JP3428247B2 - Heat exchanger with filter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger installed in an extracorporeal blood circulation circuit for heating or cooling a heat exchange fluid such as blood or myocardial protection liquid.

[0002]

2. Description of the Related Art During cardiac surgery, it is necessary to perform extracorporeal circulation using a blood circuit as an alternative means of the functions of the heart and lungs. In this blood circuit, an artificial lung for enriching blood with oxygen, a blood pump for sending blood, a blood reservoir for adjusting the blood volume in the circuit (securing a certain blood volume), and a foreign substance A filter for removing blood clots, a heat exchanger for cooling or heating the heat exchange fluid, and the like are incorporated. In a circuit for injecting a cardioplegia solution or the like into a coronary artery (coronary blood vessel), a heat exchanger cools a heat exchange fluid such as blood or a crystalloid solution, and the cooled heat exchange fluid is injected into the coronary artery. . This cools the patient's heart tissue and inhibits the metabolic function of the patient's heart. Further, when the surgery is completed, the metabolic function of the heart can be returned to the original state by injecting the heat exchange fluid that has been reheated to the living body temperature. Conventionally, various types of heat exchangers have been devised, and a heat exchanger and a filter for removing bubbles are separated, or a bubble removing unit (bubble trap) including a heat exchange unit and a filter. There is a thing with the adjoining. This is because heat is exchanged by the heat exchanger and the generated (or mixed) bubbles are removed by the filter. As an example, there is a heat exchanger using a metal bellows tube whose both ends are fixed by a seal material in a cylindrical housing.
In the heat exchanger, the heat exchange fluid is circulated outside the bellows tube in the housing, and the heat exchange medium is circulated in the bellows tube, so that the heat exchange medium and the heat exchange fluid are passed through the tube. Heat exchange with. For removing air bubbles, a filter having an opening size of 110 to 180 μm is usually provided to remove air bubbles generated in the heat exchange section or air bubbles mixed in the circuit.

[0003]

As described above, a heat exchange fluid (such as myocardial protection liquid or blood) in the case of cardiac surgery or the like.
It is known to provide a heat exchanger in the blood circuit for cooling purposes. However, the conventional heat exchanger or the blood circuit (or heat exchange fluid circuit) incorporating the heat exchanger has various drawbacks as described below.

First, the heat exchanger itself or a circuit including the heat exchanger is not compact in size and shape, and in particular, the heat exchanger and the bubble removing filter (or bubble removing section) are combined for heat exchange. There is a problem that the priming volume of the working fluid is large. This priming volume also becomes a dead volume (amount of liquid not used) at the end of liquid injection or at the time of suspension of liquid injection, in which case this amount of heat exchange fluid is wasted. Further, when changing the type of fluid, if the remaining amount of the previous fluid is large, it takes much time to replace the new fluid. For these reasons, it is desirable that the priming volume is small within a range that satisfies the heat exchange effect of the heat exchanger.

Secondly, since the filter provided in the conventional heat exchanger for removing bubbles has a large pore size as described above, it is impossible to remove foreign matters such as fine bubbles and fine particles.
Taking into account the effect on heart tissue, liquid delivery to the coronary arteries (blood delivery)
The current ones have not always been clinically satisfactory, as the filtration of the fluid carried is so important. However, since it is not unusual for blood to flow through the heat exchanger, a filter with a small pore size that can be clogged with blood
I couldn't even wear it.

Third, there was the problem of blood clots. Bubbles tend to be generated when the heat exchange fluid is heated by the heat exchanger, but this is a problem particularly when the heat exchange fluid is blood. This is because the presence of air bubbles, fine particles, and minute foreign substances in the blood makes it easier for blood clumps to form. In particular, when the heat exchanger and the filter are separately installed, the air bubbles (or minute foreign substances mixed in) generated in the heat exchanger exist in the blood without being removed to the attachment site of the filter. There is a problem that blood clots are easily formed.

[0007]

Means for Solving the Problems The present inventors
A housing, a heat exchange medium outlet provided at a lower end, a heat exchange medium inlet provided at an upper end, and a lower heat exchange fluid provided at a position between the medium outlet and the medium inlet. A heat exchange part having an inflow port and a communication port for the heat exchange fluid in the upper part, and a filtration part coupled to the heat exchange part at the communication port of the heat exchange part, Is provided with a large number of heat exchanging thin tubes whose both ends are fixed to both ends of the first housing, and a seal material covering both ends of the thin tubes liquid-tightly separates the heat exchanging fluid chamber and the medium chamber. And the fluid chambers are arranged in the order of flow such that the heat exchange fluid inlet, the first
A region outside the heat exchanging thin tube of the inner cavity of the housing communicates with the communication port, and the medium chamber communicates with the medium inflow port, the heat exchanging thin tube, and the medium outflow port. The excess portion is a cylindrical second housing, a heat exchange fluid outlet provided at the lower end, and an opening size of 20 to 60 μm mounted between the communication opening and the heat exchange fluid outlet.
The above-mentioned problems are solved by a heat exchanger characterized in that the heat exchange fluid chamber has a filter and a lumen of the second housing and the heat exchange fluid outlet communicates with the heat exchange fluid chamber. .

