the gas flow path 3. The two valves 10.11 on the external gas flow path 3 are open when blood gas exchange is performed. Various structures can be adopted as the specific internal structure of the contact chamber.

In the artificial lung device of the present invention, a pressure reduction circuit 5 having a pressure reduction device 4 is attached to the external blood flow path 2. As mentioned above, when an oxygenator is operated for a long period of time, the gas flowing inside the porous hollow fiber membrane in the contact chamber 1 often gradually invades the blood flow path outside the porous hollow fiber membrane. ,
As a result, fine air bubbles accumulate and adhere along the outside of the hollow fiber filtration membrane. The decompression circuit 5 is provided to remove the air bubbles that have accumulated and adhered in this way. In this example, it is provided on the external blood flow path 2 after the blood output lower. However, the bubble removal operation using the pressure reducing circuit 5, which may of course be attached on the external blood flow path 2 before the blood flow 6, involves closing the two valves 10, 11 on the external gas flow path 3, and It has been found that this can be easily removed by opening 12 and activating the pressure reducing circuit 5. The pressure reducing device 4 provided in the pressure reducing circuit 5 does not need to be one that generates a particularly high degree of vacuum, and a normal hydraulic vacuum pump can be suitably used; The time required to remove air bubbles may vary depending on the type of porous hollow fiber membrane used in the contact chamber 1, etc., but usually, the pressure is reduced to about 100Toor by 0.5
By keeping it for about 5 minutes, the remaining air bubbles on the outside of the hollow fiber membrane can be completely removed.

Hollow fiber membranes made of various materials can be used as the porous hollow fiber membrane made of polymer installed in the contact chamber of the oxygenator of the present invention. However, a polyolefin-based microporous hollow fiber membrane has excellent durability and gas permeation performance. Among these, the micropores in the membrane are formed in the spaces between the fibrils, which are formed by the fibrils stacked many times from one surface to the other, and the knots that fix both ends of the fibrils. Particularly preferably used are membranes that are interconnected as spaces and penetrate from one side of the membrane to the other. Examples of such hollow fiber membranes include 1, for example, polyethylene hollow fibers M (polyethylene hollow fibers El (F,
Product name: Mitsubishi Rayon ■).

[Effects of the present invention] According to the artificial lung device of the present invention, fine air bubbles generated along the outside of the hollow fiber filtration membrane in the contact chamber can be removed by operating the pressure reduction circuit as necessary. It is possible to prevent air bubbles from entering the gas exchange blood and to prevent blood clots from forming along the hollow fiber membrane, and it is also possible to maintain high blood gas exchange efficiency at all times. .

[Brief explanation of the drawing]

tIS1 is a schematic diagram showing one embodiment of the artificial lung device of the present invention. l: Contact chamber 2: External blood flow path 3: External gas flow path 4: Pressure reducing device 5: Pressure reducing circuit 6: Blood inlet lower: Blood outlet 8: Gas inlet 9: Gas outlet l01l■=Valve patent applicant Mitsubishi Rayon Co., Ltd. Company Figure 1

Claims (1)

[Claims] l) A large number of porous hollow fiber membranes made of polymer, a gas flow path for flowing oxygen-containing gas into the inner space of the hollow fiber membrane, and blood for flowing blood into the outer space of the hollow fiber membrane. In an artificial lung device having a contact chamber equipped with a flow path, a circuit equipped with a pressure reducing means is attached to the gas flow path outside the contact chamber connected to the gas flow path. Characteristic artificial lung device.