JPH0211261B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for a blood pump such as an artificial heart or an artificial lung.

An example of this type of blood pump is shown in FIG. In the figure, 3 is a flat bag-shaped blood chamber, 2 is a pressure-resistant housing outer case that houses the blood chamber 3, and the blood chamber 3 is inserted into the housing outer case 2 by a collar 4 fixed to its upper end. It is kept secret. A blood introduction conduit 6 equipped with a check valve 5 and a blood discharge conduit 8 equipped with a check valve 7 are arranged in parallel on the upper surface of the collar 4, and are used for supplying driving pressure to the housing outer case 2. The configuration is such that the blood introduced from the blood introduction conduit 6 is pumped out through the blood discharge conduit 8 by introducing and discharging driving gas from the port 1 to expand and compress the blood chamber 3.

The above blood pump has conventionally been driven using a drive device as shown in FIG. That is, a positive pressure tank 11 connected to a compressor 10 as a positive pressure source via a pressure regulating valve 16, and a vacuum pump 12 as a negative pressure source.
A negative pressure tank 13 connected via a pressure regulating valve 16 to
The positive pressure of the positive pressure tank 11 and the negative pressure of the negative pressure tank 13 are supplied to the driving pressure supply port 1 of the blood pump through the tank switching valve 14.

The positive pressure tank 11 is maintained at a predetermined positive pressure by the compressor 10 and the pressure regulating valve 16, and the negative pressure tank 13 is maintained at a predetermined negative pressure by the vacuum pump 12 and the pressure regulating valve 16. When switched to the positive pressure tank 11 side, the pressurized gas is transferred to the driving pressure outlet 1.
5, the pressurized gas is supplied into the housing outer case 2 from the driving pressure supply port 1, and the blood chamber 3 is crushed by this pressurized gas, and the blood in the blood chamber 3 passes through the check valve 7 and into the blood discharge conduit 8. being pushed out from Next, tank switching valve 1
4 is switched to the negative pressure tank 13 side, the gas in the housing outer case 2 is sucked into the negative pressure tank 13 from the driving pressure outlet 15 through the driving pressure supply port 1, and the pressure is reduced, and the blood chamber 3 is It expands due to its elastic restoring force, and blood passes through the check valve 5 and is introduced into the blood chamber 3 from the blood introduction conduit 6. This operation is sequentially repeated by the tank switching valve 14, and blood is pumped out synchronously.

In order for the blood pump described above to function as an artificial heart, first of all, the blood pressure curve exhibited by the blood pump must be as close as possible to that of a natural heart.
Most ideally, they should be the same, and for this reason, various improvements have been made to the shape and constituent materials of the blood chamber 3 and the like. However, even if the blood pressure curve exhibited by a blood pump is brought closer to that of a natural heart by making improvements to its shape and constituent materials, it will not be possible to demonstrate its characteristics unless the blood pump operates as rated. There is no.

Therefore, in the conventional drive device shown in FIG.
50 times) larger.

To explain the reason for this, when the positive pressure tank 11 is opened by the tank switching valve 14, the pressure inside the positive pressure tank 11 decreases, and when the negative pressure tank 13 is opened, the pressure inside the negative pressure tank 13 increases. However, when the tank capacity is sufficiently large, these pressure drops and pressure increases can be ignored. However, when the tank capacity is not sufficiently large compared to the pump capacity of the blood pump, the ratio of the pressure drop to the pressure rise becomes large. The pressure regulating valves 16 installed on the inlet sides of the positive pressure tank 11 and the negative pressure tank 13 generally do not have a very fast response speed, so they cannot immediately compensate for these pressure drops and pressure rises, and the tank internal pressure pulsates. The blood pump cannot operate as rated.

FIG. 3 shows the pressure waveform inside the housing outer case 2 when pressurized gas is supplied. In the figure, solid line A is the pressure waveform when the influence of the pressure drop described above appears. In addition, the dashed-dotted line B shows an ideal waveform with no pressure drop, the dotted line C shows the pressure curve of the positive pressure tank 11 without air replenishment, and the dashed-dotted line D shows the pressure curve due to the operation of the pressure regulating valve 16. ing.

As mentioned above, when using the conventional blood pump drive device, it is necessary to set the capacity of the positive pressure tank 11 and the negative pressure tank 13 to be sufficiently large, so there is a problem that the device becomes large and takes up space. .

