JP2002521150A - Pressure control system for medical injector and syringe used for the injector - Google Patents

Abstract

(57) [Summary] To control overshooting of pressure in a syringe due to blockage of a fluid supply passage. A pressure control system for an injector, wherein a passive piston or extension of the piston is connected to a plunger of an injector syringe to prevent blockage or obstruction of a fluid supply passage during an injection process. Prevent pressure from overshooting when it occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Industrial applications]

The present invention relates generally to medical injectors and syringes used in such injectors, and more particularly to a pressure control system for the injector.

[0002]

BACKGROUND OF THE INVENTION

Many powered injectors and injector syringes have been developed for use in medical procedures such as angiography, computerized X-ray tomography (CT), ultrasound and magnetic resonance imaging (MRI). Was. For example, U.S. Pat. No. 4,006,736 discloses a device for injecting fluid into the vascular system of a human or animal body. US Patent No. 4,6
No. 77,980 discloses an angiographic infusion machine in which two angiographic syringes are of a rotary turret type so that injection can be performed quickly. U.S. Pat. No. 5,383,
No. 858 discloses a front-loading injector and a syringe attachable to the injector for an injection procedure. U.S. Pat. Nos. 4,006,736, 4,677,980, 5,
No. 833,858 is hereby incorporated by reference.

[0003] Syringe-based infusion systems are susceptible to a maximum pressure above a desired set pressure during the infusion procedure, with the fluid supply passage closed or blocked. The fluid supply passage may be closed or obstructed for various reasons, such as closing the valve, twisting the tube in the fluid passage, and the like.

[0004] If the fluid supply path is closed or blocked and the fluid pressure builds up rapidly, the set maximum pressure will be exceeded in the syringe. Normally, during an injection procedure with the fluid path open, the conventional injector control system detects when the set maximum pressure is reached,
The control process for lowering the injection speed so that the pressure does not overshoot is started. However, the control system cannot disable or reverse the injection motor in the syringe and associated disposables without causing large undesired pressure instabilities. Therefore, during a normal injection, the control system stops the current to the motor at a rapid controlled rate, slowing the injection as much as possible, and avoiding large pressure instabilities. I have.

[0005] Unfortunately, these conventional control systems cannot address the problem of pressure exceeding the set maximum pressure when infused with the fluid path blocked.

[0006]

[Summary of the Invention]

Furthermore, powered injectors first need to accommodate syringes of varying stiffness. For example, powered injectors are used for both plastic and glass syringes despite the same pressure control algorithm.

[0007]

[Summary of the Invention]

The present invention relates to a pressure control system for controlling pressure overshoot occurring in syringes and related disposables in the manner of an injector, for example, due to blockage or obstruction of a fluid supply line.

Further, the present invention provides a pressure control system of an injector for a syringe having a different rigidity such as a syringe made of a synthetic resin and a syringe made of glass.

A first feature of the present invention is that, during injection, if the fluid path is accidentally blocked or obstructed, the pressure control system will reduce the pressure overshoot in the syringe and associated disposable. It is to lower.

A second feature of the present invention is that when a fluid path is blocked or obstructed during injection,
For syringes of different stiffness, without increasing pressure overshoot
Is to apply the injection machine. For example, a pressure control system can be applied to both plastic and glass syringes, despite using the same pressure control algorithm.

A third feature of the invention is that the pressure control system relates the stiffness of one type of syringe to the stiffness of another syringe. Thus, for any type of suitable syringe, the pressure control system can accurately control the pressure overshoot, even if the fluid path is abruptly blocked during injection.

In one embodiment, the pressure control system includes a compliant injector piston coupled to a plunger of an injector syringe.

[0013] In another embodiment, a pressure control system includes a piston extension connected to a conventional injector piston and a syringe plunger driven by the injector.

The invention, together with other features and advantages associated therewith, will be better understood with reference to the following detailed description in view of the accompanying drawings.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

If a sudden rise in pressure occurs in an injector syringe or disposables connected to it, such as by injecting into a blocked or obstructed fluid path, the maximum value of the pressure overshoot is directly related to the following factors: Decided. (1) Kinetic energy related to injection speed and pressure; (2) Stiffness of injection system and syringe.

[0016] The kinetic energy caused by the injection in the abnormal state in which the fluid passage is closed is converted into potential energy that causes the movement of the injector piston to be reduced and stopped. Kinetic energy is converted to potential energy by storing it in the form of pressure and deformation of the system and syringe.

