Patent ID: 8192404

Claim:
An indwelling needle assembly comprising: a hollow outer needle possessing a base end part, a distal tip and an inner cavity, the outer needle being dimensioned to puncture and be positioned in a patient's blood vessel; an outer needle hub secured to the base end part of the outer needle, the outer needle hub having an interior and an inner surface surrounding the interior; a stylet possessing an outer surface, a tip end, and a base end part, with a sharp needlepoint at the tip of the stylet, the stylet being positioned inside the hollow outer needle and extending through the interior of the outer needle hub, the stylet being positionable relative to the needle to expose the sharp needlepoint distally beyond the distal tip of the outer needle, the sharp needlepoint being configured to puncture the patient's blood vessel when the sharp needlepoint is positioned distally beyond the distal tip of the outer needle; a stylet hub secured to the base end part of the stylet; an opening at a base end part or a side part of the outer needle hub, the opening communicating with the inner cavity of the outer needle; a seal member positioned in the interior of the outer needle hub, the seal member possessing an outer surface facing the inner surface of the outer needle hub, the seal member comprising a hole or slit extending completely through the seal member, the stylet extending completely through the slit or hole in the seal member, the stylet being removable from the seal member, the slit or hole automatically closing when the stylet is removed from the seal member, the slit or hole possessing an inner surface; an operating part disposed on the outer needle hub to enable movement of the stylet and the outer needle together in a longitudinal direction to puncture the patient's blood vessel; movement suppressing means for preventing or restraining the stylet from retracting into the outer needle by inhibiting or suppressing movement of the stylet relative to the seal member when the operating part is operated; wherein said movement suppressing means comprises a varied outer diameter part on the outside surface of said stylet, wherein an outer diameter of said stylet varies abruptly, such that frictional resistance between the outside surface of said stylet and the inner surface of said hole or slit is increased; wherein said movement suppressing means is positioned to make contact with said hole or slit in the inserted condition of the stylet; wherein the seal member includes a through conduit passing completely through the seal member, the through conduit being fluidly in communication with the opening, the opening being connected to a tube; and wherein the tube extends through the stylet hub.