JPS58138466A - Pulse type blood pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to pulsatile blood pumps, and more particularly to improvements in sac-type blood pumps driven by fluid pressure, particularly gas pressure.

In recent years, progress has been made in the development of artificial hearts to supplement and temporarily replace the functions of the heart outside the body during targeted surgeries and other surgeries.

Research into a sac-type artificial heart powered by gas pressure has been conducted in Japan ahead of the rest of the world, and good results have been obtained in long-term survival studies using goats. The path to clinical application is still open, but a particular problem is the formation of blood clots inside the artificial heart, and how to impart antithrombotic properties is an extremely difficult problem. material, pump design, surface smoothness,
It is thought that problems such as the blood pump during operation and problems with the blood pattern within the blood chamber are intricately involved.

The present invention relates to a sac-type blood pump that solves the problems in shaping the sac-type blood pump and is formed so that the flow of blood in the blood chamber is ideal when actually used for treatment.

The present invention will be explained below based on the attached @ page.

FIGS. 1 to 4 show examples of basic configurations of a sac-type blood pump and a blood chamber.

The sack-type blood pump shown in FIG. 1 is composed of a pressure-resistant housing outer case 1 (made of polycarbonate, for example), and a blood chamber 2 that is shaped like a flat bag and has an arcuate paper surface.

At the upper part of this blood nine bar 2, a blood inlet pipe 3 and a blood outlet fi4 are formed upward and approximately parallel to each other, and a flange 5 is attached around the upper part. Although not shown in the drawings, a well-known square is provided inside the blood introduction v6 and the blood discharge pipe 4 to prevent backflow of blood. The collected blood is discharged through blood discharge #4. The blood chamber 2 is housed in the housing outer case 1 under the condition shown in FIG. The blood chamber 2 is kept airtight, and the volume of the blood chamber 2 alternately contracts and expands due to changes in the pressure of the air that is forced into the housing outer case through a piston provided on the bottom side of the housing outer case 1. functions as a pump.

The present invention has been developed by examining various conditions for the formation of thrombi in the blood chamber 2 and the function of the pump in animal experiments using the above-mentioned sac-type pneumatic artificial heart. The present invention was developed by developing a usable blood pump and pursuing higher functionality of the pump. This figure shows a sack-type blood pump. In this conventional sack-type blood pump, as shown in Figure #I2, the large side surface 6 forming the blood chamber 2 is mostly formed in a planar shape. A drawback of this blood bob is the problem of pump molding. In order to use a blood pump as an artificial heart, it is necessary to ensure that the blood contact area has excellent antithrombotic properties.When coating the inside of the blood pump with this antithrombotic substance, the antithrombotic substance is 8 in a common solvent with the substances that make up the pump.
A method of contacting the inner surface of the blood pump with J blood at 10% is preferably used. In this case, the inward part of the blood pump is partially swollen by the solvent, and in that state, the antithrombotic substance and the inward part of the pop contact in the presence of a common solvent, so the antithrombotic substance is ideally placed on the blood contacting surface of the pump. For example, if the blood pump is made of polycyclized vinyl, the antithrombotic substance can be coated in a common solvent such as tetrahydrofuran, dioxane, or dimethylformamide. When the blood pump is made of polyurethane acid, a common stimulant containing dimethylacetamide, dimethylformamide, hexamethylphosphoramide, or the like as a main component can be used.

With this method, the antithrombotic substance can be coated extremely smoothly, and because a common solvent is used, the coated antithrombotic substance becomes integrated with the blood pump constituent materials, and peeling occurs even when the pump is repeatedly pulsated. Although this is an extremely excellent product, as mentioned above, there are drawbacks in forming the blood pump. As shown in Figure 3, the common law
The blood chamber of the blood pump that has come into contact with the drug absorbs the drug, swells and expands as shown in FIG. 5(b), and then undergoes a drying process (solvent evaporation process).
Then, the blood chamber contracts as shown in FIG. 3(O), but during the contraction process, the blood chamber deforms, usually inward into a concave shape (as shown in FIG. 5(C)). Such deformation does not mean that the volume of the blood chamber decreases and the required pump output volume is not achieved; in actual use of the blood pump, a large degree of vacuum is required during the volume expansion phase of the pump, and therefore the blood Also, the degree of deformation of the internal recess of the blood chamber for the artificial heart is not constant, which makes quality control difficult, resulting in a high number of defective products, making it difficult to commercialize the product. This deformation, which was considered difficult, is more likely to occur as the blood chamber becomes thinner. If the thickness is about 15 to 2.0, the thickness will be reduced, but this will hinder the operation of the blood pot. That is, the sensitivity of the blood chamber to changes in external pressure caused by the drive device is significantly reduced, resulting in performance problems. Therefore, the thickness of the blood chamber is preferably 15 m or less, and more preferably 12 m or less. However, the above-described problem of deformation occurs.

