JPH11206880A - Extracorporeal blood circulation device having heat exchanging means of gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low price device which eliminates occurred demerits due to temperature difference between blood and gas when operating extracorporeal blood circulation accompanied by gas exchange. SOLUTION: This is an extracorporeal blood circulation device 1 that has a heat exchanger for blood 2, a gas exchanger 4 and a heat exchanger for gas 3. The heat exchanger for blood 2 is connected liquid-flowingly by a blood flow system to the gas exchanger 4 and the heat exchanger for gas 3. The gas exchanger 4 is connected to the heat exchanger for gas 3 by a gas flow system. The heat exchanger for blood 2 is installed on the upstream side of the blood flow system for the gas exchanger 4 and the heat exchanger for gas 3. The heat exchanger for gas 3 is installed to a position on the upstream side of the gas flow system for the gas exchanger 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extracorporeal circulation apparatus for blood used for cardiopulmonary therapy, and more particularly, to an extracorporeal circulation apparatus having a heat exchange means for gas.

[0002]

2. Description of the Related Art As an artificial lung used in open heart surgery and the like, a bubble-type artificial lung for directly injecting gas such as oxygen directly into blood to oxygenate blood, indirectly through a membrane like a human body. There is a membrane oxygenator that measures oxygenation of blood
Membrane oxygenators, which have the advantage of less blood damage, are widely used. When using this oxygenator, the patient's blood is circulated by connecting it to an extracorporeal circulation circuit.This blood circuit includes a heat exchanger for heating or cooling the blood,
It is necessary to provide a blood reservoir for temporarily storing blood.

[0003]

However, in the conventional membrane oxygenator, the blood heated or cooled in this heat exchanger is combined with oxygen gas not temperature-controlled (through a membrane). Due to the contact in the lungs, various problems occur as described below. For example, let gas flow inside the hollow fiber membrane,
When performing gas exchange using a membrane-type oxygenator that allows blood to flow outside the membrane, if the hollow fiber membrane is made of a homogeneous material such as silicone, the gas side (in the hollow fiber or in the gas outlet chamber) ) May condense water vapor, thereby obstructing the gas flow and causing a decrease in gas exchange performance. Alternatively, when the hollow fiber membrane is a porous membrane made of polypropylene or the like, the surface tension at the blood-gas interface is reduced due to the condensation formed in the hollow fiber lumen, so that plasma leakage occurs, which also causes performance deterioration. There is fear.

[0004] In order to solve the above problems, various inventions and ideas have been made in the past. For example, 63-1
Japanese Patent Application Laid-Open No. 9074 discloses that dew condensation on a hollow fiber is prevented by a blowing means such as a fan.
JP-A-58-29463 discloses that heat exchange and gas exchange are performed simultaneously by using gas as a heat exchange medium. JP-A-6-237992
The publication discloses that blood is flown outside the hollow fiber, gas-mixed liquid is flown into the hollow fiber lumen, and heat exchange and gas exchange are performed through the hollow fiber membrane. However, each of these devices has the following problems. That is, Japanese Utility Model Publication No. 63-19074 requires a separate blowing device and a device for controlling the blowing device, and this blowing method does not allow gas to be evenly delivered to a portion where hollow fibers are densely arranged. In the method disclosed in JP-A-58-29463, since heat is exchanged by gas, the heat exchange efficiency of blood is low and the performance is limited. JP-A-6-2
In the method according to Japanese Patent No. 37992, bubbles mixed in the liquid may be clogged (locked) in the hollow fiber, and gas exchange may be secondary (mixing the gas into the liquid, and further converting the liquid into the hollow fiber membrane). Contact with blood)
Lack of responsiveness when wanting to oxygenate blood rapidly.

[0005] In addition to the above, a device has been devised in which a heating means is provided at the gas outflow / inflow portion to prevent the occurrence of dew condensation when blood comes into contact with the gas. It is necessary, and means for adjusting the temperature according to the temperature of the blood is required. Due to the various problems as described above, the extracorporeal circulation device having the conventional gas exchange means cannot perform efficient gas exchange of blood. Therefore, an object of the present invention is to provide a device capable of solving the above-mentioned problem that occurs when extracorporeal blood is circulated, and to provide the device at low cost.

