JP2001046496A - Left ventricle sack imitating contracted form of left ventricle of organism and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a left ventricle sack which can imitate the contracted form of an organism left ventricle. SOLUTION: This left ventricle sack 1 comprises a sack body 2 and an elastic rubber cord 3 spirally wound on the outer periphery of the sack body 2. The sack body 2 is made from an elastic material and has an approximately shell-shaped sack part 4 and a flange part 5. Silicone, latex, polyurethane, and the like, are usable as the elastic material, with the silicone particularly desirable. The sack body 1 preferably has a capacity of 40 to 60 milliliters, and preferably 45 to 55 milliliters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a left ventricular sac, which is a blood pump for the left ventricle of a blood circulation simulator circuit used for developing medical artificial organs and the like, and a method of manufacturing the same.

[0002]

Problems such as coronary stents and medical artificial organs need to be verified based on various data simulating the blood flow of the human heart.
As a device for simulating the blood flow of the human heart, a blood circulation simulator circuit having a left ventricular pump and a liquid conduit reaching a coronary artery or the like is used. The left ventricle pump in the blood circulation simulator circuit includes a sack type pump, a straight tube type pump, and the like. The sack type pump is a pump using a shell-shaped bag called a sac made of silicone or polyurethane for the diaphragm.
In addition, a straight pipe type pump is a pump using a latex cylinder as a diaphragm. These pumps eject blood by contracting and expanding a diaphragm using a fluid such as air or water.

[0003] Among these pumps, a sack type pump is generally used as a conventional left ventricular pump. Since the left ventricle volume in the end diastole of the cardiac cycle is about 150 ml, the sack type pump has a molding volume of 150 ml. However, although this left ventricular sac was designed to simulate the external shape of the expanded ventricle, the conventional left ventricular sac contracted by squeezing the sac with pneumatic pressure. The expansion and contraction of the ventricle wall itself, such as the heart, could not occur. It is said by cardiac surgeons that there is a torsional motion in the heartbeat of the human left ventricle, and this torsional motion has been confirmed by recent image diagnosis. It is believed that this torsional movement affects the flow of blood ejected from the left ventricle to the aorta. However, with the conventional left ventricular sac, it has not been possible to simulate the torsional motion of the ventricular wall in the contraction of the left ventricle of a living body of a human.

Accordingly, an object of the present invention is to provide a left ventricular sac of a blood circulation simulator capable of simulating a contraction form of a living body left ventricle and a method of manufacturing the same.

[0005]

Means for Solving the Problems In view of the above-mentioned object, the present inventors have conducted intensive studies on a left ventricular sac simulating the torsional movement of a living heart, and found that the volume of the sac during molding was reduced from the conventional 150 ml to 50 ml. The present inventors have found that the ventricle wall itself can be expanded and contracted by changing the shape of the sac, and that the torsional motion can be simulated by spirally winding an elastic rubber cord around the outer periphery of the sack.

A left ventricular sac simulating the contracted form of the left ventricle of a living body according to the first aspect of the present invention is a helical wrap around an outer shell of a substantially shell-shaped sac body made of an elastic material. is there.

Further, the left ventricular sac simulating the contracted form of the living body left ventricle according to the second aspect is characterized in that in the first aspect,
The volume of the left ventricular sac body is 40 to 60 ml.

Further, according to a third aspect of the present invention, there is provided a method of manufacturing a left ventricular sac simulating a contracted form of a living body left ventricle, wherein an elastic rubber cord is spirally wound around the outer periphery of a substantially shell-shaped sac body made of an elastic material. It is to be wound.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a left ventricular sac simulating the contraction form of a living body left ventricle according to the present invention will be described in detail. FIG. 1 shows a left ventricular sac 1 according to an embodiment of the present invention. The left ventricular sack 1 includes a sac body 2 and an elastic rubber cord 3 spirally wound around the outer periphery of the sac body 2.
Consists of The sack main body 2 is made of an elastic material, and has a bag portion 4 and a flange portion 5 having a substantially shell shape. The flange portion 5 is for fixing to a left ventricle casing 12A used when used in a blood circulation simulator described later. As the elastic material, silicone, latex, polyurethane or the like can be used, and silicone is particularly preferable. This sack body 1 is preferably 40-6
It has a volume of 0 ml, especially 50 ml. Note that, in this specification, a substantially shell shape is a shape like a shell that is smoothly narrowed from one side to the other side, such as a bell shape or a shape obtained by dividing a long ellipse in half. Similar shapes are included.

