JP2605192B2 - Blood pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blood pump, and more particularly, to a small and lightweight blood pump which is less likely to cause hemolysis.
The present invention relates to a blood pump that can be used safely for a long time and is suitable for use in an extracorporeal circulation circuit such as a heart-lung machine or a cardio-assistive circulator after open heart surgery.

[0002]

2. Description of the Related Art Conventionally, as a blood pump for an extracorporeal circuit such as an artificial heart-lung machine or a cardio-assistive circulator after open heart surgery, a pulsating pump type for supplying a pulsating flow and a smoothing pump have been known. A centrifugal pump type blood pump is known in addition to a roller pump type for supplying a flow. 2. Description of the Related Art As a conventional centrifugal pump type blood pump, the one shown mainly in FIGS. 2 and 3 is known.

The blood pump of FIG. 2 has a conical upper end surface in the space of
When the shaft 24 is rotated by a motor (not shown), the impeller includes a cylindrical pedestal 21 having a bottom surface having a diameter much smaller than the diameter of the pedestal 21 and a plurality of blades 22 provided radially on an outer peripheral surface thereof. The structure is such that blood flows as blood flow 23 in the figure. However,
The blood pump has a vortex 25 near the outer periphery of the pedestal 21.
Is generated, and a very large stress is applied to the blood cells, so that the blood cells are destroyed and hemolysis occurs.

On the other hand, the blood pump shown in FIG. 3 has a base 2 having a substantially conical shape in the space of a housing 29.
7 and a plurality of plate-like blades 28 radially provided from a position at a fixed distance from the vertex of the pedestal 27 on the curved surface thereof. Is a structure that flows like the blood flow 31 in the figure. In this blood pump, the bottom surface of the pedestal 27 is
Since it has an area that covers almost the entire inner bottom surface of 2,
No vortex is generated as in the blood pump shown in FIG.

[0005] However, even with this blood pump, the occurrence of hemolysis cannot be effectively suppressed to a satisfactory level, and the blood discharge efficiency is not sufficient. Furthermore, since the blade 28 is a curved plate (as viewed from above), there is a problem that it is difficult to manufacture the integral molding with the pedestal 27.

In the blood pump shown in FIGS. 2 and 3, ball bearings are required to fix the shafts 24 and 30. However, when a ball bearing is used, since the ball bearing comes into contact with blood, the lubrication environment inside the bearing changes, and the lubrication performance of the ball bearing rapidly decreases as the blood pump is used more and more. Was. In order to solve this problem, the use of a sealing material such as packing instead of the ball bearing has been considered. However, it has been found that, even though the sealing material is used, the blood pump has been used for a long period of time, which causes a new problem that blood leaks from the sealing portion. Therefore, when a blood pump using a sealing material is used to solve the problem caused by the use of the ball bearing, it is inevitable to replace the blood pump in use at an appropriate time before blood leakage occurs. . However, such frequent replacement of the blood pump is cumbersome and impractical.

The present invention has been made to improve the above situation. That is, an object of the present invention is to reduce the occurrence of hemolysis, to be small and lightweight, to be used safely for a long time, and to be suitable for an extracorporeal circulation circuit such as a heart-lung machine or a heart assisting circulation device after open heart surgery. It is an object of the present invention to provide a centrifugal pump type blood pump which can be used for:

[0008]

According to the present invention, there is provided a blood discharge hole provided with a blood introduction hole on a top and opened on a side in a direction perpendicular to an opening direction of the blood introduction hole. A first housing provided with a second housing provided with a partition wall with respect to the first housing chamber;
A prime mover having a second magnet provided in the second housing and disposed on one end side facing the partition wall and having a connecting portion connecting a driving source on the other end side; A pedestal , which is rotatably supported in a point contact state by a support shaft erected on the partition wall toward the housing and is arranged in a non-contact state with respect to the partition wall, faces a blood introduction hole of the pedestal. a plurality of blades on the upper surface, comprising <br/> a first magnet at a position corresponding to the front <br/> Symbol second magnet of the pedestal, the lower surface of the base so as to discharge said support shaft near the blood And a driven body provided with a blood flow passage penetrating from the upper surface to the upper surface.

[0009]

Hereinafter, the present invention will be described in detail. In the blood pump of the present invention, the rotation of the driven body consisting of the pedestal and the blade is performed between the second magnet attached to the prime mover connected to the driving source outside the second housing chamber and the first magnet attached to the pedestal. The rotating shaft connected to an external drive source is omitted from the pedestal unlike the conventional case, and the first housing and the second housing are separated by a partition. Therefore, there is no possibility that blood in the first housing leaks out of the first housing.

Further, the pedestal is supported in a point contact state by a support shaft erected from the partition wall and in a state of floating from the partition wall. Since the blood flow passage extending to the blood ejection hole via the lower surface is formed, the retention of blood generated between the pedestal and the upper surface of the partition wall is reduced, and the accumulation of heat in the blood due to the rotation of the blades is also reduced. As a result, the hemolysis phenomenon can be reduced. Further, since the bottom surface of the pedestal is formed so as to cover substantially the entire bottom surface of the first housing chamber, the blood flow is smooth, and no eddy current of the blood is generated.
For example, stress due to, for example, shearing force or vortex applied to blood flowing in the blood pump can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a blood pump according to the present embodiment includes a first housing 1 and a second housing 4 which is adjacent to the first housing 1 with a partition wall 3 interposed therebetween. The first housing 1 and the second housing 4 are detachably connected.
The mechanism of the connection between the first housing 1 and the second housing 4 is as follows.

That is, as shown in FIG. 4, one half of the peripheral side surface of the second housing 4 extends slightly more in the axial direction than the other half, and its front end surface extends in the axial direction of the second housing 4. To form a coupling groove 4a, and the end surface 4b of the second housing 4 facing the coupling groove 4a is provided with:
A coupling pin 4c is provided. The coupling pin 4c projects from the end surface 4b of the second housing 4 by being constantly urged by an urging member (not shown), and the coupling pin 4c is pressed against the urging member by operating the operation button 4d. Can be retracted into the end face 4b of the main body.

The first housing 1 has a fitting portion 1a at the tip end thereof for fitting into the coupling groove 4a, and the coupling pin 4c at the tip end surface of the first housing 1.
Is formed by drilling a coupling hole 1b into which a hole is inserted. The first housing 1 can be integrally coupled to the second housing 4 by fitting the fitting portion 1a into the coupling groove 4a of the second housing 4 and inserting the coupling pin 4c into the coupling hole 1b. .

The first housing 1 is sterilized before use, and after being used integrally with the second housing 4, the first housing 1 is discarded. That is,
The first housing 1 can be a disposable product. Further, since the second housing 4 has no part that comes into contact with blood in particular, it is not particularly sterilized before use, and even after being used in combination with the first housing 1, It can be used any number of times in new combinations. Incidentally, the mechanism of the connection between the first housing 1 and the second housing 4 is described in FIG.
However, the present invention is not limited to the mechanism shown in FIG.

The first housing 1 has a blood inlet 5 at the top and a blood outlet 6 which opens in a direction perpendicular to the opening direction of the blood inlet 5 at the side. In the first housing 1, a pedestal 8 in which a large number of blades 9 having a circular truncated cone shape are arranged upright on the upper surface and a circular dish-shaped lower cover 8 a is fitted on the lower surface, and a lower portion of the pedestal 8. A driven body 10, which is a circular arrangement of the first magnet 11 mounted in the cover 8a, that is, an impeller is arranged.

The size of the bottom surface of the pedestal 8 is large enough to cover substantially the entire bottom surface of the first housing 1, that is, the size of the partition wall 3.
Is set to a size that substantially covers the upper surface of the. Also, inside the center of the pedestal 8, the upper half is fitted into a hemispherical concave portion provided on the pedestal 8, and the lower half faces the shaft support cylinder 8b provided at the center of the lower cover 8a. An exposed sphere 12 is arranged. Then, in the peripheral area of the sphere 12,
A required number of through holes 13 penetrating from the upper surface of the pedestal 8 to the shaft support cylinder 8b side are provided. In addition, the shaft support cylinder 8
A cylindrical slide bearing 14 is mounted on b.

At the center of the partition wall 3, a support shaft 3 a reaching substantially the upper end of the cylindrical slide bearing 14 is provided upright with a small gap between the support shaft 3 a and the inner peripheral surface of the slide bearing 14. I have. Note that the top surface of the support shaft 3a is formed slightly concave, and the spherical body 12 is located in the concave surface, so that point contact between the spherical body 12 and the support shaft 3a is realized and the follower During rotation, the sphere 12 does not deviate from the top surface of the support shaft 3a.

