Cannula having reduced flow resistance

• US 20050277870A1
• Filed: 06/10/2004
• Published: 12/15/2005
• Est. Priority Date: 06/10/2004
• Status: Abandoned Application

• Current Assignee: TC1 LLC (Abbott Laboratories)
• Original Assignee: TC1 LLC (Abbott Laboratories)
• Inventors: Pecor, Robert
• Application Number:
  US10/866,649
• Publication Number:
  US 20050277870A1
• Time in Patent Office: Days
• US Class Current: 604/43
• CPC Class Codes: A61M 1/3653 Interfaces between patient blood circulation and extra-corporal blood circuit
• CPC Class Codes: A61M 1/3659 Cannulae pertaining to extracorporeal circulation
• CPC Class Codes: A61M 1/3661 for haemodialysis

Abstract

A multilumen cannula is provided that directs blood through a patient through a single cannulation site. The multilumen cannula has a first elongate portion and a second elongate portion. The first elongate portion defines a first lumen that extends between a first proximal end and a first distal end. The second elongate portion defines a second lumen that extends between a second proximal end and a second distal end. The inner cross-section of the first lumen is greater at the first distal end than at the first proximal end.

Claims

1. A multilumen cannula for reducing resistance in blood flowing therethrough, the multilumen cannula comprising:

a first elongate body comprising a proximal portion, a transition portion having a diameter at a distal end greater than a diameter at a proximal end, a distal portion, and a first lumen that extends therethrough, the first lumen having a first cross-sectional area within the proximal portion and a second cross-sectional area within the distal portion, the second cross-sectional area being greater than the first cross-sectional area; and

a second elongate body defining a second lumen, the second elongate body extending along the proximal portion of the first elongate body.

2. The multilumen cannula of claim 1, wherein the proximal portion of the first elongate body extends into the second lumen.

3. The multilumen cannula of claim 2, wherein the longitudinal axes of the first and the second lumens are parallel.

4. The multilumen cannula of claim 3, wherein the first lumen and the second lumen are co-axial.

5. The multilumen cannula of claim 1, wherein the proximal portion extends alongside the second lumen.

6. The multilumen cannula of claim 5, wherein the first and second lumens are substantially D-shaped lumens.

7. A multilumen cannula for reducing resistance in blood flowing therethrough, the multilumen cannula comprising:

a first elongate portion defining a first lumen that extends between a first proximal end and a first distal end, the inner cross-section of the first lumen being greater proximate the first distal end than proximate the first proximal end; and

a second elongate portion defining a second lumen that extends between a second proximal end and a second distal end.

8. The multilumen cannula of claim 7, wherein the first elongate portion and the second elongate portion are axially movable relative to each other.

9. The multilumen cannula of claim 7, wherein at least a portion of the inner cross-section of the first lumen is circular.

10. The multilumen cannula of claim 7, wherein a portion of the first elongate portion extends through the second lumen.

11. The multilumen cannula of claim 10, wherein the first elongate portion and the second elongate portion are translatable relative to each other.

12. The multilumen cannula of claim 10, wherein an outer dimension of the second elongate portion is no greater than an outer dimension of the first elongate portion.

13. The multilumen cannula of claim 7, wherein each of the first elongate portion and the second elongate portion comprise a D-shaped cross-section proximate the second proximal end.

14. The multilumen cannula of claim 7, wherein the first proximal end of the first elongate portion has a D-shaped cross-section and the first distal end thereof has a circular cross-section.

15. The multilumen cannula of claim 7, further comprising means for creating substantially vortex flow.

16. The multilumen cannula of claim 15, wherein the creating means comprises an inwardly protruding ridge oriented in a helical arrangement in the first lumen.

17. A multilumen cannula for reducing resistance in blood flowing therethrough, the multilumen cannula comprising:

a first elongate portion defining a first lumen that extends between a first proximal end and a first distal end; and

a second elongate portion defining a vessel wall engagement portion and a second lumen that extends between a second proximal end and a second distal end,

wherein the inner cross-section of the first lumen is greater at the first distal end than at a location corresponding to the vascular wall engagement portion.

18. A method for accessing the vascular system of a patient, comprising:

providing a cannula comprising a first elongate portion and a second elongate portion, the first elongate portion defining a transition portion and a first lumen that extends between a first proximal end and a first distal end, the second elongate portion defining a second lumen that extends between a second proximal end and a second distal end, wherein the inner cross-section of the first lumen is greater proximate the first distal end than proximate a vessel wall engagement portion of said second elongate portion;

translating a portion of said cannula to a first position wherein said second distal end is located distal to at least a portion of said transition portion of said first elongate portion;

inserting said cannula into a blood vessel through a vascular access site such that said vessel wall engagement portion of said second elongate portion is adjacent said vessel wall;

translating a portion of said cannula to a second position wherein the second distal end is proximal to at least a portion of said transition portion.

19. The method of claim 18, wherein when said cannula is in said first position, the second distal end is located distal substantially all of said transition portion.

20. The method of claim 18, wherein when said cannula is in said second position, the second distal end is located proximal substantially all of said transition portion.

21. The method of claim 18, further comprising the step of coupling the proximal ends of the first and second elongated portions to a pump

22. The method of claim 18, wherein the first elongate portion extends axially through at least a portion of the second elongate portion

23. The method of claim 22, wherein both the first and second elongate portions have substantially circular cross-sections.

24. The method of claim 18, wherein the cannula provides a substantially constant outer cross-sectional profile when the second elongate portion is in the first position.