The present invention was made in view of the above circumstances, and
The purpose of this is to discharge and discharge blood from the blood pump.
To provide a blood pump drive device that can be miniaturized by reducing the capacities of a positive pressure tank and a negative pressure tank while bringing the blood pressure curve of aspirated blood as close as possible to the blood pressure curve of a natural heart. .

In order to achieve the above object, the present invention uses a positive pressure subtank and a negative pressure subtank to compensate for the pressure within the housing outer case of a blood pump.

Hereinafter, the present invention will be explained in detail with reference to the drawings. In addition, in the following description, positive pressure is a pressure higher than blood pressure, and negative pressure is a pressure lower than blood pressure. In addition, compensation pressure means the pressurizing pressure that prevents the pressure drop from affecting the pressure waveform in the housing outer case when a pressure drop occurs in the positive pressure tank, and also the pressure in the negative pressure tank. This means a reduced pressure that prevents this pressure increase from affecting the pressure waveform inside the housing outer case when a pressure increase occurs in the housing.

FIG. 4 shows an embodiment of the blood pump drive device of the present invention. In the figure, the same parts as those shown in FIGS. 1 and 2 are designated by the same reference numerals, and the explanation thereof will be omitted.

The embodiment shown in FIG. 4 is a device having the same configuration as the conventional blood pump drive device shown in FIG. A branch line 18 for positive pressure connects the vacuum pump 12 and the drive pressure outlet 15, that is, the drive pressure supply port 1 of the blood pump, by a branch line 20 for negative pressure. . A positive pressure sub tank 25 having a smaller capacity than the positive pressure tank 11a is provided in the middle of the positive pressure branch line 18, and a negative pressure sub tank 25 having a smaller capacity than the negative pressure tank 13a is provided in the negative pressure branch line 20. has been established.

Furthermore, electromagnetic on-off valves 27 and 28 for opening and closing passages are provided on the inlet side (compressor 10 side) and outlet side (driving pressure outlet 15 side) of the positive pressure subtank 25, respectively.
Also, the inlet side of the negative pressure subtank 26 (vacuum pump 1
Electromagnetic on-off valves 29 and 30 for opening and closing the passage are provided on the outlet side (driving pressure outlet 15 side) and the outlet side (driving pressure outlet 15 side), respectively.

The electromagnetic on-off valves 27 to 30 are controlled to open and close in synchronization with the tank switching valve 14 by a control means (not shown) as follows. That is, Figure 5a
~e is the tank switching valve 14 and the electromagnetic on-off valve 27~
30 shows a time chart of an example of opening/closing control of No. 30.
As is clear from this figure, when the tank switching valve 14 is switched to the positive pressure tank 11a side, the electromagnetic on-off valves 27 and 30 open for the same amount of time (Fig. 5 b, c), and the electromagnetic on-off valve 28 opens for the same amount of time. 29 is controlled to open and close as shown in (c and d in the same figure). Also,
When the tank switching valve 14 is switched to the negative pressure tank 13a side, the electromagnetic on-off valve 2 is switched for the same period of time.
9 and 28 open (d and c in the same figure), and the electromagnetic on-off valve 30
and 27 are controlled to open and close as shown in (e and b in the same figure).

We will now proceed to explain the operation of the above device.

When the tank switching valve 14 is switched to the positive pressure tank 11a side by the control means (not shown) described above, a predetermined pressure is passed from the positive pressure tank 11a through the tank switching valve 14, the driving pressure outlet 15, and the driving pressure supply port 1. Pressurized gas is supplied into the housing outer case 2, causing the blood chamber 3 to contract and forcing blood out through the blood discharge conduit 8.

At this time, pressurized gas in the positive pressure auxiliary tank 25, which is pressurized to a higher pressure than the positive pressure tank 11a, is supplied into the housing outer case 2 through the electromagnetic on-off valve 27, which opens in synchronization with the tank switching valve 14. . Therefore, the inside of the housing outer case 2 is pressurized to a predetermined pressure without any delay in rising, and blood is pushed out from the blood chamber 3.

