JPH0622604B2 - Blood pump for artificial heart - Google Patents

Description

The present invention relates to an artificial heart blood pump, and more particularly to a pusher plate type in which a pusher plate (disc) is fixed to a diaphragm (diaphragm). It concerns blood pumps.

(Prior Art) In general, an assisted artificial heart device is a patient whose functioning of the living heart after surgery is not sufficiently recovered and a necessary blood circulation cannot be maintained, and a conventional assisted circulation device (for example, intra-aortic paloon pumping: IABP, etc.) is used when an effective treatment cannot be performed. There are several types of blood pumps used in these assist device. As a conventional blood pump, there is, for example, one shown in FIGS. 1, 2, and 3 of JP-A-55-113459.
Basically, these are classified by type: diaphragm type (Fig. 1), suck type (Fig. 2), tube type (Fig. 3).
There are three types). Further, as the diaphragm type, there is a pusher plate type in which a pusher plate is fixed to the diaphragm. These have the following advantages and disadvantages. The tube type has a simple structure and a smooth blood flow, but has a poor volumetric efficiency. The suck type is inhaled,
It has excellent discharge responsiveness and excellent durability, but on the other hand, it has a considerable amount of blood stagnation and poor volumetric efficiency. The diaphragm type has good volume efficiency, but has a drawback in durability. Further, the pusher plate type has high volume efficiency and good controllability, but has a drawback in durability.

Among these, the present invention relates to a pusher plate type blood pump. An artificial valve for preventing backflow is attached to each of the blood inflow and outflow portions of a conventional blood pump to form an intake valve and a discharge valve. This artificial valve uses various artificial valves (for example, Bjrk-Shiley valve) generally used for valve replacement surgery for patients with valvular disorders.

(Problems to be Solved by the Invention) However, in the artificial heart, since the pressure is high, the durability of the artificial valve is a problem. Further, since the blood pump and the artificial valve are made of different materials, thrombus formation is likely to occur at the boundary. Further, blood stagnation and vortexes are likely to occur near the mounting portion of the artificial valve.

On the other hand, when a biological valve is used, the flow rate characteristics are closest to those of the living heart, but even if it is carefully sterilized with complete disinfection, there is concern about infection and it has not yet been used. Absent.

Therefore, an object of the present invention is to improve the antithrombogenicity at the valve portion and the durability by providing a pusher plate type blood pump with a valve that does not easily form a stagnation or a vortex.

(Means for Solving Problems) Therefore, according to the present invention, a drive chamber side housing, a blood chamber side housing, a diaphragm whose end portions are sandwiched between both housings, a pusher plate fixed to the diaphragm, and a drive. Between the drive pressure introducing port formed in the chamber side housing, the suction port and the discharge port formed in the blood chamber side housing, the blood chamber defined by the blood chamber side housing and the diaphragm, and the blood chamber and the suction port. In a blood pump for an artificial heart, which comprises an inhalation valve arranged in the, and an exhalation valve arranged between the blood chamber and the exhalation valve, the inhalation valve is a leaflet valve,
The shape between the inlet and the leaflet-shaped valve is formed so that the flow passage has a uniform cross-sectional area and changes continuously from the circular cross-section of the inlet to the elliptical cross-section of the leaflet-shaped valve. Is a tricuspid valve, and a rounded portion is formed on the back of the tricuspid valve.

(Operation) According to this, when pressure is supplied from the drive pressure introducing port,
The diaphragm and pusher plate act in the direction of applying pressure into the blood chamber. As a result, the blood in the blood chamber is discharged by opening the tricuspid valve, which is a discharge valve. When the fluid is sucked from the driving pressure introducing port, the diaphragm and the pusher plate act in the direction of reducing the pressure in the blood chamber. As a result, the leaflet valve, which is a suction valve, opens and blood is sucked from the suction port.

At this time, the flow path from the suction port to the leaflet-shaped valve changes from a circular cross section to an elliptical cross section, so that the blood flow is extremely smooth, and stagnation, vortex, and the like are difficult to occur.
Further, since the rounded portion is formed behind the tricuspid valve arranged at the outflow port, the blood flow at the attachment portion of the tricuspid valve becomes smooth. For this reason, it is difficult for stagnation and vortexes to form behind the tricuspid valve.

