JP2011206069A - Blood pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact blood pump in which the quantity of hemolysis and clot of blood are reduced.SOLUTION: A turbine type regeneration pump 2 is combined with a cylindrical distributor 8 having a spiral channel, and removably connected to a drive unit 1 having a motor and a magnetic coupling, thus constituting the periphery of the blood pump.

Description

  The present invention relates to a blood pump used for medical purposes such as heart-lung machine.

A heart-lung machine is used during heart surgery. During the operation, blood circulates through the heart-lung machine, the blood extracted from the vena cava is gas exchanged, the temperature is adjusted, and the blood is returned from the femoral artery to the body. Therefore, the oxygenator is composed of a blood pump that replaces the heart, an oxygenator that performs gas exchange, a heat exchanger for adjusting body temperature, and the like.
One of the problems in the heart-lung machine is the problem of the capacity of the priming solution that fills the circuit. That is, if the volume of the priming solution can be reduced, the degree of dilution of the patient's blood is small, so that postoperative recovery is good. For this reason, it is important to reduce the volume of the priming solution by reducing the volume of the heart-lung machine including the blood conduit, and downsizing the heart-lung machine or blood pump is an important technical issue. .

In addition, blood pumps are also used for assistance during cardiac surgery and other medical purposes.
Conventionally used as a blood pump is a centrifugal pump. As an example, a turbo blood pump described in Patent Document 1 is shown in FIG. A housing 91 has a pump chamber 92 that allows blood to pass therethrough and flow. The housing 91 is provided with an inflow port 93 that communicates with the upper portion of the pump chamber 92 and an outflow port 94 that communicates with the side of the pump chamber 92. An impeller 95 is disposed in the pump chamber 92, 96 is a rotating shaft thereof, 97 is an upper bearing, and 98 is a lower bearing. On the other hand, a drive shaft 99 that drives the impeller 95 via the magnetic force of the magnet is disposed at the lower portion of the housing 91.

Patent Document 2 describes a heart-lung machine that is constructed by integrating a blood pump into a cylindrical oxygenator incorporating a heat exchanger and integrating a blood pump in series and further integrating a removable drive unit in series. Has been. The blood pump used here is a wave pump (oscillating displacement moving continuous flow blood pump).
In the case of a centrifugal pump as described in Patent Document 1, the orientation of the inflow port and the outflow port with respect to the pump is limited, and there is a problem that a compact assembly cannot be performed. It was a large device that had to be installed in a separate room from the room, and required a large volume of priming liquid. In order to solve these problems, the invention described in Patent Document 2 aims to integrate an artificial lung incorporating a heat exchanger, a blood pump, and a detachable drive unit in series. We aim to realize a small heart-lung machine that can be brought into the field and can greatly reduce the volume of the priming solution.

  FIG. 12 is a cross-sectional view showing the structure of the wave pump described in Patent Document 2. The right side of the figure is the drive unit 1, the left side is the pump 2, and both can be divided by the AA line in the figure, and the pump 2 to the artificial lung 4 are disposable for each use. The drive unit 1 forms a motor with a coil 16 and a stator 17 and rotates a central drive shaft 18. An oblique tilting shaft 19 is fitted in the center of the drive shaft 18, and by the rotation of the drive shaft 13, the drive shaft 13 does not rotate itself but performs a “rubbing motion” (also referred to as precession motion or razor motion).

On the other hand, the pump 2 has a pump chamber 211 that is fan-shaped on the outside when viewed in the radial cross section. A donut-shaped disk is inserted into the pump chamber 211, and this is called a mover 213. A dish-like support plate 212 is attached to the central portion of the mover 213 and is fitted to the tip of the rotary drive shaft 13 in a state combined with the drive unit 1. As a result, the mover 213 is sequentially tilted in the pump chamber 211 in accordance with the plowing motion of the rotary drive shaft 18 to transfer the internal fluid. 22 is an inflow port and 33 is an outflow port.
JP 2007-222670 A JP 2004-154425 A

As a blood pump, it is first necessary that a predetermined flow rate can be obtained at a predetermined pressure. However, it is also important that there is little destruction of erythrocytes and less internal clotting during use. Since conventional blood pumps generally have a high rotation speed, it has been pointed out that the blood pump is liable to cause hemolysis, and a blood pump capable of obtaining a required pressure and flow rate at a lower rotation speed has been desired.
An object of this invention is to implement | achieve a compact blood pump with few hemolysis and coagulation.