While the electromagnetic on-off valve 27 is open, the electromagnetic on-off valve 30 on the side of the negative pressure auxiliary tank 26 is also opened, and the pressure inside the negative pressure auxiliary tank 26 is reduced by the vacuum pump 12 compared to the inside of the negative pressure tank 13a, and the next operation is performed. Be prepared. Then, when the tank switching valve 14 is switched to the negative pressure tank 13a side, the electromagnetic on-off valve 30 is closed.

Next, the tank switching valve 14 switches to the negative pressure tank 13a.
When the gas in the housing outer case 2 is switched to the negative pressure tank 13 through the driving pressure supply port 1, the driving pressure outlet 15, and the tank switching valve 14,
a, the pressure inside the housing outer case 2 is reduced, the blood chamber 3 expands due to its elastic restoring force, and blood is introduced into the blood chamber 3 from the blood introduction conduit 6.

At this time, the gas inside the housing outer case 2 is sucked into the negative pressure sub tank 26 which is reduced in pressure to a lower pressure than the negative pressure tank 13a through the electromagnetic on-off valve 29 which opens in synchronization with the tank switching valve 14. Therefore, the pressure inside the housing outer case 2 is reduced to a predetermined pressure without any delay in falling, and blood is introduced into the blood chamber 3.

While the electromagnetic on-off valve 29 is open, the electromagnetic on-off valve 28 on the side of the positive pressure auxiliary tank 25 is also opened, and the inside of the positive pressure auxiliary tank 25 is operated by the compressor 10 to control the positive pressure tank 11.
It is pressurized more than inside a and is ready for the next operation. Then, when the tank switching valve 14 is switched to the positive pressure tank 11a side, the electromagnetic on-off valve 28 is closed.

By repeating the above operations alternately, blood is discharged and aspirated from the blood chamber 3 of the blood pump.

FIG. 6 shows the pressure waveform inside the housing outer case 2 when pressurized gas is supplied. If only the positive pressure tank 11a is used, the predetermined pressure will not be reached until the pressure regulating valve 16 responds due to the influence of the pressure drop, as shown by the two-dot chain line F, but in the case of the present invention, the pressure is By supplying the compensating pressurized gas shown in , the pressure is compensated until the pressure regulating valve 16 responds, and the pressure waveform in the housing outer case 2 becomes as shown by the solid line E.

Moreover, FIG. 7 shows the pressure waveform inside the housing outer case 2 when the driving pressure outlet 15 and the driving pressure feeding port 1 are connected by a long and small diameter flexible pipe. If they are connected using flexible pipes, the effects of internal resistance and pipe deformation will be added, so if the positive pressure tank 11a is used alone, the pressure curve will be as shown by the two-dot chain line F. However, according to the present invention, Since pressurized gas for compensation shown by the dotted line G is supplied and pressure compensation is performed, a pressure waveform as shown by the solid line E is obtained.

The capacity of the positive pressure sub tank 25 and the negative pressure sub tank 26 is sufficient to compensate for the pressure until the pressure regulating valve 16 responds. For example, the positive pressure sub tank 26 is the same as the positive pressure tank 11a. The auxiliary negative pressure tank 26 may be about one-fifth of the negative pressure tank 13a. Therefore, the positive pressure tank 11a, the negative pressure tank 13a, and the auxiliary positive pressure tank 2
5. The total capacity of the auxiliary negative pressure tank 26 can be made smaller than that of the conventional device shown in FIG.

In the above embodiment, a blood pump equipped with a housing outer case 2 and a blood chamber 3 is shown, but any type of blood pump that is driven by alternately supplying positive pressure and negative pressure can be applied. It is.

Specific experimental numerical values for the above examples are listed below.

The blood pump shown in FIG. 1 was driven using the apparatus shown in FIG. 4, and the pressure waveform inside the housing outer case 2 was measured using a pressure transducer. The obtained pressure waveform was as shown by the solid line E in FIG. At this time, the tank capacities and pressures of the positive pressure tank 11a, negative pressure tank 13a, positive pressure auxiliary tank 25, and negative pressure auxiliary tank 26 were as follows.

[Tank name] Capacity [] Pressure [Kg/cm ² ] Positive pressure tank 11a 2 0.26 Negative pressure tank 13a 2 -0.03 Sub-tank for positive pressure 25 0.07 1.0 Sub-tank for negative pressure 26 0.07 -0.79 The conventional device shown in Fig. 2 When the blood pump shown in Fig. 1 is driven in the same manner using the positive pressure tank 1
The tank capacities of 1 and negative pressure tank 13 are respectively
Needed 10. Moreover, the pressure waveform obtained at that time became as shown by the solid line in FIG.

