| 摘要 |
A vascular/venous access device is comprised of a needle cannula disposed within the central bore at the distal end of a catheter. The distal end of the needle cannula extends outwardly from the central bore at the distal end of the catheter and the proximal end of the needle exits the central bore of the catheter through an aperture or slit formed in the wall of the catheter. A gripping member selectively holds the needle cannula in place within the bore of the catheter during insertion of the needle cannula and catheter into a patient's vascular system. After entry into the vascular system, the needle cannula is withdrawn from the catheter side wall and any desired length of the catheter may then be advanced into the vascular system. The catheter includes a relatively rigid end portion disposed along a substantial length of the needle cannula to prevent buckling and axial compression of the catheter during the insertion process. The comparatively rigid portion rapidly softens upon contact with blood such that a flexible tip is provided for non-traumatic manipulation of the catheter within the vascular system. The catheter may be formed by dipping a mandrel sequentially into polymer material. The distal tip of the expandable material can then be cut from the mandrel, the mandrel removed, and a needle cannula inserted through the side of the catheter such that its sharp tip extends from the open end.
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