(Examples) Examples of the present invention will be described below with reference to the drawings. First, description will be made with reference to FIG. The blood pump 10 includes a drive chamber side housing 20 and a blood chamber side housing 30. A drive pressure introducing port 21 is formed in the drive chamber side housing 10. Further, a hole 22 is formed in a substantially central portion of the drive chamber side housing 20, and a detection element fixture 23 is screwed into the hole 22. A Hall sensor 24, which is magnetic detection means, is incorporated in the detection element fixture 23. Drive chamber side housing 20 and blood chamber side housing 30
Are fixed by screws 25 as shown in FIG. The end portion 41 of the diaphragm 40 is sandwiched between the housings 20 and 30. Diaphragm 4
A pusher plate 50 is fixed to the central portion of 0. The pusher plate 50 has a recess 51 formed in the center thereof, and a magnet 52 is disposed in the recess 51.

The pusher plate 50 and the retainer plate 53 sandwich the diaphragm 40 so that the diaphragm 40
It is fixed to. A hole 54 is formed in the center of the retainer plate 53 so as not to disturb the magnetic field of the magnet 52.

The space defined by the drive chamber side housing 20, the diaphragm 40 and the pusher plate 50 is a drive chamber 6.
It is 0.

The blood chamber side housing 30 has a suction port 31 and a discharge port 3
2 is formed. Leaflet valve 70 which is an intake valve
Are fixed so as to contact the stepped portion 33 of the blood chamber side housing 30. A space defined by the blood chamber side housing 30, the diaphragm 40, the pusher plate 50, and the leaflet valve 70 is a blood chamber 61.

The suction port 31 is formed closer to the pusher plate 50 than the leaflet valve 70 of the blood chamber housing 30 and communicates with the blood chamber 61.

Next, referring to FIGS. 2 to 6, the suction port 31 and the discharge port 32 will be described.
The shape of will be described. First, the suction port 31 is formed in a circular shape as shown in its cross section in FIG. This circular shape gradually changes to an elliptical shape while keeping the flow passage cross-sectional area constant. The middle of this change is shown in FIG. This change has the largest elliptical shape corresponding to the portion corresponding to the central portion of the leaflet valve 70. This is the fifth
Shown in the figure. The blood chamber side housing 30 is formed with a hole 33 corresponding to the shape of the leaflet-like valve 70, and the leaflet-like valve 70 is fixed to this portion by a screw 71.

Next, the discharge port 32 is formed in a V-shaped position with respect to the suction port 31. The tricuspid valve 7 is provided at the outlet 31.
2 is formed. A rounded portion 73 is formed on the back of the tricuspid valve 72. The outlet 32 has a circular shape.

Further, as shown in FIG. 2, the portion 34 of the blood chamber side housing 30 that forms the blood chamber 61 is not a circular shape but a smooth curved shape.

The blood pump 10 is composed of a member having excellent antithrombogenicity and mechanical durability. At this time, instead of forming the blood pump 10 using the antithrombogenic member itself, a method of applying an antithrombotic member to the surface may be used.
In this example, polyurethane is used.

Next, the operation of the blood pump 10 having the above configuration will be described.

When pressure is introduced from the drive pressure introducing port 21, the diaphragm 40 and the pusher plate 50 receive a force in the right direction in the first drawing. As a result, pressure is generated in the blood in blood chamber 61. Therefore, blood is discharged from the discharge port 32 by opening the tricuspid valve 72, which is a discharge valve. At this time, since the rounded portion 73 is formed on the back portion of the tricuspid valve 72, the blood flow on the back portion of the tricuspid valve 72 flows along this roundness, and the flow can be made smooth. Therefore, the blood on the back of the tricuspid valve 72 is not swirled or stagnant. Next, when the pressure is discharged from the drive pressure introducing port 21,
The diaphragm 40 and the pusher plate 50 receive a force in the first left direction in the drawing. As a result, a negative pressure is generated in blood chamber 61. Therefore, blood is sucked from the leaflet valve 70 which is the suction port. At this time, the space between the suction port 31 and the leaflet-shaped valve 72 is as described above.
Has a circular cross-sectional shape, and this circular shape gradually changes to an elliptical shape while keeping the flow passage cross-sectional area constant. Therefore, the blood sucked from the suction port 31 flows along with the shape change from the suction port 31 to the leaflet-shaped valve 70, and the flow of blood does not have stagnation or vortex.

