A cannular device, comprising; a polymeric conduit defining an inner lumen, a proximal end having a proximal opening, and a distal end having a distal opening arranged so that the inner lumen extends from the proximal opening to the distal opening, wherein the polymeric conduit comprises a biocompatible polymeric composition free of phthalate containing materials and wherein the polymeric conduit is wire-free, wherein the polymeric conduit is arranged to have a circular cross-section defining an inner diameter and an outer diameter, the circular cross-section diminishing in size from the proximal end to the distal end from a first inner diameter and first outer diameter to a second inner diameter and a second outer diameter, the first inner diameter being larger than the second inner diameter and the first outer diameter being larger than the second outer diameter, wherein the polymeric conduit is adapted to provide means for resisting kinking so that the inner lumen remains free from obstruction when tested according to the 180° bend test, wherein the inner diameter diminishes according to a first continuous function, the function providing a gradual diminution of diameter from the proximal end to the distal end, and wherein the outer diameter diminishing according to a second continuous function, the function providing a gradual diminution of size from the proximal end to the distal end, wherein the first inner diameter and the first outer diameter define a first thickness for the polymer conduit at the proximal end opening and the second inner diameter and the second outer diameter define a second thickness for the polymer conduit at the distal end, wherein the second thickness is about 50 to about 95% of the first thickness, wherein the average wall thickness change per 2.54 cm (1 inch) length to diameter change per 2,54 cm (1 inch) length ratio is between 3 and 70. wherein the polymeric conduit comprises a biocompatible polymeric composition free of phthalate containing materials and wherein the polymeric conduit is wire-free, wherein the polymeric conduit is arranged to have a circular cross-section defining an inner diameter and an outer diameter, the circular cross-section diminishing in size from the proximal end to the distal end from a first inner diameter and first outer diameter to a second inner diameter and a second outer diameter, the first inner diameter being larger than the second inner diameter and the first outer diameter being larger than the second outer diameter, wherein the polymeric conduit is adapted to provide means for resisting kinking so that the inner lumen remains free from obstruction when tested according to the 180° bend test, wherein the inner diameter diminishes according to a first continuous function, the function providing a gradual diminution of diameter from the proximal end to the distal end, and wherein the outer diameter diminishing according to a second continuous function, the function providing a gradual diminution of size from the proximal end to the distal end, wherein the first inner diameter and the first outer diameter define a first thickness for the polymer conduit at the proximal end opening and the second inner diameter and the second outer diameter define a second thickness for the polymer conduit at the distal end, wherein the second thickness is about 50 to about 95% of the first thickness, wherein the average wall thickness change per 2.54 cm (1 inch) length to diameter change per 2,54 cm (1 inch) length ratio is between 3 and 70.