JPH0523394A - Medical blood circuit - Google Patents

Abstract

PURPOSE:To facilitate manufacture, to reduce manufacturing cost and to repetedly use a probe for an electromagnetic flowmeter by attaching the coil part constituting the probe for the electromagnetic flowmeter to a medical conduit in a detachable manner. CONSTITUTION:A horizontal U-shape core 22 and the magnetic field generating coil 23 wound around the central part of the core 22 are embedded in a horizontal U-shape cover material 21a made of an epoxy resin. The cover material 21a is mounted so as to straddle the annular thick-walled part 20 provided to a connector cylindrical part 20a. The press part 21b provided to the cover material 21a on one end side thereof in a shakable manner by a shaft 21c is inwardly energized by a spring 21d to be fixed to the annular thick-walled part 20. Further, contacts 25A, 25B, 25C are fitted in the cover material 21a and the press part 21b so as to come into contact with the platinum electrodes 24A, 24B, 24C provided to the annular thick-walled part 20. By this constitution, even when a connector is discarded, the probe 21 for an expensive electromagnetic flowmeter can be detached from the connector main body for the sake of reuse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical blood circuit, and more particularly to a medical blood circuit used for external circulation.

[0002]

2. Description of the Related Art A medical practice in which blood circulating in a living body is guided to the outside of a living body by a cannula or a tube, and while being circulated in a predetermined device outside the living body, the blood is manipulated or treated and then returned to the living body. There is. Such medical practice is called external circulation.

A typical example of the external circulation is the so-called artificial heart-lung system in which blood that perfuses the heart at the time of heart surgery is flown through a cannula into an artificial heart-lung machine (oxygenation device) and oxygen is added back to the artery. There is circulation.

In the artificial heart-lung machine as described above, it is extremely important to measure the blood flow rate in a medical conduit such as a cannula, a tube, and a connector connecting these, and control the flow rate to an appropriate value. For this purpose, a flow meter called an electromagnetic blood flow meter is used, and a probe for measurement is attached to the medical conduit so as to face the blood flow path.

A medical conduit containing such an electromagnetic flowmeter probe cannot be insert-molded by injection molding because of the structure and strength of the magnetic field generating coil. This is because in injection molding, the coil and yoke move during molding due to the injection pressure. Therefore,
The probe is a clamp-on type (fitted in the enclosure),
Regardless of the type of plug-in (insert in the pipe),
A medical conduit is molded by the method of casting an epoxy resin.

However, the inner surface of the medical conduit molded by the casting method must be smooth from the viewpoint of preventing thrombus formation. Therefore, after molding, the inner surface of the probe and its periphery must be manually finished. I won't. This manual work causes a great increase in cost, and is not preferable in appearance. Further, in the medical device, the part that directly contacts the blood is difficult to completely clean, and therefore it is disposable after being used. Therefore, the probe embedded in the medical conduit is also discarded together with the medical conduit. But,
This probe is very expensive because it is expensive.

In particular, the connector needs to have a shape in which the ring-shaped thrombus is unlikely to adhere to its end, and for that purpose, the wall thickness of the end face must be 0.1 mm or less. In order to achieve such an acute angle of the edge portion, the connector body needs to be made of engineering plastic, and its molding is advantageous in terms of workability and productivity from injection molding. However, it is difficult for the casting method to reduce the thickness of the end face to 0.1 mm or less.

[0008]

It is an object of the present invention to provide a medical blood circuit in which a medical conduit such as a cannula or a tube can be easily manufactured at low cost, and an electromagnetic flowmeter probe can be repeatedly used, which is economical. Is intended.

[0009]

The present invention relates to a medical blood circuit in which a coil portion constituting an electromagnetic flowmeter probe is detachably attached to a medical conduit.

[0010]

EXAMPLES Examples of the present invention will be described below. First, the outline of the external circulation by the heart-lung machine will be described. FIG. 1 is a circuit diagram showing a blood flow path for external circulation by an artificial heart-lung machine.

Superior vena cava 2 connected to the right atrium 1a of the heart 1.
The distal end portion of the suction beak tube 6 is inserted into the tube, and the venous blood in the superior vena cava 2 is stored in the reservoir 15 through the suction beak tube 6 and the tube 7A by driving the pump P1. Blood removal with a suction beak is performed to prevent a large amount of bleeding during a heart incision from interfering with surgery. Reservoir 15
In addition to the above, the blood, the infusion solution, and the drug (all not shown) added to the heart-lung machine are also injected.

A tip of a cannula 8 is inserted into the superior vena cava 2 separately from the suction beak tube 6, and a tip of a cannula 9 is inserted into the inferior vena cava 3. The venous blood in the superior and inferior vena cava can be artificially lunged through the cannulas 8 and 9 and the branch tubes 10a and 10b of the bifurcated tube 10 and the main tube 10c by drop suction.
Introduced in 16.

