| 摘要 |
A catheter and insertion needle assembly comprising a catheter having a catheter hub and an insertion needle for disposition within the catheter and catheter hub. The assembly further comprises a shielding means comprising a generally cylindrical sleeve and means for locking the needle within the shielding means so as to safely enclose the tip of the needle to prevent exposure to clinicians. The shielding means preferably includes a retainer ring externally positioned thereon, wherein the retainer ring is configured to engage a corresponding retainer depression in an internal wall of the catheter hub. The locking means includes a locking ring on the exterior of the needle and a short, generally cylindrical, rigid insert disposed tightly within the interior of the shielding means. The insert has a slight decreasing taper at its proximal end and comprises cantilevered segments that may be biased outward to form a spring to permit movement of the locking ring in one direction, but not the other. The rigid insert is preferably positioned so that, when the insertion needle and locking ring are withdrawn proximally through the insert, the locking ring may be axially restricted between the insert and the proximal end of the shielding means. Further pulling would dislodge the needle and shielding means from the catheter hub, leaving the tip of the needle shielded from inadvertent contact.
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