Bidirectional check valve catheter

DETAILED DESCRIPTION The present invention provides an improved bidirectional check valve catheter which is easy to manufacture, installs easily and permits long term placement in the patient's bloodstream.
In one aspect of the invention, a valved catheter includes a valve assembly adapted for bidirectional flow of fluid between the proximal and distal ends of the catheter, but which prevents diffusion of blood into the catheter when it is not in use.
In an illustrative embodiment of the invention, a bidirectionally valved catheter includes an elongated, flexible tubular element which extends along a central axis, and defines a lumen extending along that central axis from a proximal end to a distal end.
A valve assembly is formed at the distal end in cooperation with the tubular element.
The assembly includes an aspiration valve for permitting fluid flow from outside to inside of the tubular element for aspiration of blood from the patient's bloodstream and an infusion valve for permitting fluid flow from inside to outside of the tubular element for delivery of fluid into the patient's bloodstream.
The aspiration valve is a sleeve valve including one or more inflow ports extending between the exterior and interior surfaces of the tubular element.
A flexible tubular sleeve is disposed adjacent to the inner surface of the portions of the tubular element that include the inflow ports.
The valve action is formed by the sleeve, which is nominally urged against the interior surface of the tubular element in a manner which normally prevents fluid inflow and essentially prevents fluid outflow through the inflow ports.
A portion of the sleeve is displaceable to permit fluid inflow when the static fluid pressure outside of the ports is higher than the static fluid pressure inside the tubular element by an amount sufficient to force a portion of the sleeve away from the interior surface of the tubular element.
The infusion valve is a slit valve and in one form of the invention includes a normally closed "duck bill"-type valve at the distal tip of the tubular element