In a heart with weakened or stopped beating,
In particular, the myocardium of the left ventricle is damaged when a sudden expansion occurs, so the tip of the vent tube 11 is inserted into the left ventricle 1b, and the blood in the left ventricle 1b is driven by the pump P2.
Reservoir 15 through vent tube 11 and tube 7B
Is introduced and stored in.

The venous blood stored in the reservoir 15 enters the artificial lung 16 through the tube 7C.

The conductive part from the living body to the artificial lung is
It is called a blood removal circuit.

Oxygen is sent to the artificial lung 16 from the cylinder 17 through the tube 7D, and the venous blood in the artificial lung 16 is added with oxygen to become arterial blood.
It is kept at a predetermined temperature through the thermostat 18A and the tube 7F, and then enters the artificial lung 16 again. The arterial blood kept at a predetermined temperature is transferred from the artificial lung 16 to the tube 7 by driving the pump P3.
G, sent through the cannula 12 to the arterial arch 5.

In addition, the cardioplegia solution in the container 18 is dipped in the ice water tank 18B by driving the pump P4,
It passes through the tube 7H and the cannula 13 and is cooled and sent to the ascending aorta 4.

The above-mentioned arterial arch 5 and arterial blood to the ascending aorta 4 and the portion where the myocardial protection liquid is conducted is called a blood supply circuit.

In this example, it should be noted that the suction beak tube 6 and the tube 7A are connected, the cannulas 8 and 9 and the bifurcated tube branch tubes 10a and 10b are connected, the vent tube 11 and the tube 7B are connected, The connection between the tube 7G and the cannula 12 and the connection between the tube 7H and the cannula 13 are connected using the connector 20 to which the probe 21 for the electromagnetic flow meter is attached, and the connector 20 has a structure described later. That is.

Each probe 21 is electrically connected to an electromagnetic flow meter (not shown), the blood flow rate in each of the above conduits is measured, and each blood flow rate is controlled based on the measurement result. Thus, the surgery will be performed under ideal blood flow conditions and safe medical practice is guaranteed.

FIG. 2 is an enlarged sectional view taken along the central axis (not shown) of the above connector, and FIG. 3 is an enlarged sectional view taken along the line III--III of FIG.

In the connector 20, most of the electromagnetic flowmeter probe 21 formed separately from the connector 20 is an electrode portion and a blood flow path is formed.
It is fitted and fixed so as to face 30. Hereinafter, this will be described in detail.

The U-shaped core 22 and the magnetic field generating coil 23 wound around the center of the core 22 are made of epoxy resin and are embedded and protected in a U-shaped coating material 21a. Coating material
Reference numeral 21a denotes an annular thick portion (the outer diameter of which is made thicker) 20b (thick portion 20 provided on the connector cylindrical portion 20a.
b may be omitted. ) Is attached so that it straddles.
A pressing portion 21b, which is attached to one end side of the covering material 21a so as to be swingable by a shaft 21c, is biased inward by a spring 21d, so that these are fixed to the annular thick portion 20b.
At the position facing the coil 23 of the annular thick portion 20b, at a position 180 degrees from this position, and at the center position between these positions, there are frustoconical through-holes 20d, 20d, 20d whose diameter decreases outward.
Are provided, and a frustoconical platinum electrode is provided in these through holes.
24A, 24B and 24C are inserted. By forming the through hole and the platinum electrode into the truncated cone shape as described above, the platinum electrode does not come out of the cylindrical portion due to the pressure of the blood 31. Contact 25 so that it contacts platinum electrodes 24A, 24B, 24C
A, 25B and 25C are fitted in the covering material 21a and the pressing portion 21b. Contact 25 for platinum electrodes 24A, 24B, 24C
Alignment of A, 25B, and 25C is performed by local concavo-convex fitting as shown in A of FIG. The contacts 25A, 25B and 25C are taken out as terminals 28 by the conductor 27, and both ends of the coil 23 are taken out by the conductor 27 as terminals 28, respectively. An electromagnetic flowmeter probe 21 is configured by the above-mentioned parts. Probe for electromagnetic flowmeter
Each component of 21 is magnetically shielded from each other by a plastic covering material 21a and a pressing portion 21b.

Since the flow rate of the fluid is proportional to the electromotive force generated between the electrodes, regardless of the viscosity, temperature, turbulence, etc. of the fluid,
The flow rate of blood 31 can be accurately and easily detected as an electric signal. Then, based on this detection result, the pump P1 of FIG.
The drive of a drive device (not shown) that drives P2, P3, and P4 is controlled. However, from the upper and lower vena cava 2 and 3 to the artificial lung 16
Blood flow to the is controlled by an electrically operated control valve CV.

