Keep vein open method and injector with keep vein open function

• US 20050182371A1
• Filed: 02/13/2004
• Published: 08/18/2005
• Est. Priority Date: 02/13/2004
• Status: Active Grant

• Current Assignee: Mallinckrodt Incorporated (Mallinckrodt plc)
• Original Assignee: Liebel-Flarsheim Company (Mallinckrodt plc)
• Inventors: Wagner, Gary S., Fago, Frank
• Granted Patent: US 7,491,191 B2
• Time in Patent Office: Days
• US Class Current: 604/218
• CPC Class Codes: A61M 2005/1404 Keep vein-open rate [KVO], i.e. low flow rate
• CPC Class Codes: A61M 2005/3112 Incorporating self-aspirating means, e.g. to provide flashback
• CPC Class Codes: A61M 5/007 for contrast media
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/1456 with a replaceable reservoir comprising a piston rod to be moved into the reservoir, e.g. the piston rod is part of the removable reservoir
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence

Abstract

The present invention embodies a method and an injector adapted to incorporate this method, for keeping a patient'"'"'s vein open during an intravenous contrast injector procedure without injecting a saline solution from a separate syringe. The injector includes a controller having a programable software module to allow an operator to configure the injector to push some contrast media fluid through an injection site and then retract a plunger drive ram. A syringe is adapted to allow a patient'"'"'s blood pressure to move the syringe plunger back towards its starting position, thus enabling a patient'"'"'s blood to pass through the injection site. Alternatively, the syringe is adapted with an elastic plunger which as it enlarges and contracts facilitates fluid communication through the injection site. Additionally, the plunger drive ram can be adapted to gradually pull as well as push the plunger, thereby causing fluid to flow across the injection site.

Claims

1. A syringe for use with a patient comprising:

a barrel having an inner wall;

a plunger slidably positioned within the barrel, the plunger having a head and a pushrod attached to the head;

a fluid chamber distally located from the plunger in the barrel, the fluid chamber having a volume, the volume of the fluid chamber being adjustably defined by the position of the plunger within the barrel;

wherein the plunger is adapted to increase the volume of the fluid chamber without manually withdrawing the pushrod from the barrel.

2. The syringe of claim 1 wherein the patent has a blood pressure and wherein plunger is adapted to slide within the barrel so as to increase the volume of the fluid chamber when a pressure, not greater than the blood pressure of the patient, is applied to the head.

3. The syringe of claim 2 wherein the blood pressure is between about 50 to about 200 mm-Hg.

4. The syringe of claim 1 wherein the pushrod is adapted to elastically expand and elastically contract the head;

wherein the expansion and contraction of the head adjusts the volume of the fluid chamber.

5. The syringe of claim 4 further comprising a backer plate sandwiched between the pushrod and the head.

6. The syringe of claim 1 further comprising:

a stretcher in operable contact with the head, the stretcher adapted to advance the head independent of the pushrod and allow the head to retract independent of the pushrod;

wherein the movement of the head adjusts the volume of the fluid chamber.

7. The syringe of claim 6 wherein the stretcher is at least one of the following:

a pin, a rod, a bar, and a shaft.

8. An injector for injecting fluids into a patient comprising:

a plunger drive ram;

a drive motor for moving the plunger drive ram;

a syringe for holding a fluid having a plunger in operable contact with the drive ram, the syringe adapted to inject the fluid when the drive ram depresses the plunger and, after the drive ram is retracted, to allow a blood flow, having a blood pressure, to move the plunger back against the drive ram;

a controller connected to the drive motor, the controller controlling the drive motor to advance and retract the drive ram;

wherein the movement of the fluid and the blood discourages blood clotting without the injection of a saline solution from a second syringe.

9. The injector of claim 8 wherein the controller includes a programable software module whereby an operator controls the advancement and retraction of the drive ram.

10. The injector of claim 9 further comprising:

a catheter is operably connected to the syringe and connected to the patient at an injection site;

wherein the software module is configured to cause the syringe to push

11. The injector of claim 10 wherein the syringe is adapted to allow the blood pressure to push between about 0.1 to about 1 milliliter of blood through the injection site.

12. An injector for injecting fluids from a syringe into a patient comprising:

a plunger drive ram;

a drive motor for moving the drive ram;

a syringe for holding and injecting a fluid, the syringe having a plunger in operable contact with the drive ram, the plunger having an elastic head distally positioned from the drive ram and a stretcher positioned between and in operable contact with the head and the drive ram, the head adapted to elastically expand as the drive ram advances against the stretcher and elastically contract as the drive ram retracts from the stretcher; and

a controller connected to the drive motor, the controller controlling the drive motor to advance and retract the drive ram.

13. The injector of claim 12 wherein the stretcher is at least one of the following:

a pin, a rod, a pushrod, a bar, and a shaft.

14. The injector of claim 12 further comprising a backer plate sandwiched between the stretcher and the head.

15. The injector of claim 12 wherein the controller includes a programable software module whereby an operator controls the advancement and retraction of the plunger drive ram.

16. The injector of claim 15 further comprising:

a catheter operably connected to the syringe and connected to the patient at an injection site;

wherein the software module is configured to cause the syringe to push between about 0.1 to about 1 milliliter of the fluid through the injection site.

17. An injector for injecting fluids from a syringe into a patient comprising:

a plunger drive ram;

a drive motor for moving the drive ram;

a syringe for holding and injecting a fluid having a plunger attached to the drive ram; and

a controller connected to the drive motor, the controller controlling the drive motor to advance and retract the drive ram and the plunger.

18. The injector of claim 17 wherein the controller includes a programable software module whereby an operator controls the advancement and retraction of the plunger drive ram.

19. The injector of claim 18 further comprising:

a catheter operably connected to the syringe and connected to the patient at an injection site;

wherein the software module is configured to cause the syringe to push between about 0.1 to about 1 milliliter of the fluid through the injection site.

20. A method of discouraging blood clotting without the injection of saline comprising:

pushing a fluid from a syringe through an injection site;

retracting a plunger drive ram;

moving a syringe plunger having a head back towards a starting position whereby blood flows through the injection site.

21. The method of claim 20 further wherein the drive ram pulls the plunger back towards the starting position.

22. The method of claim 20 wherein the head moves independently of the retraction of the drive ram.

23. The method of claim 20 wherein the head elastically moves.

24. The method of claim 23 further comprising moving a stretcher.

25. The method of claim 20 further comprising waiting a designated time period before subsequently advancing the plunger drive ram and moving the plunger back towards a starting position.

26. The method of claim 25 further comprising programming a controller to control the advancement and retraction of the plunger drive ram.