Self-occluding intravascular cannula assembly

A self-occluding cannula assembly comprising:

• a generally tubular cannula sheath having a proximal end, a distal end, and an inner lumen extending axially therethrough;
• a connecting hub formed on the proximal end of said cannula sheath, said connecting hub having an axial bore formed therein, said axial bore being fluidly consistent with the inner lumen of said cannula sheath;
• and
• an occluding means comprising:
• a frusto conical dilator projection;
• an annular seating groove formed around
• said frusto conical dilator projection;
• and
• an obturator member comprising a generally disc shaped body disposed transversely within said connecting hub, proximal to said dilator projection, said disc shaped body having at least one elastically openable and closable aperture and at least one notch formed therein;
• said obturator member normally residing in an "occluding" position wherein said openable and closable aperture remains closed so as to substantially preclude fluid from flowing through said cannula lumen;
• said obturator member being slidably movable relative to said dilator projection such that the application of distally directed pressure against said obturator member will cause said obturator member to distally advance to a "non-occluding" position wherein at least a portion of said obturator member is advanced into said seating groove and the notch portion of said obturator member is advanced over at least a portion of said frusto conical dilator projection such that said dilator projection exerts sufficient pressure against said obturator member to cause said openable and closable aperture to assume an open configuration whereby fluid is permitted to flow through said cannula lumen and further whereby, upon removal of said distally directed pressure, said obturator member will resiliently return to its "occluding" position.