JPH0424064B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hollow fiber oxygenator that removes carbon dioxide from blood and adds oxygen to blood in extracorporeal blood circulation.

[Prior Art] Conventionally, when performing surgery using an artificial lung using hypothermia, for example, a heat exchanger is sometimes used attached to the artificial lung to lower the blood temperature or conversely to warm or keep the blood warm. .

[Problem to be solved by the invention] By the way, when constructing an extracorporeal blood circulation circuit using an artificial lung, it is necessary to prevent the formation of bubbles in the blood due to elution of gas dissolved in the blood. Must. Preventing the generation of bubbles prevents the bubbles from closing the blood vessels of living organisms, such as the cerebral blood vessels, leading to the death of living cells, and also prevents the bubbles from adhering to the gas exchange membrane, reducing its effective membrane area and reducing the gas flow. This is extremely important in order to avoid reducing exchange efficiency.

The present invention prevents the generation of air bubbles in the blood without impairing the heat exchange function when the hollow fiber oxygenator is additionally equipped with a heat exchange function and a blood storage function, and even if air bubbles occur in the blood, The purpose of this invention is to reliably and easily degas the bubbles and improve the safety of blood circulation and gas exchange performance using this artificial lung.

[Means for Solving the Problems] A hollow fiber oxygenator according to a first aspect of the present invention integrally includes at least a heat exchange mechanism section, a hollow fiber oxygenator, and a blood storage tank, In the lung, an assembly of a large number of hollow fiber membranes is housed in a cylindrical housing along the axial direction.The inside of the hollow fiber membrane is a gas flow path, the outside is a blood flow path, and the axis of the housing is The heat exchange mechanism is located upstream of the hollow fiber oxygenator when viewed in the blood flow direction, and is located below the blood flow path of the oxygenator. The blood reservoir is located above the oxygenator and is directly connected to the upper part of the oxygenator through the communication path through the communication path. be.

A hollow fiber oxygenator according to a second aspect of the present invention integrally includes at least a heat exchange mechanism, a hollow fiber oxygenator, and a blood storage tank, and the hollow fiber oxygenator is housed in a cylindrical housing. An assembly of a large number of hollow fiber membranes is housed along the axial direction, the inside of the hollow fiber membrane is used as a gas flow path, the outside is used as a blood flow path, and the axis of the housing is used in the vertical direction. The heat exchange mechanism section is located upstream of the hollow fiber oxygenator when viewed in the blood flow direction, and is directly connected to a lower part of the blood flow path of the oxygenator via a communication path. The blood reservoir is located above the oxygenator and is directly connected to the upper portion of the oxygenator through which blood flows through a window-like communicating path.

[Action] According to the first aspect of the present invention, there are the following effects.

Unlike the present invention, if the heat exchange function section is located downstream of the hollow fiber oxygenator, the blood will be heated at the heat exchange mechanism section after gas exchange (oxygen addition) at a low temperature. This heating lowers the solubility of the gas (oxygen) and the gas in the blood becomes supersaturated, creating dangerous bubbles in the blood. On the other hand, according to the present invention, since the heat exchange mechanism is located upstream of the hollow fiber oxygenator, the blood is not heated after gas exchange, and the air bubbles as described above are prevented. Occurrence can be prevented.

Although the solubility of gas (carbon dioxide) decreases due to the heating of the blood by the heat exchange mechanism installed upstream of the oxygenator, the degree to which carbon dioxide is added in the body is lower than that of oxygen in the oxygenator. Since the solubility of carbon dioxide is not as large as that of oxygen and the solubility of carbon dioxide is greater than that of oxygen, no air bubbles are generated due to the heating of blood by the heat exchange mechanism of the present invention.