[0006]

According to the present invention, there is provided a blood heat exchange section in which heat is exchanged by extracorporeally circulating blood coming into indirect contact with a heat exchange medium, and the heat exchanged blood is indirectly exchanged with gas. A gas exchange section that is gas-exchanged by contact, and a gas heat exchange section that raises and lowers the gas temperature to the contacted blood temperature by indirect contact between the gas before flowing into the gas exchange section and the circulating blood. The blood extracorporeal circulation device having the blood heat exchange unit is connected to the gas exchange unit and the gas heat exchange unit by a blood flow path so as to be able to flow, and the gas exchange unit is a gas heat exchange unit by the gas flow path. The heat exchange section for blood is provided on the blood flow path upstream side of the gas exchange section and the heat exchange section for gas, and the heat exchange section for gas is provided on the gas flow path upstream side of the gas exchange section. Extracorporeal blood circulator Thus, the above-mentioned problems are eliminated.

The present inventor has made various studies on a method for reducing the difference in temperature between blood and gas when oxygen is added to blood by indirectly bringing gas into contact with blood in cardiopulmonary surgery or the like. . As a result, before gas exchange (for oxygenation,
It has been found that by bringing the gas (before contact with blood) into contact with the blood after heat exchange in advance, the gas temperature can be efficiently brought close to the temperature of the blood to be gas-exchanged. That is, a gas heat exchange unit that can indirectly contact the gas before gas exchange with the circulating blood after heat exchange is provided, and the gas heat exchange unit is arranged near the downstream side of the blood flow path of the blood heat exchange unit. As a result, the gas temperature can be efficiently brought close to the blood temperature. According to this method, a special heat exchange medium for gas and its related devices are not required, so that the method can be implemented simply and inexpensively. Further, since the gas temperature is adjusted in conjunction with the temperature of the blood to be gas-exchanged, a device for controlling the gas to have the same temperature as that of the blood is not particularly necessary.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to make the extracorporeal blood circulation apparatus of the present invention more concrete, one embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the extracorporeal blood circulation device 1 of the present invention mainly includes a blood heat exchange unit 2, a gas heat exchange unit 3, and a gas exchange unit 4. These three exchange units are connected in the order of the blood heat exchange unit 2 → the gas heat exchange unit 3 → the gas exchange unit 4 via the blood flow path. In addition, the gas heat exchange unit 3 and the gas exchange unit 4 have a gas flow path, and the gas heat exchange unit 3 →
Contact is made in the order of the gas exchange unit 4. When the flow paths are connected in such an order, the gas before gas exchange can come into contact with blood immediately after the heat exchange in the heat exchange section 2 and the heat loss is small, so that the gas gas can be exchanged efficiently. As described above, the gas heat exchanging section 3 is preferably provided on the upstream side of the blood flow path of the gas exchanging section 4. The heat exchange unit 3 may be provided downstream of the gas exchange unit 4 in the blood flow path. When the blood flow velocity increases, the effect of heat loss of blood due to gas exchange decreases, and there is no problem even if the gas heat exchange unit 3 is provided substantially downstream of the gas exchange unit 4.

Next, the structure of each exchange unit will be described. A large number of heat conductive hollow tubes 5 are arranged in the blood heat exchange unit 2 and the gas heat exchange unit 3 with both ends potted. The hollow tube lumen 6 of the blood heat exchange unit is a flow path for the heat exchange medium, and the hollow tube lumen of the gas heat exchange unit is a gas flow path. And the outside 7 of the hollow tube of both the heat exchange part for blood and for gas is the blood flow path. The gas exchange section 4 has a large number of gas-permeable hollow fiber membranes 8 potted at both ends, the hollow fiber lumen is a gas flow path, and the outside of the hollow fiber is a blood flow path. As shown in the figure, in this embodiment, the blood heat exchange part 2, the gas heat exchange part 3, and the gas exchange part 4 are provided independently by separate housings, respectively, and the blood flow path and gas flow path of each exchange part are provided. Are connected by a conduit 9. The housing of each exchange unit is provided with a blood inlet and a blood outlet, respectively. The housings of the gas heat exchange unit and the gas exchange unit are provided with a gas inlet and a gas outlet, respectively. Further, a heat medium inlet 12 and a heat medium outlet 13 are provided in the housing of the blood heat exchange unit.