In the present invention, a two-component silicone RTV rubber can be used as the silicone, and is preferably an addition type silicone having a hardness (JIS) of about 40 and an elongation of about 300%. is there. Such a silicone cures in about 24 hours at room temperature after mixing the base and the curing agent. At the time of preparing this silicone, dimethyl silicone oil is mixed in an amount of about 20 to 30% by weight with respect to 100% by weight of the main ingredient in addition to the main ingredient and the curing agent to adjust the viscosity. Since silicone immediately after mixing contains many air bubbles, air bubbles are removed by a defoaming machine. Using such silicone, a sac main body 1 having a substantially shell shape is manufactured by a mold described later.

As the elastic material constituting the elastic rubber cord 2, silicone, latex, polyurethane or the like can be used, but the same material as the sac main body 1 in terms of adhesiveness to the sac main body 1 can be used. It is preferably used. The elastic rubber cord 2 is not particularly limited as long as it can be wound around the sack body 1, but is usually 3 to 5 mm
Those having a diameter of the order of magnitude are preferred. For example, in the case of an elastic rubber cord made of silicone, the elastic rubber cord as described above is obtained by filling silicone inside a metal pipe having an inner diameter corresponding to a desired elastic cord diameter and curing the same. Can be. In particular, it is preferable to use an aluminum pipe having a circular cross section with an inner diameter of 3 to 5 mm.

Next, a method of manufacturing the left ventricular sack as described above will be described.

The left ventricular sac 1 is formed by spirally winding a silicone elastic cord 3 around a sac body 2 formed by using a mold 6 having a volume of 50 ml as shown in FIG. . The preferred mold 6 is formed by processing duralumin with an NC lathe, but may be formed by molding it with silicone or the like and copying it with an epoxy resin.

A case where a single-shaft rotary molding machine is used will be described below as an example of molding the sack body 2. In the single-shaft rotary molding machine, the mold 6 is mounted on a horizontal rotating shaft, silicone is applied to the surface of the mold 6, and the sac body 2 is formed while rotating the shaft at a constant speed. A preferred single-shaft rotary molding machine is one in which a stepping motor is installed in a constant temperature controlled heater oven so that the rotating shaft is horizontal, and the mold 6 is attached to the rotating shaft. It is sufficient that the temperature in the oven can be controlled to about 50 to 150 ° C. In addition, the rotation speed of the stepping motor is 1000 rpm at the maximum.
It suffices if m constant rotation drive can be performed.

In such a single-shaft rotary molding machine, a silicone flange 5 is provided on the side of the sack opening of the mold 6.
A metal plate (not shown) is attached perpendicularly to the long axis 7 in order to integrally mold with the bag portion 4 of the sack body 2. The flange portion 5 is for fixing the left ventricle sack 1 to a left ventricle casing used when used in a blood circulation simulator described later.

Then, the left ventricular sack 1 is manufactured according to the following procedures (a) to (e). (A) The mold 6 is mounted on a rotating shaft of a single-shaft rotary molding machine. At this time, when the mold 6 is made of a resin such as an epoxy resin, it is preferable to apply a release agent to the mold 6.
When the mold 6 is made of metal, it is not necessary to apply the mold 6 in particular. (B) While rotating the mold 6 at 50 to 60 rpm, silicone is uniformly applied to the mold 6 and the flange 5. The amount of silicone applied at one time is preferably 9 to 10 g. Applying more silicone makes it difficult to produce a left ventricular sac of uniform thickness. The function as the left ventricular sac is different due to the difference in the thickness of the left ventricular sac. Usually, a single coating is preferable, but when a thick sack is manufactured, the silicone applied once is cured and then applied twice or three times. (C) After applying silicone, mold 6
Rotate at rpm and turn on the heater. The set temperature of the heater is set to 120 ° C., and after the temperature in the oven reaches 120 ° C., the heater is left for about 30 minutes. (D) The curing of the silicone is completed in about 30 minutes (the curing time of the silicone is about 24 hours at room temperature, but the curing is faster at higher temperatures at higher temperatures). When the curing is completed, the mold is removed from the single-shaft rotary molding machine. (E) While adhering silicone elastic rubber cords manufactured in advance with silicone,
That is, it is wound around the sack main body 2 formed outside the mold 6. The winding direction of the elastic elastic cord is clockwise as viewed from the tip of the mold.

