A bi-directional flow catheter for insertion into the body of a patient for the simultaneous introduction into and withdrawal therefrom of fluid. The catheter includes a primary tube having open distal and proximal ends, and a pair of branching tubes, each of which branch from a different side of the primary tube. The primary tube also has an opening in one side thereof to allow introduction of fluid. An elongate trocar/valve member is disposed in the primary tube and is movable longitudinally therein between an insert position and a flow position. One end of the trocar/valve member tapers to a cutting edge which protrudes from the opening in the distal end of the primary tube when the member is in the insert position. The trocar/valve member is formed to prevent communication between the side opening and the opening in the distal end of the primary tube, and to cover the passageways between the primary tube and respective ones of the branching tubes when the member is in the insert position. When the member is in the flow position, the cutting end thereof is withdrawn from the distal opening and communication is allowed between the side opening and one of the branching tubes and between the distal opening and the other of the branching tubes to thereby allow simultaneous introduction of fluid into and withdrawal of fluid from the body of a patient.

A double lumen, single needle, catheter is provided having an improved insertion tip which aleviates the trauma induced when inserted in a blood vessel or fistula.

A dual-lumen fistula needle for use in hemodialysis treatment. The needle has a gently tapered neck and is divided into arterial and venous lumens by a center septum which is bonded in place. The septum is formed so that the lumens have substantially equal cross sections substantially throughout the length of the needle to promote equal flow rates in the lumens. The diameter of the needle at the tip is similar to that of single-lumen needles in order to reduce discomfort on insertion.

A double lumen catheter made up of an elongated integral flexible plastic thin-walled tubular body extending from a proximal end part, through an intermediate part, to a distal end part, terminating in a tip. The intermediate part has an outer wall and an internal septum wall containing juxtaposed arterial and venous lumens. The terminal end of each lumen in the proximal part is adapted for connection to an access tube to hemodialysis apparatus. At the junction of the intermediate part and the distal part, the arterial lumen is terminated and the venous lumen continued at least part way to the tip of the distal part. The outside surface of the outer walls are continuous and smooth to offer minimum resistance to insertion into the body of a patient. The walls are also relatively thin to provide for lumens of relatively large cross-section compared to the total cross-section of the catheter body. Removable obturators are inserted in the lumens to prevent the catheter from buckling. The inner surface of the outer walls and the surfaces of the septum wall are continuous and smooth and any change of direction in the lumen wall is in a gradual curve to accommodate negotiation by a flexible obturator. Alternatively, the catheter may be made from tubing sufficiently resistant in itself to buckling for the catheter to be inserted without the use of obturators. One such form of tubing is made of alternating hard and soft plastic rings welded together. Another form employs wire reinforcing within the walls. Welding and molding methods for making the catheters are disclosed.

A cannula assembly including a tube cannula and a hollow introducer needle. At the proximal end of the cannula are three fittings: first, a first luer fitting affixed to the proximal end of the tube cannula; second, a luer fitting removably attached to the first luer fitting, this second luer fitting having a first air porous water locking plug at a proximal end penetrated by the needle; and, third, a needle handle removably attachable to the second luer fitting. The proximal end of the needle handle is blocked also by a second air porous water blocking plug. The second plug prevents escape of blood from the hollow needle upon penetration of the arterial wall. The first plug controls the rate of flow of blood to the cannula tube and allows clamping of the tube after withdrawal of the introducer needle and prior to connection to a cardioplegia supply line.