JPS622540B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blood pump device for an artificial heart, and more particularly to an improvement in a blood pump driven by fluid 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 open-heart surgery and other surgeries. Research on a pump-type artificial heart driven by pneumatic pressure is being conducted in Japan ahead of the rest of the world, and good results have been obtained in long-term survival records using goats. The path to clinical application has not yet been opened, and the particular problem is that
These are the problem of thrombus formation inside the artificial heart and the problem of valve installation. The present invention relates to a valve loading section in a blood pump. The present invention will be explained below based on the drawings. FIG. 1 shows the basic form of a sac-type blood pump and a blood chamber, which are an example of a blood pump. Sock-type blood pumps are made of a pressure-resistant (for example, polycarbonate) housing outer case 1.
and a blood chamber 2 which is shaped like a flat bag and has an arcuate bottom surface. At the upper part of this blood chamber 2, a blood inlet pipe 3 and a blood discharge pipe 4 are formed upward and substantially parallel to each other, and a flange 5 is attached around the upper part. Furthermore, a known valve 6 is provided inside the blood introduction tube 3 and the blood discharge tube 4 to prevent backflow of blood, so that the blood introduced from the blood introduction tube 3 into the blood chamber 2 is The blood is discharged from a blood discharge pipe 4. The blood chamber 2 is housed in a housing outer case 1 as shown in FIG. 1, and is held airtight by a flange 5. Then, the volume of the blood chamber 2 is alternately contracted and expanded due to changes in the pressure of the fluid, such as air, that is pumped into the housing outer case through a pipe 7 provided on the bottom side of the housing outer case 1, thereby functioning as a pump. Function. The present invention relates to the improvement of the valve loading portion of such a blood pump, and the valve type may be a known heart valve replacement valve, for example, a disk valve using pyrolite carbon, or an elastic valve such as Duramata. Any leaflet valve constructed from a membrane can be used. As shown in FIG. 2, these valves have, for example, a metal ring-shaped valve annulus 8 and a pyrolyte carbon disc 9 incorporated therein, and are opened and closed by a specially designed mechanism. These valves are connected to the blood inlet pipe 3 of the blood pump;
The blood discharge tube 4 is loaded at an appropriate position. For example, as shown in FIG. 2, the valve annulus 8 is made of a metal ring formed in an outwardly concave shape, and the valve is attached by forming a convex portion corresponding to the concave portion of the valve annulus on the blood conduit to which it is attached. It is attached so that it fits into this. When actually using a blood pump, the blood chamber alternately expands and contracts in volume in response to positive and negative changes in external pressure.
During deflation, significant pressure (positive or negative) will be exerted on the valve and the conduit in which it is mounted. Moreover, this pressure occurs alternately between positive and negative pressures at a frequency of 60 to 90 times per minute, and each time the force is applied to the valve annulus and the conduit that holds the valve annulus. In particular, the pressure when pumping blood out of the chamber can reach as high as 300 mmHg, and the problem at this time is that the valve ring may come off the predetermined set position, and in this case, the function as a pulsatile blood pump is naturally impaired. can be lost, and the patient being treated can suffer a fatal blow. Therefore, for safety reasons, in conventional blood pumps, the concave part of the valve annulus is fitted into a ring-shaped convex part provided at a predetermined position where the blood conduit should be fitted. The pressure generated not only acts on the valve annulus but also has a large effect of expanding the tube into which the valve annulus is fitted, and the pressure applied to the blood drain tube that pumps out blood is particularly large. Polyurethane or soft polyvinyl chloride is used as a known material for blood pumps, but since these are elastic bodies in nature, they are easily deformed by pressure. However, appropriate elastic deformation is required for the blood inlet tube and blood discharge tube when the valve is installed.
It is required to prevent elastic deformation during use after installation. As a solution to this problem, for example, once the valve is installed in a predetermined position in the blood conduit, it is tightened from the top of the conduit with a tape-like fastener made of metal or polymeric material, such as nylon with strong mechanical strength. A convenient method has been used in which the valve annulus is tightened from the outside along the ring to prevent the valve annulus from slipping off during use. However, with this method, when tightening the valve annulus from the outside, if the tape-shaped tightening tool deviates from the valve annulus, or if it tilts even slightly against the valve annulus surface, local force may be applied to the valve annulus. This causes the valve to malfunction. For example, a blood pump has a