Next, another embodiment in which each exchange unit is provided in one housing will be described with reference to FIGS. In this extracorporeal blood circulation apparatus 1, the heat exchange part 2 for blood, the heat exchange part 3 for gas, and the gas exchange part 4 are provided in one housing, and the blood flow shared by the three exchange parts is provided in the housing. There is a path, and a gas flow path shared by the two exchange sections through which gas flows in the order of the gas heat exchange section and the gas exchange section. In the above embodiment, as shown in FIG. 1, a blood inlet and a blood outlet, a gas inlet and a gas outlet, or a heat medium inlet and a heat medium outlet (heat exchange part for blood) are provided in each exchange part. However, in this embodiment, one blood inlet 10, blood outlet 11, heat medium inlet 12, heat medium outlet 13, gas inlet 14, and gas outlet 15 are provided in the housing. The problem associated with pressure loss can be reduced. Further, since the conduit 9 connecting the housings is not required, the structure is simple and the manufacture is easy. In addition, the blood filling amount can be reduced, and it is useful to use this extracorporeal circulation device as an artificial lung with heat exchange means.

In this embodiment, the inside of the heat exchange section for blood and the inside of the heat exchange section for gas have the same structure, and a large number of heat-conductive hollow tubes 5 are arranged by potting at both ends. A flow path connected to the hollow tube lumens of the two heat exchange sections is divided by a partition 16 into two, a heat medium flow path and a gas flow path. Also, the gas heat exchange unit and the gas exchange unit
The partition 17 separates a gas inlet downstream area 18 and a gas outlet upstream area 19 so that the gas before heat exchange does not mix with the gas after gas exchange. The gas storage area 20 for storing the gas heat-exchanged in the gas heat exchange section before flowing to the gas exchange section is not partitioned like the gas heat exchange section and the gas exchange section, and has one space. Only.
The space in the gas storage area 20 minimizes gas heat loss caused by heat exchange with the outside of the housing,
Preferably, it is as small as possible. As in the previous embodiment, the gas exchange section has a large number of gas-permeable hollow fiber membranes 8 arranged at both ends by potting.

In FIG. 2, the flow of the heat exchange medium and the gas is easy to understand, but the flow of the blood is difficult to understand. Therefore, FIG. 3 is a schematic cross-sectional view of FIG.
The blood flowing into the housing from the blood inlet 10 passes through the outer gap of the hollow tube 5 or the outer gap of the hollow fiber membrane 8,
Although not divided, the blood outlet 11 passes through the blood heat exchanger 2 → the gas heat exchanger 3 → the gas exchanger 4.
It is discharged out of the housing. When the structure shown in FIGS. 2 and 3 is used as an artificial lung, there is a particularly preferable embodiment. One is that the total blood filling volume is 10
0 to 500 ml, and an artificial lung having a heat exchange function in which the effective surface area of the hollow tube of the gas heat exchange section is 100 to 500 cm2. If the blood filling amount is large, the burden on the patient increases, and if the blood filling amount is too small, the gas exchange ability of the blood decreases, and the blood cannot be gas exchanged sufficiently. In addition, if the effective surface area of the hollow tube for heat exchange of gas in the gas heat exchange unit is small, heat cannot be effectively exchanged for gas. Conversely, if it is too large, the overall size becomes large.

[0013] As a second preferred embodiment, the three fixed portions of the hollow fiber fixing portion of the gas exchanging portion, the hollow tube fixing portion of the gas heat exchanging portion, and the hollow tube fixing portion of the blood heat exchanging portion are provided. There is an extracorporeal blood circulation device having a structure in which the ends of the fixed portions on the flow path side are flush with each other and have substantially no step between the ends of the three fixed portions. The circulation device as described above is a heat exchange unit for blood,
After temporarily fixing the hollow tube of the gas heat exchange unit and the hollow fiber of the gas exchange unit with resin or other physical methods, put the resin into the outside of the hollow tube and hollow fiber of each part and simultaneously potting By doing so, it is possible to form a structure in which the ends of the fixed portions of the respective portions are flush with each other. Such a structure is advantageous in terms of antithrombotic properties, low stagnation and the like when performing blood circulation for a long period (time).

Next, the flow of blood, a heat exchange medium, the flow of gas, and the heat exchange of each fluid will be described by taking the extracorporeal blood circulation device 1 in which one exchanger is provided in one housing as an example.
First, regarding the blood heat exchange unit 2, the water of the heat exchange medium flowing from the inlet 12 flows out of the outlet 13 through the hollow tube lumen 6. At this time, the blood flowing from the inflow port 10 is flowing through the outside of the hollow tube 7 and exchanges heat with the heat exchange medium via the heat conductive hollow tube 5. The heat-exchanged blood then flows outside the hollow tube 7 of the gas heat exchange section. Similarly, the oxygen of the gas flowing from the inflow port 14 flows through the hollow tube bore 6 into the gas storage area 20. Therefore, gas storage area 2
The gas flowing out to zero is exchanged with blood through the hollow tube 5. Through the gas heat exchanger 3, the blood then flows through the gas exchanger 4. The gas flowing from the gas storage area 20 to the gas exchange section 4 passes through the hollow fiber lumen 8 and the gas outlet 1
Spilled out of 5. At this time, the temperature of the gas flowing through the gas exchange unit 4 is substantially the same as the temperature of the blood flowing through the hollow fiber outside 7. For this reason, it is possible to suppress the performance deterioration of the gas exchange due to the condensation described above.

