Importance

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Abstract

An improved disposable syringe for taking arterial blood samples for blood gas testing, and the like, wherein the syringe barrel has a reverse-taper section at the forward end thereof so that, in such section, the inner diameter of the barrel is progressively larger the closer it is to the forward end of the barrel. Preferably, the syringe plunger has a compressible elastomeric tip member which has a peripheral annular wiper that extends axially toward the forward end of the syringe and radially outwardly at an acute angle to the longitudinal center line of the barrel and plunger to form an excellent seal with the inner surface of the syringe barrel while at the same time providing only a gentle pressure against such surface and hence an exceptionally low resistance to axial movement of the tip member and plunger. The syringe, preferably, also has means for preventing further forward movement of the plunger so that, when the plunger tip is moved forward to eject air and excess liquid anti-coagulant, a predetermined amount of the anti-coagulant remains in a space of predetermined volume between the plunger tip and the forward end of the syringe barrel.

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First Claim