Flush syringe having anti-reflux stopper

Abstract

An I.V. flush syringe assembly includes a barrel having an inside surface defining a chamber for retaining fluid, an open proximal end and a distal end including a distal wall with an elongate tip extending distally therefrom having a passageway therethrough in fluid communication with the chamber. A plunger having an elongate body portion and a stopper slidably positioned in fluid-tight engagement with the inside surface of the barrel is provided. Anti-reflux structure for controlling stopper deflection when fluid has been delivered from the chamber and the stopper is in contact with the distal wall is provided.

1 . An I.V. flush syringe assembly comprising: 
 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 including a conically shaped distal wall with an elongate tip extending distally therefrom having a passageway therethrough in fluid communication with said chamber, said chamber including a flush solution;    a plunger including an elongate body portion having a proximal end, a distal end and a stopper slidably positioned in fluid-tight engagement with said inside surface of said barrel for drawing fluid into and driving fluid out of said chamber by movement of said stopper relative to said barrel, said stopper having a conically shaped distal surface, said elongate body portion extending outwardly from said open proximal end of said barrel; and    said total included angle of said distal wall is greater than said total included angle of said stopper distal surface such that said stopper contacts and seals said passageway when fluid has been delivered from said chamber.    
   
   
       2 . The syringe assembly of  claim 1  wherein stopper deflection is controlled by the contact and sealing between said stopper and said passageway.  
   
   
       3 . The syringe assembly of  claim 1 , wherein said total included angle of said distal wall is greater than said total included angle of said stopper distal surface by at least 6°.  
   
   
       4 . The syringe assembly of  claim 1 , wherein said total included angle of said distal wall is greater than said total included angle of said stopper distal surface by at least 10°.  
   
   
       5 . The syringe assembly of  claim 1  wherein said total included angle of said stopper distal surface is about 110°.  
   
   
       6 . The syringe assembly of  claim 1  wherein the total included of said distal wall of said barrel is about 120°.  
   
   
       7 . The syringe assembly of  claim 1  further including at least one projection on said distal surface of said stopper positioned mostly in the space between said distal surface and said conically shaped inside surface of said distal wall when said distal surface of said stopper first contacts said conically shaped inside surface.  
   
   
       8 . The syringe assembly of  claim 1  further including a tip cap releasably connected to said tip of said syringe barrel for sealing said passageway.  
   
   
       9 . The syringe assembly of  claim 1  wherein said flush solution is selected from the group consisting of saline flush solution and heparin lock flush solution.  
   
   
       10 . 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.  
   
   
       11 . 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.  
   
   
       12 . An I.V. flush syringe assembly comprising: 
 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 including a conically shaped distal wall with an elongate 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, a distal end and a stopper slidably positioned in fluid-tight engagement with said inside surface of said barrel for drawing fluid into and driving fluid out of said chamber by movement of said stopper relative to said barrel, said stopper having a conically shaped distal surface, said elongate body portion extending outwardly from said open proximal end of said barrel;    at least one projection on said distal surface of said stopper positioned mostly in the space between said distal surface and said conically shaped inside surface of said distal wall when said distal surface first contacts said conically shaped inside surface; and    said total included angle of said distal wall is greater than said total included angle of said stopper distal surface such that said stopper contacts and seals said passageway when fluid has been delivered from said chamber.    
   
   
       13 . The syringe assembly of  claim 12  wherein stopper deflection is controlled by the contact and sealing between said stopper and said passageway.  
   
   
       14 . The syringe assembly of  claim 12 , wherein said total included angle of said distal wall is greater than said total included angle of said stopper distal surface by at least 6°.  
   
   
       15 . The syringe assembly of  claim 12 , wherein said total included angle of said distal wall is greater than said total included angle of said stopper distal surface by at least 10°.  
   
   
       16 . The syringe assembly of  claim 12  wherein said total included angle of said stopper distal surface is about 110°.  
   
   
       17 . The syringe assembly of  claim 12  wherein the total included angle of said distal wall of said barrel is about 120°.  
   
   
       18 . The syringe assembly of  claim 12  further including a tip cap releasably connected to said tip of said syringe barrel for sealing said passageway.  
   
   
       19 . The syringe assembly of  claim 12  further include a flush solution in said chamber.  
   
   
       20 . The syringe assembly of  claim 19  wherein said flush solution is selected from the group consisting of saline flush solution and heparin lock flush solution.  
   
   
       21 . The syringe assembly of  claim 12  wherein said stopper is made of material selected from the list consisting of thermoplastic elastomers, natural rubber, synthetic rubber, thermoplastic materials and combinations thereof.  
   
   
       22 . The syringe assembly of  claim 12  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.  
   
   
       23 . A method of flushing a catheter comprising the steps of: 
 (a) providing a syringe assembly having a barrel 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 including a conically shaped distal wall with an elongate 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, a distal end and a stopper slidably positioned in fluid-tight engagement with said inside surface of said barrel for drawing fluid into and driving fluid out of said chamber by movement of said stopper relative to said barrel, said stopper having a conically shaped distal surface, said elongate body portion extending outwardly from said open proximal end of said barrel, a quantity of flush solution in said chamber, wherein said total included angle of said distal wall is greater than said total included angle of said stopper distal surface;    (b) providing a catheter having a proximal end, a distal end a passageway therethrough and a housing having a hollow interior connected to said catheter and in fluid communication with said passageway, said housing having an access valve for allowing fluid communication with said hollow interior;    (c) placing said distal end of said catheter in a blood vessel;    (d) engaging said elongate tip of said barrel with said access valve so that said passageway of said syringe barrel is in fluid communication with said hollow interior of said housing;    (e) applying force to said plunger to move said plunger in a distal direction with respect to said barrel so that said flush solution in said chamber flows through said passageway into said hollow chamber of said housing and through said passageway of said catheter;    (f) continue applying force to the plunger until said stopper contacts and seal said passageway to control stopper deflection; and    (g) disengaging said elongate tip from said access valve.    
   
   
       24 . The method of  claim 23  wherein said total included angle of said distal wall is greater than said total included angle of said stopper distal surface by at least 6°.