U.S. patent application number 14/852622 was filed with the patent office on 2016-02-11 for dialysis catheter.
This patent application is currently assigned to Rex Medical, L.P.. The applicant listed for this patent is Rex Medical, L.P.. Invention is credited to Stephan A. DeFonzo.
Application Number | 20160038715 14/852622 |
Document ID | / |
Family ID | 44118169 |
Filed Date | 2016-02-11 |
United States Patent
Application |
20160038715 |
Kind Code |
A1 |
DeFonzo; Stephan A. |
February 11, 2016 |
DIALYSIS CATHETER
Abstract
A dialysis catheter including a first portion having an outer
wall having a first diameter, an elongated distal portion having a
second diameter smaller than the first diameter, and a transition
region between the first portion and distal portion. A first
longitudinally extending venous lumen is configured to deliver
blood. First and second independent longitudinally extending
arterial lumens are configured to withdraw blood from a patient.
The venous lumen and arterial lumen have first and second regions
each positioned a first distance from the outer wall of the
catheter and a third region positioned a second shorter distance
from the outer wall of the catheter to form an arch shaped wall
portion progressively increasing in thickness from the third region
toward the first region and from the third region to the second
region.
Inventors: |
DeFonzo; Stephan A.; (Wayne,
PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rex Medical, L.P. |
Conshohocken |
PA |
US |
|
|
Assignee: |
Rex Medical, L.P.
Conshohocken
PA
|
Family ID: |
44118169 |
Appl. No.: |
14/852622 |
Filed: |
September 13, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14076179 |
Nov 9, 2013 |
9149601 |
|
|
14852622 |
|
|
|
|
13108154 |
May 16, 2011 |
8591450 |
|
|
14076179 |
|
|
|
|
61352195 |
Jun 7, 2010 |
|
|
|
Current U.S.
Class: |
604/6.16 |
Current CPC
Class: |
A61M 25/0023 20130101;
A61M 25/0026 20130101; A61M 1/3661 20140204; A61M 25/0032 20130101;
A61M 1/3653 20130101; A61M 1/3659 20140204 |
International
Class: |
A61M 25/00 20060101
A61M025/00; A61M 1/36 20060101 A61M001/36 |
Claims
1-19. (canceled)
20. A dialysis catheter for delivering and withdrawing blood from a
patient's body, the dialysis catheter comprising a dialysis
catheter body defining first, second, third and fourth quadrants in
a transverse cross-section at an intermediate portion and having
first and second arterial lumens and a venous lumen, the venous
lumen being circular in configuration and positioned off-center of
a central longitudinal axis of the catheter, the venous lumen
having an equal portion in each of the third and fourth quadrants,
the first and second arterial lumens being asymmetric in
configuration, the first arterial lumen positioned in a portion of
the second and third quadrants with a major portion positioned in
the second quadrant and having a first convex outer wall and a
first curved inner wall, and the second arterial lumen positioned
in a portion of the first and fourth quadrants with a major portion
of the second arterial lumen positioned in the first quadrant, the
second arterial lumen having a second convex outer wall and a
second curved inner wall, the first and second inner walls being
closer to the venous lumen than the first and second outer
walls.
21. The dialysis catheter of claim 20, wherein the first outer wall
has a length greater than a length of the first inner wall.
22. The dialysis catheter of claim 20, wherein the second outer
wall has a length greater than a length of the second inner
wall.
23. The dialysis catheter of claim 21, wherein the second outer
wall has a length greater than a length of the second inner
wall.
24. The dialysis catheter of claim 20, wherein the length of the
first outer wall is equal to the length of the second outer
wall.
25. The dialysis catheter of claim 20, wherein the length of the
first inner wall is equal to the length of the second inner
wall.
26. The dialysis catheter of claim 24, wherein the length of the
first inner wall is equal to the length of the second inner
wall.
27. The dialysis catheter of claim 20, wherein the first outer wall
and first inner wall are joined by a radiused wall.
28. The dialysis catheter of claim 27, wherein the second outer
wall and second inner wall are joined by a radiused wall.
29. The dialysis catheter of claim 21, wherein the first and second
arterial lumens are spaced a same distance from a center point of
the transverse cross section of the dialysis catheter.
30. The dialysis catheter of claim 29, wherein the venous lumen is
adjacent the center point of the transverse cross section of the
dialysis catheter.
31. The dialysis catheter of claim 20, wherein the venous lumen is
adjacent the center point of the transverse cross section of the
dialysis catheter.
32. The dialysis catheter of claim 20, wherein the first and second
inner walls are concave.
33. The dialysis catheter of claim 20, wherein the first and second
arterial lumens are of a same configuration.
34. The dialysis catheter of claim 31, wherein the first and second
inner walls are concave and face the venous lumen.
35. The dialysis catheter of claim 20, wherein the first arterial
lumen does not extend into the first and fourth quadrants.
36. The dialysis catheter of claim 35, wherein the second arterial
lumen does not extend into the second or third quadrants.
37. The dialysis catheter of claim 36, wherein the venous lumen is
adjacent the center point of the transverse cross section of the
dialysis catheter.
38. The dialysis catheter of claim 37, wherein the first and second
arterial lumens are of a similar configuration.
Description
BACKGROUND
[0001] This application is a continuation of prior application Ser.
No. 13/108,154, filed on May 16, 2011, which claims priority from
provisional application 61/352,195, filed Jun. 7, 2010, the entire
contents of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] This application relates to a catheter and more particularly
to a multi-lumen catheter which facilitates hemodialysis.
BACKGROUND OF RELATED ART
[0003] Hemodialysis is a well known method of providing renal
(kidney) function by circulating blood. The kidneys are organs
which function to extract water and urea, mineral salts, toxins,
and other waste products from the blood with filtering units called
nephrons. From the nephrons the collected waste is sent to the
bladder for excretion. For patients having one or both defective
kidneys, the hemodialysis procedure is life saving because it
provides a machine to simulate the function of the kidneys.
[0004] In the hemodialysis procedure, blood is withdrawn from the
patient's body through a catheter or tube and transported to a
dialysis machine, also commonly referred to as a kidney machine.
The catheter is typically inserted through the jugular vein and
maneuvered into position through the superior vena cava into the
right atrium to provide high blood flow. In the dialysis machine,
toxins and other waste products diffuse through a semi-permeable
membrane into a dialysis fluid closely matching the chemical
composition of the blood. The filtered blood, i.e. with the waste
products removed, is then returned to the patient's body. In some
instances, the catheter may be left in place for several years. As
can be appreciated, proper access to the patient's blood and
transport of the blood to and from the dialysis machine for this
extended period of time is critical to hemodialysis.
[0005] One example of a dialysis catheter currently being marketed
is the MedComp Ash Split catheter. This catheter has two lumens,
one for arterial flow and the other for venous flow, which are each
D-shaped in cross-sectional configuration. The catheter is
bifurcated at its distal end to separate the lumens and the
catheter is manually split to the desired length for selected
separation before insertion into the target area. Another
well-known catheter is a Med Comp catheter which has the venous
flow lumen terminating proximally, i.e. axially recessed, from the
arterial flow lumen. Each of these lumens is also D-shaped in
cross-sectional configuration.
[0006] The use of a tear away sheath in catheter insertion is well
known. It would be advantageous if a dialysis catheter could be
provided which would also provide for readily insertion without the
use of a tear away sheath in certain instances. Such insertion
method, if utilized, can decrease the complexity of the
procedure.
[0007] Another area of dialysis catheter design is to maximize
venous and arterial flow rates while preventing collapsing the
lumens. That is, it is known that the larger lumens will maximize
flow rates, reduce arterial and venous pressure and improve
dialysis by providing fastener dialysis. However, given the limited
amount of space in the dialysis catheter, which is typically about
15-16 French, the size of the lumens is limited. The size is also
limited by the fact that if the lumens are too large, the wall
thickness of the catheter becomes too thin, thereby reducing the
strength of the wall and resulting in collapse of the lumens which
has a detrimental affect on the blood flow.
[0008] In navigating vessels to access the target site, such as the
right atrium, it is desirable to provide the smallest catheter
profile, i.e. the smallest outer diameter catheter body. This
profile facilitates insertion through smaller vessels as it reduces
the likelihood of the catheter engaging the wall of the vessel and
reduces trauma to the vessel by minimizing frictional contact with
the vessel wall. However, the desire for smaller diameter catheters
must be balanced against the need for providing sufficient sized
lumens to enable proper blood flow. If the lumens are too small,
sufficient blood flow may not be able to be maintained and the
blood can be damaged during transport. Also, a sufficient
relationship must be maintained between the size of the lumens and
the overall diameter of the catheter to maintain the structural
integrity of the catheter.
[0009] Numerous attempts have been made in the prior art to
optimize the multi-lumen configuration. In some approaches, such as
disclosed in U.S. Pat. Nos. 4,568,329 and 5,053,023, the inflow and
outflow lumen are provided side by side in D-shaped form. In other
approaches, such as those disclosed in U.S. Pat. Nos. 4,493,696,
5,167,623 and 5,380,276 the inflow and outflow tubes are placed in
concentric relation. Other examples of different lumen
configurations are disclosed in U.S. Pat. Nos. 5,221,256,
5,364,344, and 5,451,206. Commonly assigned U.S. Pat. Nos.
6,814,718 and 7,011,645 disclose other lumen configurations.
[0010] The catheter lumen configuration must accommodate two
competing factors: keeping the catheter as small as possible to
facilitate insertion while keeping the lumens as large as possible
for blood flow. This balance must be achieved while maintaining the
structural integrity of the catheter. It would therefore be
advantageous to provide a catheter which reaches an optimum
compromise between these two competing factors.
[0011] Another important feature of dialysis catheters is the
suction openings to withdraw blood. Keeping the suction openings
clear of thrombolytic material and away from the vessel wall is
clearly essential to dialysis function since an adequate supply of
blood must be removed from the patient to be dialyzed.
[0012] The need therefore exists for an improved dialysis catheter
which facilitates the surgical dialysis procedure, reduces unwanted
kinking of the catheter during insertion and use, and strikes an
optimal balance between overall catheter size and lumen size.
SUMMARY
[0013] The present invention provides in one aspect a dialysis
catheter comprising an outer wall, a first portion having a first
diameter, an elongated distal portion having a second diameter
smaller than the first diameter, and a transition region between
the first portion and distal portion. A first longitudinally
extending substantially circular venous lumen configured to deliver
blood is positioned off center of a central longitudinal axis of
the catheter and terminates in a distal opening at the distalmost
end of the catheter.
[0014] The catheter includes first and second independent
longitudinally extending arterial lumens configured to withdraw
blood from a patient, each terminating in an opening in the
transition region spaced proximally of the distal opening of the
venous lumen. The venous lumen is in a venous lumen region and has
a first region, a second region and a third region between the
first and second regions. The first and second regions are each
positioned a first distance from the outer wall of the catheter and
the third region is positioned a second distance from the outer
wall of the catheter, the second distance being less than the first
distance to form a first arch shaped wall portion progressively
increasing in thickness from the third region toward the first
region and from the third region toward the second region.
[0015] The first arterial lumen is in a first arterial lumen region
and has a first region, a second region and a third region between
the first and second regions. The first and second regions of the
first arterial lumen are each positioned a third distance from the
outer wall of the catheter, and the third region of the first
arterial lumen is positioned a fourth shorter distance from the
outer wall of the catheter to form a second arch shaped wall
portion progressively increasing in thickness from the third region
of the first arterial lumen toward the first region of the first
arterial lumen and from the third region of the first arterial
lumen toward the second region of the first arterial lumen.
[0016] In some embodiments, the transition region tapers toward the
distal portion. In some embodiments, a reinforcing rib extends
longitudinally from the transition region and terminates proximally
of the distalmost end of the catheter.
[0017] In some embodiments, the second arterial lumen has a first
region, a second region and a third region between first and second
regions. The first and second regions of the second arterial lumen
are each positioned a fifth distance from the outer wall of the
catheter, and the third region of the second arterial lumen is
positioned a sixth shorter distance from the outer wall of the
catheter to form a third arch shaped wall portion progressively
increasing in thickness from the third region of the second
arterial lumen toward the first region of the second arterial lumen
and from the third region of the second arterial lumen toward the
second region of the second arterial lumen. In some embodiments,
the third and fifth distances and/or the fourth and sixth distances
are substantially equal.
[0018] A stiffening member can be removably positionable within the
catheter to temporarily increase the stiffness of the catheter to
facilitate insertion. The stiffening member can be removably
received in the venous lumen and can have a lumen formed therein
configured to receive a guidewire therethrough. The stiffening
member can extend distally of a distalmost end of the catheter body
when inserted therein. The stiffening member can be secured to the
catheter by a threaded engagement.
[0019] In another aspect, the present invention provides a dialysis
catheter comprising an outer wall, a first portion having a first
diameter, an elongated distal portion having a second diameter
smaller than the first diameter, and a transition region between
the first portion and distal portion. A first venous lumen region
has a first longitudinally extending substantially circular venous
lumen configured to deliver blood, terminating in a distal opening
at the distalmost end of the catheter. First and second independent
longitudinally extending arterial lumens are configured to withdraw
blood from a patient, each of the arterial lumens terminating in an
opening in the transition region spaced proximally of the distal
opening. The first arterial lumen has a first region, a second
region and a third region between the first and second regions. The
first and second regions are each positioned a first distance from
the outer wall of the catheter, and the third region is positioned
a second distance from the outer wall of the catheter, wherein the
second distance is less than the first distance to form an arch
shaped wall portion in a first arterial lumen region progressively
increasing in thickness from the third region toward the first
region and from the third region toward the second region of the
first arterial lumen.
[0020] The second arterial lumen has a first region, a second
region and a third region between first and second regions. The
first and second regions of the second arterial lumen are each
positioned a third distance from the outer wall of the catheter,
and the third region of the second arterial lumen is positioned a
fourth shorter distance from the outer wall of the catheter to form
an arch shaped wall portion in a second arterial lumen region
progressively increasing in thickness from the third region of the
second arterial lumen toward the first region of the second
arterial lumen and from the third region of the second arterial
lumen toward the second region of the second arterial lumen.
[0021] The venous lumen can be positioned off center of a
longitudinal axis of the catheter.
[0022] A stiffening member can be removably positionable within the
venous lumen of the catheter to temporarily increase stiffness of
the catheter to facilitate insertion. The stiffening member can
have a lumen dimensioned to receive a guidewire.
[0023] In another aspect, the present invention provides a dialysis
catheter for delivering and withdrawing blood from a patient's body
comprising a catheter body defining four quadrants in a transverse
cross-section at an intermediate portion and having first and
second arterial lumens and a venous lumen having a substantially
circular cross section. The venous lumen is positioned in a portion
of the third and fourth quadrants with a first region adjacent the
intersection of the four quadrants and a second region opposite the
first region. A wall thickness of the catheter at the second region
of the venous lumen has a first dimension and increases in
thickness in a direction toward the third quadrant and in a
direction toward the fourth quadrant to form a first arch shaped
wall portion, the arch shaped wall portion thereby having a thinner
portion at the portion aligned with a diameter bisecting the first
and fourth quadrants from the second and third quadrants and
progressively thicker portions in the third and fourth
quadrants.
[0024] The first arterial lumen is positioned in a portion of the
second and third quadrants and the second arterial lumen is
positioned in a portion of the first and fourth quadrants, wherein
a major portion of the first arterial lumen and the center of the
first arterial lumen are positioned in the second quadrant and a
major portion of the second arterial lumen and the center of the
second arterial lumen are positioned in the first quadrant. The
catheter wall portion forms a second arch shaped wall portion
adjacent the first arterial lumen having a first pinnacle and first
and second portions of increasing thickness extending away from the
pinnacle. The first pinnacle preferably lies in the second
quadrant.
[0025] Preferably, the catheter wall portion forms a third arch
shaped wall portion adjacent the second arterial lumen having a
second pinnacle and first and second portions of increasing
thickness extending away from the second pinnacle. Preferably, the
second pinnacle of third arch shaped wall portion lies in the first
quadrant.
[0026] A stiffening member can be provided removably positionable
within the catheter to temporarily increase stiffness of the
catheter to facilitate insertion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Preferred embodiment(s) of the present disclosure are
described herein with reference to the drawings wherein:
[0028] FIG. 1 is a perspective view of the distal portion of the
multi-lumen catheter of the present invention;
[0029] FIG. 1A is transverse a cross-sectional view of the catheter
taken along line A-A of FIG. 1;
[0030] FIG. 1B is a transverse cross-sectional view of the catheter
taken along line B-B of FIG. 1;
[0031] FIG. 1C is a transverse cross-sectional view of the catheter
taken along line C-C of FIG. 1;
[0032] FIG. 2 is a front view of the catheter of FIG. 1;
[0033] FIG. 3 is a perspective view of a proximal portion of the
catheter;
[0034] FIG. 4 is a transverse cross-sectional view taken along line
4-4 of FIG. 1;
[0035] FIG. 4A is an enlarged view similar to FIG. 4 showing the
thicknesses of the catheter wall portions and the quadrants of the
circle for ease of explanation;
[0036] FIG. 5 is a plan view illustrating insertion of the catheter
through the right internal jugular vein and superior vena cava into
the right atrium of a patient's body;
[0037] FIG. 6 is a longitudinal cross-sectional view of a dilator
for use with the insertion of the catheter of FIG. 1;
[0038] FIG. 6A is a perspective view of the proximal portion of the
dilator of FIG. 6;
[0039] FIG. 7 is a perspective view of a tunneling trocar
attachable to the catheter of FIG. 1 to aid insertion of the
catheter; and
[0040] FIG. 8 is a perspective view of a stiffener for use with the
catheter of FIG. 1 to aid insertion.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0041] Referring now in detail to the drawings where like reference
numerals identify similar or like components throughout the several
views, the catheter of the present invention is designated
generally by reference numeral 10. The catheter 10 is typically
inserted into an area of high velocity blood flow to ensure
sufficient blood can be transported from the body for dialysis.
FIG. 5 illustrates the catheter 10 inserted through the right
internal jugular vein "a", into the superior vena cava "b", and
into the right atrium "c". The catheter 10 can also be inserted for
example into the left internal jugular vein, into the superior vena
cava "b" and into the right atrium "c". Insertion into the right
atrium, from either the right or left side provides the necessary
high blood flow to the dialysis machine. Note that the catheter
body (catheter tube) 11 is sufficiently flexible to enable it to
bend to accommodate the anatomical curves as shown.
[0042] With reference to FIGS. 1, 3 and 5, catheter 10 has a
catheter body or catheter tube 11 having a distal portion 31 and a
proximal portion 33. Distal portion 31 terminates in elongated nose
portion 32. Proximal end portion 33 includes hub 12, where the
lumens formed within catheter tube 11 are connected, i.e.
transition, to the respective inflow and outflow tubes 16 and 18a,
18b, respectively, to enable return and withdrawal of blood for
dialysis. Tube clamps 27 and 29 cut off blood flow through inflow
and outflow tubes 16, 18a, 18b as desired. As used herein, the
terms "inflow" and "outflow" refer to the direction of blood or
fluid flow with respect to the catheter such that "return",
"delivery" or "venous flow" refers to flow from the dialysis
machine and delivered to the body while "intake", "withdrawal" or
"arterial flow" refers to blood or fluids withdrawn from the body
and transported to the dialysis machine.