The stiffness of the syringe is designed by selecting the material and the wall thickness to adapt to the predetermined pressure level. The injector mechanism can be adjusted or passive (c
The ompliance) adds or significantly deforms, lowering the pressure in the syringe by conserving more potential energy in the form of deformation and less in the form of pressure. Storing potential energy in the spring by adding a spring with a controlled spring constant into the mechanism (e.g., in the piston or in the form of a piston extension);
Reduce the maximum pressure of the system when injecting into a closed fluid path.

In the drawings, preferred embodiments of the pressure control system (20) according to the present invention include:
It has a passive piston extension (22). The piston extension, which is supplied in a sealed plastic package (10), is equipped with the following parts as described below.

Urethane Spring (5) As best shown in FIGS. 1, 2, 5a-c, a urethane spring (5) with a Shore hardness of 95A may be used in the passive piston extension (22). Desirably, this absorbs potential energy generated during injection into a closed fluid path. It is possible to use a standard steel coil spring.However, considering that the deformation of the container may exceed the capacity limit of the steel used for the coil spring, urethane is required because a large spring constant is required. A spring (5) is preferred.

Body (1) As best shown in FIGS. 1, 2 and 3a-d, the body (1) of the resilient piston extension (22) contains a urethane spring (5), Guide the ends (see below) to integrate the mechanism (1a) including the slot and attach the body (1) to the injector piston. In an additional embodiment, the body (1) is connected to the piston using a bayonet connection as shown and described in US Pat. No. 4,677,980.

The body (1) is preferably made of Delrin ™. It has good mechanical strength and impact resistance and low coefficient of friction. Delrin ™ is easy to clean because no contrast agent adheres to its surface.

Screw End (7) As best shown in FIGS. 1, 2 and 4a-d, the screw end (7) transfers the syringe load to the urethane spring (5) and also has a syringe plunger. With screws that connect directly to In another embodiment, the syringe plunger is connected to the screw end (7) by using an attachment mechanism that is not a screw. For example, a syringe plunger and threaded end (7) are connected using a bayonet connection as shown and described in U.S. Pat. No. 4,677,980.

The screw end fitting 7 is desirably made of Delrin (trademark) from the viewpoint of facilitating connection with the syringe and cleaning, and from the viewpoint of abrasion resistance.

Foam Filling Ring (6) As best shown in FIGS. 1, 2 and 6a-c, the foam (or elastomer) filling ring (6) prevents fluid from entering the spring area. Prevent and form a region that is deformed by weak force during injection. The foam ring (6) also prevents contaminants from entering the controlled displacement during injection.

Through Bolt (8) As shown in FIGS. 1 and 2, with the shape having a square neck, the through bolt (8) holds the elements of the resilient piston extension (22) together and has a threaded end. Tools (7)
The screw end (7) is prevented from rotating relative to the main body (1) when connecting the syringe. The screw of the through bolt (8) is tightened to the body by the spiral coil (4).
(loctited), it is desirable to prevent rotation.

In another embodiment, fasteners that are not through bolts (8) can be used. For example, a stud can be used to achieve almost the same function as the bolt (8).

Plug (9) As best shown in FIGS. 1, 2 and 7a-c, the plug (9) covers the head of the through bolt (8) and increases the rigidity of the screw end (7). In addition, it is possible to prevent foreign substances from entering from a suppressed displacement portion during injection.

Short Plunger (3) As shown in FIGS. 1 and 2, the short plunger (3) comprises a resilient piston extension (27).
Helps to keep the piston on the injector piston. The short plunger (3) may cause the resilient extension (27) to move undesirably on the piston while positioning the injector head at the corresponding recess (not shown) in the injector piston. To prevent

Syringe (30) As shown in FIGS. 8a and 8b, the syringe (30) is a resilient piston extension according to the invention.
Can be used with (22). The syringe (30) has a plunger (32) disposed inside the cartridge body (34). Front end of cartridge body (34)
(36) is surrounded by a luer lock lid (38) (40), a gasket (42) and a lid holder (44). The rear end (46) of the cartridge body (34) is surrounded by a flange member (48).

As shown, the syringe plunger (32) has an internal thread corresponding to the external thread on the piston (22). In other embodiments, the syringe plunger (32) can connect the syringe plunger (32) and the piston (22) by other attachment mechanisms. For example, as shown in U.S. Pat. No. 4,677,980, a syringe plunger (32) extends from a piston (22) with a hook or projection (not shown) extending rearward therefrom. Flange members can be connected.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiment of the elastic piston extension according to the present invention is specifically designed to reduce the overshoot of pressure in a 100 ml glass syringe when injected into a closed fluid path. I have. In particular, the overshoot of pressure is 100m
It was required to reduce the pressure level to the level occurring in plastic syringes.