  The present invention according to claim 1 is a regenerative pump comprising an impeller with a coring, a first casing that houses the impeller, and a second casing that faces the impeller. The casing has an incomplete circumferential semi-circular groove with less than one circumference, and an inflow port is opened near the center of one end and an outflow port is opened near the outer diameter of the other end. Is a blood pump characterized by

According to a second aspect of the present invention, the impeller with a coring is driven via a magnetic coupling including a magnet disposed therein and a magnet disposed in a driving unit. The blood pump according to claim 1.
According to a third aspect of the present invention, there is an opening connected to the outflow port on the outflow port side of the second casing, and a spiral channel that is open over the entire circumference is connected to the opposite side. The blood pump according to claim 1 or 2.

According to a fourth aspect of the present invention, the bearing of the impeller is provided at a pivot-shaped shaft end portion attached to the center position of both surfaces of the impeller and the center positions of the first and second casings on both sides. The blood pump according to claim 2 or 3, comprising a receiving portion.
The present invention according to claim 5 is the blood pump according to any one of claims 2 to 4, wherein the impeller is provided with a plurality of holes penetrating both surfaces of the impeller near the center thereof. It is.

  According to the present invention, a blood pump that is small and light, requires a small amount of priming solution, and has little internal clotting and hemolysis can be realized, which has an excellent effect of greatly contributing to lifesaving in an emergency such as cardiac arrest.

  The emergency lifesaving apparatus of this invention is demonstrated with drawing. FIG. 1 is a cross-sectional view showing a blood pump of the embodiment and its peripheral part, wherein 1 is a drive unit, 11 is a motor, 12 is a yoke attached to its rotating shaft, 13 is a base plate to which the motor 11 is attached, and 14 is a base plate. Numeral 15 is a magnet embedded in the yoke 12. Although details of the pump 2 will be described later, reference numeral 25 denotes an impeller, which also has a magnet 253 embedded therein. The casing of the pump 2 that houses the impeller 25 is divided into a first casing 23 and a second casing 24. This is for assembly, and in use, the two casings 23, 24 are integrated together. It is joined. The pump 2 is directly fixed to the base plate 13 by the first casing 23 and the locking claw 14. Therefore, the pump 2 can be detached from the drive unit 1 between the base plate 13 and the first casing 23 by opening the locking claws 14.

In FIG. 1, for example, an artificial lung is connected to the left part from the pump 2. Since the patient's blood flows through these parts when used, these parts must be made disposable after each use. Therefore, it is desirable that they be made of resin by injection molding, etc., and be lightweight, small and inexpensive.
The rotation shaft of the motor 11 does not reach the pump 2 directly, but the rotation is transmitted by a magnetic coupling composed of opposing magnets 15 and 253. Therefore, the yoke 12, the base plate 13, the casings 23 and 24, etc. are preferably non-magnetic materials such as titanium and resin in the sense that they do not interfere with the lines of magnetic force. Since the rotating shaft does not penetrate the casing, the blood in the pump 2 does not leak to the drive unit 1 side, and there is no possibility that foreign matter such as lubricating oil is mixed in the blood. Note that driving the pump using magnetic force is a publicly known matter described in Patent Document 1 shown above.