Further, according to the present invention, the heat exchange mechanism provided upstream of the oxygenator is not connected to the blood flow path of the oxygenator via a long connecting tube, but is integrated into the oxygenator. It is directly connected to the blood flow path. Therefore, even if the heat exchange mechanism is installed upstream of the oxygenator, it makes the blood return route to the human body much longer than when it is installed downstream of the oxygenator. isn't it.
Therefore, the blood whose temperature has been adjusted in the heat exchange mechanism maintains its temperature adjustment state as much as possible without having the opportunity to lose its temperature adjustment state due to heat radiation in the long intermediate connecting tube. This means that blood can be returned to the human body without impairing the heat exchange function.

Further, according to the present invention, since the hollow fiber oxygenator is used while being positioned in the vertical direction, even if air bubbles are generated in the blood, the air bubbles float upward and are easily removed. If the bubbles are not positioned vertically, the bubbles will not come out easily and will adhere to the hollow fiber membrane surface, reducing the effective membrane area and reducing gas exchange efficiency.

The above-mentioned collection and deaeration of air bubbles can be carried out reliably and easily.

That is, according to the present invention, the blood reservoir is located in the upper part of the blood flow of the oxygenator,
Air bubbles floating upward in the blood flow path of the artificial lung can be collected in the blood reservoir.

Furthermore, in the present invention, the blood reservoir provided in the upper part of the oxygenator is not connected to the blood flow path of the oxygenator via a long connecting tube, but is integrated with the oxygenator. Directly connected to the blood flow path. Therefore, the air bubbles floating above the blood flow path do not adhere to the inner wall of the long intermediate connecting tube and accumulate in the blood, but are smoothly repaired in the blood reservoir and can be degassed.

According to the second aspect of the present invention, in addition to the effects described above, there are the following effects.

The blood reservoir is not connected to the upper part of the blood flow of the artificial lung through a simple communication path, but is directly connected to the upper part of the blood flow through a window-like communication path.

Therefore, blood transferred from the oxygenator to the blood reservoir overflows the lower side of the window-like communication passage provided in the upper portion of the blood flow of the oxygenator, flows into the blood reservoir, and is stored. Therefore, the blood stored in the blood storage tank does not apply pressure to the blood flowing upward in the blood flow path of the oxygenator, and as a result, blood leakage sites or blood cell destruction due to increased internal pressure of the oxygenator are prevented. You can ensure the safety of blood circulation without having to worry about it.

[Example] Fig. 1 is a perspective view showing a hollow fiber oxygenator according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of a main part of the hollow fiber oxygenator, and Fig. 3 is a hollow fiber oxygenator. FIG. 2 is a circuit diagram showing a blood circuit to which an artificial lung device is applied.

As shown in FIG. 3, a hollow fiber oxygenator 110 and a pump 100 are interposed in the blood circuit to which the present invention is applied from the venous side to the arterial side. The hollow fiber oxygenator device 110 is an oxygenator 120
The blood storage tank 134 and the heat exchange mechanism section 137 are integrally provided.

The housing 121 of the oxygenator 120 has an inner cylinder portion 1
22 and an outer cylinder portion 123. Inner cylinder part 1
22 accommodates an assembly 125 of hollow fiber membranes 124. Both ends of the hollow fiber membrane 124 are connected to the inner cylinder part 12
Partition walls 126, 1 held at both upper and lower ends of 2
It is liquid-tightly supported by the inner cylinder part 122 via 27. Both the inner cylinder part 122 and the outer cylinder part 123 are made of a rigid material such as polycarbonate, acrylic resin, or acrylic-styrene copolymer resin.

Headers 128, 1 are provided at both ends of the inner cylinder portion 122.
29 are joined. The inner surface of the header 128 and the partition wall 127 define a gas inflow chamber communicating with the internal space of the hollow fiber membrane 124, and the header 128 is formed with a gas inflow port 130 for a gas containing oxygen. In addition, the inner surface of the header 129 and the partition wall 1
26 defines a gas outflow chamber, and the header 129
A gas outflow port 131 is formed in the. That is, in the case of the oxygenator 120, gases such as oxygen and air supplied from the gas inflow port 130 are allowed to flow into the hollow fiber membrane 124. Note that the header 129 may not be particularly provided, and the gas flowing out from the hollow fiber membrane 124 may be directly released into the atmosphere without forming the gas outflow chamber and the gas outflow port 131.