Blood pump 10 inhales and discharges blood by repeating the above operation.

Here, in the blood pump 10 described above, the leaflet-like valve 72 is configured separately from the blood chamber side housing 30, but it may be configured integrally with the blood chamber side housing 30. At this time, the leaflet valve 72
It is also possible to insert a reinforcing member in the vicinity of the joint portion of the above.

Next, FIG. 7 shows an example of a case where the blood pump 10 of the present invention is driven using the auxiliary artificial heart drive device. In this example, a liquid such as silicone oil is introduced and discharged through the driving pressure introducing port 21 to drive the blood pump 10.
The drive device will be described with reference to FIG. Reciprocating drive means 110
Has a drive shaft 111. Reciprocating drive means 110
For example, an electromagnetic motor that includes a coil, a movable core, a spring, and the like, and that displaces the movable core to a position where the magnetic force generated by the coil balances the spring can be used. With this device, the amount of displacement of the core can be easily controlled by the value of the energizing current, and energization is only required when the core is held at that position. The drive shaft 111 is driven by a motor such as a linear motor or a step motor.
It is also possible to use one that controls the amount of displacement and the displacement speed of the reciprocating motion of the. These linear motors and stepper motors are
The displacement amount and displacement speed can be easily controlled. It should be noted that the drive unit 110 may be any drive unit that can control the displacement amount and displacement speed of the drive shaft 111 with good responsiveness without using these motor units.

A position detection sensor 180, which is a first position detection means, is arranged in the drive means 110. The position detection sensor 180 detects the displacement position of the drive shaft 111 and outputs a signal to the electronic control means 160. .

The drive pump means 120 is composed of a first housing 121 and a second housing 122, and a diaphragm 123 is sandwiched between the two housings 121, 122. The diaphragm 123 is provided with a plate 124 at the center thereof, and the plate 124 is provided on the plate 124.
1 is fixed. Then, the second housing 122
An output chamber 125 is formed by the diaphragm 123 and the diaphragm 123. A communication hole 126 is provided in the first housing 121 and communicates with the atmosphere. Second housing 1
A pressure sensor 181 serving as a pressure detecting unit is arranged at 22 to detect the pressure in the output chamber 125 and output a signal to the electronic control unit 160.

Further, the output chamber 125 is connected to the fluid passage 130, which is a fluid circuit, via the second housing 122.

The output of the hall sensor 24 of the blood pump 10 outputs a signal to the electronic control means 160. The electronic control means 160
The battery 190 is provided as a power source, and the battery 190 is charged by the charger 191.

The drive pressure introducing port 21 of the blood pump 10 is connected to the pipe 130.

Next, the pressure correction circuit 150, which is the pressure correction means arranged in the pipe 130, will be described. The pressure correction circuit 150 is arranged between the pipe 130 and the output chamber 125 of the drive pump 120. Check valve 15 from pipe 130
It is connected to the pressure chamber 155 via 3, 154. The pressure chamber 155 is connected to the output chamber 125 via the orifice 151. A buffer 152 is arranged in the pressure chamber 155.

The pipe 130 is provided with a flow rate sensor 182, which is a flow rate detecting means for detecting the flow rate of the fluid.

Silicon oil is used as the working fluid.

Next, the schematic operation of the drive device will be described. Drive means 110
When the drive shaft 111 moves to the right in FIG. 7 (hereinafter referred to as forward movement), the drive pump means 1
20 pusher plates 124 and diaphragms 12
3 compresses silicone oil. As a result, pressure is generated in the drive chamber 60 of the blood pump 10, and the pusher plate 50 and the diaphragm 40 move to the right in FIG. Therefore, pressure is generated in the blood chamber 61, the blood opens the tricuspid valve 72, and the blood is discharged.
On the contrary, the drive means 110 operates and the drive shaft 111 moves to the seventh position.
In the figure, when it is moved to the left (hereinafter referred to as reverse movement), the pusher plate 124 of the drive pump means 120 is moved.
And the diaphragm 123 sucks the silicone oil. As a result, a suction force acts on the drive chamber 60 of the blood pump 10, and the pusher plate 50 and the diaphragm 40.
Moves to the left in FIG. Therefore, blood chamber 6
A suction force is generated in the blood vessel 1, the blood opens the leaflet valve 70, and the blood is inhaled. By repeating the above operation, blood is inhaled and discharged to operate as an auxiliary artificial heart.

