Abstract: A sheath and obturator is provided for facilitating the insertion of certain medical devices into a patient's vascular system, a vein, or venous system and in particular an in vivo extrapulmonary blood gas exchange device having a bundle comprised of a plurality of elongated gas permeable tubes being potted at each end and enclosed within a respective air tight proximal and distal chamber. The sheath is hollow and substantially tubular with a tapered receiving portion and a nontapered, curved entry portion. The obturator has a tip at the distal end of the obturator and a trip at the proximal end with an elongate member therebetween. The sheath is configured to receive the obturator in sliding engagement such that when the obturator is fully inserted within the sheath, the tip closes the opening at the entry end of the sheath and protrudes slightly therefrom. The obturator has a vent which provides a passage from space exterior to the sheath into the hollow interior of the sheath.

Abstract: An in vivo extrapulmonary blood gas exchange device is disclosed having a hollow fiber bundle in gaseous communication with a coaxial dual lumen tube and having a furling apparatus for twisting one coaxial lumen relative to the other. The furling apparatus enables the outside diameter of the bundle of gas permeable tubes to be selectively adjusted to provide either a furled, small insertion diameter when inserting the apparatus into the venae cavae of a patient or an unfurled, expanded oxygenation diameter after the apparatus is in place within the venae cavae and the bundle of gas permeable tubes is deployed therein. The oxygenator is inserted into the patient through a single incision at one of the right external iliac, common femoral, or internal jugular veins. A novel distal tip configuration permits the oxygenator to be inserted into the patient utilizing an over-the-guidewire intravascular insertion technique.