Reference numeral 5 denotes a blood inflow tube. The blood fed from the blood removal cannula (Kanule, insertion tube) enters the pump 2 through the inflow tube 5, is evenly distributed in the circumferential direction by the distributor 8 and enters the artificial lung, which is shown in FIG. It is fed into the blood cannula from the outflow port and returns to the patient's body.
FIG. 2 is a perspective view showing a part of the impeller 25 of the regenerative pump 2 according to the embodiment, in which 251 is a blade, and 252 is a coring. It is well known from documents such as “Handbook of Engineering” (edited by the Japan Society of Mechanical Engineers)

253 is the magnet described above, 254 is a plurality of holes penetrating both surfaces of the impeller provided near the center of the impeller 25, 255 is a pivot-shaped shaft end provided at the center position of both surfaces of the impeller 25, In this case, it is a sphere. These will be described later.
FIG. 3 is a plan view of the second casing 24 facing the impeller. A groove 241 having a semicircular cross section that is incomplete and less than one round is provided, and an inflow port 244 opens at a position near the center of one end, and an outflow port 245 opens at a position near the outer diameter at the other end. Reference numeral 242 denotes a coring groove corresponding to the coring, 243 denotes a receiving portion which will be described later, and in this case, a spherical recess. This indentation is also provided in the first casing 23 in the same manner.

  FIG. 4 is an explanatory diagram for explaining the pump action of the pump 2. The blood flowing into the pump 2 from the inflow port 244 of the second casing 24 as indicated by the arrow A hits the rotating blade 251 and is caused to flow outward with respect to the rotation axis as indicated by the arrow B by the centrifugal force, and as indicated by the arrow C. From the outflow port 245. At this time, a part of the blood also flows into the gap between the rear side of the impeller 25 and the first casing 23 as indicated by an arrow a, but the hole 254 closer to the center of the impeller 25 as indicated by an arrow b. It passes back to the front side of the impeller 25 as shown by the arrow c and joins the entire flow, so that blood does not stay in the gap and cause blood clots.

  FIG. 5 is a perspective view of the distributor 8 as seen from the pump side, and FIG. 6 is a perspective view of the distributor 8 as seen from the opposite side (for example, the oxygenator side). The distributor has a thin cylindrical shape, and the size (diameter) corresponds to the outflow port 245 of the pump 2. On the pump side, an opening connected to the outflow port 245 is provided, and on the opposite side, a spiral flow path 81 that is opened over the entire circumference is provided. Thereby, for example, blood flows out almost evenly from the entire circumference of the oxygenator, so that it can be distributed evenly to all the elements of the cylindrical oxygenator.

  FIG. 7 is a partial cross-sectional view showing a bearing structure between the impeller and the casings on both sides. Reference numeral 25 denotes an impeller, 255 denotes a pivot-shaped shaft end attached to the center position of the surface of the impeller 25, It is a receiving portion provided in the central portion of the second casing 24. There is also a similar receiving part on the first casing 23 side. That is, the bearing of the impeller 25 includes a pivot-shaped shaft end portion 255 provided at the center position on both surfaces of the impeller and receiving portions provided at the center positions of the first and second casings on both sides. In this example, the shaft end portion 255 is a sphere, and the receiving portion 243 is a corresponding spherical recess. Since there is almost no gap between the sphere and the indentation, blood will not enter and coagulate. In addition to attaching such a small sphere as the shaft end portion, the shaft itself may be sharpened or pointed, and the receiving portion may have a corresponding shape. In the case of a sphere, a hard object such as a steel ball or a ceramic ball, and a receiving part having good lubricity, for example, jewelry such as ruby or crystal, metal, resin, etc. are desirable.

The receiving part 243 preferably has a shape raised from the surface of the casing. In FIG. 7, the rising dimension e of the receiving portion 243 is required for the gap d between the impeller 25 and the casing, whereby the blood flow in FIG. 4 is smoothly converted from the arrow a to the arrow b, Since no stagnation occurs, blood coagulation and hemolysis do not occur.
As a blood pump, a flow rate of 5 to 6 liters per minute and a pressure (differential pressure) of about 500 mm of mercury are required. FIG. 8 is a graph showing the performance test results of the six-blade pump of the embodiment of the present invention. For the above performance, 1800 revolutions per minute is necessary, but if the pressure is about 50 to 100 mm, 800 revolutions per minute is sufficient. FIG. 9 also shows the case of the 12-blade pump of the embodiment of the present invention. For the above performance, 1600 revolutions per minute is necessary. However, if the pressure is about 50 to 100 mm, 800 revolutions per minute is sufficient. It can be seen that it is. On the other hand, FIG. 10 is a graph showing the performance test results of the wave pump described in Patent Document 2. In order to exert a pressure of 50 to 100 mm, 1200 revolutions per minute are required, and 2400 revolutions per minute are necessary for the originally required performance. Thus, if it is a turbine type | mold regenerative pump used by this invention, since required performance can be exhibited at the rotation speed of about 2/3 of a wave pump, there is little hemolysis and an emergency treatment can be performed without a disorder | damage | failure.