The above is the basic operation. Next, detailed control will be described. In the case of the auxiliary artificial heart, it is necessary to drive it in synchronization with the pulsation of the heart of the living body. That is, it is necessary to control the operation timing, discharge pressure, discharge flow rate, etc. of the auxiliary heart (blood pump 10) according to the heart rate, blood pressure, discharge flow rate, etc. of the living heart. In particular, of these, the discharge pressure is preferably changed to a square wave shape in which the rise of the discharge pressure is steep so that the discharge pressure is similar to the pulsation of the heart of the living body. This device controls these based on the following control logic.

(1) When the relationship between the displacement amount of the pusher plate 50 of the blood pump 10 and the discharge amount is measured, it becomes as shown in FIG. Here, the displacement amount of the pusher plate 50 is detected by the hall sensor 24. That is, the hall sensor 2
Since the detection output of No. 4 is obtained in proportion to the position of the pusher plate 50, the Hall sensor 24 in one displacement
The displacement amount of the pusher plate 50 can be detected by the difference between the maximum value and the minimum value of the detection output of. According to FIG.
The displacement amount of the pusher plate 50 and the discharge flow rate of the blood pump 10 are in a proportional relationship. Therefore, the discharge flow rate of the blood pump 10 can be controlled by controlling the displacement amount of the pusher plate 50.

(2) The discharge pressure of the blood pump 10 is the pusher plate 5
It can be controlled by a forward speed of zero. That is,
By increasing the forward speed of the pusher plate 50, the rise of the pressure generated in the blood chamber 61 becomes sharp. Therefore, the rising of the discharge pressure and the discharge flow rate can be made steep.

(3) When the blood pump 10 is inhaling, by slowing the backward speed of the pusher plate 50, blood can be inhaled without causing an excessive negative pressure on the inhalation side.

The above is the operation control relating to the blood pump 10, and the present drive device uses the drive pump means 120 via the silicone oil.
It is controlled by. Therefore, in the present device, the operation of the blood pump 10 is detected by the hall sensor 24, and the drive means 110 is controlled based on this signal.

According to the above control logic, the following signals are available as the control signals for the driving means 110.

(A) A signal that indicates the timing of operation in synchronization with the pulsation of the living heart.

(B) A signal that indicates the discharge / inhalation time ratio (S / D ratio).

(C) A signal that indicates the initial position and displacement range of the drive shaft.

(D) A signal that indicates the displacement speed of the drive shaft.

Based on these control logics, the control of this device will be described in detail below.

An electrocardiogram (ECG) signal is input from the living body to the electronic control unit 160. This electrocardiogram signal is shown in FIG. Based on this electrocardiogram signal, the electronic control means 160 analyzes the waveform, extracts the R wave pattern, and uses this as the trigger signal.

Further, as an external signal input to the electronic control unit 160, the setting unit 170 instructs the discharge flow rate. This discharge flow rate is determined by the state of the living heart. That is, the amount of auxiliary circulation is instructed according to the discharge capacity of the heart of the living body. The electronic control unit 160 can perform basic control based on the two instructions of the electrocardiogram signal and the discharge flow rate.

Hereinafter, the waveform of each part will be shown in FIGS. 10 to 13, and the operation will be described.

The electronic control unit 160 first outputs an initial control signal based on the input discharge flow rate instruction signal. This signal is shown in FIG. The initial control signals at this time are the delay time, the forward signal and the backward signal. The delay time is calculated by the electronic control means 160 from the electrocardiogram signal and set to a predetermined value. The forward movement signal changes the displacement speed as described above. In this example, the displacement speed is controlled in two steps. The displacement speed is set relatively high in the initial stage of the operation, and thereafter, the displacement speed is set relatively slow. These displacement rates are set to predetermined values obtained from the state of the living body. The ratio of the two displacement speeds is set to 3: 7 in this example. The reverse drive signal is set to a value obtained in advance so that excessive negative pressure does not occur during suction. This backward signal is continuously output until the next R wave signal arrives. When the next R wave signal is triggered,
Although it is the delay time, the backward signal is still held during this time.

