| abstract |
The invention provides a dual lumen catheter comprising outer and inner tube materials. A main portion extends axially and has a selected first cross-section. The main portion includes main portions of the respective outer and inner tube materials which together define an annular intake lumen and a main part of a return lumen contained inside the intake lumen. A tubular transition portion is made up integrally of both the outer and inner tube materials and has a second cross-section smaller than the first cross-section. The transition portion extends axially from the distal end of the main portion and this can be extended to include a tip portion made up only of outer tube material and which extends axially from the transition portion. The transition portion on its own, or with the tip portion, defines a tip section which is a continuation of said main part of the return lumen to complete the return lumen. |