In this embodiment, the tank capacity can be reduced to approximately one-fifth of that of the conventional device shown in FIG.

As explained above, according to the present invention, the pressure within the housing outer case of the blood pump is compensated using the positive pressure subtank and the negative pressure subtank. It is possible to reduce the capacity of the positive pressure tank and negative pressure tank while making the blood pressure curve of the blood expelled and aspirated from the heart as close as possible to the blood pressure curve of the natural heart, making it possible to further miniaturize this type of drive device. It has excellent effects.

Further, according to the present invention, by changing the opening duration of the electromagnetic on-off valves disposed on the inlet sides of the positive pressure sub tank and the negative pressure sub tank, the positive pressure sub tank and the negative pressure sub tank are It is possible to freely adjust the accumulated pressure from the maximum pressure of the positive pressure source or negative pressure source to any low pressure, and the electromagnetic on-off valve is installed on the outlet side of each of the positive pressure subtank and negative pressure subtank. By changing the respective open duration times, it becomes possible to arbitrarily change the application time of the compensation pressure supplied from the positive pressure subtank and the negative pressure subtank. Therefore, by appropriately setting the open duration time of the electromagnetic on-off valve and the capacity of the positive pressure auxiliary tank and the negative pressure auxiliary tank, it is possible to arbitrarily change the compensation pressure value and the pressure application time over a wide range. This makes it possible to compensate for pressure not only at the beginning of pressurization and depressurization, but also during the period until the pressure regulating valves of the main positive pressure tank and negative pressure tank respond, allowing for a wide range of pressure compensation when driving the blood pump. It also has excellent effects in that it can be done accurately.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a blood pump, FIG. 2 is a block diagram of a conventional blood pump drive device, FIG. 3 is a pressure waveform diagram of the conventional device, and FIG. 4 is a block diagram of an embodiment of the present invention. FIG. 5 is a time chart of an example of opening/closing control of the tank switching valve and electromagnetic on-off valve in the device of the present invention, and FIG. 6 is a pressure waveform diagram of the device of the present invention.
FIG. 7 is a pressure waveform diagram of the device of the present invention when a flexible pipe is used, and FIG. 8 is an actual pressure waveform diagram of the conventional device shown in FIG. 2. 1... Driving pressure supply port, 3... Blood chamber, 10... Compressor (positive pressure source), 12... Vacuum pump (negative pressure source), 11a... Positive pressure tank, 13a... Negative pressure tank, 14... Tank switching valve , 16...pressure regulating valve, 18
...branch line for positive pressure, 20...branch line for negative pressure,
25... Sub tank for positive pressure, 26... Sub tank for negative pressure,
27-30...Solenoid on-off valve.

Claims (1)

[Claims] 1. A positive pressure tank connected to a positive pressure source via a pressure regulating valve, and a negative pressure tank connected to a negative pressure source via a pressure regulating valve, the positive pressure tank and the negative pressure A blood pump drive device that drives the blood pump by alternately switching and supplying positive pressure and negative pressure from a tank to a drive pressure supply port of the blood pump through a tank switching valve, wherein the positive pressure source and the drive pressure supply are connected to each other. A branch line for positive pressure that connects between the ports for supplying pressure and a branch line for negative pressure that connects the negative pressure source and the drive pressure supply port are provided, and an electromagnetic on-off valve for opening and closing the passage is installed in the middle of the branch line for positive pressure. Sub-tanks for positive pressure installed on the side and outlet sides are connected in series with the passage, and sub-tanks for negative pressure are installed in the middle of the negative pressure branch line with electromagnetic on-off valves placed on the inlet and outlet sides for opening and closing the passage. A tank is connected in series to the passage, and when the tank switching valve is switched to the positive pressure tank side, the solenoid on-off valve on the outlet side of the positive pressure auxiliary tank and the solenoid on-off valve on the inlet side of the negative pressure auxiliary tank are opened; A blood pump for a blood pump characterized in that when the tank switching valve is switched to the negative pressure tank side, the solenoid on-off valve on the outlet side of the negative pressure auxiliary tank and the solenoid on-off valve on the inlet side of the positive pressure auxiliary tank are opened. Drive device.