The valve opens and closes at a rate of 90 times per minute, but if this opening and closing does not occur smoothly, patients whose lives depend on the blood pump are at great risk. The inventors of the present invention paid careful attention to these points and conducted various studies regarding the material and thickness of the loading part of the valve, and found that the valve can be mounted and the valve can be held stably even during use. It has been found that if certain conditions are met regarding the material and the thickness range of the loading part of the valve, the valve can be mounted stably and safely, and there will be no trouble at all during use. First, the material used is soft polyvinyl chloride containing a predetermined amount of plasticizer. The degree of polymerization of the polyvinyl chloride used in carrying out the present invention is preferably 500 to 2,000.
The amount of plasticizer is important and
40 to 120 parts by weight, preferably 50 to 120 parts by weight
80 parts by weight is good. If it is less than 40 parts by weight, it lacks softness, and if it is more than 120 parts by weight, it becomes too soft and becomes unsuitable for valve loading, valve operation, etc. As the plasticizer used, DOP (dioctyl phthalate) and DOA (dioctyl adipate) are preferably used from the viewpoint of non-toxicity. The present invention also provides that at least the blood discharge pipe has a wall thickness of 1.3 mm or more and 5.0 mm or less, preferably 2.0 mm or more and 3.2 mm or less over at least 10 mm in the length direction of the pipe from the attachment part of the valve. It is a blood pump that is characterized by: If the blood discharge tube has a wall thickness of 1.3 mm or less, there is a risk that the conduit will swell due to pressure, causing the valve annulus to dislodge or the valve to malfunction, as described in detail above.
Furthermore, even if the annulus does not come off, the part where the annulus is attached is greatly deformed when the pump is used, and blood is trapped at the contact area between the annulus and the tube, which often leads to the formation of thrombi. When this thrombus is used as an artificial heart or an auxiliary heart, it has the fatal defect that it flows as a small embolus into the blood stream and embolizes cerebral arteries. Furthermore, if the thickness exceeds 5.0 mm, the conduit becomes stiff, making it difficult to attach the valve and causing great inconvenience in use. Further, the reason why the thickness of these parts is set to be at least 10 mm from the mounting part of the valve is that if the thickness is less than 10 mm, the effect of the wall thickness is lost. The wall thickness of the tube is not limited to the blood discharge tube 4, but also applies to the blood introduction tube 3 as well. As explained above, the present invention allows the valve to be easily installed by adjusting the material and thickness of the conduit in which the valve is installed within a predetermined range, and once installed, the valve operates stably and during use. It has the characteristic that the valve does not dislodge or thrombus is generated in the valve annulus. In addition, after the valve is attached, you may further press down the valve annulus and conduit with a tape-like material just to be sure. In the case of the present invention, there is no need to strongly tighten the valve, so that the valve does not malfunction due to clumsiness during tightening as in the conventional case. The present invention will be explained in more detail with reference to Examples below. Examples 1 to 11 Using the sac-type blood pump shown in Figure 1, the thickness of the blood inlet tube and the blood outlet tube were varied, and the fluid inlet tube of the outer case was connected to a separately installed pneumatic drive device to inject physiological saline. The operating condition of the valve was investigated using The results are summarized in the table below. In the table, polyvinyl chloride was carried out using Zeon Paste manufactured by Nippon Zeon Co., Ltd., and polyurethane was carried out using Esten 5740 (manufactured by Gutstoritsi Co., Ltd.) and Paraprene P300 (manufactured by Nippon Elastra Co., Ltd.). 【table】

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a sac-type blood pump, and FIG. 2 is a partial vertical sectional view of a blood discharge pipe equipped with a blood discharge valve. In the symbols, 1 is a housing outer case, 2 is a blood chamber, 3 is a blood inlet pipe, 4 is a blood discharge pipe, 5 is a flange, 6 is a valve, 7 is a fluid delivery pipe, 8 is a valve ring, and 9 is a disk. Each shown.

Claims (1)

[Claims] 1. A flange in which a blood introduction tube and a blood discharge tube are arranged substantially parallel to each other, each having a built-in blood introduction valve and a blood discharge valve, and a flat bag-shaped blood bag in which the flange communicates with the blood introduction tube and the blood discharge tube. A blood pump having chambers arranged in series, and a housing outer case attached to the flange to accommodate the blood chamber, wherein at least one of the blood inlet pipe and the blood discharge pipe having the built-in valve is a blood pump. The pipe is made of polyvinyl chloride containing 40 to 120 parts by weight of a plasticizer per 100 parts by weight of polyvinyl chloride, and the wall thickness of the pipe is at least 10 mm in the length direction of the pipe from the mounting part of the valve.
A blood pump characterized by having a diameter of 1.3 mm to 5.0 mm.