Bent co-axial catheter

Abstract

The invention provides a co-axial dual lumen catheter having a main section, a tip section, and a U-shaped proximal portion extending from the main section, and ending at a junction where intake and outlet tubes are connected to the proximal portion. An inner tube extends from the junction to the tip of the catheter to define a return lumen, and combines with outer tubes in the main section and the proximal portion to define an intake lumen. The inner tube is thin walled relative to the wall thickness of a first outer tube used in the main section, and a second outer tube used in the proximal portion has a greater cross-sectional area than the first outer tube. A proximal end structure is also described in which the intake and outlet tubes extend generally parallel with the main body and to one side of the main body.

1. A co-axial dual lumen catheter comprising:
 a main section having proximal and distal ends and including a first outer tube;  
 a tip section at said distal end;  
 an attachment at said proximal end for anchoring the catheter to a patient immediately adjacent an incision where the catheter entry is effected;  
 a U-shaped proximal portion having a distal end attached to the main section at said proximal end of the main section and having a proximal end, the proximal portion including a second outer tube;  
 a junction attached to the proximal end of the proximal portion;  
 an inner tube extending loosely inside the first and second outer tubes and anchored at the tip and the junction to define a return lumen and combining with the first and second outer tubes to define an annular intake lumen;  
 intake and outlet tubes attached to the junction, the tubes extending generally in parallel with the main section and to one side of the main section and being coupled to the respective intake and return lumens; and  
 the inner tube being thin walled relative to the wall thickness of the first outer tube, and the second outer tube having a greater cross-sectional area than the first outer tube.  
 
     
     
       2. A catheter as claimed in  claim 1  in which the attachment is a wing structure. 
     
     
       3. A catheter as claimed in  claim 1  in which the attachment is a cuff. 
     
     
       4. A catheter as claimed in  claim 1  in which the first outer tube defines intake openings providing access into the intake lumen, and the tip section is of smaller cross-section than the main section, the tip section having at least one return opening. 
     
     
       5. A catheter as claimed in  claim 4  and further comprising a transition portion at the distal end of the main section, the transition portion being formed of material provided in overlapping parts of the inner tube the tip section and the first outer tube, the inner tube being inside the tip section which is inside the first outer tube, the inner tube blending smoothly internally into the tip section at the transition portion and the outer tube blending smoothly externally into the tip section with the intake lumen ending at the transition portion, the tip section forming a continuation of the return lumen and the return lumen ending at said return opening. 
     
     
       6. A catheter as claimed in  claim 5  in which the inner tube and the first outer tube are spaced from one another radially where the intake lumen terminates. 
     
     
       7. A catheter as claimed in  claim 5  in which the transition portion is tapered smoothly to converge from the first outer tube to the tip section. 
     
     
       8. A catheter as claimed in  claim 4  in which the inner tube, first and second outer tubes and tip section are round in cross-section. 
     
     
       9. A catheter as claimed in  claim 8  in which the diameter of the tip section is greater than that of the inner tube and less than that of the first outer tube. 
     
     
       10. A co-axial dual lumen catheter comprising:
 a main section having proximal and distal ends and including a first outer tube, the first outer tube extending along a longitudinal axis and defining intake openings;  
 a U-shaped proximal section including a proximal and a distal end, said distal end of said U-shaped proximal section being attached to the proximal end of the main section, the proximal section including a second outer tubes ;  
 an inner tube extending through the first and second outer tubes; the inner tube defining a return lumen and combining with the first and second outer tubes to define an annular intake lumen;  
 intake and outlet tubes;  
 a junction coupling the intake and outlet tubes to the proximal section with the intake tube coupled for receiving blood from the intake lumen and the outlet tube coupled for delivering treated blood to the return lumen; and  
 the intake and outlet tubes leaving the junction generally parallel with the main section and to one side of the main section and with an angle of divergence between the intake and the outlet tubes of less than about 30 degrees and spaced substantially equally to either side of an extension of said  the longitudinal axis of said U-shaped proximal section at said proximal end thereof.  
 
     
     
       11. A catheter as claimed in  claim 10  in which the angle of divergence is about 15 to 20 degrees. 
     
     
       12. A catheter as claimed in  claim 10  in which the inner tube is located against the second outer tube inside the junction. 
     
     
       13. A co-axial dual lumen catheter for use in dialysis, the catheter comprising:
 a main section for insertion and having a selected cross-section;  
 a tip section of smaller cross-section than the selected cross-section and attached to a distal end of the main section;  
 a U-shaped proximal section extending from a proximal end of the main section and having a cross-section greater than said selected cross-section;  
 the main section having a first outer tube of a selected wall thickness and having said selected cross-section and the proximal section having a second outer tube having a wall thickness greater than said selected wall thickness;  
 an inner tube extending from the tip section through the first and second outer tubes and having a wall thickness less than said selected wall thickness whereby an intake lumen is defined in the space between the inner tube and the first and second outer tubes, and a return lumen is defined by the inner tube and the tip section; and  
 a junction coupled to the inner tube and the second outer tube to facilitate connecting the catheter to dialysis equipment.  
 
