High performance cannulas

• US 20050038408A1
• Filed: 07/07/2004
• Published: 02/17/2005
• Est. Priority Date: 07/07/2003
• Status: Active Grant

• Current Assignee: Coraflo Ltd.
• Original Assignee: Coraflo Ltd.
• Inventors: von Segesser, Ludwig K.
• Granted Patent: US 7,967,776 B2
• Time in Patent Office: Days
• US Class Current: 604/506
• CPC Class Codes: A61B 17/3439 with means for changing the inner diameter of the cannula, e.g. expandable A61B17/3423, A61B17/3431 take precedence; catheters A61M25/0662
• CPC Class Codes: A61B 2017/00867 shape memory effect
• CPC Class Codes: A61M 1/3661 for haemodialysis
• CPC Class Codes: A61M 1/84 Drainage tubes; Aspiration tips for negative pressure wound therapy A61M1/90; for surgical cutting instruments A61B17/32

Abstract

A cannula having a proximal end, a distal end, and a lumen extending between the proximal and distal ends is provided. The diameter of the lumen of the cannula can be varied to take into account differences in the diameter of access and target vessels during cannulation. The cannula is further characterized by at least one mechanism that, upon actuation, serves to alter the conformation of the cannula between a normal profile conformation and a low profile conformation. The normal profile conformation is characterized by the cannula having a lumen diameter at the point of insertion, which is smaller than the lumen diameter both proximal and distal to the point of insertion, with the lumen diameter distal to the point of insertion also expandable to the diameter of the cannulated vessel of the patient. The low profile conformation is characterized by the cannula having a lumen diameter at the point of insertion that is greater than the lumen diameter distal to the point of insertion.

Claims

1. A cannula adapted for insertion at a point of insertion, the cannula comprising:

a cannula body having a proximal end, a distal end, and a lumen extending between the proximal and distal ends, the lumen having a diameter, the cannula body comprising a plurality of flexible filaments that allow the diameter of the lumen to be varied, wherein the distal end optionally further comprises a tip, wherein the tip is removable or eccentrically located;

at least one mechanism that, upon actuation, serves to alter the conformation of the cannula between a normal profile conformation and a low profile conformation, wherein the mechanism is selected from the group consisting of a mandrel, an electric motor, a change in pressurization, a wrapping string, a balloon and a sheath;

wherein, when the cannula is in use, the normal profile conformation is characterized by the cannula having a lumen diameter at the point of insertion which is smaller than the lumen diameter both proximal and distal to the point of insertion,

wherein the lumen diameter distal to the point of insertion is expandable up to the diameter of a surrounding vessel or to the maximum lumen diameter; and

wherein the low profile conformation is characterized by the cannula having a lumen diameter at the point of insertion that is greater than the lumen diameter distal to the point of insertion.

2. The cannula of claim 1, wherein the plurality of flexible filaments comprises one or more materials selected from the group consisting of metals, shape-memory metals, alloys, plastics, textile fibers, synthetic fibers, and combinations thereof.

3. The cannula of claim 1, wherein the plurality of flexible filaments have a shape selected from the group consisting of round, oval, flattened, triangular, rectangular and combinations thereof.

4. The cannula of claim 2, wherein the metal is stainless steel.

5. The cannula of claim 1, wherein the plurality of flexible filaments are textile fibers.

6. The cannula of claim 1, wherein the plurality of flexible filaments are braided together.

7. The cannula of claim 1, wherein the plurality of flexible filaments are knitted together.

8. The cannula of claim 1, wherein the plurality of flexible filaments are interwoven.

9. The cannula of claim 1, wherein the plurality of flexible filaments are interlaced.

10. The cannula of claim 1, wherein the cannula is inserted into hollow organ.

11. The cannula of claim 10, wherein the hollow organ is selected from the group consisting of a vein, an artery, a urethra, a ureter, an intestine, an esophagus, a trachea, a bronchial tube, a pleural space, and a peritoneum.

12. The cannula of claim 1, wherein the cannula is in its normal profile conformation when in use and wherein the lumen diameter distal to the point of insertion varies in relation to the diameter of the surrounding vessel.

13. The cannula of claim 1, wherein the cannula is in its normal profile conformation when in use and wherein the portion of the cannula distal to the point of insertion supports an inner surface of the surrounding vessel.