The 100 ml glass syringe was measured to be 28% more rigid than the 100 ml plastic syringe. This 28% stiffness difference was the primary cause of higher pressure overshoot for injectors using 100 ml glass syringes. Thus, the passive piston extension (22) (which was used in connection with a 100 ml glass syringe during injection) provided a 100 ml glass syringe with an implantable rigidity constant of 100 ml plastic to the injector. The stiffness of the syringe was made to be the same or lower. Elastic piston extension
The rigidity constant or elastic constant of (22) was calculated from the relational expression of the series spring.

[0033]

(Equation 1)

For this design, the urethane spring (5) can be used from 2065 pounds per inch to 6384 pounds.
It was set in the pound / inch range. The upper end of the range was determined from the above equation and the measured stiffness of the syringe. The lower limit was determined by dividing the high pressure specification for the injector by the deformation obtained in the extension.

In the preferred embodiment described above, the pressure control system (20) has described a piston extension (22) connecting the piston to the injector. However, the following points should be particularly remembered. That is, the pressure control system (20) and the piston extension (22) can be integrated into the injector piston and operatively associated with a drive mechanism such as the injector drive motor and associated gears.

The present invention, including the pressure control system (20) and the piston extension (22), has been illustrated for filing. It must be confirmed that the above-described examples and embodiments are not for the purpose of explanation but for the purpose of limitation.

[Brief description of the drawings]

FIG. 1 is an exploded view of a preferred embodiment of the pressure control system of the present invention.

FIG. 2 is a cross-sectional view of the pressure control system shown in FIG.

3a to 3d are various views of the body of the pressure control system.

FIGS. 4a-e are various views of a threaded end of a pressure control system.

5a to 5c are various views of a urethane spring of the pressure control system.

6a-c are various views of a foam filling ring of a pressure control system.

FIGS. 7a-c are various views of a plug of a pressure control system.

8a and 8b are various views of a syringe used in a preferred embodiment of the pressure control system according to the present invention.

[Explanation of symbols]

 (20) Pressure control system (22) Passive piston extension (5) Urethane spring (1) Body (7) Screw end (6) Foam filling ring (8) Through bolt (9) Plug (30) Syringe (32) Syringe plunger

Claims (13)

[Claims] 1. A pressure control system for an injector, wherein the pressure control system is operable in communication with a drive mechanism of the injector, the first member having a front end, and operable in communication with the first member. A second member having a rear surface and a front end formed to be connectable to a plunger of a syringe mounted on the injector; and between a front end of the first member and a rear surface of the second member. And a spring member that is capable of adjusting the pressure rise in the syringe. 2. The pressure control system as defined in claim 1, wherein the front end of the second member comprises a thread for engaging and connecting to a screw of the syringe plunger. 3. The pressure control system according to claim 1, wherein the spring member comprises a urethane spring. 4. The first member has at least one wall member extending from a front end thereof, the second member has at least one flange member extending therefrom, and at least one of the second members has at least one flange member. The pressure control system defined in claim 1, wherein one flange member is operable in communication with at least one wall member of the first member. 5. The pressure control system as defined in claim 4, further comprising a ring disposed between at least one wall member of the first member and at least one flange member of the second member. 6. The pressure control system according to claim 4, wherein the ring is formed of a foam. 7. The pressure control system according to claim 1, wherein each of the first member, the second member, and the spring member forms a space inside them. 8. The method according to claim 7, further comprising a stop member disposed through a space formed inside the first member, the second member, and the spring member, and holding the members together. Pressure control system. 9. The pressure control system as defined in claim 8, wherein the stop comprises a bolt. 10. The pressure control system defined in claim 8, further comprising a plug member disposed within the cavity of the second member and operably rigidizing the second member. 11. The pressure control system defined in claim 1, wherein the first member further comprises a rear end removably connected to a piston of the injector. 12. The pressure control system according to claim 11, wherein a mounting member for connecting the first member to the piston is provided at a rear end of the first member. 13. A plunger member at least partially disposed in a cavity formed in the first member, the plunger member operably connected to a piston of the injector, A pressure control system as defined in claim 1, wherein the first member is retained on a piston.