     
     
       14. A catheter as claimed in  claim 13  and further comprising a distal transition portion where the inner tube, tip section, and first outer tube of the main section meet, the  said transition portion presenting a smooth tapered outer surface to facilitate insertion. 
     
     
       15. A co-axial catheter as claimed in  claim 13  in which said junction includes intake and outlet tubes, the tubes being connected respectively to the intake and return lumens and lying generally parallel to the main section and to one side of the main section. 
     
     
       16. A catheter as claimed in  claim 13  in which the inner tube, first outer tube and tip section are round in cross-section. 
     
     
       17. A catheter as claimed in  claim 13  in which the tip section includes an opening at the distal end of the catheter. 
     
     
       18. A catheter as claimed in  claim 13  in which the inner tube and the first outer tube are spaced from one another concentrically where the intake lumen terminates. 
     
     
       19. A catheter as claimed in  claim 18  in which an end part of the inner tube is engaged inside a part of the tip section which in turn is engaged inside a part of the first outer tube to form a transition portion, and in which the transition portion is tapered smoothly to converge from the first outer tube to the tip section. 
     
     
       20. A dual lumen catheter as claimed in  claim 19  in which the tip section is more flexible than the main section. 
     
     
       21. A dual lumen catheter comprising:
   a main section having a proximal end and a distal end and comprising a first outer tube;        a tip section at said distal end of said main section;        a generally U-shaped proximal portion having a distal end and a proximal end, said distal end of said proximal portion being attached to said proximal end of the main section, and said proximal portion comprising a second outer tube;        a junction attached to said proximal end of said proximal portion;        an inner tube extending inside said first outer tube and said second outer tube and enclosing a return lumen, a first end of said inner tube being anchored at said tip section and a second end of said inner tube being anchored at said junction, said inner tube combining with said first outer tube and said second outer tube to define an annular intake lumen between said inner tube and said first and second outer tubes, each of said return lumen and said intake lumen communicating at the respective distal ends thereof with the exterior of said catheter.     
     
     
       22. A dual lumen catheter as recited in  claim 21 , further comprising an attachment structure secured between said proximal end of said main section and said distal end of said proximal portion, said attachment structure being capable of use for anchoring the catheter to the body of a patient immediately adjacent an incision through which said tip section and said main section of said catheter are entered into the body of the patient. 
     
     
       23. A dual lumen catheter as recited in  claim 21 , wherein the longitudinal axis of said proximal portion at said distal end thereof is parallel to the longitudinal axis of said proximal portion at said proximal end thereof. 
     
     
       24. A dual lumen catheter as recited in  claim 21 , wherein the cross section of said return lumen is circular. 
     
     
       25. A dual lumen catheter as recited in  claim 21 , further comprising:
   an inlet tube attached to said junction and coupled therethrough with said intake lumen at said proximal end of said proximal portion; and        an outlet tube attached to said junction and coupled therethrough with said return lumen at said proximal end of said proximal portion.     
     
     
       26. A dual lumen catheter as recited in  claim 25 , wherein said outlet tube and said inlet tube at said junction form an angle of divergence of less than about  30 °. 
     
     
       27. A dual lumen catheter as recited in  claim 25 , wherein said outlet tube and said inlet tube at said junction are disposed symmetrically on opposite sides of the longitudinal axis of said proximal portion at said proximal end thereof. 
     
     
       28. A dual lumen catheter as recited in  claim 21 , wherein the thickness of the wall of said inner tube is less than the thickness of the wall of said first outer tube. 
     
     
       29. A dual lumen catheter as recited in  claim 21 , wherein said second outer tube has an outer cross section that is greater than the outer cross section of said first outer tube. 
     
     
       30. A dual lumen catheter as recited in  claim 21 , wherein the outer surface of said tip section tapers radially inwardly to an end opening through which said return lumen communicates with the exterior of said catheter. 
     
     
       31. A dual lumen catheter as recited in  claim 30 , wherein a return opening is formed through the wall of said tip section proximal of said end opening thereof, said return lumen communicating through said return opening with the exterior of said catheter. 
     
     
       32. A dual lumen catheter as recited in  claim 21 , wherein an intake opening is formed through the wall of said first outer tube proximate said distal end of said main section, said intake lumen communicating through said intake opening with the exterior of said catheter. 
     
     
       33. A dual lumen catheter as recited in  claim 32 , wherein said intake lumen terminates distal of said intake opening. 
     
     
       34. A dual lumen catheter as recited in  claim 21 , wherein the outer cross section of said tip section is smaller than the outer cross section of said first outer tube. 
     