In addition, the inner wall of the housing 121, the hollow fiber membrane 12
The outer wall of No. 4 and the partition walls 126 and 127 define a blood chamber 132, and a blood inflow port 133A is connected to the lower end side of the inner cylinder portion 122. That is, in the case of the oxygenator 120, gases such as oxygen and air supplied from the gas inflow port 130 flow through the hollow fiber membrane 124, and blood supplied from the blood inflow port 133A flows through the hollow fiber chamber 132. The gas is allowed to flow around the thread membrane 124 in a turbulent state, making it possible to perform gas exchange.

Here, the inner surface of the portion of the inner cylindrical portion 122 forming the housing 121 with which the blood inflow port 133A communicates is an inner surface that expands outward from the inner surface of the intermediate portion of the inner cylindrical portion 122, and An annular blood flow path 133B as shown in FIG. 2 is formed between the blood flow path 133B and the aggregate 125.
Each hollow fiber membrane 12
4. Blood can be distributed smoothly. Further, the expanded inner surface of the inner cylindrical portion 122
5, the blood flow path 133B is arranged eccentrically in the direction including the blood inflow port 133A, and the flow path area of the blood flow path 133B facing the blood inflow port 133A is larger. That is, the flow area of the blood flow path 133B is gradually decreased as it moves away from the blood inflow port 133A, the amount of blood distributed from the blood flow path 133B is made uniform in the circumferential direction of the aggregate 125, and the flow area of the blood flow path 133B is made uniform in the circumferential direction of the blood chamber 132. The flow rate of blood towards aggregate 1
25 can be made uniform in the circumferential direction.

Furthermore, in the artificial lung 120, the inner cylinder part 122 and the outer cylinder part 12 forming the housing 121 are
3, a blood reservoir 134 is attached above the oxygenator 120 and communicates with the blood chamber 132 thereof. Inner cylinder part 1 enclosed in outer cylinder part 123
Window-like communication passages 135 are opened in the side wall of 22 at intervals in the circumferential direction, and the blood chamber 132 in the inner cylinder part 122 and the blood storage tank 134 can be directly connected.

Further, a gas vent 136 equipped with a breathable and bacteria-impermeable filter is provided at the upper part of the outer cylinder part 123.
is formed to prevent contamination of the oxygenator 120 with bacteria during use and to maintain the inside of the blood reservoir 134 at atmospheric pressure at all times. In addition, blood storage tank 13
A scale is engraved on the side of 4 to indicate the amount of blood stored. In addition, the volume of the blood storage tank 134 is such that even in the unlikely event that venous blood removal becomes insufficient or blood leaks due to a tube breakage, etc., a certain amount of blood flow can be maintained, that is, safety can be ensured. The planned extracorporeal circulating blood volume (ml/
The size is set such that even if approximately half of the blood (min) is stored, the upper surface of the stored blood is located below the lower side of the communication path 135. That is, by setting the volume of the blood reservoir 134 as described above, when blood flows upward through the blood chamber 132 from the blood inflow port 133, the gas-exchanged blood flows through the lower side of the communication path 135. The blood overflows and flows down to the blood storage tank 134 and is stored therein, so that the stored blood in the blood storage tank 134 flows into the blood chamber 132.
It is designed so that no pressure is applied to the blood flowing upward.

