Reinforced multi-lumen catheter

Abstract

A reinforced multi-lumen catheter and method of manufacturing the same. An assembly for manufacturing the multi-lumen catheter includes a catheter body substrate including a septum, one or more mandrels, a reinforcing element and one or more sleeves. The septum may have a distal region with a cross-sectional thickness greater than that of a proximal region. The septum can be separately formed. The septum can be split along a length of the distal region. The reinforcing element can be positioned over at least a proximal region of the catheter body substrate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 533,683, filed Dec. 31, 2003, which is expressly incorporated by reference as if fully set forth herein.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not applicable. REFERENCE TO A COMPACT DISK APPENDIX [0003] Not applicable. BACKGROUND OF THE INVENTION [0004] Multi-lumen catheters are used for the purpose of creating two or more separate fluid pathways, such as in hemodialysis applications. A primary goal of hemodialysis access is to provide a reliable and effective means of dialysis, which means that a sufficient volume of blood over a period of time must be removed from and returned to the patient. Because the contaminated and cleansed blood must be kept separate for an effective dialysis procedure, a dual lumen catheter is generally used. Typically, a dual lumen catheter for hemodialysis is configured so that there is a shorter lumen ...

AI Technical Summary

Benefits of technology

[0014] In one embodiment, a multi-lumen catheter is provided with a septum having a cross-sectional thickness in a distal region that is greater than a cross-sectional thickness in a proximal region. The difference in septum thickness is provided to enhance functionability particular to the proximal and distal end of the catheter. Thus, the proximal region of the catheter will generally be constructed with a relatively thin septum to allow for better overall flow performance, while the distal region of the catheter will generally be constructed with a relatively thick septum to allow the catheter to be split and tipped in a secondary production procedure, which provides numerous manufacturing advantages. In particular, the septum distal region may be cut using a razor or other tool once the catheter has been constructed. In order to impart additional kink resistance and support to the septum proximal region, a reinforcing region may be provided over the outer wall of the catheter along at least a portion of the length of the septum proximal region. One noted advantage to such a design is that a catheter can be provided with different lumen cross-sectional areas along the length of the catheter without altering the catheter outer diameter, thereby minimizing the risk of air embolism during placement of the catheter through an introducer sheath when compared with a catheter in which the outer diameter varies along with the variation of lumen cross-sectional area.

[0017] In yet another manufacturing variation of the present invention, a reinforced split-tip catheter can be constructed utilizing a proximal dual lumen substrate and two separate D-shaped lumen substrates. Two D-shaped mandrels are placed through the lumens of the proximal substrate and into the proximal end of the distal substrates. The proximal and distal substrates are brought into contact with one another and a reinforcing element is disposed over the proximal substrate (and may overlap onto the distal substrate to fortify the bond between the proximal and distal substrates). A sleeve is then placed over the assembly, extending to a point proximal the distal end of the D-shaped lumen substrates and shrink tubing is placed over the sleeve. Heat is applied, causing the sleeve to melt onto the substrates and causing the inner lumens to conform to the mandrel shapes. The shrink tubing is then removed. The separate D-shaped lumen substrates should already be separated over their length distal to where the sleeve and shrink tubing extended and thus, further separation tipping procedures are not necessary. However, refinement of the tips and / or other finishing processing is possible.

[0018] It should be noted that the tensile strength of the bond between thick and thin septum sections may be improved by moving the bond to a location beneath the reinforcing element, meaning that the transition from thin to thick septum portion occurs within the reinforcing region in the above-described variations. This improved bond strength may be particularly useful in the case where two D-shaped lumen substrates are bonded onto a proximal dual lumen substrate.

[0020] In one manufacturing variation of the present invention, an independently formed septum is inserted into a lumen of a cylindrical tube that has been provided with a reinforcing element. There are various ways to assure that the septum and the tube fit tightly together prior to bonding. In one variation, a longitudinal strain can be applied to the septum during insertion in order to temporarily reduce the cross sectional area of the septum. Once the septum is in position within a lumen of the outer tube, the tension is released, allowing the septum to expand. The reinforcing element prevents the cylindrical tube from being deformed into an oval cross-sectional shape when the septum is allowed to expand. In another variation, the inner surface of the outer tube is modified (e.g., a notch or recessed area is provided) to accommodate the septum so that insertion thereof is facilitated without affecting the cross-sectional shape of the cylindrical tube. The septum is bonded to the cylindrical tube by chemical (e.g., solvent bonding), ultrasonic, heat-shrink, or other methods known to one of skill in the art.

Problems solved by technology

The primary problems occurring in dual lumen dialysis catheters include thrombosis and fibrin sheath formation, which can act to occlude distal tips of the dialysis catheter lumens, resulting in loss of catheter function when such an occlusion prevents blood flow.

A secondary problem relates to the arterial lumen “sucking” against the vessel wall, in which the arterial lumen openings become fully occluded by the patient's vasculature.

While the split-tip catheter design has led to improved functioning of dialysis catheters, it has been difficult to manufacture a split-tip catheter having reinforcement along a length thereof due to the change in configuration at the distal end.

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