Dialysis catheter tip and method of manufacture

1 . A multi-lumen catheter comprising:

a first lumen extending through the catheter to a first distal opening;

a second lumen extending through the catheter to a second distal opening which is distal to the first distal opening so that an extending portion of a septum separating the lumens extends distally past the first distal opening; and

a tip overmolded on the extending portion, the tip including a first ramp adjacent to the first distal opening and a second ramp adjacent to the second distal opening, the ramps directing fluids exiting the openings away from a longitudinal axis of the catheter.

2 . The catheter according to claim 1 , wherein the first distal opening opens at a first angle relative to the septum and the second distal opening opens at a second angle relative to the septum.

3 . The catheter according to claim 2 , wherein the first angle is approximately 45 degrees and the second angle is approximately 225 degrees.

4 . The catheter according to claim 1 , wherein the first ramp projects at a first angle relative to the septum and the second ramp projects at a second angle relative to the septum.

5 . The catheter according to claim 4 , wherein the first angle is between approximately 150 and 175 degrees relative to the septum and the second angle is between approximately 185 and 210 degrees relative to the septum.

6 . The catheter according to claim 1 , wherein a cross-sectional area of an extension portion of the second lumen distal of the first distal opening is increased relative to a cross-sectional area of a portion of the second lumen proximal to the first distal opening.

7 . The catheter according to claim 6 , wherein the extension portion is defined by the extending portion of the septum and an outer wall of the catheter, and wherein the extending portion of the septum angles radially outward from a longitudinal axis of the second lumen to increase the cross-sectional area of the extension portion.

8 . The catheter according to claim 6 , wherein at least portions of the tip are formed integrally with a body of the catheter.

9 . A method of forming a distal tip for a multi-lumen catheter comprising:

providing a catheter with a first lumen extending through the catheter to a first distal opening and a second lumen extending through the catheter to a second distal opening distal to the first distal opening so that an extending portion of a septum separating the lumens extends past the first distal opening; and

overmolding on the extending portion a tip including a first ramp adjacent to the first distal opening and a second ramp adjacent to the second distal opening, the first ramp directing fluids from the first distal opening at a first angle relative to a longitudinal axis of the catheter and the second ramp directing fluids exiting the second distal opening at a second angle relative to the longitudinal axis of the catheter.

10 . The method according to claim 9 , further comprising:

creating the first distal opening by removing at a third angle α first portion of a catheter wall surrounding the first lumen; and

creating the second distal opening by removing at a fourth angle α second portion of the catheter wall surrounding the second lumen.

11 . The method according to claim 10 , wherein the third angle is approximately 45 degrees relative to the septum and the fourth angle is approximately 225 degrees relative to the septum.

12 . The method according to claim 10 , further comprising:

expanding the second distal opening so that a cross-sectional area thereof is larger than a cross-sectional area of the second lumen, while maintaining a cross-sectional area of the tip substantially constant.

13 . The method according to claim 12 , wherein the first ramp projects at the first ramp angle relative to the septum and the second ramp projects at the second ramp angle relative to the septum.

14 . The method according to claim 13 , wherein the first angle is between approximately 150 and 175 degrees relative to the septum and the second angle is between approximately 185 and 210 degrees relative to the septum.

15 . The method according to claim 9 , wherein the tip is bonded to the extending portion by one of a mechanical fitting, a friction fitting, chemical bonding and thermal bonding.

16 . The method according to claim 9 , wherein the first distal opening is separated from the second distal opening by about 1.0 cm to 1.5 cm.

17 . A multi-lumen catheter comprising:

a first lumen extending through the catheter to a first distal opening;

a second lumen extending through the catheter to a second distal opening which is distal to the first distal opening so that an extending portion of a septum separating the lumens extends distally past the first distal opening;

a tip formed on the extending portion, the tip including a first ramp adjacent to the first distal opening and a second ramp adjacent to the second distal opening, the ramps directing fluids exiting the openings away from a longitudinal axis of the catheter; and

a pair of side walls disposed on an exposed area of the extending portion between the first distal opening and the first ramp.

18 . The catheter according to claim 17 , wherein the tip is overmolded on the extending portion.

19 . The catheter according to claim 17 , wherein the first distal opening is formed at a predetermined angle relative to the extending portion.

20 . The catheter according to claim 19 , wherein the angle is approximately 45 degrees.

21 . The catheter according to claim 20 , wherein proximal top edges of the side walls meet the first distal opening proximal to a junction of the tip and the extending portion.

22 . The catheter according to claim 21 , wherein distal top edges of the side walls meet the tip when the tip has ascended from the extending portion to an amount equal to a height of the side walls.

23 . The catheter according to claim 17 , wherein the side walls extend from the septum between approximately 0.015 and 0.035 inches.