The present invention solves these problems, and the base body of a blood pump (formed W before being coated with antithrombotic material)
When molding, the large area of the blood chamber bulges out in an arc shape, i.e., the cross section of the blood chamber of the blood pot (a cross section cut with a line perpendicular to the direction of the blood inlet/outlet). ) has an outwardly symmetrical arc-shaped curve, and most of this curve is 5OR, 50
0R.

Preferably 80R to 500R1, more preferably 100R1
R ~ 200R is formed as a percentage value '0 Here, rLR indicates a part of a circle with a radius of 4 squares (according to JIS regulations) 0 The above curve is If it is smaller than 5OR, the blood chamber becomes too round and the blood flow pattern inside the pump becomes inconsistent when the pump is operated, causing blood coagulation or blood loss II (hemolysis, etc.) inside the pump, which is not desirable.Also, 500R If the size is too large, the effect of the present invention will not be achieved, and deformation will occur when the antithrombotic material is coated and dried, making it impossible to achieve the purpose of the present invention.

If the blood chamber before being coated with the antithrombotic material is formed to meet the above conditions, surprisingly, when applying the antithrombotic material, a common solvent is brought into contact with the blood pump base, and the blood chamber is coated with the solvent. swelling,
We discovered that during the process of expansion and drying, the blood chamber always maintains its original shape without deformation.The shape of the blood chamber before being coated with antithrombotic material has such an important controlling force Furthermore, one of the major features of the present invention is the excellent functionality of the blood pot to which the antithrombotic material is added without causing deformation. be.

In other words, the blood pump is driven by alternating compression and expansion of the blood chamber due to changes in the external pressure of the blood chamber, thereby changing the volume and, accordingly, introducing or extracting blood into the blood pump. The blood pump according to the present invention functions as a pulsating pump.
The large area vsifii of the blood chamber has an arcuate curved surface on the outside, and is stable in this shape when no load is applied to the blood chamber. When the head is replaced, just by applying a very light degree of vacuum, the shape of the blood chamber has a restoring force, that is, a natural expansion force, and when the external pressure of the blood chamber is reduced by the action of the drive device, it becomes much more sensitive than conventional products. We have discovered that the introduction and extraction of blood into a blood pump that reacts and exhibits high functionality is performed in an extremely ideal manner.The present invention improves the functionality of conventional sac-type blood pumps. In order for blood to always flow in a constant pattern with each beat in the blood chamber, the basic shape of the blood chamber must be under the following conditions: The basic shape of the blood chamber of the blood pump according to the present invention may be a flat one as shown in FIG. ~50, preferably 16-2.
5, more preferably 18-23.

Further, it is preferable that the ratio between the total height on the center line of the blood chamber 2 and the maximum weight is α8≦D, /L≦2.0.

In a blood chamber that satisfies conditions similar to those described above, the pattern of crushing caused by air pressure can be made constant with each beat.

The blood chamber portion 2 and the blood introduction and discharge pipes 6, 4 used in the present invention are made of an elastic polymeric material, and soft polyvinyl chloride or polyurethane is particularly suitable as the material.

In this case, it may be formed from a soft polyvinyl chloride wire and a so-called polyvinyl chloride paste made of polyvinyl chloride and a plasticizer composition.

In this case, the amount of plasticizer mixed is preferably 40 to 100% by weight, more preferably 50 to 80% by weight, based on the polyvinyl chloride.

The polyvinyl chloride may also contain a known suitable stabilizer, such as a non-toxic calcium-lead organic complex. The degree of polymerization of polyvinyl chloride is 500 to 2000
It is preferable to use

The polyurethane used as the material in this example can be roughly divided into polyether polyurethane and polyester polyurethane, both of which can be used, but it is preferable to use polyether polyurethane from the viewpoint of elastic properties and fatigue resistance. is preferred.

Molded articles using these polyurethanes may be crosslinked to increase their mechanical strength.

Polyester-based polyurethane is suitable for producing hard elastomers with high elastic modulus, high tear strength, and is therefore suitable for constructing flange pipes. More preferably, the amount is 3 weight per component amount. Further, the preferable range of the heat treatment temperature is 60 to 150C, and the temperature of the nest is preferably 80 to 120G.
, even more preferably 80 to 110C.

Further, when the blood chamber 2 used in the present invention is made of soft polyvinyl chloride, the wall thickness of the blood chamber 2 used in the present invention is preferably from L5 to T5, in view of its repulsion characteristics and fatigue resistance. It is more preferable that the thickness is 15 to t3, and even more preferable that it is α6 to t2.If the blood chamber 2 is made of a polyurethane material, the thickness of α2 to t3 is preferable; L3~t2■ is preferable, and 15~tOW is even more preferable.If this thickness is too large, the false timing of the blood chamber 2 may be delayed or deformed when the inside of the housing outer case 1 is pressurized or depressurized. Since the time is extended for a long time, it is not possible to obtain an appropriate blood pumping behavior.On the other hand, if this wall thickness is too thin, the deformation behavior of the blood chamber becomes sensitive, making it difficult to control it. The blood chamber 2 can be molded using a known molding method, such as injection molding, cast molding, roastwat, etc. When the present invention is molded using polyvinyl chloride plastisol, - The method may be as follows: First, a heated molding die is immersed in plastisol, and the heat of the molding die causes the plastisol in contact with the die to gel.