14. The cannula of claim 1, wherein the plurality of flexible filaments are elastic.

15. The cannula of claim 1, wherein the plurality of flexible filaments are plastic.

16. The cannula of claim 1, wherein at least a portion of the cannula is coated with a water-tight coating.

17. The cannula of claim 16, wherein the water-tight coating is plastic.

18. The cannula of claim 1, wherein the cannula tip comprises a photoactivated epoxy.

19. The cannula of claim 1, further comprising a connecting sleeve.

20. The cannula of claim 1, wherein the flow rate of fluid through the cannula is less than about 150 mL/min.

21. The cannula of claim 1, wherein the flow rate of fluid through the cannula is between about 1 mL/min and about 10 mL/min.

22. A method for using the cannula of claim 1 in a medical context, the method comprising:

placing the cannula in its low profile conformation;

inserting the cannula into a hollow organ of a patient at a point of insertion; and

returning the cannula to its normal profile conformation, wherein in the normal profile conformation, the cannula expands distal to the point of insertion up to the diameter of the hollow organ or to the maximum diameter of the lumen.

23. The method of claim 22, wherein, when the cannula is in the normal profile conformation, the diameter of the cannula distal to the point of insertion varies in relation to the diameter of the hollow organ.

24. The method of claim 22, wherein inserting the cannula into the hollow organ of the patient comprises inserting the cannula into a location selected from the group consisting of the peritoneum, the trachea, the chest, the cardiovascular system, the kidneys, and the urinary system.

25. The method of claim 24, wherein the hollow organ is selected from the group consisting of a vein, an artery, a urethra, a ureter, an intestine, an esophagus, a trachea, a bronchial tube, a pleural space, and a peritoneum.

26. The method of claim 25 wherein the cannula is inserted into the trachea.

27. The method of claim 26 wherein the cannula is inserted transorally, transnasally, or through a tracheotomy.

28. The method of claim 22, wherein, when the cannula is used during cardiac surgery, the flow rate of fluid through the cannula is between about 100 mL/min and 6 L/min.

29. The method of claim 22, wherein, when the cannula is used during dialysis or hemofiltration, the flow rate of fluid through the cannula is between about 100 mL/min and 500 mL/min.

30. The method of claim 22, wherein, when the cannula is used for intravenous delivery of fluids, the flow rate of fluid is between about 1 mL/min and about 10 mL/min.

31. A method for using the cannula of claim 1 in a non-medical context, the method comprising:

placing the cannula in its low profile conformation;

inserting the cannula into an object to be cannulated selected from the group consisting of tubing, a container, a fluid-filled container, a powder-filled container, and a gas-filled container; and

returning the cannula to its normal profile conformation,

wherein in the normal profile conformation, the cannula expands distal to the point of insertion up to the diameter of the object or up to the maximum lumen diameter.

37. A method for manufacturing the cannula of claim 1, wherein the method is selected from the group consisting of injection molding, laser-cutting, water-cutting, extrusion and combinations thereof.

32. A dual lumen cannula adapted for insertion at a point of insertion for use in peritoneal dialysis, hemodialysis or hemofiltration, the cannula comprising:

a first cannula body having a proximal end, a distal end, and a lumen extending between the proximal and distal ends, and a second cannula body having a proximal end, a distal end, and a lumen extending between the proximal and distal ends, the lumen of the first and second cannula bodies having a diameter, the first and second cannula bodies comprising a plurality of flexible filaments that allow the diameter of the first and second lumen to be varied, wherein the first and second distal ends optionally further comprise a tip, wherein the tip is removable or eccentrically located;

at least one mechanism that, upon actuation, serves to alter the conformation of the first cannula body, the second cannula body, or both the first cannula body and the second cannula body, between a normal profile conformation and a low profile conformation;

wherein, when the dual lumen cannula is in use, the normal profile conformation is characterized by the first and second cannula bodies having a lumen diameter at the point of insertion which is smaller than the lumen diameter both proximal and distal to the point of insertion, and wherein the lumen diameters of the first and second cannula bodies distal to the point of insertion are expandable up to the diameter of a surrounding vessel or to the maximum lumen diameter; and

wherein the low profile conformation is characterized by the first and second cannula bodies having a lumen diameter at the point of insertion that is greater than the lumen diameter distal to the point of insertion.

33. The dual lumen cannula of claim 32, wherein the plurality of flexible filaments comprises one or more materials selected from the group consisting of metals, shape-memory metals, alloys, plastics, textile fibers, synthetic fibers, and combinations thereof.

34. The dual lumen cannula of claim 32, wherein the at least one mechanism is selected from the group consisting of a mandrel, an electric motor, a change in pressurization, a wrapping string, a balloon and a sheath.

35. The dual lumen cannula of claim 32, wherein the first and second cannula bodies are positioned coaxially.

36. The dual lumen cannula of claim 32, wherein the first and second cannula bodies are positioned adjacently.