| 摘要 |
<p>This invention is a large diameter expandable sheath (11) for use in introducing a catheter or other medical instrument into a vessel in the body of a patient. The expandable sheath (11) comprises an elongated sheath tube (12) that has proximal and distal extremities, and a passage (16) extending therethrough of a maximum predetermined diameter. The distal extremity of the elongate sheath tube (12) is folded longitudinally to a smaller folded diameter. A back flow adapter (21) is secured to the proximal extremity of the elongate sheath tube (12). A normally closed primary valve (40) is disposed in the central opening of the back flow adapter (21), and is movable to an open position. A normally open secondary valve (56) is movable to a closed position. In one preferred embodiment the sheath assembly (311) includes an outer tubular member (313), and an inner tubular member (314) with a conically shaped cap (319) at its distal end. A locking mechanism (320) prevents advancement of the inner tubular member (314) and associated cap (319) in a distal direction of the vessel of the patient independent of the outer tubular member (313).</p> |
