Puncture device

摘要

A puncture device is provided that does not allow an outer needle to collapse or rise at the time of puncture and exhibits small puncture resistance.;A puncture device 1 includes: a hollow outer needle 2; an outer needle hub 3 provided at a proximal end portion of the outer needle 2; a hollow inner needle 4 inserted into the outer needle 2 for use; and an inner needle hub 5 provided at a proximal end portion of the inner needle 4. The inner needle 4 includes, from the distal side, a sharp needlepoint 41, a small diameter portion 42 having an almost uniform outer diameter; an intermediate portion 43 formed as a tapered portion which is progressively increased in outer diameter as it goes toward the proximal end; and a larger diameter portion 44 having inner and outer diameters larger than inner and outer diameters, respectively, of the small diameter portion 42. If the puncture device 1 is assembled, the needlepoint 41 is most projected from the distal opening 24 of the outer needle 2 and the proximal end of the small diameter portion 42 and the distal end of the large diameter portion 4 are located inside the outer needle 2. The inner diameter of the outer needle 2 at a portion L1 where the outer needle 2 covers the small diameter portion 42 of the inner needle 4 is smaller than the large diameter portion 44 of the inner needle 4.

主权项

1. A puncture device comprising:
a hollow outer needle having a lumen communicating with a distal opening of the outer needle; an outer needle hub provided at a proximal end portion of the outer needle and having a lumen portion communicating with the lumen of the outer needle; a hollow inner needle positioned in the lumen of the outer needle and configured to be completely removable from the lumen of the outer needle, the hollow inner needle having a lumen and a sharp needlepoint at a distal end, the inner needle possessing a distal opening communicating with the lumen of the inner needle; an inner needle hub provided at a proximal end portion of the inner needle and having a lumen portion communicating with the lumen of the inner needle; the outer needle and the inner needle, and the inner needle hub and the outer needle hub, being configured so that a proximal end of the outer needle hub is contactable by the inner needle hub; wherein the inner needle includes:
a smaller diameter portion located near the needlepoint and having an almost uniform outer diameter, the almost uniform outer diameter of the smaller diameter portion terminating at a proximal-most end;an intermediate portion possessing a distal-most end directly connected to the proximal-most end of the smaller diameter portion, the intermediate portion also possessing a proximal-most end, the entirety of the intermediate portion being a non-stepped smooth tapered portion which is progressively increased in outer diameter towards the proximal-most end of the intermediate portion to reduce insertion resistance encountered when the intermediate portion of the puncture device is inserted into an insertion site;a larger diameter portion located closer to a proximal end of the inner needle than the smaller diameter portion and having an outer diameter larger than that of the smaller diameter portion, the larger diameter portion possessing a distal-most end directly connected to the proximal-most end of the intermediate portion; the proximal-most end of the smaller diameter portion possessing an outer diameter the same as the outer diameter of the distal-most end of the intermediate portion so that a smooth non-stepped transition exists between the smaller diameter portion and the intermediate portion; the sharp needlepoint of the inner needle projecting distally beyond a distal-most end of the outer needle when the proximal end of the outer needle hub is contacted by the inner needle hub so that during puncture of a living body with the puncture device, the living body is first punctured by the sharp needlepoint of the inner needle; the inner needle being positioned in the lumen of the outer needle in such a manner that with the needlepoint projecting distally beyond the distal opening of the outer needle, the proximal end of the smaller diameter portion is located in and covered by the outer needle, and the inner diameter of the outer needle at a portion where the outer needle covers the smaller diameter portion is smaller than the outer diameter of the larger diameter portion; and the inner diameter of the outer needle at the portion where the outer needle covers the smaller diameter portion is smaller than the outer diameter of the smaller diameter portion of the inner needle in a given range from a distal end of the outer needle.