DR. JOHN CHARLES VAN STONE, M.D.
Osteopathic Medicine at Lemone Industrial Blvd, Columbia, MO

5209723, May 11, 1993

Oct 8, 1991

7/772613

Zbylut J. Twardowski - Columbia MO
John C. Van Stone - Columbia MO
W. Kirt Nichols - Columbia MO

The Curators of the University of Missouri - Columbia MO

A61M 300

604 43

A multiple lumen, intravenous catheter for hemodialysis or the like defines a distal end portion in which at least a pair of the catheter lumens each communicates with the exterior through aperture means. By this invention the aperture means of one of the lumens defines a first port at essentially the distal catheter end, and the aperture means of the other of the lumens defines a second port spaced proximally along the catheter from the distal end and first port. The second port is positioned to face radially inwardly to at least a slight degree to avoid engagement of the wall of the blood vessel that the catheter occupies. Additionally, the tip of the catheter distal of the second port is preferably of substantially helically shape, being sized to assist in keeping the second port away from the blood vessel wall. As another feature, the catheter may be angled in its as-manufactured, unstressed condition to avoid pressing by elastic memory against internal blood vessel walls. Also, the catheter may define an inflatable balloon positioned between the first and second ports as a means for spacing particularly the second port away from blood vessel walls.

5405320, Apr 11, 1995

Apr 8, 1993

8/045016

Zbylut J. Twardowski - Columbia MO
John C. Van Stone - Columbia MO
W. Kirt Nichols - Dept. of Surgery University of Missouri Hospital 65212 MO

The Curators of the University of Missouri - Columbia MO

A61M 300

604 43

A catheter for hemodialysis comprises a flexible catheter tube defining a plurality of separate lumens. The catheter defines an arc angle of generally U-shape in its natural, unstressed configuration. Thus, the catheter may be implanted with a distal catheter portion residing in a vein of the patient, the distal catheter portion being of substantially the shape of the vein in its natural, unstressed condition. Also, a proximal catheter portion resides in a surgically created tunnel extending from the vein and through the skin of the patient, this section of the catheter also being typically in its natural, unstressed condition. Thus blood may be removed from the vein through one lumen of the catheter, and blood may be returned to the vein through another lumen of the catheter, while the catheter is subject to long term indwelling in the body. Improved results are achieved because of the lack of mechanical stress in the shape of the catheter, which stress causes the catheter to press unduly against adjacent tissues.

5509897, Apr 23, 1996

Feb 15, 1995

8/389283

Zbylut J. Twardowski - Columbia MO
John C. Van Stone - Columbia MO
W. Kirt Nichols - Columbia MO

The Curators of the University of Missouri - Columbia MO

A61M 300

604 43

A catheter for hemodialysis comprises a flexible catheter tube defining a plurality of separate lumens. The catheter defines an arc angle of generally U-shape in its natural, unstressed configuration. Thus, the catheter may be implanted with a distal catheter portion residing in a vein of the patient, the distal catheter portion being of substantially the shape of the vein in its natural, unstressed condition. Also, a proximal catheter portion resides in a surgically created tunnel extending from the vein and through the skin of the patient, this section of the Catheter also being typically in its natural, unstressed condition. Thus blood may be removed from the vein through one lumen of the catheter, and blood may be returned to the vein through another lumen of the catheter, while the catheter is subject to long term indwelling in the body. Improved results are achieved because of the lack of mechanical stress in the shape of the catheter, which stress causes the catheter to press unduly against adjacent tissues.

7695450, Apr 13, 2010

Mar 28, 1995

08/412114

Zbylut J. Twardowski - Columbia MO, US
John C. Van Stone - Columbia MO, US
W. Kirt Nichols - Columbia MO, US

Curators of the University of Missouri, The University of Missouri - Columbia MO

A61M 31/00

604 9301

A catheter for hemodialysis comprises a flexible catheter tube defining a plurality of separate lumens. The catheter defines an arc angle of generally U-shape in its natural, unstressed configuration. Thus, the catheter may be implanted with a distal catheter portion residing in a vein of the patient, the distal catheter portion being of substantially the shape of the vein in its natural, unstressed condition. Also, a proximal catheter portion resides in a surgically created tunnel extending from the vein and through the skin of the patient, this section of the catheter also being typically in its natural, unstressed condition. Thus blood may be removed from the vein through one lumen of the catheter, and blood may be returned to the vein through another lumen of the catheter, while the catheter is subject to long term indwelling in the body. Improved results are achieved because of the lack of mechanical stress in the shape of the catheter, which stress causes the catheter to press unduly against adjacent tissues.

5685867, Nov 11, 1997

Jun 7, 1995

8/474376

Zbylut J. Twardowski - Columbia MO
W. Kirt Nichols - Columbia MO
John C. Van Stone - Columbia MO

The Curators of the University of Missouri - Columbia MO

A61M 2500

604280

Blood is circulated through a multiple lumen catheter which connects between a vein of a patient and the blood treatment device. The catheter and the lumens thereof each define distal ends which are positioned within the vein. By this invention, one withdraws blood from the vein through one of the lumens at a flow rate of at least about 200 ml. /min. while also inserting blood into the vein through another of said lumens at a similar flow rate. The distal ends of the lumens are longitudinally spaced from each other by no more than about 5 mm. It have been found that the following advantages can be achieved by this method: less clot formation coupled with low direct blood recirculation and longer catheter survival. Also, the catheter works well in either direction of blood flow through the respective lumens.

5569182, Oct 29, 1996

Feb 9, 1995

8/386473

Zbylut J. Twardowski - Columbia MO
W. Kirt Nichols - Columbia MO
John C. Van Stone - Columbia MO

The Curators of the University of Missouri - Columbia MO

A61M 300

604 43

Blood is circulated through a multiple lumen catheter which connects between a vein of a patient and the blood treatment device. The catheter and the lumens thereof each define distal ends which are positioned within the vein. By this invention, one withdraws blood from the vein through one of the lumens at a flow rate of at least about 200 ml. /min. while also inserting blood into the vein through another of said lumens at a similar flow rate. The distal ends of the lumens are longitudinally spaced from each other by no more than about 5 mm. It have been found that the following advantages can be achieved by this method: less clot formation coupled with low direct blood recirculation and longer catheter survival. Also, the catheter works well in either direction of blood flow through the respective lumens.

5961486, Oct 5, 1999

Nov 5, 1998

9/187100

Zbylut J. Twardowski - Columbia MO
W. Kirt Nichols - Columbia MO
John C. Van Stone - Columbia MO

A61M 300

604 43

Blood is circulated through a multiple lumen catheter which connects between a vein of a patient and the blood treatment device. The catheter and the lumens thereof each define distal ends which are positioned within the vein. By this invention, one withdraws blood from the vein through one of the lumens at a flow rate of at least about 200 ml. /min. while also inserting blood into the vein through another of said lumens at a similar flow rate. The distal ends of the lumens are longitudinally spaced from each other by no more than about 5 mm. It has been found that the following advantages can be achieved by this method: less clot formation coupled with low direct blood recirculation and longer catheter survival. Also, the catheter of this invention works well in either direction of blood flow through the respective lumens.