| 主权项 |
1. A self-dilating cannula assembly for introduction into a patient's vasculature, comprising:
a stylet comprising a distal end; a cannula, comprising:
an elongate body, the elongate body having a proximal end, a distal end, and a fluid-flow lumen extending therebetween, wherein the fluid-flow lumen is the only longitudinally-extending lumen defined in the cannula; andan atraumatic tip positioned at the elongate body's distal end, the atraumatic tip having a blunted nose and a conical shape, wherein the atraumatic tip comprises a plurality of axially elongate fluid-flow openings on a conical portion of the atraumatic tip proximal to the blunted nose and configured to disperse fluid from the fluid-flow lumen in a plurality of directions with respect to the atraumatic tip, and wherein the atraumatic tip further comprises an opening in the blunted nose sized to a guidewire; an external concentric stop slideable along the elongate body, the stop including a locking mechanism for holding the stop in place on the elongate body for controlling a degree of insertion of the distal end of the self-dilating cannula into a patient's vasculature; and an obturator, comprising a lumen sized to receive the stylet, wherein the obturator is configured to reduce fluid flow through the fluid-flow lumen during introduction of the cannula into a blood vessel, the obturator sized to slide within the fluid-flow lumen from the proximal end towards the distal end of the fluid-flow lumen, wherein the obturator and stylet are sized to provide an interference fit between the distal end of the stylet and an inside surface of a distal end of the obturator, wherein the interference fit is configured to control an amount of stylet insertion into the obturator. |
