Flush syringe having anti-reflux stopper

摘要

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 5 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 10 with the distal wall is provided. The anti-reflux structure includes the stopper having a conically shaped distal surface and the inside surface of the barrel and the distal wall being conically shaped wherein the total included angle A of the inside surface of the barrel at the distal wall is greater than the total included angle B of the distal surface of the stopper by at least 60.