Further, on the upstream side of the oxygenator 120 in the blood flow direction, there is a blood inflow port 133A.
It is a heat exchange tank 138 that is directly connected to the blood flow path 133B below the oxygenator 120 via a communication path (communication path) and has a heat exchange mechanism section 137 built therein. The heat exchange mechanism section 137 includes a pair of partition walls 13 in the heat exchange tank 138.
It consists of a bundle of thin tubes 141 supported at both ends by tubes 9 and 140 and open to both the blood inflow port 133A side and the blood introduction port 133 side, and the internal space of the thin tubes 141 is used as a blood flow path, and the partition walls 139 and 140 and the thin tubes 141 A heat medium flow path is formed by the outer wall of the heat transfer medium. A hot and cold water inflow port 142A and a hot and cold water outflow port 142B are connected to this heat medium flow path. Note that the thin tube 141 is formed of a stainless steel tube, an aluminum tube, or the like having high thermal conductivity. That is, the hollow fiber oxygenator 11
When the temperature is 0, the blood temperature can be lowered in the heat exchange tank 138, or conversely, it can be heated or kept warm.

Here, a microporous membrane is used as the hollow fiber membrane 124. That is, the hollow fiber membrane 124 is made of a porous polyolefin resin such as polypropylene or polyethylene, with polypropylene being particularly suitable. This hollow fiber membrane 124 has a large number of pores that communicate between the inside and outside of the wall. The inner diameter of the pore is 100~1000μ,
The wall thickness is 10-50μ, the average pore diameter is 200-2000A, and the porosity is 20-80%. When the hollow fiber membrane 124 made of a microporous membrane is used, gas movement is performed as a sedimentary flow, so the membrane resistance in gas movement is reduced, and high gas exchange performance can be obtained. Note that the hollow fiber membrane 12
4 does not necessarily use a microporous membrane, but may also use a silicone membrane in which gas movement is performed by dissolution and diffusion.

Next, the operation of the above embodiment will be explained.

In the hollow fiber oxygenator 110, the blood flowing from the blood inlet 133 flows into the heat exchange tank 11.
After the blood temperature is lowered or conversely warmed or kept warm by the heat exchange mechanism section 137 of 38, the blood enters the oxygenator 1 from the blood inflow port 133A.
20. The blood that has flowed into the oxygenator 120 passes through the hollow fiber membrane 124 while flowing upward into the blood chamber 132.
The gas flows around the gas in a turbulent state, and gas exchange takes place. This gas-exchanged blood then passes through the communication channel 1.
35 and flows down to the blood storage tank 134 where it is stored, and then supplied to the living body.

However, according to the artificial lung device 110,
A heat exchange mechanism section 1 is provided on the upstream side of the hollow fiber oxygenator 120.
37, the blood will not be heated after gas exchange (oxygenation), and the solubility of gas (oxygen) will not decrease due to heating after this gas exchange, and as a result, the blood will not be heated. No bubbles are observed.

Although the solubility of gas (carbon dioxide) decreases due to the heating of blood by the heat exchange mechanism 137 provided upstream of the oxygenator 120, the degree to which carbon dioxide is added inside the body is lower than that of the oxygenator. 120
Since the solubility of carbon dioxide is not as high as that of oxygen and the solubility of carbon dioxide is greater than that of oxygen, bubbles are not generated due to the heating of blood by the heat exchange mechanism 137 of the present invention.

Further, the heat exchange mechanism section 137 provided on the upstream side of the oxygenator 120 is not connected to the blood flow path of the oxygenator 120 via a long connecting tube or the like, but is integrated into the oxygenator 120 and is connected to the blood flow path of the oxygenator 120. Directly connected to the flow path. Therefore, the heat exchange mechanism section 137
Although it is provided upstream of the oxygenator 120, it does not make the blood return route to the human body significantly longer than when it is provided downstream of the oxygenator 120. Therefore, the blood whose temperature has been adjusted in the heat exchange mechanism section 137 maintains its temperature adjustment state as much as possible without losing the temperature adjustment state due to heat radiation in the intermediate connecting tube. This means that blood can be returned to the human body without impairing the heat exchange function.