     
       35. A dual lumen catheter as recited in  claim 34 , further comprising a transition section located between said distal end of said main section and said tip section, the exterior of said transition portion tapering smoothly radially inwardly from said outer cross section of said first outer tube to said outer cross section of said tip section. 
     
     
       36. A dual lumen catheter as recited in  claim 21 , wherein said main section is substantially straight. 
     
     
       37. A dual coaxial lumen hemodialysis catheter, the catheter comprising:
   a main section for insertion into the body of a patient, said main section having a proximal end and a distal end, said main section comprising a first outer tube;        a tip section attached to said distal end of said main section, said tip section having a smaller outer cross section than the outer cross section of said first outer tube;        a generally U-shaped proximal portion extending from said proximal end of said main section, said proximal portion comprising a second outer tube; and        an inner tube extending from said tip section through said first outer tube and said second outer tube and enclosing a return lumen that communicates with the exterior of said catheter through said tip section, the space between said inner tube and said first outer tube and said second outer tube defining an intake lumen; and        wherein the outer cross section of said proximal portion is greater than the outer cross section of said first outer tube.     
     
     
       38. A dual lumen catheter comprising:
   a main section having a proximal end and a distal end;        a generally U-shaped proximal portion attached to said proximal end of said main section;        an inner tube extending through said main section and said proximal portion said inner tube defining a return lumen therewithin, and said inner tube combining with said main section and said proximal portion to define an intake lumen between said inner tube and said main section and said proximal portion;        a tip section at said distal end of said main section attached to a first end of said inner tube, the outer surface of said tip section tapering radially inwardly in a distal direction to an end opening through which said return lumen communicates with the exterior of said catheter; and        wherein the outer cross section of said proximal portion differs from the outer cross section of the main section.     
     
     
       39. A dual lumen catheter as recited in  claim 38 , wherein said outer cross section of said proximal portion is greater than said outer cross section of said main section. 
     
     
       40. A dual lumen catheter as recited in  claim 39 , further comprising a proximal transition portion intermediate said proximal portion and said main section, said proximal transition portion tapering radially inwardly in a distal direction smoothly interconnecting the outer surface of said proximal portion with the outer surface of said main section. 
     
     
       41. A catheter comprising:
   a main section having a proximal end and a distal end;        a generally U-shaped proximal portion attached to said proximal end of said main section;        a central conduit extending through said proximal portion and said main section and projecting distally beyond said distal end of said main section,        the portion of said central conduit projecting distally beyond said distal end of said main section defining a tip section projecting from said distal end of said main section and having a smaller outer cross section than the outer cross section of said main section at said distal end thereof,        said central conduit defining therewithin a return lumen, and        said central conduit in combination with said proximal portion and said main section defining an intake lumen between the exterior of said central conduit and the interiors of said proximal portion and said main section;        a distal transition portion at said distal end of said main section terminating the distal extent of said intake lumen and smoothly and continuously interconnecting the outer surface of said main section with the outer surface of said tip section;        attachment means on the distal end of said proximal portion for anchoring said catheter to the skin of a patient, when said main section and said tip section are implanted in the body of the patient;        a junction at the end of said proximal portion opposite from said main section; said junction being attached to the proximal end of said central conduit;        an inlet tube attached to said junction and coupled therethrough to said intake lumen; and        an outlet tube attached to said junction and coupled therethrough to said return lumen, said inlet tube and said outlet tube being positioned on a single side of said main section.     
     
     
       42. A cardiovascular access catheter comprising:
   an outer conduit having a distal end and a proximal end, a portion of said outer conduit adjacent said proximal end thereof being configured into a generally U-shaped proximal portion;        a central conduit extending through said outer conduit from said proximal end to said distal end thereof and projecting distally beyond said distal end of said outer conduit,        the portion of said central conduit projecting distally beyond said distal end of said outer conduit defining a tip section projecting from said distal end of said outer conduit and having a smaller outer cross section than the outer cross section of said outer conduit at said distal end thereof,        said central conduit defining therewithin a return lumen, and        said central conduit and said outer conduit defining an intake lumen between the exterior of said central conduit and the interior of said outer conduit;        a distal transition portion at said distal end of said outer conduit terminating the distal extent of said intake lumen and smoothly and continuously interconnecting the outer surface of said outer conduit at said distal end thereof with the outer surface of said tip section; and        means for affording fluid access individually to the proximal end of said return lumen and to the proximal end of said intake lumen.     
     
     
       43. A cardiovascular access catheter as recited in  claim 42 , wherein said means for affording access comprises:
   a junction interconnecting said proximal end of said outer conduit with said proximal end of said central conduit;        an inlet tube attached to said junction and coupled therethrough to said intake lumen; and        an outlet tube attached to said junction and coupled therethrough to said return lumen, said inlet tube and said outlet tube being generally parallel with the portion of said outer conduit distal of said U-shaped proximal portion, being disposed on a common side thereof, and being spaced substantially symmetrically to either side of the longitudinal axis of said proximal section at said proximal end thereof.