In this control, the switching of the displacement speed and the switching between forward and reverse are controlled by the detection output of the position detection sensor 180. According to this, when the R-wave signal trigger occurs, the drive shaft 111 advances relatively quickly after a predetermined delay time, and when the drive shaft 111 reaches a predetermined displacement position, the drive shaft 111 switches to a relatively slow speed and advances. A pressure is generated in the blood pump 10 by the operation of the drive shaft 111, and blood is discharged. Next, the inhalation operation starts. That is, as the drive shaft 111 moves backward at a predetermined speed, the blood pump 10
The pusher plate 50 of the
Inhaled into. When the drive shaft 111 reaches a predetermined displacement position in this state, it is held at that position.

The above displacement of the drive shaft 111 is shown in FIG.

The discharge pressure generated by the pusher plate 50 of the blood pump 10 by the above control is shown in FIG. This discharge pressure depends on the displacement speed of the pusher plate 50 as described above. That is, the rising at the beginning of the operation with a high displacement speed is steep.

FIG. 13 shows the discharge flow rate discharged by the blood pump 10.

These control operations are detected by the hall sensor 24 arranged in the blood pump 10. That is, in all of the above-described controls, the drive shaft 111 of the drive means 110 is controlled to a predetermined value, and the actual operation of the pusher plate 50 of the blood pump 10 is not directly controlled. Therefore, the feedback control is performed by the output of the hall sensor 24. This is based on the characteristic diagram shown in FIG. That is, the displacement amount of the pusher plate 50 is detected by the output of the hall sensor 24, and the blood pump 10 is detected from this.
Calculate the discharge amount of. The calculation discharge amount setting means 170
It is compared with the set discharge amount input more. The following control is performed based on this comparison value.

That is, assuming that the set discharge amount is Vset, the calculated discharge amount is Vc, the displacement amount initialized from the set discharge amount is Soo, and the feed back controlled displacement amount is So, the following control is performed.

(1) When Vest-Vc>0; So = Soo + α (2) When Vest-Vc <0; So = Soo-α (3) When Vest-Vc = 0; So = Soo where α is a predetermined value With this feedback control, the displacement amount of the driving means 110 is controlled and adjusted to the set discharge flow rate.

For these discharge amount controls, the pressure correction circuit 150 corrects the pressure. Drive shaft 1 of drive means 110
In the initial stage of the displacement, 11 is displaced at a relatively high speed, so that the pressure rises steeply. However, if this rising is steep, a very high pressure is momentarily generated in the pusher plate 50. This is not preferable because excessive pressure is applied to the living body. Therefore, the check valve 15 of the pressure correction circuit 150
Excessive pressure is cut by 3. The valve opening pressure of the check valve 153 is set to a high pressure that does not adversely affect the living body. This is because the blood pressure of the living body is generally 80 to 140 mmHg,
It is set to 40 mmHg. Therefore, the discharge pressure has a waveform obtained by cutting the overshoot after the steep rise, as shown in FIG. In addition, if excessive pressure occurs,
When the check valve 153 opens, pressure is generated in the pressure chamber 155 to contract the buffer 152 and absorb it. Check valve 15
When the valve 3 is closed, the pressure in the pressure chamber 155 becomes 1
It is gradually returned to the output chamber 125 via 51.

Next, when blood is inhaled, it is not preferable for the living body to generate excessive negative suction pressure. Therefore, check valve 1
The valve opening pressure of 54 is set and absorbed. That is, when an excessive negative pressure is generated, the check valve 154 is opened to generate a negative pressure in the pressure chamber 155, and the buffer 152 is expanded to absorb the negative pressure. When the pressure is restored, the fluid flows from the output chamber 125 into the pressure chamber 155 through the orifice 151.

Further, in this device, the pressure sensor 181 allows the output chamber 1
25 pressures are monitored. Then, the pressure correction circuit 15
When an abnormal pressure occurs due to the case where 0 does not operate normally, this can be detected and displayed. Further, the operation of the driving means 110 can be stopped by this signal.

