Positive displacement flush syringe

Patent metadata

Field	Value
Publication number	US-9522237-B2
Application number	US-3115105-A
Country	US
Kind code	B2
Filing date	Jan 7, 2005
Priority date	Jan 7, 2005
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A flush syringe assembly comprises a barrel including a cylindrical side wall having an inside surface defining a chamber for retaining fluid, an open proximal end and a distal end having a passageway therethrough in fluid communication with the chamber. A plunger including an elongate body portion having a stopper at its distal end is provided. The stopper is slidably positioned in fluid-tight engagement with the inside surface of the barrel for driving fluid out of the chamber through the passageway. The stopper includes a distal portion and a proximal portion separated by a spring element and configured to compress when fluid is being driven through the passageway by motion of the plunger and to continue to drive fluid through the passageway after motion of the plunger has stopped.

First claim

What is claimed is:

1. A flush syringe assembly for reducing reflux of blood into a vascular access device during and after a flush procedure comprising:
a barrel including a cylindrical side wall having an inside surface defining a chamber for retaining fluid, an open proximal end having an inwardly directed annular projection and a distal end including a distal wall with a tip extending distally therefrom having a passageway therethrough in fluid communication with said chamber;
a plunger including an elongate body portion having a proximal end having a radially directed projection and a secondary radially directed projection, and a distal end, a stopper slidably positioned in fluid-tight engagement with said inside surface of said barrel for driving fluid out of said chamber by movement of said stopper relative to said barrel, said elongate body portion extending outwardly from said open proximal end of said barrel, the radially directed projection on the proximal end of the plunger and the secondary radially directed projection positioned to snap past the inwardly directed annular projection on the proximal end of the barrel to retain the plunger and to prevent further distal and proximal motion of the plunger with respect to the barrel;
a discontinuity including an outwardly directed fixed radial projection on said elongate body portion on said plunger having a distal surface extending beyond the cylindrical side wall of the barrel for direct engagement of the plunger with said barrel for stopping the distal motion of said plunger before said stopper fully delivers all liquid from said chamber,
said stopper including a proximal stopper portion connected to said distal end of said plunger and a distal stopper portion separated from said proximal stopper portion by a spring for moving said distal stopper portion in a distal direction to drive more liquid out of said chamber after said discontinuity on said plunger engages said barrel to stop distal motion of said plunger, wherein said distal stopper portion has at least one circumferential rib engaging said inside surface of said barrel and said proximal stopper portion has at least two circumferential ribs engaging said inside surface of said barrel to engage said inside surface of said barrel so that less force is required to move the distal stopper portion along said chamber than said proximal stopper portion.

2. The syringe assembly of claim 1 wherein said spring element includes a coil spring.

3. The syringe assembly of claim 1 wherein said spring is an annular cantilevered element.

4. The syringe assembly of claim 1 wherein said spring includes an air space between said distal stopper portion and said proximal stopper portion.

5. The syringe assembly of claim 1 wherein said discontinuity on said plunger is configured to engage a discontinuity on said barrel to retain the plunger and prevent further distal and proximal motion of said plunger with respect to said barrel during normal use of said syringe assembly.

6. The syringe assembly of claim 1 wherein said plunger defines an aperture for allowing air trapped between said proximal stopper portion and said distal stopper portion to escape toward said open proximal end of said barrel.

7. The syringe assembly of claim 1 wherein there is a less than air-tight fit between said plunger and said proximal stopper portion for allowing air trapped between said proximal stopper portion and said distal portion to escape toward said open proximal end of said barrel.

8. The syringe assembly of claim 1 wherein an outside diameter of said proximal stopper portion includes at least one discontinuity for allowing air trapped between said proximal stopper portion and said distal portion to escape toward said open proximal end of said barrel.

9. The syringe assembly of claim 1 wherein deflection of said spring occurs when said liquid pressure is about 5 mm Hg. (0.1 psi) or more.

10. The syringe assembly of claim 1 including flush solution in said chamber.

11. The syringe assembly of claim 10 wherein said flush solution is selected from the group consisting of saline flush solution and heparin lock flush solution.

12. The syringe assembly of claim 10 further including a tip cap releasably connected to said tip of said syringe barrel for sealing said passageway.

13. The syringe assembly of claim 1 wherein said stopper is made of material selected from the list consisting of thermoplastic elastomers, natural rubber, synthetic rubber, thermoplastic materials and combinations thereof.

14. The syringe assembly of claim 1 further comprising a needle assembly including a cannula having a proximal end, a distal end and a lumen therethrough, and a hub having an open proximal end containing a cavity and a distal end attached to said proximal end of said cannula so that said lumen is in fluid communication with said cavity, said needle assembly being removably attached to said tip of said barrel through engagement of said tip to said cavity so that said lumen is in fluid communication with said chamber.

15. The syringe assembly of claim 1 , wherein a single user can engage the discontinuity with the barrel to prevent distal motion of the plunger using one or two hands.

Assignees

• Alheidt Thomas
• Kosinski Anthony J
• Becton Dickinson Co

Inventors

• Alheidt Thomas
• Kosinski Anthony J

Classifications

• A61M5/502 Primary

  for blocking the piston · CPC title

• A61M25/1018

  Balloon inflating or inflation-control devices · CPC title

• A61M25/00

  Catheters; Hollow probes (dilators A61M29/00; {peritoneal catheters A61M1/285; tracheal tubes A61M16/04; for drainage A61M27/00; for uterus, vagina or rectum A61M31/00} ; for measuring or testing A61B; {materials for catheters A61L29/00}) · CPC title

• A61M2005/31508

  provided on the piston-rod · CPC title

• A61M5/31515 Primary

  Connection of piston with piston rod · CPC title