When insert-molding the covering material 21a and the pressing portion 21b, this insert-molding is performed by a casting method so that the core 22, the coil 23, the contacts 25A, 25B, 25C and the conductors 26, 27 do not move. Both ends of the connector 20 are tapered surfaces whose inner diameter increases toward the end face so that a conduit such as the suction beak tube 6 or the like and a conduit such as the tube 7A are externally fitted and connected to each other so that a step that causes a thrombus is minimized. 20c, 20c are formed, and the wall thickness d of the end face is 0.1 mm or less as described above. The connector 20 cannot be molded to such a dimension by the casting method, and is made of polycarbonate by injection molding.
It is made of polysulfone and other engineering plastics.

Since the electromagnetic flowmeter probe 21 is separate from the connector body and has the above-described structure, the electromagnetic flowmeter probe 21 can be attached to and detached from the connector body.
Therefore, even if the used connector main body is discarded, the expensive probe for the electromagnetic flow meter can be detached from the connector main body and reused, which is very economical. The platinum electrode 24
A, 24B and 24C can be reused by simply pulling them out into the cylindrical portion 20a after removing the covering material 21a and the pressing portion 21b. Further, by providing the electromagnetic flow meter probe 21 on the connector 20 for connecting various conduits, handling becomes easy. However, it goes without saying that the probe may be provided on the cannula or the tube.

Connection between the suction beak tube 6 and the tube 7A in FIG. 1, the branch tube 10 of the cannulas 8 and 9 and the bifurcated tube 10.
Connections with a and 10b and connections with the tubes 7B, 7G and 7H and the vent tube 11 and cannulas 12 and 13 are as shown in FIGS. 4, 5 and 6, respectively. In addition, in FIG. 5, three tubes 37 can be connected as shown by the reference numerals in parentheses. In addition, as shown in FIGS. 7 and 8, two tubes 37, 37
The connector 20 including the probe for the electromagnetic flow meter can also be used to connect the two cannulas 38, 38 to each other.

Although the embodiments of the present invention have been described above, various modifications can be made to the above embodiments based on the technical idea of the present invention. For example, the probe for an electromagnetic flow meter attached to the connector body may have various structures other than those described above, and the fixing position thereof may be changed, for example, to the upstream body side. In addition, the above example is an example of assisted circulation (ECMO) using a membrane oxygenator,
In addition to this, the present invention can be applied to the right heart bypass method, the left heart bypass method, and dialysis therapy (hemodialysis) using an artificial kidney in the same manner as above.

[0029]

According to the present invention, the coil portion constituting the probe for the electromagnetic flow meter is detachably attached to the medical conduit, so that the blood flow rate can be accurately measured and the safety of medical treatment is guaranteed. In addition, the coil portion can be removed from the medical conduit and reused when the medical conduit is discarded after use. Therefore, the electromagnetic flowmeter probe is expensive, which is very economically advantageous. In addition, since the probe for the electromagnetic flow meter has a delicate structure, it is difficult to insert and mold this probe by injection molding, so what is the medical conduit with a built-in electromagnetic flow meter probe that was molded by the casting method? Differently, the probe for the electromagnetic flowmeter formed by inserting and molding the coil portion is manufactured separately from the medical conduit (because it is detachable). As a result, the medical conduit can be molded by injection molding with high productivity, and the productivity is significantly improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a blood flow path of extracorporeal circulation by an artificial heart-lung machine according to an embodiment.

FIG. 2 is an enlarged sectional view taken along the central axis of the connector used in FIG.

FIG. 3 is an enlarged cross-sectional view taken along line III-III of FIG.

FIG. 4 is a schematic front view of an enlarged portion of FIG.

5 is an enlarged partial schematic front view of a portion different from FIG. 4 in FIG. 1. FIG.

6 is an enlarged partial schematic front view of a portion different from FIGS. 4 and 5 in FIG. 1. FIG.

FIG. 7 is an enlarged partial schematic front view showing a connection between tubes according to another embodiment.

FIG. 8 is an enlarged partial schematic front view showing the connection between cannulas according to another embodiment.

[Explanation of symbols]

1 heart 2 superior vena cava 3 inferior vena cava 4 Ascending aorta 5 arterial arch 6 suction beak tube 6A, 7A, 7B, 7C, 7D, 7E, 7F, 7G, 7H, 37 tubes 8, 9, 12, 13, 38 cannula 10 bifurcated tubes 10a, 10b Bifurcated tube branch pipe 11 Vent tube 15 reservoir 16 oxygenator 17 oxygen cylinder 20 connector 21 Electromagnetic flowmeter probe 22 core 23 coils 24A, 24B, 24C electrodes 25A, 25B, 25C contact 30 blood flow path 31 blood CV control valve P1, P2, P3, P4 pumps

Claims (2)

[Claims] 1. A medical blood circuit in which a coil portion constituting a probe for an electromagnetic flowmeter is detachably attached to a medical conduit. 2. The medical blood circuit according to claim 1, wherein the medical conduit is a tubular connector for connecting a plurality of medical conduits different from the medical conduit.