Next, the step of bonding the elastic rubber string of silicone will be described with reference to FIG. First, the mold 6 is placed with the flange 7A facing down, and one end of the elastic rubber cord 3 is bonded to the vicinity of the joint between the flange 7A and the sack body 2 (FIGS. 3 (a) and 3 (b)). For bonding, a small amount of silicone is applied to the end of the elastic rubber cord 3 with a brush 8 or the like, and the silicone rubber is applied to a bonding portion with the sac main body 2 and cured with a dryer 9. It is preferable that the dryer 9 used here has a strong tip with a diameter of about 7 mm. The silicone cures in about 10 seconds by using a powerful dryer 9.

After one end of the elastic rubber string 3 is adhered, the elastic rubber string 3 is held 1.5 to 2.0
Stretched twice and 45-60 ° to the flange 7A
(See FIG. 3 (c)).
Then, silicone is applied to the contact surface between the elastic rubber string 3 and the sack main body 2 to a position about 2 cm from the first bonded portion, and the elastic rubber string 3 is adhered using a dryer while the elastic rubber string 3 is stretched. As in the case of 2 cm before the second bonded portion, the elastic rubber string 3 is bonded to the flange surface of the flange portion 7A while keeping the angle at 45 to 60 °. The same operation is performed again from the third bonding portion (FIG. 3D).

The fourth bonding portion is 1 /
When the position of the elastic rubber string 3 is reached, the elastic rubber cord 3 is adhered to the outer periphery of the mold 6 while gradually changing its angle from 60 to 80 ° with respect to the flange surface (FIG. 3).
(E)). Also at this time, the elastic elastic cord 3 is 1.5 to 2.0.
Stretch twice. Sack body 2 from the fifth bonded part
(FIG. 3 (f)). Then, the left ventricle sack 1 can be manufactured by cutting the excess elastic rubber cord 3 with scissors 10 or the like (FIG. 3).
(G), (h)).

In the above-described step of winding the elastic rubber cord 3, there are two types of bonding methods. That is, one is a method in which an adhesive is applied to the entire elastic rubber cord 3 and the whole is adhered, and the other is a method in which the elastic elastic cord 3 is adhered not at the whole but at five or six points. In the second method, the point where the elastic rubber cord is stretched in each step in the above manufacturing procedure may be bonded. In either case, the method of winding the elastic elastic cord 3 is the same.

Next, a method of using the left ventricular sac as described above will be described.

The left ventricular sac is used as a pump for the left ventricle in the blood circulation simulator circuit. FIG. 4 shows an example of the blood circulation simulator circuit. In the figure, a blood circulation simulator circuit 11 includes a left ventricle casing 12A.
The left ventricular sack 12 includes a left ventricular sack 12 housed in the left ventricular sack 12 and a simulated aorta 14 which is a pipe provided annularly on an attachment member 13 attached to a flange portion of the left ventricular sac 12.
An aortic valve 15 is provided on the mounting member 13 on the outlet side of the device. In the middle of the simulated aorta 14, a compliance tank 16, a resistor 17, and an overflow tank 18 are provided, respectively, and the inflow portion thereof is connected to the left ventricular sack 12 via a mitral valve 19 provided on the mounting member. Inflow. The left ventricular sack 12 is in communication with a pneumatic drive device 20 for driving. In the circuit 11 described above, the simulated aorta 14 may be a PVC (polyvinyl chloride) tube, a Tygon tube, or a silicone aortic arch simulating the shape of a human living aorta. The compliance tank 16 and the resistor 17 are concentration elements for simulating a compliance element and a resistance element in peripheral blood vessels. Further, the left ventricle casing 12A is provided with a left ventricular sac.
A housing for separating blood (or physiological saline) from the air sent from the pneumatic drive device 20 through the air pump 12.

FIG. 5 shows an example of the left ventricle casing 12A. The casing 12A is made of transparent acrylic resin, and an attachment member 13 having a simulated aorta 14 having an aortic valve 15 and a mitral valve 19 is detachable from a flange portion 12B of the casing. Left ventricular sack 12
Fix the flange part. The driving method of the left ventricular sack 12 is to make the inside of the casing 12A negative by the negative pressure to expand the sack 12, and to contract the sack 12 by the positive pressure. To this end, the pneumatic drive 20 has two pressure tanks, one positive pressure tank and the other a negative pressure tank. The pressure for driving the left ventricular sac is supplied by switching these two pressure tanks with solenoid valves, which are controlled by electrical circuits. The heart rate and left ventricular contraction time ratio are determined by controlling the solenoid valve. A preferred pneumatic drive 20 has a heart rate of 40-120 BPM,
Left ventricular systolic time ratio 20-50%, positive pressure 0-350m
It suffices if mHg and negative pressure can be adjusted between 0 and -100 mmHg, respectively.

The driving condition of the left ventricular sac 12 is to simulate a normal human heart function.
M, heart rate 4.5-6.0 l / min, aortic pressure 90-110 under left ventricular contraction time ratio 33-37%
The resistor 17 of the positive pressure, negative pressure and blood circulation simulator circuit 11 is adjusted to be mmHg. Pneumatic drive 20
As a guide for the set values of positive pressure and negative pressure,
200 mmHg, negative pressure is in the range of -5 to -30 mmHg.

Further, since the volume of the left ventricle of a normal human living body is about 120 ml at the end diastole, the left ventricular sac 12 is also driven with the end diastolic volume of about 120 ml, for example, the cardiac output of 5.0 liter. / Min, heart rate 6
At 0 BPM, the volume of one beat is about 83 ml / beat, so that the volume change range when the left ventricular sack is driven may be about 40 (end systole) to 120 (end diastole) ml.

Although the standard method of using the left ventricular sac has been described above, various other drive parameters can be set to appropriate values in order to reproduce various human heart functions.

The operation of the above configuration will be described. By activating the blood circulation simulator circuit 11 and activating the pneumatic drive device 20 under the predetermined conditions, negative pressure and positive pressure are alternately applied in the left ventricle casing 12A, thereby expanding the left ventricular sack 12; The contraction is repeated, and the blood, physiological saline, and the like in the simulated aorta 14 circulate through the circuit 11 accordingly. In such a blood circulation simulator circuit 11, as shown in FIG.
Since the elastic rubber cord 3 is wound around the outer periphery of the left ventricular sac main body 2, the torsional movement of the living body left ventricle can be simulated. For this reason, a swirling flow is generated in the flow of the liquid flowing out of the left ventricular sack 1 due to the torsional motion. This swirling flow is a flow that cannot be obtained in the conventional left ventricular sack, and by using the left ventricular sac 1 of the present invention, it becomes possible to examine the influence of the blood flow on the aortic valve and blood vessels. Also, by setting the molding volume of the left ventricular sac 1 to 50 ml, the liquid itself is discharged by expanding and contracting in the same manner as in a normal human living heart, so that the long axis during the cardiac contraction and expansion is extended. It is possible to simulate a change in diameter in the minor axis direction.

[0028]

The present invention will be described in more detail with reference to the following specific examples. Example 1 Swirling flow measurement experiment

FIG. 6 shows an experimental apparatus for examining the effect of the torsional movement of the left ventricular sack 1 during pulsation as shown in FIG. 1 on the blood flowing from the left ventricle to the aorta. In this experiment, the circulation of blood flow flowing from the left ventricle to the aorta is examined. In this experiment, a comparison was made with a conventional left ventricular sack, that is, a left ventricular sack with a molding volume of 150 ml and no elastic elastic cord wound.

The experimental apparatus shown in FIG. 6 is a schematic diagram of a Windkessel-type blood circulation simulator circuit, and has basically the same configuration as the blood circulation simulator circuit shown in FIG. The reference numerals are used, and the detailed description is omitted. In FIG. 6, a swirling flow measuring device 21 is installed in the simulated aortic tube 14. This swirl flow measuring device
In FIG. 7, a simulated aortic duct 14 is provided with a propeller 22 for turning measurement in the simulated aortic tube 14 as shown in FIG.
The movement of 22 can be observed through the observation window 23 installed on the downstream side, and in particular, the degree of rotation of the blood flow can be checked by measuring the rotation speed of this propeller 22 with the high-speed camera 24 It is.

Table 1 shows the experimental conditions, and FIG. 8 shows the experimental results.
The experiment was conducted with a standard human heart rate of 60 BPM, 9
Performed at 0 BPM. Table 2 shows the results of a significant difference test (t test) of the rotation speed of the propeller for each heart rate in FIG.

[0032]

[Table 1]

[0033]

[Table 2]

From Table 2, it can be seen that there is a significant difference between the turning of the left ventricular sac of the present invention and the conventional left ventricular sac, and that the torsional motion of the left ventricular sac during pulsation is from the left ventricle to the aorta. It was found that the outflowing blood generates a swirling flow. Example 2 Comparison experiment of contraction form

An experiment was conducted to compare the change in diameter in the major axis and minor axis direction during contraction and expansion of the left ventricular sac of the present invention as shown in FIG. 1 with those of a normal living heart and a conventional left ventricular sac. FIG. 9 shows an experimental apparatus for this experiment.

The experimental apparatus shown in FIG. 9 is a schematic diagram of a Windkessel type blood circulation simulator circuit, and has basically the same configuration as the blood circulation simulator circuit shown in FIG. The reference numerals are used, and the detailed description is omitted. In FIG. 9, a high-speed camera 25 is provided toward the left ventricular sack 12.
Thereby, the inflation / deflation state of the left ventricular sack 12 can be intermittently photographed. In the experiment, the left ventricular sac was pulsated under a standard human heart rate of 60 BPM, a cardiac output of 5.5 l / min, and an average aortic pressure of about 90 mmHg. Was photographed with a high-speed camera. FIG. 10 shows the states of left ventricular expansion and contraction based on images at the end systole and end diastole of these left ventricular sac. For reference, FIG. 10 also shows the state of diastole and contraction based on the left ventricle contrast image at the end of systole and end of diastole of a normal human living heart.

FIG. 10 shows that the conventional left ventricular sac has a small diameter change in the long axis direction, ie, the vertical direction, whereas the left ventricular sac of the present invention has a long axis, short axis direction, ie, both the vertical and horizontal directions. There is a change in diameter. This change in diameter in the major axis and minor axis directions is also found in a normal human living heart. Therefore, it can be understood that the left ventricular sac of the present invention can simulate a change in diameter in the major axis and minor axis direction during cardiac contraction and dilation in a normal human living heart.

[0038]

The left ventricular sac simulating the contracted form of the living body left ventricle according to the first aspect of the present invention is obtained by spirally winding an elastic rubber cord around the outer periphery of a sac body made of an elastic material. It is possible to simulate the torsional movement of the left ventricle of the living body, whereby a swirling flow is generated in the flow of the liquid flowing out of the left ventricular sac.

Further, the left ventricular sac simulating the contracted form of the living body left ventricle according to the second aspect is the same as the first aspect,
Since the volume of the left ventricular sac body is 50 milliliters, the liquid itself is discharged by expanding and contracting in the same manner as a normal human living heart, so that the long axis during cardiac contraction and expansion is It is possible to simulate a change in diameter in the minor axis direction.

Further, in the method of manufacturing a left ventricular sac simulating the contracted form of the living body left ventricle according to the third aspect, an elastic rubber cord is spirally wound around the outer periphery of a sac body made of an elastic material. Thus, a left ventricular sac that simulates the contracted form of the left ventricle of a living body can be efficiently manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a left ventricular sac simulating a contracted form of a living left ventricle according to an embodiment of the present invention.

2A is a plan view and FIG. 2B is a side view showing a mold used for manufacturing a left ventricular sac.

FIG. 3 is a process diagram showing a procedure for winding an elastic elastic cord of silicone.

FIG. 4 is a schematic diagram showing a circuit configuration of a blood circulation simulator.

FIG. 5 is a front view showing a left ventricle casing.

FIG. 6 is a schematic diagram showing a swirling flow measurement experimental device.

FIG. 7 is a schematic view showing a swirling flow measuring device according to the third embodiment.

FIG. 8 is a graph showing the results of a swirl flow measurement experiment.

FIG. 9 is a schematic view showing a contraction mode comparison experiment apparatus.

10A and 10B are schematic diagrams comparing (a) a left ventricular sac of the present invention, (b) a conventional left ventricular sac, and (c) a normal human left ventricular contraction / expansion mode.

[Explanation of symbols]

 1 left ventricular sack 2 sack body 3 elastic rubber string

Claims (3)

[Claims] 1. A left ventricular sac simulating a contracted form of a living body left ventricle, wherein an elastic rubber cord is spirally wound around an outer periphery of a substantially shell-shaped sac body made of an elastic material. 2. The volume of the left ventricular sack main body is 40 to 6
The left ventricular sac simulating the contracted form of the left ventricle of a living body according to claim 1, wherein the sac is 0 ml. 3. A method of manufacturing a left ventricular sac that simulates a contracted form of a living left ventricle, wherein an elastic rubber cord is spirally wound around an outer periphery of a substantially shell-shaped sac body made of an elastic material.