Since the thickness of the gelled layer can be adjusted, the thickness of the edge portion can also be arbitrarily determined by adjusting the molding die and heat capacity.

The present invention makes it possible to greatly improve the functionality of conventional sac-type blood pumps, eliminates the problem of deformation of the blood chamber during molding as described in detail, and opens the way to the practical application of blood pumps for artificial hearts. Hereinafter, the present invention will be explained in more detail by way of implementation.

Comparative Example 1 A sac-type blood pump used as an artificial heart was made of a polyvinyl chloride molded product (plasticizer 80% by weight (based on polyvinyl chloride) with a blood chamber having a flat side surface with a large area as shown in Fig. 2). ) was created. The internal volume of the blood pump is 80cm.

The thickness of the sack portion was tO■. A tetrahydrofuran/diokit/solution (2/1) of an antithrombotic material containing polyurethane and polydimethylsiloxane as constituent components was applied to this. After application, the blood pump absorbs the solvent, swells, and expands in volume. ◇-If left overnight, the solvent evaporates and conversely contracts, causing the large area of the blood chamber to deform inward into a concave shape (6th (see figure (c)). Repeat the same experiment 5
Although 6 blood pumps were prototyped, only 4 usable pumps did not suffer from the above deformation, and 52 pumps suffered from the above deformation. Moreover, the degree of deformation was not constant even though the coating conditions were the same, and quality control was impossible.

Example 9141 A polyvinyl chloride cleft blood pump (112T!!! agent 80% by weight vs. polyvinyl chloride) having a blood chamber as shown in FIG. 4 was manufactured. In this example, the large area of the blood chamber was formed so that the bulge toward the outside of the surface had a 10OR curve, the thickness was 10cm, and the total volume of the pump was 100mm. As in Comparative Example 1, the blood pump was coated with an antithrombotic material containing polyurethane and polydimethylsiloxane dissolved in a tetrahydrofuran/dioxane solvent Vc bath.◇After the treatment, the blood pump absorbed the solvent and swelled, causing the blood chamber to become The volume expanded 〇 - When it dried at night, the bath salt evaporated and contracted, or the shape did not change compared to its original shape and maintained the same shape.

The same example was repeated and 28 blood pumps were made as prototypes, but none showed any deformation. Further, even if the thickness of the blood chamber of the blood pump was set to αB, no deformation of the blood chamber was observed.

Example 2 and Comparative Example 2 In this example, polyurethane was used as the material of the blood pump,
A blood chamber having a shape as shown in FIG. 4 (curved surface 200R on the wide side surface of the blood chamber) was made by the roast wax method. The total capacity of the pump was 100 m, and the thickness of the blood chamber was α8. Polydimethylsiloxane-polyurethane copolymer was dissolved in dimethylformamide as an antithrombotic material, coated on the inner surface of the blood pump, and dried. No deformation was observed after drying and the original shape was maintained. In the same manner, 18 test tubes were made, but only one case showed deformation.

For comparison, the wide side of the blood chamber as shown in Figure 2-
When a polyurethane blood chamber base with a flat surface was prepared, an antithrombotic material was coated and dried in the same manner as above, four out of five cases had a concave inner surface as shown in Figure 3 (cl). Deformation was observed, and the states of deformation were all different.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of a sack-type vehicle fluid pump, and Figure 2 is an I of the blood chamber that constitutes a conventional sack-type blood pump.
Each cross-sectional view of Eth (-3, @ plane (b), flat ffi+,), Figure 45 shows a side cross-sectional view of the process of applying the anti-thrombotic material to the blood chamber, (a) shows before application of the anti-thrombotic material, (b) shows the shape when swollen and expanded after application, (C) shows the shape when contracted and deformed after drying, and FIG. 4 shows the blood chamber 1 according to the present invention.
- A sectional rlii diagram (-) bulging into an arc, a plan view (b), a front sectional view (C), and a plan view (4). In the code, 1Fi housing outer case, 2 blood chamber, 5#'i blood introduction space, 4 blood discharge pipe, sF
I Show each flange 〇Special fraud applicant Nippon Zeon Co., Ltd.”
Tono
(c) Thatch 4 Figure (shi L)
((S)■U-)

Claims (1)

[Scope of Claims] t. A pulsating blood pump in which a flat bag-shaped blood chamber is formed in communication with a blood inlet pipe and a blood discharge pipe, and blood is introduced and discharged by the pulsation of the blood chamber, wherein the blood A pulsatile type of blood that is patented in that opposing long sides in the transverse direction of the chamber (a cross section taken at right angles to the direction of the blood inlet tube and outlet tube) form a symmetrical arcuate curve outward. pump. 2. The arcuate curve formed in the blood chamber is 50
The pulsatile blood pot according to claim 1, which has R to 50 R.