Furthermore, according to the hollow fiber oxygenator device 110, the oxygenator 120 is used while being positioned vertically, so that even if air bubbles are generated in the blood, the air bubbles easily move upward and escape. If the bubbles are not positioned in the vertical direction, the bubbles will not come out easily and will adhere to the surface of the hollow fiber membrane 124, reducing the effective area and reducing the gas exchange efficiency. Artificial lung device 110
The above-mentioned action of collecting and degassing air bubbles can be carried out reliably and easily.

That is, the blood reservoir 134 is located above the blood flow of the oxygenator 120, and the oxygenator 1
Air bubbles floating upward in the blood flow path 20 can be collected in the blood storage tank 134.

Furthermore, the blood reservoir 134 provided in the upper part of the oxygenator 120 is not connected to the blood flow path of the oxygenator 120 via a long connecting tube or the like, but is integrated with the oxygenator 120 and the blood flow path is connected to the oxygenator 120. is directly connected to Therefore, the air bubbles floating above the blood flow path do not adhere to the inner wall of the long intermediate connecting tube and remain in the blood, but smoothly flow into the blood storage tank 134.
The gas is collected and can be degassed.

Further, the blood transferred from the oxygenator 120 to the blood reservoir 134 overflows the lower side of the window-like communication passage 135 provided in the upper part of the blood flow of the oxygenator 120, flows into the blood reservoir 134, and is stored. Ru. Therefore, the blood stored in the blood storage tank 134 does not apply pressure to the blood flowing upward in the blood flow path of the oxygenator 120, and as a result, a blood leak site or blood cell leakage occurs due to an increase in the internal pressure of the oxygenator 120. The safety of blood circulation can be ensured without destruction.

[Effects of the Invention] As described above, according to the present invention, when a hollow fiber oxygenator is additionally equipped with a heat exchange function and a blood storage function, generation of bubbles in the blood can be prevented without impairing the heat exchange function. Even if air bubbles are generated in the blood, the air bubbles can be deflated reliably and easily, and the safety of blood circulation and gas exchange performance using this artificial lung can be improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a hollow fiber oxygenator according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a main part of the hollow fiber oxygenator, and FIG. 3 is a perspective view of a hollow fiber oxygenator according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a blood circuit to which the present invention is applied. 110... Hollow fiber oxygenator, 120... Oxygenator, 121... Housing, 124... Hollow fiber membrane, 125... Assembly, 133A... Blood inflow port (communication path), 134... Blood storage tank , 137...
Heat exchange mechanism section.

Claims (1)

[Claims] 1. The hollow fiber oxygenator integrally includes at least a heat exchange mechanism, a hollow fiber oxygenator, and a blood storage tank, and the hollow fiber oxygenator comprises:
An assembly of a large number of hollow fiber membranes is housed in a cylindrical housing along the axial direction, the inside of the hollow fiber membrane is used as a gas flow path, the outside is used as a blood flow path, and the axis of the housing is oriented vertically. The heat exchange mechanism is located upstream of the hollow fiber oxygenator in the blood flow direction, and
The blood reservoir is directly connected to the lower part of the blood flow path of the oxygenator via a communication path, and the blood reservoir is located in the upper part of the oxygenator, and is directly connected to the upper part of the blood flow path of the oxygenator through the communication path. A hollow fiber oxygenator characterized by: 2. The hollow fiber oxygenator integrally includes at least a heat exchange mechanism, a hollow fiber oxygenator, and a blood storage tank, and the hollow fiber oxygenator comprises:
An assembly of a large number of hollow fiber membranes is housed in a cylindrical housing along the axial direction, the inside of the hollow fiber membrane is used as a gas flow path, the outside is used as a blood flow path, and the axis of the housing is oriented vertically. The heat exchange mechanism is located upstream of the hollow fiber oxygenator in the blood flow direction, and
The blood reservoir is directly connected to the lower part of the blood flow path of the oxygenator via a communication path, and the blood reservoir is located in the upper part of the oxygenator, and is connected to the upper part of the blood flow path of the oxygenator and the window-shaped communication path. A hollow fiber oxygenator, characterized in that it is directly connected to a hollow fiber oxygenator.