Patents by Inventor W. Kirt Nichols

W. Kirt Nichols has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7695450
    Abstract: 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.
    Type: Grant
    Filed: March 28, 1995
    Date of Patent: April 13, 2010
    Assignee: Curators of the University of Missouri, The University of Missouri
    Inventors: Zbylut J. Twardowski, John C. Van Stone, W. Kirt Nichols
  • Patent number: 5961486
    Abstract: 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.
    Type: Grant
    Filed: November 5, 1998
    Date of Patent: October 5, 1999
    Inventors: Zbylut J. Twardowski, W. Kirt Nichols, John C. Van Stone
  • Patent number: 5685867
    Abstract: 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.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: November 11, 1997
    Assignee: The Curators of the University of Missouri
    Inventors: Zbylut J. Twardowski, W. Kirt Nichols, John C. Van Stone
  • Patent number: 5569182
    Abstract: 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.
    Type: Grant
    Filed: February 9, 1995
    Date of Patent: October 29, 1996
    Assignee: The Curators of the University of Missouri
    Inventors: Zbylut J. Twardowski, W. Kirt Nichols, John C. Van Stone
  • Patent number: 5509897
    Abstract: 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.
    Type: Grant
    Filed: February 15, 1995
    Date of Patent: April 23, 1996
    Assignee: The Curators of the University of Missouri
    Inventors: Zbylut J. Twardowski, John C. Van Stone, W. Kirt Nichols
  • Patent number: 5405320
    Abstract: 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.
    Type: Grant
    Filed: April 8, 1993
    Date of Patent: April 11, 1995
    Assignee: The Curators of the University of Missouri
    Inventors: Zbylut J. Twardowski, John C. Van Stone, W. Kirt Nichols
  • Patent number: 5209723
    Abstract: 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.
    Type: Grant
    Filed: October 8, 1991
    Date of Patent: May 11, 1993
    Assignee: The Curators of the University of Missouri
    Inventors: Zbylut J. Twardowski, John C. Van Stone, W. Kirt Nichols
  • Patent number: 5171227
    Abstract: A peritoneal dialysis catheter comprises a distal tubular section and a proximal tubular section, connected together by a nonintegral tubular connector so that the respective sections are connected together in sealed flow relation. Such a catheter may be surgically implanted in the peritoneal cavity, extending to the chest of the patient with an end thereof protruding from the chest. The respective ends of the catheter section may be connected to each other through the tubular connector as the tubular sections are surgically implanted, and typically after such implantation is substantially complete.
    Type: Grant
    Filed: April 16, 1991
    Date of Patent: December 15, 1992
    Assignee: The Curators of the University of Missouri
    Inventors: Zbylut J. Twardowski, Ramesh Khanna, W. Kirt Nichols, Karl D. Nolph