Further, if the flow rate sensor 182 detects the actual flow rate of the fluid circuit 130, displays it, and monitors it,
A more accurate instruction can be given from the setting means 170.

By the above operation, the discharge amount of the blood pump 10 is controlled to the set value.

In this device, the setting means 170 instructs and controls the discharge amount, but the setting means 170 sets the ratio of forward speed, reverse speed, discharge and suction, that is, S / D.
If the ratio, the displacement start position of the drive shaft 111, and the like are made variable, finer control becomes possible.

〔effect〕

As described above, according to the present invention, the suction valve is a leaflet valve, and the shape between the suction port and the leaflet valve is such that the cross section of the flow passage is uniform and continuous from the circular cross section of the suction port. The shape of the discharge valve is a tricuspid valve, and a rounded portion is formed on the back of the tricuspid valve. As a result, the flow of blood in the flow path from the suction port to the leaflet valve is extremely smooth, and it is difficult for stagnation and vortex to occur. In addition, the rounded portion on the back of the tricuspid valve disposed at the discharge port makes the blood flow at the attachment portion of the tricuspid valve smooth. For this reason, it is difficult for stagnation and vortexes to form behind the tricuspid valve.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the blood pump of the present invention,
FIG. 2 is a plan view showing an embodiment of the blood pump of the present invention,
FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is IV in FIG.
-IV sectional view, FIG. 5 is a sectional view taken along line VV of FIG. 2, FIG. 6 is a sectional view taken along line VI-VI of FIG. 2, and FIG. 7 is an example of a driving device for driving the blood pump of the present invention. FIG. 8 is a configuration diagram, FIG. 8 is a graph showing the relationship between the discharge amount of the blood pump of the present invention and the output of the Hall sensor, and FIG.
FIG. 0 is a graph showing a control signal for driving the driving means, FIG. 11 is a graph showing a displacement of the driving shaft of the driving means,
FIG. 12 is a graph showing the driving pressure of the driving pump means, and FIG. 13 is a graph showing the discharge amount of the blood pump. 10 ... Blood pump, 20 ... Drive side housing, 21
...... Driving pressure introducing port, 24 ...... Hall sensor (magnetic detecting means), 30 ...... blood chamber, 31 ...... suction port, 32 ...... discharging port, 40 ...... diaphragm, 50 ...... pusher plate, 60 ... ... Drive chamber, 61 ... Blood chamber, 70 ... Leaflet valve (suction valve), 71 ... Tricuspid valve (discharge valve)

Claims (4)

[Claims] 1. A drive chamber side housing, a blood chamber side housing, a diaphragm whose ends are sandwiched between the two housings, a pusher plate fixed to the diaphragm, and a drive chamber side housing. A drive pressure inlet, an inlet and an outlet formed in the blood chamber-side housing, a blood chamber defined by the blood chamber-side housing and the diaphragm, and an arrangement between the blood chamber and the inlet. A blood pump for an artificial heart, which comprises an inhalation valve and a discharge valve arranged between the blood chamber and the discharge port,
The suction valve is a leaflet-shaped valve, and the shape between the suction port and the leaflet-shaped valve has a uniform flow passage cross-sectional area and is continuous from a circular cross-section of the suction port to an elliptical cross-section of the leaflet-shaped valve. A blood pump for an artificial heart, wherein the discharge valve is a tricuspid valve and a rounded portion is formed on the back of the tricuspid valve. 2. The blood chamber side housing is arranged at a position where the leaflet-shaped valve faces the pusher plate, and the suction port is arranged in a state substantially parallel to the leaflet-shaped valve. The blood pump for an artificial heart according to claim 1, wherein the discharge port is arranged closer to the pusher plate than the leaflet valve. 3. The blood pump for an artificial heart according to claim 2, wherein the discharge port is arranged at a position forming a substantially V-shape with respect to the suction port. 4. The drive chamber side housing includes a magnetic detection means fixed to a substantially central portion of the drive chamber side housing, and the pusher plate is a magnet fixed to a substantially central portion of the pusher plate. The blood pump for an artificial heart according to claim 1, further comprising: