U.S. patent application number 12/826795 was filed with the patent office on 2011-01-06 for catheter having an expandable lumen and method of manufacture.
This patent application is currently assigned to TYCO HEALTHCARE GROUP LP. Invention is credited to Michael R. Sansoucy.
Application Number | 20110004197 12/826795 |
Document ID | / |
Family ID | 43413060 |
Filed Date | 2011-01-06 |
United States Patent
Application |
20110004197 |
Kind Code |
A1 |
Sansoucy; Michael R. |
January 6, 2011 |
Catheter Having an Expandable Lumen and Method of Manufacture
Abstract
A single or multiple lumen catheter is disclosed which includes
an expandable lumen. The expandable lumen is movable from a
collapsed or sealed configuration to an open or expanded
configuration. In the open configuration, the expandable lumen is
dimensioned to receive a guidewire or stylet or facilitate the
introduction of fluids into a patient.
Inventors: |
Sansoucy; Michael R.;
(Wrentham, MA) |
Correspondence
Address: |
TYCO HEALTHCARE GROUP LP
15 HAMPSHIRE STREET
MANSFIELD
MA
02048
US
|
Assignee: |
TYCO HEALTHCARE GROUP LP
Mansfield
MA
|
Family ID: |
43413060 |
Appl. No.: |
12/826795 |
Filed: |
June 30, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61222561 |
Jul 2, 2009 |
|
|
|
Current U.S.
Class: |
604/523 ;
264/166; 264/171.26; 264/209.1 |
Current CPC
Class: |
A61M 2025/0035 20130101;
A61M 25/0102 20130101; B29L 2031/7542 20130101; A61M 2025/0037
20130101; A61M 25/0009 20130101; B29C 48/9105 20190201; B29C 48/12
20190201; B29C 48/91 20190201; A61M 2025/0031 20130101; B29C 48/15
20190201; A61M 25/0026 20130101; B29C 48/001 20190201; B29C 48/912
20190201; B29C 48/21 20190201; A61M 2025/0025 20130101; A61M 25/09
20130101; B29C 48/10 20190201; B29C 48/11 20190201; D01D 5/24
20130101; A61M 2025/0024 20130101 |
Class at
Publication: |
604/523 ;
264/209.1; 264/166; 264/171.26 |
International
Class: |
A61M 25/00 20060101
A61M025/00; D01D 5/24 20060101 D01D005/24; B29C 47/08 20060101
B29C047/08 |
Claims
1. A catheter comprising: an elongated body having a proximal end
and a distal end and defining at least one lumen, the body
including a longitudinal slit which is expandable from a
substantially sealed configuration to an expanded configuration to
define an expandable lumen positioned adjacent the at least one
lumen.
2. The catheter according to claim 1, wherein the expandable lumen
is dimensioned to receive a guidewire in the expanded
configuration.
3. The catheter according to claim 1, wherein the expandable lumen
is configured to receive a stylet in the expanded
configuration.
4. The catheter according to claim 1, wherein the at least one
lumen includes a single lumen.
5. The catheter according to claim 4, wherein the expandable lumen
extends longitudinally along an inner wall of the elongated body
defining the single lumen.
6. The catheter according to claim 5, wherein the expandable lumen
is defined between the inner wall of the elongated body and a
resilient membrane.
7. The catheter according to claim 6, wherein the resilient
membrane is formed integrally with the elongated body.
8. The catheter according to claim 1, wherein the at least one
lumen includes a first lumen and a second lumen.
9. The catheter according to claim 8, wherein the elongated body
includes a longitudinal septum positioned between the first lumen
and the second lumen.
10. The catheter according to claim 9, wherein the longitudinal
slit extends along the longitudinal length of the septum, such that
when the longitudinal slit is in the expanded configuration, the
expandable lumen extends through the septum.
11. The catheter according to claim 10, wherein the septum is
positioned substantially along the diameter of the elongated
body.
12. The catheter according to claim 1, wherein the catheter is
formed of a first material having a first coefficient of friction
and a second material having a second coefficient of friction which
is less than the first coefficient of friction, at least a portion
of the elongated body defining the slit being formed of the second
material.
13. The catheter according to claim 8, wherein the first lumen and
the second lumen are substantially D-shaped.
14. A method of manufacturing a multi-lumen catheter, the method
comprising the following steps: i) extruding a catheter body having
a first lumen and a second lumen and a septum separating the first
lumen from the second lumen, the septum including a removable
material positioned within and extending along the length of the
septum, wherein the septum is extruded from an elastomeric
material; and ii) removing the removable material from the septum
to define a slit which extends through the septum along the length
of the septum, the slit being expandable to define a third
lumen.
15. The method according to claim 14, wherein the step of removing
the removable material from the septum includes pulling the
removable material from the septum.
16. The method according to claim 14, wherein the removable
material is a dissolvable or degradable material and the step of
removing the removable material from the septum includes exposing
the catheter to a solvent to dissolve or degrade the removable
material within the septum.
17. The method according to claim 16, further including the
following step: iii) flushing the third lumen to remove the
dissolved/degraded material from the third lumen.
18. A method of manufacturing a multi-lumen catheter, the method
comprising the following steps: i) extruding a catheter body having
a first lumen and at least one additional lumen, the catheter body
being formed of a first material having a first melting
temperature; providing a second material on an inner surface of the
first lumen, the second material having a melting temperature
greater than the first material; directing a fluid through the at
least one additional lumen to move the first lumen to a collapsed
configuration; melting the first material without melting the
second material while the first lumen is in the collapsed
configuration; and cooling the first material to allow the first
material to set with the first lumen in the collapsed
configuration.
19. The method according to claim 18, wherein the at least one
additional lumen includes second and third lumens.
20. The method according to claim 19, wherein the step of extruding
a catheter body includes providing a septum between the second and
third lumens, the first lumen extending through the septum.
21. A method of manufacturing a multi-lumen catheter, the method
comprising the following steps: i) extruding a catheter body having
a first lumen, a second lumen, and a third lumen positioned between
the first and second lumens and extending through a septum of the
catheter body, the catheter body being formed of a first material
having a first melting temperature; providing a layer of second
material on an inner surface of the catheter body defining the
first and second lumens, the second material having a melting
temperature lower than the first material; directing a fluid
through the first and second lumens to move the third lumen to a
collapsed configuration; melting the second material without
melting the first material while the third lumen is in the
collapsed configuration; and cooling the second material to allow
the second material to set with the third lumen in the collapsed
configuration.
22. A method of manufacturing a multi-lumen catheter, the method
comprising the following steps: i) extruding a catheter body from a
first material, the catheter body having a first lumen, a second
lumen, and a septum positioned between the first and second lumens;
and ii) positioning a flat tube extending longitudinally through
the septum during the extrusion step.
23. The method according to claim 22, wherein the extruding step
does not include melting the flat tube.
24. The method according to claim 20, wherein the flat tube is
formed from a second material which has enhanced lubricity as
compared to the first material forming the catheter body.
25. The method according to claim 20, further including the
following step: iii) forcing a fluid through the hollow tube to
expand the hollow tube.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to U.S.
Provisional patent application Ser. No. 61/222,561 filed Jul. 2,
2009, the entire contents of which is incorporated by reference
herein.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates to a medical catheter and,
more particularly, to a medical catheter including an expandable
lumen.
[0004] 2. Background of Related Art
[0005] Catheters for supplying and/or withdrawing fluids into
and/or from the body are well known in the art. Such catheters may
be employed for medication delivery, urine removal, blood
treatment, e.g., dialysis, etc. In the area of dialysis, single,
double and triple lumen catheters are well known. Typically, double
or dual lumen dialysis catheters define an arterial lumen and a
venous lumen for simultaneously withdrawing and returning blood
from and to the body. A pair of single lumen catheters can be used
to achieve the same function. Triple lumen catheters generally
include arterial and venous lumens and a guidewire lumen. The
guidewire lumen is provided to accommodate a guidewire to
facilitate catheter placement within the body and/or facilitate
delivery of a medical fluid into the body.
[0006] One drawback associated with providing a guidewire lumen
within a catheter is that the inclusion of a guidewire lumen
effectively reduces the cross-sectional area available to
accommodate the remaining lumen or lumens. Thus, the maximum fluid
flow rate in the remaining lumen or lumens of the catheter as
compared to a catheter not having a guidewire lumen is reduced.
[0007] Accordingly, a continuing need exists in the medical arts
for a catheter including a guidewire lumen with improved flow rates
through the existing lumen or lumens.
SUMMARY
[0008] The present disclosure relates to a catheter comprising an
elongated body having a proximal end and a distal end and defining
at least one lumen. The body includes a longitudinal slit which is
expandable from a substantially sealed configuration to an expanded
configuration to define an expandable lumen positioned adjacent the
at least one lumen. The expandable lumen is dimensioned to receive
a guidewire and/or a stylet in the expanded configuration. In one
embodiment, the catheter includes a single lumen and the expandable
lumen extends longitudinally along an inner wall of the elongated
body defining the single lumen.
[0009] In one embodiment, the expandable lumen is defined between
the inner wall of the elongated body and a resilient membrane. The
resilient membrane may be formed integrally with the elongated
body. Alternatively, the resilient membrane may be secured to the
inner wall of the elongated body using for example, adhesives or
welding.
[0010] In an alternative embodiment, the at least one lumen
includes a first lumen and a second lumen and a longitudinal septum
positioned between the first lumen and the second lumen. In this
embodiment, the longitudinal slit extends through the septum such
that when the longitudinal slit is in the expanded configuration,
the expandable lumen extends through the septum. The septum can be
positioned substantially along the diameter of the elongated body
such that the first lumen and the second lumen are substantially
D-shaped. Alternatively, the septum may be positioned to define
first and second lumens which have different cross-sectional
areas.
[0011] The catheter may be formed of a first material having a
first coefficient of friction and a second material having a second
coefficient of friction which is less than the first coefficient of
friction, wherein at least a portion of the elongated body defining
the slit is formed of the second material.
[0012] The present disclosure also relates to a method of
manufacturing a multi-lumen catheter, comprising the following
steps:
[0013] i) extruding a catheter body having a first lumen and a
second lumen and a septum separating the first lumen from the
second lumen, the septum including a removable material positioned
within and extending along the length of the septum, wherein the
septum is extruded from an elastomeric material; and
[0014] ii) removing the removable material from the septum to
define a slit which extends through the septum along the length of
the septum, the slit being expandable to define a third lumen.
[0015] In one embodiment, the step of removing the removable
material from the septum includes pulling the removable material
from the septum. In another embodiment, the removable material is a
dissolvable or degradable material and the step of removing the
removable material from the septum includes exposing the catheter
to a solvent to dissolve or degrade the removable material within
the septum. This method may also include the step of flushing the
third lumen to remove the dissolved/degraded material from the
third lumen.
[0016] In an alternative method of manufacturing a multi-lumen
catheter, the method comprises the following steps:
[0017] i) extruding a catheter body having a first lumen, a second
lumen, and a third lumen positioned between the first and second
lumens and extending through a septum of the catheter body, the
catheter body being formed of a first material having a first
melting temperature;
[0018] ii) providing a layer of a second material on an inner
surface of the septum defining the third lumen, the second material
having a melting temperature greater than the first material;
[0019] iii) directing a fluid through the first and second lumens
to move the third lumen to a collapsed configuration;
[0020] iv) melting the first material without melting the second
material while the third lumen is in the collapsed configuration;
and
[0021] v) cooling the first material to allow the first material to
set with the central lumen in the collapsed configuration.
[0022] In yet another embodiment of the method of manufacturing a
multi-lumen catheter, the method comprises the following steps:
[0023] i) extruding a catheter body having a first lumen, a second
lumen, and a third lumen positioned between the first and second
lumens and extending through a septum of the catheter body, the
catheter body being formed of a first material having a first
melting temperature;
[0024] ii) providing a layer of second material on an inner surface
of the catheter body defining the first and second lumens, the
second material having a melting temperature lower than the first
material;
[0025] iii) directing a fluid through the first and second lumens
to move the third lumen to a collapsed configuration;
[0026] iv) melting the second material without melting the first
material while the third lumen is in the collapsed configuration;
and
[0027] v) cooling the second material to allow the second material
to set with the central lumen in the collapsed configuration.
[0028] In yet another embodiment of the method of manufacturing a
multi-lumen catheter, the method comprises the following steps:
[0029] i) extruding a catheter body having a first lumen, a second
lumen, a septum positioned between the first and second lumens, and
a hollow tube extending longitudinally through the septum; and
[0030] ii) forcing a fluid through the hollow tube to expand the
hollow tube.
In this embodiment, the extruding step does not include melting the
hollow tube. The hollow tube may be formed from a material which
has enhanced lubricity as compared to a material forming the
septum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Various embodiments of the presently disclosed catheter with
expandable lumen and methods of manufacturing such a catheter are
disclosed herein with reference to the drawings, wherein:
[0032] FIG. 1 is a side perspective view of one embodiment of the
presently disclosed catheter with expandable lumen;
[0033] FIG. 1A is a front view from the distal end of the catheter
shown in FIG. 1 with the lumen in a sealed configuration;
[0034] FIG. 2 is a front view from the distal end of the catheter
shown in FIG. 1 with the lumen in an expanded configuration and a
guidewire extending through the lumen;
[0035] FIG. 3 is a side perspective view from the distal end of
another embodiment of the presently disclosed catheter with
expandable lumen;
[0036] FIG. 4 is a front view of the distal end of the catheter
shown in FIG. 3 with the expandable lumen in a sealed
configuration;
[0037] FIG. 5 is a front view of the distal end of the catheter
shown in FIG. 4 with the expandable lumen in an expanded
configuration.
[0038] FIG. 6 is a front view of another embodiment of the
presently disclosed catheter with expandable lumen with the lumen
in an expanded configuration and a guidewire positioned within the
lumen;
[0039] FIG. 7 is a cross-sectional view of the catheter shown in
FIG. 6 with the lumen in an expanded configuration and a stylet
positioned within the lumen;
[0040] FIG. 8 is a front view of an extruded catheter body, during
a first manufacturing process, having a removable material
positioned through a septum of the catheter body;
[0041] FIG. 9 is a front view of an extruded catheter body, during
an alternative manufacturing process, with the expandable lumen
extruded in an expanded configuration in the septum to define a
lumen through the septum;
[0042] FIG. 10 is a front view of the extruded catheter body shown
in FIG. 9 after the expandable lumen has been collapsed and the
catheter has been heated to retain the collapsed configuration of
the expandable lumen;
[0043] FIG. 11 is a front view of an extruded catheter body during
another alternative manufacturing process with the expandable lumen
in an expanded configuration and a second material positioned on
inner walls of the catheter body defining first and second lumens
of the catheter body;
[0044] FIG. 12 is a front view of the catheter body shown in FIG.
11 after the expandable lumen has been collapsed during the
manufacturing process and the second material has been heated and
cooled to retain the expandable lumen in the collapsed
configuration; and
[0045] FIG. 13 is a front view of a catheter body having first and
second lumens and an expandable central lumen which is coated with
a material of enhanced lubricity.
DETAILED DESCRIPTION OF EMBODIMENTS
[0046] Embodiments of the presently disclosed catheter having an
expandable lumen and methods for manufacturing the catheter will
now be described in detail with reference to the drawings wherein
like reference numerals designate identical or corresponding
elements in each of the several views.
[0047] The exemplary embodiments of the catheter disclosed herein
are discussed in terms of medical catheters for the administration
of fluids (withdrawal or introduction) relative to the body of a
subject and, more particularly, in terms of a hemodialysis
catheter. However, it is envisioned that the present disclosure may
be employed with a range of catheter applications including
surgical, diagnostic and related treatments of diseases and body
ailments of a subject. It is further envisioned that the principles
relating to the catheter disclosed include employment with various
catheter related procedures, such as, for example, hemodialysis,
cardiac, abdominal, urinary, intestinal, and in chronic and acute
applications. Moreover, the catheter can be used for administration
of fluids such as, for example, medication, saline, bodily fluids,
blood and urine.
[0048] In the discussion that follows, the term "proximal" or
"trailing" will refer to the portion of a structure that is closer
to a clinician, while the term "distal" or "leading" will refer to
the portion that is further from the clinician. As used herein, the
term "subject" refers to a human patient or other animal. The term
"clinician" refers to a doctor, nurse or other care provider and
may include support personnel.
[0049] FIGS. 1-2 illustrate one embodiment of the presently
disclosed catheter with expandable lumen shown generally as 10.
Catheter 10 includes an elongated body 12 having a proximal end 12a
and a distal end 12b. Elongated body 12 defines a lumen 13 which
extends from proximal end 12a of elongated body 12 to the distal
end 12b of elongated body 12. A longitudinal slit 16 is defined
along the length of body 12 between body 12 and a resilient
membrane 18. Membrane 18 can be formed integrally with elongated
body 12 or, alternatively, can be formed separately from and
secured to body 12 using conventional techniques, e.g., welding,
adhesives, etc. Resilient membrane 18 is positioned along body 12
to define an expandable lumen 20 (FIG. 2) which is dimensioned to
receive a stylet (FIG. 7) or guidewire 22 (FIG. 2) or facilitate
introduction or removal of fluid, e.g., medication, contrasting
agent, saline, etc., through the catheter 10. As illustrated in
FIG. 1A, in its normal or collapsed configuration, membrane 18 is
positioned adjacent an inner wall 24 of catheter 10. Thus, when
membrane 18 is in its collapsed configuration, substantially the
full diameter of lumen 14 is available for fluid flow and the fluid
flow rate at a given pressure for a catheter having a specified
diameter can be maximized.
[0050] FIGS. 3-5 illustrate another embodiment of the presently
disclosed catheter with expandable lumen shown generally as 100.
Catheter 100 includes an elongated body 112 having a proximal end
112a and a distal end 112b. A pair of lumens 114a and 114b extend
from the proximal end 112a to the distal end 112b of body 112. A
septum 116 extends along the length of elongated body 112 between
lumens 114a and 114b. Although septum 116 is illustrated as being
positioned along the diameter of body 112 to define two lumens of
substantially equal cross-sectional area, it is envisioned that the
septum 116 can be positioned to define two lumens of unequal
cross-sectional areas.
[0051] Catheter 100 may be made of any suitable material. In
certain embodiments, catheter 10 is formed of polyurethane, such as
an aliphatic or aromatic polyurethane. However, catheter 100 may be
made of any suitable polymer such as thermoplastic, polyolefin,
fluoropolymer (such as fluorinated ethylene propylene ("FEP"),
polytetrafluoroethylene PEFE, perfluoroalkoxy ("PFA")
polyvinylidene fluoride (PVDF)), polyvinyl chlorideneoprene PVC,
silicone elastomer of fluoroelasatomers (such as copolymers of
hexafluoropropylene (HFP) and vinylidene fluoride (VDF or VF2),
terpolymers of tetrafluoroethylene (TFE), vinylidene fluoride (VDF)
and hexafluoropropylene (HFP), and perfluoromethylvinylether
(PMVE).
[0052] Referring particularly to FIGS. 4 and 5, a slit 118 is
defined along the length of septum 116. Septum 116 is formed of an
elastomeric material, such that the slit is expandable from a
closed or substantially closed or collapsed configuration (FIG. 4)
to an expanded or open configuration (FIG. 5). in the expanded or
open configuration, the slit 118 defines a third lumen 120 which
can be dimensioned to receive a guidewire 122 (FIG. 6) or to
facilitate introduction or removal of fluid, e.g., medication,
contrasting agent, saline, etc. into a patient.
[0053] FIGS. 6 and 7 illustrate front and cross-sectional views of
another embodiment of the presently disclosed catheter shown
generally as 200. Catheter 200 is substantially similar to catheter
100 and includes an elongated body 212 including a septum 216
defining a pair of lumens 214a and 214b. Septum 216 includes an
expandable slit 218 which is expandable from a closed configuration
(not shown) to an open or expanded configuration (FIGS. 6 and 7) to
define a third lumen 220. Catheter 200 differs from catheter 100 in
that at least a portion of septum 216 defining slit 218 of catheter
200 is formed of a second material different from the material used
to form catheter 200. More specifically, although it is desirable
to form elongated body 212 from a soft elastomeric material, the
coefficient of friction associated with soft elastomeric materials
may render guidewire or stylet insertion through the expandable
slit 218 difficult. As such, septum 216 or at least a portion of
septum 216 defining the slit 218 can be formed of a second material
having a lower coefficient of friction than the elongated body 212
of catheter 200. In one embodiment, the slit 218 is defined by a
layer, liner or coating 222 of the second material having a lower
coefficient of friction than the body 212 of the catheter 200.
Alternatively, the entire septum 216 or portions of septum 216 can
be formed of the second material. Yet further, during an extrusion
process used to form the body 212, a layer, liner or coating 222
can be employed having a higher melting temperature than the
material used to form body 212, thereby ensuring the slit 218 does
not adhere to itself, such as by melting, during the manufacturing
process.
[0054] As illustrated in FIGS. 6 and 7, slit 218 can be dimensioned
to receive a guidewire 225 (FIG. 6) and/or a stylet 226 (FIG. 7)
when slit 218 is in its expanded or open configuration. Stylet 226
may include a guidewire lumen 228 and may be formed of a material
having a low coefficient of friction to facilitate stylet insertion
through the slit 218.
[0055] A catheter having a septum including an expandable slit 216,
or third lumen 120, can be manufactured in a variety of different
ways. Referring to FIG. 8, in one presently disclosed embodiment,
catheter body 312 of catheter 300 is extruded of a first material,
e.g., silicone, polyurethane, or other soft polymeric material,
with a second removable material 330 positioned within the septum
316 to define the slit 318. (Extrusion is a manufacturing process
known in the art in which a material is forced through an orifice
of a die to form an object having a desired cross-section). The
extruded catheter body 312 defines a first lumen 314a and a second
lumen 314b. For example, in one embodiment, the removable material
330 can be tailored to neck-down or shrink when a tensile force is
applied, wherein a tensile force applied to the removable material
330 can be effective in removing the removable material 330 from
the catheter body 312 and forming the slit 318. In yet another
embodiment, after catheter body 312 is extruded, catheter body 312
can be exposed to a solvent capable of swelling the first material
in which the catheter body 312 is constructed, such as by a dipping
process, to effect swelling of the catheter body 312. Thereafter,
removable material 330 is pulled from septum 316 to provide a slit
through septum 316. Most flexible polymer materials neck-down or
shrink when a tensile force is applied and therefore could be used
in the application described above. To be even more specific,
polymers such as polyurethanes, polyethylenes, polypropylenes,
polyvinyichlorides, polyacetal, and so forth, as well as
combinations comprising multiple polymer systems or blends can be
employed. Also, to one skilled in the art, it is to be apparent
that the specific solvent, or chemical employed to induce swelling
to the catheter body 312 can be numerous and should be suited to
the specific polymer employed such that a majority of the physical
properties are retained once the solvent has evaporated from the
catheter. In one specific example, isopropyl alcohol can be
employed to swell an aliphatic polyurethane sufficiently to pull
out removable material 330.
[0056] Referring again to FIG. 8, alternatively, the second
removable material 330 may include a degradable/dissolvable
material positioned within septum 316 to define slit 318. The
degradable/dissolvable material 330 can be a starch based material
or other known degradable or dissolvable material. After the
extrusion process, catheter 300 can be exposed to a solvent which
causes the degrading or dissolving of the material 330 to define
slit 318. After exposure to the solvent, the expandable lumen
defined by slit 318 can be flushed to remove the degraded or
dissolved material from the expandable lumen.
[0057] Referring to FIGS. 9 and 10, in another embodiment of the
presently disclosed manufacturing process, catheter body 412 of
catheter 400 is extruded from a first material 430 with three
district lumens 414a, 414b and 414c, wherein central lumen 414c
(FIG. 9) is defined through septum 416 (FIG. 9). A thin layer of a
second material 432 having a higher melting temperature than the
first material is provided within septum 416 to define central
lumen 414c. Second material 432 can be provided on the inner
surface of septum 416 during the extrusion process or,
alternatively, after the extrusion process. Next, catheter 400 is
positioned within an outer mold and a heated fluid (air, liquid) is
forced through lumens 414a and 414b at equal pressure such that the
area of the central lumen 414c is decreased, i.e., the central
lumen 414c collapses (FIG. 10). The first material is then melted
using the heated fluid or other heat source at a temperature which
will not melt or render the second material tacky. Thereafter, the
first material is cooled to allow the first material to set with
the central lumen 414c having a decreased area or collapsed
configuration (FIG. 10).
[0058] In yet another embodiment of the presently disclosed
manufacturing process, shown in FIGS. 11 and 12, catheter body 512
of catheter 500 is extruded with a first material 528 defining
catheter body 512 and a second material 530 covering the inner
walls of body 512 defining first and second lumens 514a and 514b.
The second material 530 is selected to have a melting temperature
lower than the first material 528. A central lumen 514c of catheter
body 512 is extruded in an expanded orientation. The extruded
catheter 500 (FIG. 11) is placed in an outer mold (not shown) and a
heated fluid is forced through lumens 514a and 514b of body 512 to
collapse central lumen 514c to define slit 518. The catheter 500 is
then heated above the melting temperature of the second material
530 but below the melting temperature of the first material 528. A
fluid can be used to collapse slit 518 and a second heating
technique can be used to heat the second material 530 above its
melting temperature. Alternatively, the fluid can be used to both
collapse and heat the catheter body 512. Thereafter, the second
material 530 is cooled and allowed to set to provide a catheter
body 512 having a closed or collapsed slit 518 (FIG. 12).
[0059] Referring to FIG. 13, an additional step can be performed
with respect to each of the above-identified processes to provide
enhanced lubricity or ease of manufacture to the central lumen.
More specifically, inner walls of septum 616 defining central lumen
or slit 618 can be covered with a third material having a low
coefficient of friction or enhanced lubricity or differing physical
or thermal properties (e.g., higher melting temperature). In one
embodiment, the catheter body 612 is extruded with a hollow tube
634 positioned within a die (not shown) to define slit 618 through
septum 616. Hollow tube 636 is not melted during the extrusion
process such that a liquid can be forced through hollow tube 636 to
open slit 618. Ribbon 636 can be formed from polyethylene
terephtalate (PET), polybutylene terephtalate (PBT), FEP, PTFE, or
other polymer which will not become tacky or melt at the
temperatures reached by the polymer melt employed to form the
catheter body 612.
[0060] Although specific features of the disclosure are shown in
some drawings and not in others, this is for convenience only as
each feature may be combined with any or all of the other features
in accordance with the disclosure.
[0061] It will be understood that various modifications may be made
to the embodiments disclosed herein. For example, the various
manufacturing processes disclosed to manufacture dual lumen
catheters with expandable lumens may also be used to form a single
lumen catheter with an expandable lumen where applicable.
Therefore, the above description should not be construed as
limiting, but merely as exemplifications of embodiments. Those
skilled in the art will envision other modifications within the
scope and spirit of the claims appended hereto.
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