[0008]

By integrating the heat exchanger and the filter, the size and shape are made compact and the priming volume of the heat exchange fluid is reduced. Further, by adopting a filter having an appropriate opening size, small air bubbles and minute foreign matter are removed, and even if blood is flown, it is filtered without clogging. In addition, air bubbles that tend to be generated in the heat exchanger are
Since it is immediately removed by the method, blood clots are unlikely to occur.

[0009]

An embodiment of the present invention will be described in more detail with reference to the drawings. A heat exchanger 1 with a filter according to the present invention shown in FIG. 1 has a heat exchange section B for increasing or decreasing the temperature of a fluid, and a filtration section C for removing air bubbles, minute foreign matters and the like. Have and. The heat exchange section B and the filtration section C communicate with each other through the communication port 4. The heat exchange section B is a cylindrical first
The housing 2, the heat exchange medium inlet 5 provided at the upper end thereof, the heat exchange medium outlet 6 provided at the lower end thereof, and the heat exchange medium outlet 6 provided slightly above the heat exchange medium outlet 6. The heat exchange fluid inlet 7 and the communication port 4 provided slightly below the heat exchange medium inlet 5.
As shown in FIG. 2, for heat exchange, a large number of heat exchanging thin tubes 8 are arranged in the heat exchanging portion B in the axial direction of the first housing 2, and the thin tubes 8 are left open at both ends. It is fixed to both ends of the first housing 2 in this state. The shape of the thin tube 8 is not particularly limited, but a straight tube or the like is selected because it is simple. As a material of the heat exchange thin tube, a material having high heat conductivity, for example, stainless steel, aluminum, copper, titanium or the like is preferable. From the viewpoint of heat exchange efficiency, the outer shape of the thin tube 8 is 0.8 to 1.8 mm, The effective length (the length by which the fluid can directly contact the thin tube 8) is preferably in the range of 50 to 200 mm. Both ends of the heat exchange thin tube 8 are covered with a seal material 9,
The seal material 9 liquid-tightly isolates the heat exchange section B between the heat exchange fluid chamber and the medium chamber. The fluid chamber communicates with the heat exchange fluid inlet 7, the region outside the heat exchange thin tube in the inner cavity of the first housing 2, and the communication port 4 in the order of flow,
The medium chamber communicates with the medium inlet 5, the heat exchange thin tube 8, and the medium outlet 6. The filtration part C is a cylindrical second
The housing 3, the heat exchange fluid outlet 10 provided at the lower end thereof, and a filter mounted between the communication port 4 and the heat exchange fluid outlet 10 so as to remove bubbles and minute foreign matter. 11 and 11. The opening size of the filter 11 is preferably 20 to 60 μm, and if it is larger than this, it is impossible to remove minute foreign matters and small bubbles in the fluid storage container such as the coring, and if it is small, it is possible to immediately use blood etc. as the fluid. It will be blocked. The communication port 4 and the heat exchange fluid outlet 10 communicate with the heat exchange fluid chamber so that the heat-exchanged fluid can pass through the filtration section C. The filter 11 is mounted in a pleated state so as to improve the effective permeable membrane area. A degassing port 12 for removing bubbles is provided at the upper end portion (at least above the communication port 4) of the filtration part C. The degassing port 12 has a membrane made of a hydrophobic material attached to the ventilation hole, and allows only gas to pass without passing fluid. The degassing port 12 may be provided between the communication port 4 and the filter-11, between the filter-11 and the heat exchange fluid outlet 10, or both as necessary. In addition, the filtration part C has a pressure monitor-line connection port 13 for measuring fluid injection pressure at its upper end and a temperature sensor-insertion port 1 at its lower end.
4 is provided to measure the pressure of blood pressure and other fluids,
The temperature of the fluid can also be measured over time. As described above, by the heat exchanger 1 of the present invention described above, the priming volume that combines the heat exchange section B and the filtration section C, that is, the fluid from the heat exchange fluid inlet 7 to the heat exchange fluid outlet 10 is supplied. The volume when injected was 30 to 50 ml, which was significantly reduced compared to the case where the heat exchange section B and the filtration section C were separately provided. (If the heat exchange efficiency is equivalent, the priming volume is 70 to 100 ml.) Next, how the heat exchange fluid and the heat exchange medium flow through the heat exchanger 1 with a filter. It will be explained in the order of circulation whether the bubbles and the foreign matter are removed by heat exchange. First, a heat exchange medium such as water enters from the heat exchange medium inflow port 5, and a heat exchange thin tube 8
And exits from the heat exchange medium outlet 6. The fluid entering from the heat exchange fluid inlet 7 passes through the heat exchange fluid chamber surrounded by the inner wall of the first housing 2 and the seal materials 9 at both ends thereof, and passes through the thin tube 8 to form the heat exchange medium. And heat exchange with. At that time, bubbles are often generated in the fluid, especially when the temperature is reheated (after the surgery, the lowered body temperature is increased). Even if large bubbles do not pass through the filter,
Although it is naturally discharged from the deaeration valve, small bubbles may be retained in the capillaries 8 and the corners of the housing, or may be introduced into the living body. The small air bubbles and minute foreign matters are filtered by the filter-11 provided in the filtering section C, and the filtered fluid flows out from the heat exchange fluid outlet 10 provided at the lower end of the second housing 3. To do. The small air bubbles trapped in the filter-11 aggregate into large air bubbles and are discharged from the degassing port.