  Table 1 compares the amount of hemolysis of each pump under the conditions of a flow rate of 5 liters per minute and a pressure of 100 mm. The hemolysis index NIH indicates the amount of free hemoglobin, that is, the amount of erythrocyte destruction, and the smaller one is preferable. Example 1 is a turbine-type pump 6-blade according to an embodiment of the present invention, Example 2 is a turbine-type pump 12-blade according to an embodiment of the present invention, a comparative example is a wave pump described in Patent Document 2, and a conventional example is This is a centrifugal pump used in a conventional cardiopulmonary apparatus as described in Patent Document 1. It is recognized that the numerical value of NIH corresponds to the structure of the pump and the rotation amount. In the examples, the 12-blade has a lower NIH value and is superior in hemolysis because the flow rate of the 12-blade is larger at the same rotation speed, so the rotation speed should be reduced accordingly. This is thought to be possible.

It is sectional drawing which shows the blood pump and peripheral part of an Example of this invention. It is a perspective view which cuts and shows a part of impeller of a turbine type pump of an example of the present invention. FIG. 6 is a plan view of a second casing according to the embodiment of the present invention. It is explanatory drawing explaining the pump effect | action of the pump of an Example. It is the perspective view which looked at the distributor of an example from the pump side. It is the perspective view which looked at the distributor of an example from the artificial lung side. It is a fragmentary sectional view which shows the bearing structure of the impeller of an Example. It is a graph which shows the performance test result of the pump of an Example of this invention. It is a graph which similarly shows the performance test result of the pump of an Example of this invention. It is a graph which shows the performance test result of the pump in a prior art. It is sectional drawing which shows the centrifugal pump of a prior art. It is sectional drawing which shows the structure of the wave pump of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive unit 2 Pump 5a Inflow pipe 8 Distributor 11 Motor 12 Yoke 13 Base plate 14 Locking claw 15, 253 Magnet 16 Coil 17 Stator 18, 99 Drive shaft 19 Inclined shaft 22, 93, 244 Inflow port 23 1st casing 24 1st casing 24 2 casing 25 impeller 33, 94, 245 outflow port 81 flow path 91 housing 92, 211 pump chamber 95 impeller 96 rotating shaft 97 upper bearing 98 lower bearing 212 support plate 213 mover 241 groove 242 coring groove 243 receiving part (Recess)
251 Blade 252 Core ring 254 Hole 255 Shaft end (sphere)

Claims (5)

  A regenerative pump comprising an impeller with a coring, a first casing that houses the impeller, and a second casing that faces the impeller, the second casing being incomplete and less than one round A blood pump having a circumferential groove with a semicircular cross section, wherein an inflow port is opened near the center of one end, and an outflow port is opened near the outer diameter of the other end.   The impeller with a coring is driven via a magnetic coupling composed of a magnet arranged inside the magnet and a magnet arranged on the driving means side. Blood pump.   3. The spiral flow path having an opening connected to the outflow port on the side of the outflow port of the second casing, and having an opening extending substantially over the entire circumference, is connected to the opposite side. Blood pump.   The bearing of the said impeller consists of the pivot-shaped shaft edge part provided in the center position of both surfaces of an impeller, and the receiving part provided in the center position of the 1st and 2nd casing of both sides. 3. The blood pump according to 3. The blood pump according to any one of claims 2 to 4, wherein the impeller is provided with a plurality of holes penetrating both surfaces of the impeller near the center thereof.

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