The slide bearing 14 is made of ceramics, preferably, Si ₃ N ₄ . With such a structure, the pedestal 8 is rotatably supported by the support shaft 3a in a point-contact manner and in a state of being separated from the partition wall 3, and the through hole 13 A blood flow passage is formed as shown by a dotted line in FIG. 1 and communicates with the blood discharge port 6 through the minute gap and between the lower cover 8a and the partition wall 3.

On the other hand, the second housing 4 has a rotating shaft 15
The second magnet 16 ring through the disc-shaped support member to the upper end of the and the back yoke 17 is first magnet 1
A prime mover 18 integrally mounted so as to face 1 is arranged. The rotating shaft 15 is rotatably supported inside the second housing 4 by a lower bearing 19, and its rear end is exposed at the lower end side of the second housing 4, and is driven by a driving source such as a motor via a flexible shaft (not shown). (Not shown).

In the above configuration, when the driving source is started, the rotating shaft 15 rotates, and the second magnet 16 mounted on the rotating shaft 15 also rotates. Then, the second magnet 16 and the first magnet 16
Since a magnetic force (attraction force) acts between the first magnet 1 and the first magnet 1 as the second magnet 16 rotates.
One also rotates. That is, the follower 10 also rotates together with the first magnet 11, whereby the blood inlet 5
From the first housing 1, and is discharged to the blood discharge port 6 by the blades 9 of the driven body 10.

As is apparent from the above configuration, in this embodiment, unlike the conventional example, the follower 10 is completely separated from the prime mover 18 by the partition wall 3, so that the rotating shaft as in the conventional example is used. The haemolysis phenomenon caused by the rotation of is eliminated or significantly reduced. Further, since the pedestal 8 is provided with the above-described blood flow passage, blood stagnation between the lower surface of the pedestal 8 and the upper surface of the partition wall 3 can be prevented, and blood can be discharged smoothly. Further, since the sliding bearing 14 is made of ceramics, it is excellent in wear resistance and can realize smooth rotation of the driven body without requiring lubricating oil.

The present invention is not limited to the above embodiment,
Various modifications can be made without departing from the scope of the invention. For example, the first magnet is
In addition to the arrangement shown in FIG. 1, it is also possible to fix to the lower surface of the pedestal 8. As the structure of the blade, a conventionally known structure can be applied to the present invention, and a cone other than a truncated cone can be employed as the shape of the pedestal. An inverted cone may be used instead of the sphere 12.

[0023]

According to the blood pump of the present invention, the follower is completely separated from the prime mover, and the blood flow path is formed in the base of the follower, so that hemolysis can be significantly reduced. . Furthermore, since it is small, lightweight, and hard to break down, it can be used safely for a long period of time.

Therefore, the present invention is extremely suitable for use in an extracorporeal circulation circuit such as a heart-lung machine or a heart assisting circuit after open heart surgery.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing an embodiment of a blood pump according to the present invention.

FIG. 2 is a cross-sectional view showing a main part of a conventional blood pump.

FIG. 3 is a cross-sectional view showing a main part of another conventional blood pump.

FIG. 4 is a perspective view showing a mechanism of connection between a first housing and a second housing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st housing room 3 Partition wall 4 2nd housing room 8 Pedestal 9 Blade 10 Follower 11 First magnet 13 Through hole 15 Rotation axis 16 Second magnet 18 Primer

Claims (3)

(57) [Claims] 1. A first housing having a blood introduction hole at a top portion and a blood ejection hole opening at a side in a direction orthogonal to an opening direction of the blood introduction hole, and a first housing chamber. A second housing provided with a partition wall therebetween, and a second magnet provided inside the second housing and disposed at one end side facing the partition wall, and a drive source connected to the other end side. And a pedestal that is rotatably supported in a point contact state by a support shaft erected on the partition wall toward the inside of the first housing and is disposed in a non-contact state with respect to the partition wall. a plurality of blades on the upper surface toward the <br/> blood introduction hole of the pedestal, and the first magnet at a position corresponding to <br/> the second magnet of the pedestal
And a driven body having a blood flow passage penetrating from the lower surface to the upper surface of the pedestal so as to discharge blood around the support shaft. 2. The blood pump of claim 1, wherein said pedestal is frustoconical with a bottom surface substantially covering the entire bottom surface of the first housing chamber. 3. The blood pump according to claim 1, wherein the first housing and the second housing are detachably assembled.