[0010]

First of all, by integrating the filter and the heat exchanger, the size and shape of the whole extracorporeal circulation circuit can be made compact and can be simplified. Further, since the circuit is simplified, the priming volume of the heat exchange fluid can be reduced, and a heat exchanger with good heat exchange efficiency and less dead volume can be realized.

Secondly, since a filter having an appropriate opening size is used, it is possible to remove minute bubbles and foreign matters, and circulate either a crystalline liquid or blood as a heat exchange fluid. It is possible to It is also possible to inject by changing the heat exchange fluid from the crystalloid to blood or vice versa from the middle of the procedure, depending on the clinical need. be able to.

Thirdly, since the filter is installed immediately after the heat exchanger, the air bubbles generated in the heat exchanger are also immediately removed by this filter, and blood clots are unlikely to occur. In addition, foreign matter such as blood clots and mixed fine particles generated for some reason can be filtered by the filter before the filter portion without being clogged by the filter.

Further, if necessary, the following effects can be obtained by adopting the following configurations. By installing a degassing port having a hydrophobic film on the upper part of the filter part, it is possible to easily remove air bubbles even if they are mixed. Further, by providing the pressure monitor-line connection port and the temperature sensor-insertion port in the filtration section, the extracorporeal circulation circuit can be further simplified.

[Brief description of drawings]

FIG. 1 is a front perspective view showing the overall structure of the present invention.

FIG. 2 is a cross-sectional view taken along a plane including line AA in FIG. 1 and perpendicular to the direction of the heat exchange thin tube.

[Explanation of symbols]

1. Heat exchanger with filter 2. First housing 3. Second housing 4. Communication port 5. Heat exchange medium inlet 6. Heat exchange medium outlet 7. Heat exchange fluid inlet 8. Heat exchange thin tube 9. Seal material 10. Heat exchange fluid outlet 11. Filter- 12. Degassing 13. Pressure monitor-line connection port 14. Temperature sensor-insertion port B. Heat exchange section C. Filtration department

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-56-95056 (JP, A) JP-A-54-164399 (JP, A) JP-A-57-134165 (JP, A) JP-A-6- 327765 (JP, A) JP-A-2-102661 (JP, A) JP-A-2-128769 (JP, A) Actually open flat 3-16944 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) A61M 1/36 515

Claims (4)

(57) [Claims] 1. A cylindrical first housing, a heat exchange medium outlet provided at a lower end and a heat exchange medium inlet provided at an upper end, and a position between the medium outlet and the medium inlet. A heat exchange part having a lower heat exchange fluid inlet and an upper heat exchange fluid communication port, and a filtration part coupled to the heat exchange part at the heat exchange part communication port; And a plurality of heat exchanging thin tubes having both ends fixed to both ends of the first housing are arranged in the heat exchanging portion, and a heat exchanging fluid is provided by a seal material covering both ends of the thin tube. Is fluid-tightly separated into a chamber and a medium chamber, and the fluid chamber communicates with a fluid inlet for heat exchange, a region outside the thin tube for heat exchange in the lumen of the first housing, and a communication port in the order of flow. And the medium chamber communicates with the medium inlet, the heat exchange thin tube, and the medium outlet. The filtration part is adjacent to the communication port between the second housing having a tubular shape, the heat exchange fluid outlet provided at the lower end, and the communication port and the heat exchange fluid outlet.
Opening size 20 to 60 installed so as to be in contact with each other
A heat exchanger having a μm filter, wherein the inner cavity of the second housing and the heat exchange fluid outlet communicate with the heat exchange fluid chamber. 2. The heat exchanger according to claim 1, wherein a deaeration port having a hydrophobic film is attached to an upper portion of the filtration section above the communication port. 3. The pressure monitor-line connection port for measuring a fluid injection pressure is provided on the upper part of the filtration part, and the sensor insertion port for temperature measurement is provided on the lower part of the filtration part. The heat exchanger according to the section. 4. The priming volume when the fluid is injected from the heat exchange fluid inflow port to the heat exchange fluid outflow port is 30 to 50 ml. Heat exchanger.