Hemodialysis cannular for subclavian insertion
First Claim
1. A double lumen cannula suitable for insertion into a large vein such as the subclavian vein of a patient for blood removal therefrom and blood return thereto, said cannula comprisingan elongated flexible tubular outer member comprising a main elongated portion of first cross section, an integral convergent section having a smooth continuous outer surface and a flexible distal end portion having a second cross section which is smaller than said first cross sectiona plurality of blood flow apertures, spaced apart from one another in the side wall of said main portion of said first cross section adjacent the convergent section;
- at least one blood flow aperture disposed centrally in the tip of said flexible distal end portion;
an elongated flexible tubular inner member having an opening at each end and having a cross section smaller than said first cross section, the inner member being disposed within the outer member, the distal end of said inner member being disposed in substantially sealing end contact with the convergent section of the outer member so as to form, with the outer member, a pair of concentrically arranged discrete fluid flow lumens, the inner lumen constituted by said inner member and said distal end portion of the outer member, the outer lumen constituted by the main portion and the convergent section of the outer member;
the inner member being releasable and withdrawable from within the outer member.
0 Assignments
0 Petitions
Accused Products
Abstract
A double lumen cannula for hemodialysis and similar applications such as haemoperfusion comprises elongated flexible tubular members, disposed one within the other, for semi-permanent insertion into the sub-clavian vein of a patient, leaving semi-permanent access thereto for repeated hemodialysis treatments. The cannula is formed of an elongated flexible outer member, having a smooth exterior surface, and made up of an elongated main portion, a convergent, constricting portion and a narrower distal end portion which is tapered at the tip to fit over a Seldinger guide wire. There is also an inner member having a diameter substantially the same as that of the distal end portion. The inner member is insertable into the outer member to come into sealable engagement with the interior walls of the constricting portion, so as to form a continuous inner lumen with the distal end portion of the outer member, and is removable therefrom for removal of clot or replacement purposes. Both members are sufficiently flexible to permit curving thereof on a 12 cm radius without reduction in internal cross section thereof, i.e. without substantial kinking or buckling, so as to avoid constriction of fluid flows. Because the cannula provides two pathways for simultaneous extraction and return of blood there is no need to use a single needle machine to produce an alternating blood flow.
259 Citations
9 Claims
-
1. A double lumen cannula suitable for insertion into a large vein such as the subclavian vein of a patient for blood removal therefrom and blood return thereto, said cannula comprising
an elongated flexible tubular outer member comprising a main elongated portion of first cross section, an integral convergent section having a smooth continuous outer surface and a flexible distal end portion having a second cross section which is smaller than said first cross section a plurality of blood flow apertures, spaced apart from one another in the side wall of said main portion of said first cross section adjacent the convergent section; -
at least one blood flow aperture disposed centrally in the tip of said flexible distal end portion; an elongated flexible tubular inner member having an opening at each end and having a cross section smaller than said first cross section, the inner member being disposed within the outer member, the distal end of said inner member being disposed in substantially sealing end contact with the convergent section of the outer member so as to form, with the outer member, a pair of concentrically arranged discrete fluid flow lumens, the inner lumen constituted by said inner member and said distal end portion of the outer member, the outer lumen constituted by the main portion and the convergent section of the outer member; the inner member being releasable and withdrawable from within the outer member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification