U.S. patent application number 10/445731 was filed with the patent office on 2004-12-02 for methods and apparatus for inserting multi-lumen spit-tip catheters into a blood vessel.
Invention is credited to Albrecht, Stephen E., Anand, PJ., Nimkar, Shekhar, Tobin, Eric.
Application Number | 20040243095 10/445731 |
Document ID | / |
Family ID | 33450923 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040243095 |
Kind Code |
A1 |
Nimkar, Shekhar ; et
al. |
December 2, 2004 |
Methods and apparatus for inserting multi-lumen spit-tip catheters
into a blood vessel
Abstract
Methods and apparatus are disclosed for inserting flexible,
multi-lumen catheters into blood vessels, and in particular, for
inserting flexible, split-tip catheters into blood vessels. The
invention accomplishes these objects by temporarily stiffening each
catheter lumen and tip independently through use of intra-catheter
stiffener elements disposed within the catheter lumens. This
provides means for advancing the catheter/stiffeners assembly
through a subcutaneous tunnel, and over a plurality of guidewires
until a distal tip of the catheter is at a desired position within
the vessel. The intra-catheter stiffener elements are sufficiently
stiffening to allow advancing the catheter over guidewires, but
sufficiently flexible to allow bending and looping of the catheter
for proper placement within the vessel.
Inventors: |
Nimkar, Shekhar;
(Swampscott, MA) ; Albrecht, Stephen E.; (South
Walpole, MA) ; Anand, PJ.; (Acton, MA) ;
Tobin, Eric; (North Andover, MA) |
Correspondence
Address: |
NUTTER MCCLENNEN & FISH LLP
WORLD TRADE CENTER WEST
155 SEAPORT BOULEVARD
BOSTON
MA
02210-2604
US
|
Family ID: |
33450923 |
Appl. No.: |
10/445731 |
Filed: |
May 27, 2003 |
Current U.S.
Class: |
604/500 |
Current CPC
Class: |
A61M 25/09 20130101;
A61B 17/3415 20130101; A61M 25/0102 20130101; A61M 1/16 20130101;
A61M 29/00 20130101; A61M 25/0194 20130101; A61M 25/0026
20130101 |
Class at
Publication: |
604/500 |
International
Class: |
A61M 031/00 |
Claims
What is claimed is:
1. A method for inserting a multi-lumen catheter into a blood
vessel comprising: inserting a distal portion of each of a
plurality of guidewires into a vessel at a first location;
inserting an intra-catheter stiffening element into a proximal end
of each lumen of a multi-lumen catheter, the catheter having a
distal portion for placement in the vessel and a proximal end for
connection to a treatment device and further having a plurality of
lumens; threading a proximal end of each of the guidewires through
a distal end of a respective intra-catheter stiffening element
until said guidewire exits the proximal end of the catheter;
advancing the catheter into a desired location within the vessel;
and removing each of the guidewires and each of the intra-catheter
stiffener elements from the lumens of the catheter.
2. The method of claim 1, wherein advancing the catheter into a
desired location within the vessel further comprises: advancing the
catheter over the guidewires until a distal end of the catheter is
adjacent to the vessel; and further advancing the catheter and the
guidewires into the vessel until the distal portion of the catheter
is at the desired location within the vessel.
3. The method of claim 1, further comprising dilating the blood
vessel subsequent to inserting a first guidewire.
4. The method of claim 3, further comprising dilating the blood
vessel using a size 6-French sheath/dilator.
5. The method of claim 1, further comprising coupling a proximal
end of each said intra- catheter stiffening element to a proximal
end of a respective catheter lumen.
6. The method of claim 1, wherein the step of advancing the
catheter into a desired location within the vessel comprises
twisting the catheter while advancing.
7. The method of claim 1, wherein the catheter has a split-tip.
8. A method for inserting a multi-lumen catheter into a blood
vessel comprising: inserting a distal portion of each of a
plurality of guidewires into a vessel at a first location; forming
a subcutaneous tunnel between the first location and a second
location; passing a catheter through the tunnel, the catheter
having a distal portion for placement in the vessel and a proximal
end for connection to a treatment device and further having a
plurality of lumens; inserting an intra-catheter stiffener element
into the proximal end of each of the catheter lumens; threading a
proximal end of each of the guidewires through a distal end of a
respective intra-catheter stiffener element until said guidewire
exits the proximal end of the catheter; advancing the catheter into
a desired location within the vessel; and removing each of the
guidewires and each of the intra-catheter stiffener elements from
the lumens of the catheter.
9. The method of claim 8, wherein advancing the catheter into a
desired location within the vessel further comprises: advancing the
catheter over the guidewires until a distal end of the catheter is
adjacent to the vessel; and further advancing the catheter and the
guidewires into the vessel until the distal portion of the catheter
is at the desired location within the vessel.
10. The method of claim 8, further comprising dilating the blood
vessel subsequent to inserting a first guidewire.
11. The method of claim 10, further comprising dilating the blood
vessel using a size 6-French sheath/dilator.
12. The method of claim 8, wherein forming a subcutaneous tunnel
further comprises inserting a distal end of a pointed stylet
through the skin at the second location; and pushing the stylet
toward the first location until the distal end of the stylet
extends therefrom.
13. The method of claim 12, wherein the step of passing a catheter
through the tunnel further comprises: removeably attaching the
distal end of the catheter to the proximal end of a stylet; pulling
the stylet toward the first location until the distal end of the
catheter extends therefrom; and releasing the catheter from the
stylet.
14. The method of claim 12, wherein the stylet has a shape adapted
to tunnel through subcutaneous tissue.
15. The method of claim 8, wherein each intra-catheter stiffener
element is inserted into the catheter prior to passage of the
catheter through the tunnel.
16. The method of claim 8, wherein each intra-catheter stiffener
element is inserted into the catheter after passage of the catheter
through the tunnel.
17. The method of claim 8, wherein the proximal end of each
catheter lumen has a coupler adapted to mate with a coupler
disposed at the proximal end of an intra-catheter stiffener
element.
18. The method of claim 8, further comprising dilating the vessel
to accommodate the distal portion of the catheter.
19. The method of claim 18, further comprising: dilating the vessel
with a first dilator; and dilating the vessel with at least one
larger further dilator.
20. The method of claim 19, wherein the larger further dilators are
adapted to dilate the vessel to slidably receive the distal portion
of the catheter having each catheter lumen stiffened by a
respective intra-catheter stiffener element disposed therein.
21. The method of claim 19, wherein the first dilator is a size
12-French dilator.
22. The method of claim 19, wherein the further dilators are any of
the group consisting of a size 14-French and a 16-French
dilator.
23. The method of claim 8, wherein the step of advancing the
catheter further comprises looping the catheter between the first
location and the vessel so as to facilitate advancing the distal
portion of the catheter into the vessel.
24. The method of claim 23, further comprising pulling the proximal
end of the catheter to remove the loop subsequent to advancing the
distal portion of the catheter into the vessel.
25. The method of claim 8, wherein the step of advancing the
catheter further comprises twisting the catheter to facilitate
advancement of the distal portion of the catheter to the desired
location within the vessel.
26. The method of claim 8, further comprising coupling the catheter
to a hemodialysis treatment device.
27. The method of claim 26, wherein the catheter is a dual-lumen
antegrade tunneled hemodialysis catheter.
28. A method for inserting a multi-lumen catheter into a blood
vessel comprising: inserting a distal portion of each of a
plurality of guidewires into a vessel at a first location; placing
intra-catheter stiffener elements into each lumen of a multi-lumen
catheter; threading a proximal end of each of the guidewires
through a distal end of a respective intra-catheter stiffener
element disposed within the catheter lumen until said guidewire
exits a proximal end of the intra-catheter stiffener element;
advancing the catheter into a desired location within the vessel;
removing each of the guidewires and each of the intra-catheter
stiffener elements from the lumens of the catheter; forming a
subcutaneous tunnel between the first location and a second
location; passing the catheter through the tunnel; and connecting
an adapter to a proximal end of each of the catheter lumens, the
adapter configured to connect to a treatment device.
29. The method of claim 28, wherein advancing the catheter into a
desired location within the vessel comprises advancing the catheter
over the guidewires until the distal end of the catheter is
adjacent to the vessel; and further advancing the catheter and the
guidewires into the vessel until the distal end of the catheter is
at the desired location within the vessel.
30. The method of claim 28, further comprising dilating the blood
vessel subsequent to inserting a first guidewire.
31. The method of claim 30, further comprising dilating the blood
vessel using a size 6-French sheath/dilator.
32. The method of claim 28, wherein forming a subcutaneous tunnel
further comprises: inserting a distal end of a pointed stylet
through the skin at the first location; and pushing the stylet
toward the second location until the distal end of the stylet
extends therefrom.
33. The method of claim 28, wherein the step of passing a catheter
through the tunnel further comprises: removeably attaching the
proximal end of the catheter to the proximal end of a stylet;
pulling the stylet back toward the second location until the
proximal end of the catheter extends therefrom; and releasing the
catheter from the stylet.
34. The method of claim 33, wherein the distal end of the stylet
has a sharpened point adapted to tunnel through subcutaneous
tissue.
35. The method of claim 33, wherein the proximal end of the stylet
has a feature adapted to removably affix the proximal end of the
catheter.
36. The method of claim 28, wherein each intra-catheter stiffener
element releasably attaches to the proximal end of its respective
catheter lumen.
37. The method of claim 36, wherein each intra-catheter stiffener
element stiffens its respective catheter lumen.
38. The method of claim 36, wherein the proximal end of each
catheter lumen has a removable coupler adapted to mate with a
coupler disposed at the proximal end of an intra-catheter stiffener
element.
39. The method of claim 28, further comprising dilating the vessel
to accommodate the distal portion of the catheter.
40. The method of claim 39, further comprising: dilating the vessel
with a first dilator; and dilating the vessel with at least one
larger further dilator.
41. The method of claim 40, wherein the larger further dilators are
adapted to dilate the vessel to slidably receive the distal portion
of the catheter having each catheter lumen stiffened by a
respective intra-catheter stiffener element disposed therein.
42. The method of claim 40, wherein the first dilator is a size
12-French dilator.
43. The method of claim 40, wherein the further dilators are any of
the group consisting of a size 14-French and 16-French dilator.
44. The method of claim 28, further comprising coupling the
catheter to a hemodialysis device.
45. The method of claim 44, wherein the catheter is a dual-lumen
retrograde tunneled hemodialysis catheter.
46. A kit for applying a multi-lumen catheter into a blood vessel
comprising: a plurality of guidewires, each adapted to have a
distal portion inserted in a blood vessel; and a plurality of
intra-catheter stiffener elements, each of the intra-catheter
stiffener elements sized to be slidably disposed within a lumen of
a multi-lumen catheter and each having a lumen sized to slide over
a guidewire.
47. The kit of claim 46, further comprising a vessel dilator
adapted to be advanced into the blood vessel over a first inserted
guidewire, the vessel dilator sized to dilate the blood vessel to
accommodate insertion of further ones of the guidewires.
48. The kit of claim 47, wherein the vessel dilator is a size
6-French sheath/dilator.
49. The kit of claim 49, further comprising at least one further
vessel dilator sized to dilate a blood vessel to accommodate
insertion of a catheter.
50. The kit of claim 49, wherein the further vessel dilators are
any size of the group consisting of size 12-French, 14-French and
16-French.
51. The kit of claim 46, wherein the intra-catheter stiffener
elements have a tapered distal portion.
52. The kit of claim 46, wherein each intra-catheter stiffener
element has a coupler disposed at a proximal end adapted to
releasably couple to a coupler disposed at the proximal end of a
respective catheter lumen.
53. The kit of claim 52, wherein the intra-catheter stiffener
elements are releasably coupled to a proximal end of the catheter
lumens.
54. The kit of claim 52, wherein the intra-catheter stiffener
elements have a predefined length corresponding to a length of a
catheter selected for use in a particular application.
55. The kit of claim 54, wherein the catheter is a hemodialysis
catheter.
56. The kit of claim 46, further comprising a multi-lumen
catheter.
57. The kit of claim 56, wherein the intra-catheter stiffener
elements are pre-disposed within the lumens of the catheter.
58. A kit for applying a multi-lumen catheter into a blood vessel
comprising: a multi-lumen catheter comprising a distal portion to
be placed in a blood vessel and a coupler disposed at a proximal
end of each catheter lumen; and a plurality of intra-catheter
stiffener elements, each of the intra-catheter stiffener elements
sized to be slidably disposed within a lumen of the catheter and
each having a lumen sized to slide over a guidewire, the
intra-catheter stiffener elements having a tapered distal portion
and a proximal end having a coupler adapted to mate with the
coupler at the proximal end of a catheter lumen.
59. The kit of claim 58, further comprising a vessel dilator
adapted to be advanced into the blood vessel over a first inserted
guidewire, the vessel dilator sized to dilate the blood vessel to
accommodate insertion of further ones of the guidewires.
60. The kit of claim 59, wherein the vessel dilator is a size
6-French sheath/dilator.
61. The kit of claim 60, further comprising at least one further
vessel dilator sized to dilate a blood vessel to accommodate
insertion of a catheter.
62. The kit of claim 61, wherein the further vessel dilators are
any size of the group consisting of 12-French, 14-French and
16-French.
63. The kit of claim 58, wherein the intra-catheter stiffener
elements have a predefined length corresponding to a length of the
catheter selected.
64. The kit of claim 58, wherein the intra-catheter stiffener
elements have an exterior shape sized to be received by an interior
shape of the catheter lumens.
65. The kit of claim 58, wherein the intra-catheter stiffener
elements are pre-disposed within the lumens of the catheter.
66. The kit of claim 58, wherein the catheter is a hemodialysis
catheter.
67. The kit of claim 58, wherein the distal portion of the catheter
has a split-tip.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to methods and apparatus for inserting
a catheter into a body cavity and, more particularly, though not
exclusively, to methods and apparatus for inserting a multi-lumen
split-tip hemodialysis catheter into a blood vessel for
hemodialysis.
[0002] Multi-lumen catheters are desirable for various treatment
applications such as hemodialysis where fluid extraction and
infusion occur simultaneously. These multi-lumen catheters provide
a single catheter application having multiple lumen channels each
supporting independent flow, thus precluding the need for inserting
multiple catheters or multiple-catheter assemblies. Further,
because a patient might require frequent dialysis, often only days
apart, it is desirable to secure placement of the catheter for
extended periods of time. Extended placement, however, requires
extreme catheter flexibility to avoid damage to the vessel and
permit the catheter to move in the blood flow to minimize the
possibility of the catheter remaining in pressure contact with the
wall of the vessel for prolonged periods.
[0003] Unfortunately, the desired flexibility of these catheters
presents insertion difficulties. For example, simply advancing the
catheter over a guidewire is very difficult since the catheter
lacks sufficient stiffness to slide easily through the vessel wall
and into the blood vessel to the desired location. Flexible
catheters present additional difficulties associated with
subcutaneous tunneling and placement.
[0004] Known insertion methods and assemblies attempt to overcome,
or at least mitigate, these insertion difficulties by stiffening
the catheter temporarily during the insertion process. For example,
one known method involves temporarily inserting a rigid tubular
applicator into one of the lumens. This permits the stiffened
catheter/applicator assembly to be passed over a guidewire into a
desired position, at which point the applicator can be removed. For
example, U.S. Pat. No. 5,405,341 attempts to solve the problem with
a single rigid applicator that is designed for insertion into one
lumen but also passes through a portion of the second lumen (at the
distal end of the instrument) to effectively stiffen the two lumens
of the catheter together during insertion. This approach is
cumbersome, at best, and presents additional difficulties in
maneuvering the instrument. Further, this temporary rigid
applicator approach, however, is poorly suited for placement of a
catheter having a split at its distal end into two or more separate
lumens (e.g., to further isolate a fluid extraction lumen from a
return infusion lumen) because only one tip can be secured.
[0005] Hence, there exists a need for better and more effective
methods and apparatus for insertion of flexible catheters into
vessels.
SUMMARY
[0006] The invention provides methods and apparatus for inserting
flexible, multi-lumen catheters into blood vessels, and in
particular, for inserting flexible, split-tip catheters into blood
vessels. The invention accomplishes these objects by temporarily
stiffening each catheter lumen and tip independently through use of
intra-catheter stiffener elements disposed within the catheter
lumens. This provides means for advancing the catheter/stiffeners
assembly through a subcutaneous tunnel, and over a plurality of
guidewires until a distal portion of the catheter is at a desired
position within the vessel.
[0007] The intra-catheter stiffener elements are sufficiently
stiffening to allow advancing the catheter over guidewires, but
also sufficiently flexible to allow bending and looping of the
catheter for proper placement within the vessel. Further, the
intra-catheter stiffener elements prevent catheter kinking during
the insertion process. In one embodiment, the intra-catheter
stiffener elements have tapered distal ends which can facilitate
entry of the catheter/stiffeners assembly into a blood vessel
and/or assist in dilating the blood vessel.
[0008] One aspect of the invention provides methods and apparatus
for inserting an antegrade tunneled, split-tip, hemodialysis
catheter into a blood vessel. A distal portion of each of a
plurality of guidewires is disposed in a blood vessel at a first
location, generally in proximity to the vessel in which a portion
of the catheter is to be placed. A subcutaneous tunnel is formed
between the first location and a second location where a proximal
end of the catheter can extend from the patient. An intra-catheter
stiffener element is inserted into the proximal end of each
catheter lumen until it extends beyond the distal end of that
catheter lumen. The intra-catheter stiffener element can be
releasably coupled, following insertion, to the proximal end of its
respective catheter lumen via, for example, a mating luer assembly.
Each guidewire can be inserted into to a distal end of a lumen in a
respective intra-catheter stiffener element until that guidewire
extends from the proximal end of that intra-catheter stiffener
element. The catheter can then be advanced over the guidewires and
into the blood vessel. Alternatively, the catheter can be advanced
over the guidewires until a distal end of the catheter is adjacent
to the vessel, at which point the catheter and guidewires can be
advanced together into the vessel until the distal end of the
catheter is at a desired location therein. Twisting the catheter
while simultaneously advancing it along the guidewires can
facilitate placement of the catheter into the vessel.
[0009] In another aspect, the methods and apparatus of the
invention provide for inserting a retrograde tunneled hemodialysis
catheter into a blood vessel. A distal portion of each of a
plurality of guidewires is inserted into a blood vessel at a first
location generally as described above. An intra-catheter stiffener
element is placed in each catheter lumen until it extends from a
distal end of the catheter, and can be releasably connected to the
proximal end of its respective catheter lumen, as noted above. A
proximal end of each guidewire is threaded through the distal end
of a lumen of each intra-catheter stiffener element until the
guidewire extends beyond the proximal end of that stiffener
element. The catheter is advanced over the guidewires, optionally
using a twisting motion, until a distal portion of the catheter is
disposed at a desired location within the vessel, or alternatively,
the catheter can be advanced until its distal end is adjacent to
the vessel, at which point the catheter and guidewires can be
advanced together until the distal end of the catheter is disposed
at a desired location within the vessel. The guidewires are removed
from the catheter lumens. A subcutaneous tunnel is then formed
between the first location and a second location, and the proximal
end of the catheter is passed through the first location until it
extends from the second location. (If the stiffener elements have
not previously been removed, they can be removed from the catheter
body following passage of the catheter through the tunnel.) An
access port is connected to the proximal end of each of the
catheter lumens allowing fluid connection with a treatment device,
such as a hemodialysis infuser.
[0010] In a related aspect, the methods and kits of the present
invention can provide for dilating the desired vessel subsequent to
inserting the distal portion of a first guidewire. For example, a
size 6-French sheath/dilator can be threaded over the first
guidewire. Further guidewires can then be inserted into the
expanded vessel, or through a lumen in the sheath and into the
vessel. After placement of the guidewires into the vessel, the
dilator or sheath can be removed.
[0011] In a further related aspect, the methods provide for
tunneling between the first and second location by using a pointed
stylet. A distal end of a pointed stylet can be inserted through
the skin at the second location and pushed toward the first
location until the distal end extends therefrom. The distal end of
the catheter is removably attached to a proximal end of the stylet.
The stylet is then pulled from the first location until the distal
end of the catheter extends therefrom, to facilitate an antegrade
tunneled catheter.
[0012] Alternatively, a pointed distal end of a stylet can be
inserted through the skin at the first location and pushed until it
extends from the second location. The proximal end of the catheter
can be removably attached to the proximal end of the stylet. The
stylet is then pulled back toward the second location until the
proximal end of the catheter extends therefrom. The catheter is
then released from the stylet, thus positioning a retrograde
tunneled catheter. To facilitate movement of the catheter within
the tunnel, the proximal end of the catheter having mating lures or
other coupling features can be removed or severed prior to
attachment to the stylet. After tunneling the catheter, fluid
couplings or other attachments can be disposed to the proximal end
of the lumens.
[0013] Preferably, the vessel is expanded to accommodate placement
of the distal portion of the catheter in the vessel. Vessel
dilators of increasing size can be sequentially inserted into the
vessel for this purpose. For example, a size 12-French dilator
followed by a size 14-French, which is then followed by a size
16-French dilator, can be inserted into the vessel before advancing
the catheter along the guidewires. In other embodiments, fewer (or
more) dilators of different sizes can be used. Differing size and
number of vessel dilators can be used corresponding to the catheter
chosen for the desired application. Use of intra-catheter stiffener
elements can preclude use of vessel dilators sized larger that the
catheter since the stiffener elements and the catheter itself can
provide vessel dilation.
[0014] Another aspect of the invention provides for apparatus, in
the form of a kit, to insert a multi-lumen catheter into a blood
vessel. The kit comprises guidewires each adapted to have a distal
portion inserted into a blood vessel. A plurality of intra-catheter
stiffener elements preferably having tapered distal ends are also
provided, each having a lumen extending along its length sized to
accommodate a guidewire, and each having an outside diameter sized
to be slidably disposed within a lumen of the catheter. The
intra-catheter stiffener elements can be provided in one or more
predetermined lengths corresponding to a length of a catheter and
its lumens selected for a particular use, or can be of the same
length. Further, the intra-catheter stiffeners can be provided with
mating devices, such as lures, disposed at a proximal end
correspond with mating connectors disposed at a proximal end of the
catheter lumens.
[0015] One or more vessel dilators can also be provided in the kit,
each corresponding in size to a particular application. For
example, a size 6-French sheath/dilator can be provided to dilate
the vessel to accommodate a plurality of guidewires. A size
12-French, 14-French, as well as a size 16-French, dilator can be
provided to dilate the vessel to accommodate the distal tip of the
catheter.
[0016] The present invention is applicable in the field of
hemodialysis, among others, for inserting a multi-tip catheter into
a blood vessel. The methods and apparatus provide for insertion of
a split-tip catheter without using a tearable sheath and avoid the
problems associated with prior art approaches of split tip catheter
insertion over a single guidewire.
BRIEF DESCRIPTION OF THE INVENTION
[0017] These and other objects, advantages and features of the
present invention will be readily appreciated as the same becomes
better understood by reference to the following detailed
description when considered in connection with the accompanying
drawings, in which like reference numerals designate like parts
throughout the figures thereof and wherein:
[0018] FIG. 1 is a schematic, partially cutaway, side view of a
hemodialysis catheter insertion system according to the
invention;
[0019] FIG. 2 is a schematic illustration of an initial step of a
method according to the invention in which a distal portion of a
first guidewire is inserted in a vessel;
[0020] FIG. 3 is a schematic illustration of another step of the
method of the invention in which a blood vessel dilating sheath and
a distal portion of a second guidewire are inserted in a
vessel;
[0021] FIG. 4 is a schematic illustration of another step of the
method in which an antegrade catheter is disposed in a subcutaneous
tunnel between a first location and a second location according to
the invention;
[0022] FIG. 5 is a schematic illustration of another step of the
method in which the first guidewire is threaded through a first
lumen of a catheter assembly according to the invention, in which
the catheter assembly has an intra-catheter stiffener element
disposed in each lumen of the catheter;
[0023] FIG. 6 is a schematic illustration of another step of the
method in which the second guidewire is threaded through the second
lumen of the catheter assembly to a point where two loops of
guidewire remain to facilitate placement of the distal end of the
catheter in the vessel;
[0024] FIG. 7 is a schematic illustration of another step of the
method in which the catheter assembly has been advanced along the
guidewires until the distal portion of the catheter is positioned
within the vessel at a desired location;
[0025] FIG. 8 shows the catheter of FIG. 7 with the intra-catheter
stiffener elements and guidewires removed;
[0026] FIG. 9 is a schematic illustration showing a step of a
method according to the invention wherein a retrograde catheter is
shown having a distal end disposed in a vessel;
[0027] FIG. 10 is a schematic illustration showing a further step
of the method wherein the catheter has been subcutaneously tunneled
subsequent;
[0028] FIG. 11 shows the catheter with fluid-couplers installed;
and
[0029] FIG. 12 shows a kit according to the invention for
installing catheters such as those described above.
DETAILED DESCRIPTION OF THE INVENTION
[0030] In FIG. 1 a catheter system 10 according to the invention is
shown having a catheter body 12 with two internal lumens 14A and
14B. The catheter body 12 has a "split-tip" distal end 16 in which
the body (and lumens) separate into two distal tip portions, 18A
and 18B. The split tips can, but need not have one or more side
ports 20A and 20B, in fluid communication with one or the other of
the lumens to facilitate blood removal and return, respectively,
during hemodialysis. Alternatively, or in conjunction with side
ports, the distal ends can be open to provide fluid passageways for
blood removal and return. The proximal end 22 of the catheter body
can also be split into separate segments 22A and 22B and terminates
with two access ports 28A and 28B, which can include couplings,
such luer-locks or the like, to couple the catheter to a
hemodialysis machine in which blood is circulated and purified. The
overall system or kit of the invention can also include two
intra-catheter stiffener elements 24A and 24B and two guidewires
26A and 26B (shown within the respective lumens 14A and 14B). The
catheter body 12 is typically a very flexible silicone,
polyurethane or other biocompatible composition (e.g., having a
stiffness in the range of about 65 to about 85 durometers).
Preferably, the intra-catheter stiffener elements 24A and 24B are
composed of a stiffer form of polyethylene or other biocompatible
material. In addition to stiffening the assembly, the stiffener
elements can also help to prevent kinking of the catheter during
insertion.
[0031] The catheter system 10 of FIG. 1 provides for insertion of
the distal end of the multi-lumen, split-tip, flexible catheter
body 12 into a blood vessel using the intra-catheter stiffener
elements and guidewires, as will be explained below. Briefly, a
distal portion of each guidewire is disposed at a desired position
within the vessel. An intra-catheter stiffener element having a
tapered tip to facilitate insertion into the vessel and to provide
catheter stiffening is slidably disposed along the length of each
catheter lumen until it extends beyond the distal tip of that
catheter lumen. A proximal end of each guidewire is threaded
through a distal end of a lumen extending along each of the
intra-catheter stiffener elements. The catheter is then advanced
over the guidewires and into the blood vessel. Alternatively, the
catheter can be advanced over the guidewires until the distal end
is adjacent to the vessel, at which point the catheter and
guidewires can be advanced together into the blood vessel. The
guidewires and intra-catheter stiffener elements are then removed
from the catheter. The methods and application kit described can be
used for any split-tip catheter, and are particularly useful for
insertion of subcutaneously tunneled hemodialysis catheters.
[0032] A method of insertion according to the invention will next
be described in connection with FIGS. 2-8. The procedure involves
not only inserting the catheter tips into a blood vessel but also
forming a subcutaneous tunnel below a patient's skin to secure the
catheter in place and is sometimes described as antegrade or
forward insertion. It will be appreciated, however, that the
methods described herein can be used for inserting catheter tips
into a blood vessel where tunneling is not necessary or
desired.
[0033] FIG. 2 schematically shows an initial step of a method
according to the invention in which a distal portion of a first
guidewire 26A is inserted in a vessel 4 of a patient 2. The entry
location 6 of the guidewire 26A is referred to herein as the "first
location" or the "venotomy site." This first location is typically
a surgical incision that provides access to the desired blood
vessel which typically includes the internal or external jugular,
femoral or subclavian vein, and the vena cava, for example. In one
preferred embodiment, the blood vessel chosen for catheter
placement can be the right side internal jugular vein.
[0034] In FIG. 3, a blood vessel sheath/dilator 30 is shown
inserted over the first guidewire 26A to dilate the vessel. The
distal portion of a second guidewire 26B is then inserted in the
vessel 4 via the sheath/dilator 30.
[0035] With reference to FIG. 4, a subcutaneous tunnel 40 is formed
(before or after the insertion of guidewires 26A and 26B) to anchor
the catheter body in place and provide two remote ports for
coupling the two lumens of the catheter to a dialysis machine. In
FIG. 4, a catheter body 12 of an antegrade catheter has been
disposed in a subcutaneous tunnel 40 between the first (venous
access) location 6 and a second (exit) location 32, such that the
distal end of the instrument including the split tips 18A and 18B
extend from the first location. Prior to insertion, each of the
lumens of catheter body 12 has been fitted with a hollow, tubular,
intra-catheter stiffener element or liner, 24A and 24B,
respectively.
[0036] In FIG. 5, the first guidewire 26A is threaded through a
first lumen of the catheter assembly (i.e., through the lumen of
intra-catheter stiffener element 24A). In FIG. 6, the second
guidewire 26B is threaded through the second lumen of the catheter
assembly (i.e., through the lumen of intra-catheter stiffener
element 24B). Each of the guidewires is advanced through the
catheter assembly to a point where two short loops of guidewire
remain to facilitate placement in the vessel.
[0037] As shown in FIG. 7, the catheter assembly is then advanced
along the guidewires until the distal end 16 of the catheter is
positioned at a desired position within the vessel. In a preferred
embodiment, the catheter is advanced over the guidewires until the
distal end is adjacent to the vessel, and then the catheter and the
guidewires can be advanced together until the distal end of the
catheter is positioned at a desired position within the vessel. The
guidewires 26A and 26B can then be removed by withdrawing them via
the proximal end 22 of the catheter body. Likewise, the
intra-catheter stiffener elements 24A and 24B can be removed
(either subsequent to the guidewires or at the same time).
[0038] Advantageously, this method precludes using a vessel dilator
larger than the catheter/stiffeners assembly for placement of the
catheter within the vessel since the intra-catheter stiffener
elements and the catheter itself provide vessel dilation.
[0039] FIG. 8 shows the catheter of FIG. 7 with the intra-catheter
stiffener elements and guidewires removed. The venous access
incision is then closed and the catheter is secured subcutaneously
(e.g., via an implanted cuff and/or sutures).
[0040] Although the above detailed description has been presented
in connection with an antegrade insertion, it should be clear that
the methods and systems of the present invention are equally useful
in retrograde or reverse insertions (where the catheter body is
passed through the subcutaneous tunnel from venotomy site to the
remote exit location).
[0041] Thus, a method according to the invention for insertion of a
retrograde catheter will next be described. An initial step for
insertion of a retrograde catheter begins with placement of
guidewires within the vessel as described above in connection with
FIGS. 2 and 3.
[0042] FIG. 9 illustrates a step of the method wherein the catheter
body 12 has each of the lumens fitted with a hollow, tubular,
intra-catheter stiffener element or liner, 24A and 24B,
respectively. The intra-catheter stiffener elements can have a
coupler at a proximal end that releasably couple to a mating
coupler at a proximal end of the respective catheter lumen.
Guidewires 26A and 26B are threaded through the lumens of the
catheter assembly as described above in FIGS. 5 and 6. The catheter
body is advanced along the guidewires until the distal end of the
catheter in a desired location within the vessel. Alternatively,
the catheter body can be advanced along the guidewires until the
distal end is adjacent to the vessel, and then the catheter and the
guidewires can be advanced until the distal end is located at a
desired position within the vessel. The guidewires and, optionally,
the intra-catheter stiffener elements are then removed from the
lumens.
[0043] FIG. 10 shows a step of the method wherein the catheter has
been subcutaneously tunneled. A subcutaneous tunnel is formed
between a second location 32 (exit location) and the first location
6 (venotomy site). Couplers at the proximal end 22 of the catheter
lumens are removed, or alternatively, severed therefrom to allow
the proximal end of the catheter to be pulled through the tunnel
40. In one embodiment, the proximal end of the catheter is pulled
through subcutaneous tunnel from the first location until it
extends from the second location.
[0044] FIG. 11 illustrates the catheter after tunneling with access
ports 28A and 28B installed, or alternatively, replaced and ready
to be coupled to a hemodialysis machine for blood purification.
[0045] As noted above, it will be appreciated that the use of the
intra-catheter stiffener elements provide sufficient stiffness so
that the flexible split tips can be slid over the guidewires into
the desired position with less effort and reduced likelihood of
trauma. Catheter kinking is mitigated during the insertion process,
thus reducing complexity of catheter insertion.
[0046] FIG. 12 shows contents of a preferred embodiment of a kit 48
providing equipment to perform the above described methods.
Illustrated are two intra-catheter stiffener elements 50A and 50B,
two guidewires 52A and 52B, a 6-French sheath/dilator 54 and two
vessel dilators of differing sizes 56 and 58. It will be
appreciated by one skilled in the art that other arrangements are
contemplated, each having at least two intra-catheter stiffener
elements. For example, in one embodiment, the insertion kit has a
split-tip catheter and two intra-catheter stiffener elements. The
kit is suitable for insertion of either antegrade or retrograde
catheter configurations according to the illustrated methods
described above.
[0047] Intra-catheter stiffener elements 50A and 50B are
illustrated as 5-French in size and of the same length. However,
intra-catheter stiffener elements 50 need not be of the same size
and length, but can be selected according to the size and length of
the catheter to be inserted. Further, intra-catheter stiffener
elements need not have a round exterior shape, but rather, can have
an external shape according to the size and shape of an interior of
a catheter lumen, for example, oval shaped. In a preferred
embodiment, each intra-catheter stiffener element has a tapered
configuration along a distal portion to aid in dilating the
catheter lumen, with a releasable coupler at a proximal end such as
a luer-coupler at a proximal end. Each has a hollow bore or lumen
running along its length sized to slidably receive a guidewire as
described above. Each preferably has stiffness sufficient to
prevent the catheter from kinking or otherwise distorting during
the insertion procedure. It will be appreciated that the
intra-catheter stiffener elements can be in kit form as separate
from, or disposed within, the catheter lumens.
[0048] Guidewires 52A and 52B are illustrated as J-straight 0.038"
guidewires, however each can vary according to the application and
catheter configuration. Each can have a removable sheath to
accommodate handling and facilitate placement within a desired
location such as a vein.
[0049] Sheath/dilator 54 is illustrated as size 6-French, however,
other sizes may be used to puncture a wall of a vessel and
accommodate one or more guidewires. Dilators 56 and 58 are
illustrated as size 14-French and 16-French, respectively, and are
suitable for many catheter insertion procedures. In a preferred
embodiment, a size 12-French is provided in addition to or instead
of one of the illustrated dilators.
[0050] It will be appreciated, therefore, that the above methods
and kits are useful for inserting hemodialysis catheters in a
patient, and in general for multi-lumen split-tip catheters
intended for other functions where body fluids are extracted and
introduced. As such, the invention is not limited to those
embodiments described above, but rather, is limited by the claims
that follow.
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