[0015]

EXAMPLE An artificial lung having a structure as shown in FIGS. 2 and 3 in which a heat exchange part for blood, a heat exchange part for gas, and a gas exchange part were provided in one housing was produced. The shape and dimensions of the housing are 90.0mm in height, 70.0mm in width, and 200.0mm in height.
And the material is lightweight and tough polycarbonate.
The total filling volume of blood in this artificial lung is 300 ml. The effective surface area of the hollow tube of the gas heat exchange section is 2.40 m2. The hollow tube is made of stainless steel, diameter 1.25mm, wall thickness 0.10
140 mm as heat exchange units for blood and 60 as heat exchange units for gas were arranged in a square. The heat exchange medium of the present embodiment is water.

[0016]

According to the extracorporeal blood circulation apparatus of the present invention, various problems caused by the temperature difference between the blood and the gas to be brought into contact and a decrease in the performance of the gas exchange can be reduced when exchanging the blood gas. Next, a heat exchange medium for heating and cooling the gas, and related devices such as a heating and cooling device for the medium and a circulation device are unnecessary, and the temperature of the gas is controlled to be the same as that of blood. A simple configuration and structure can be achieved in view of the functions to be provided, such as the need for a special device. Further, the extracorporeal blood circulation device of the present invention can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an extracorporeal blood circulation device of the present invention.

FIG. 2 is a schematic sectional view showing another example of the extracorporeal blood circulation device.

FIG. 3 is a schematic sectional view taken along line A-A 'of FIG.

[Explanation of symbols]

 1. Extracorporeal blood circulation device 2. Heat exchange unit for blood 3. Gas heat exchange unit 4. Gas exchange unit 5. (Heat transfer) hollow tube 6. hollow tube lumen 7. Outside of hollow tube 8. Hollow fiber (membrane) Conduit 10. Blood inlet 11. Blood outlet 12. Heat medium inlet 13. Heat medium outlet 14. Gas inlet 15. Gas outlet 16. Partition 17. Partition 18. Gas inlet downstream area19. Gas outlet upstream area 20. Gas storage area 21. Hollow tube fixing part (heat exchange part for blood) 22. 23. Hollow tube fixing part (gas heat exchange part) Hollow fiber fixing part

Claims (5)

[Claims] 1. A blood extracorporeal circulation device having a blood heat exchange part, a gas exchange part, and a gas heat exchange part, wherein the blood heat exchange part is formed by a blood flow path. The gas exchange part is connected to the gas heat exchange part by the gas flow path, and the blood heat exchange part is located upstream of the blood flow path of the gas exchange part and the gas heat exchange part. An extracorporeal blood circulation device provided, wherein the gas heat exchange unit is provided on the gas flow path upstream side of the gas exchange unit. 2. The gas heat exchanging section is provided upstream of the gas exchanging section in a blood flow path.
The extracorporeal blood circulation device according to claim 1. 3. The blood heat exchange section, the gas heat exchange section, and the gas exchange section are provided in one housing, and a blood flow path shared by each of the three exchange sections is provided in the housing. 2. The method according to claim 1, wherein the housing is provided with one blood inlet and one blood outlet, and the housing is further provided with one gas inlet and one gas outlet. The extracorporeal blood circulation device according to any one of the above items 2 4. The method according to claim 1, wherein the total blood filling amount of the extracorporeal blood circulation device is 100 to 500 ml, and the effective surface area of the hollow tube of the gas heat exchange unit is 100 to 500 cm 2. An extracorporeal blood circulation device according to any of the above items. 5. The three fixing portions on the blood flow path side in the three fixing portions of the hollow fiber fixing portion of the gas exchange portion, the hollow tube fixing portion of the gas heat exchange portion, and the hollow tube fixing portion of the blood heat exchange portion. The extracorporeal blood circulation device according to any one of claims 1 to 4, wherein the end portions are flush with each other, and the structure has substantially no step between the three fixing end portions.