[0043] As shown in FIG. 5, intermediate portion 35 of catheter 10
in certain uses of the catheter extends through subcutaneous tissue
tunnel "t", and curves downwardly toward the target site, e.g. the
right atrium. This tunnel "t" secures the catheter in place for
dialysis for a period of weeks, or even months, with a fibrous cuff
enabling tissue ingrowth. The formation of the tunnel "t" and the
insertion of the catheter 10 therethrough will be discussed below
in conjunction with the discussion of the catheter insertion
method.
[0044] It should be appreciated that although the catheter is shown
emerging from the tissue tunnel "t" at a second incision site,
alternatively, the tissue tunnel would not have an exit opening at
a second site but instead would exit through the same incision
through which initial access is made by the needle and dilator into
the internal jugular vein "a". This is described in more detail
below.
[0045] Several lumens are formed in catheter tube 11 for
transporting blood from the patient's body to a dialysis machine.
As is well known in the art, a dialysis machine essentially
functions as a kidney for patients suffering from kidney failure.
Blood is removed from the patient and transported to the dialysis
machine where toxins are removed by diffusion through a
semi-permeable membrane into a dialysis fluid. The filtered blood
is then returned through the lumen of the catheter body to the
patient.
[0046] More specifically, and with reference to FIGS. 1, 2 and 4,
details of the catheter lumens will now be described.
Longitudinally extending venous lumen 40 is formed within catheter
tube 11, extends the entire length of the tube and is designed to
transport filtered blood to the patient. Lumen 40 extends through
the reduced diameter nose portion 32 and is preferably
substantially circular in cross section and offset from the central
longitudinal axis of the tube 11. As shown in FIG. 4A, a first (or
top region as viewed in the orientation of FIG. 4A) lies at the
intersection of the four quadrants of the circular cross-section of
the catheter tube (or at the center) and the opposite second region
lies adjacent the intersection of the third and fourth quadrants.
Lumen 40 terminates in distal opening 49 to communicate with the
patient's body so blood can be delivered through distal opening 49.
One or more side holes 48 can be provided in the side wall of the
tube 11 for blood delivery. The lumen 40 preferably has a diameter
of about .082 inches and a cross-sectional area of about 0.00528
inches.
[0047] Venous lumen 40 is also configured to receive a guidewire 20
(FIG. 5) to direct the catheter to the desired position. The
guidewire 20 can be received directly through the lumen 40 or if a
stiffening member is utilized, the stiffening member would be
inserted through the lumen 40 and the guidewire would be inserted
through a lumen of the stiffening member (thereby extending through
lumen 40).
[0048] The wall of the tube forming the venous lumen 40
advantageously forms a bridge or arch to add to the stability of
the catheter and limit kinking of the catheter 10 during insertion
and use. More specifically, venous lumen region has wall portion 13
having a thicker area 13a and 13b (see FIG. 4A), thereby forming an
arch with pinnacle at area 13c. In other words, the thinner portion
13c can be viewed as adjacent the intersection of the third and
fourth quadrants, aligned with a diameter dividing the first and
fourth quadrants from the second and third quadrants. Thus, the
arch increases in thickness as it extends in opposite directions
from area 13c into the third and fourth quadrants (containing
respective areas 13a, 13b).
[0049] In an exemplary embodiment, wherein the diameter of the tube
(proximal of the nose portion 32) is about 0.114 inches (tapering
to about 0.104 inches) and the diameter of the venous lumen is
about 0.082 inches, the distance d1, d2 from the edges 41a, 41b of
the lumen 40 to the tube outer wall 14 (see tangent lines L1 and
L2) is about 0.054 inches.
[0050] This can be compared to the distance d3 (FIG. 4) of about
0.021 inches taken from the outer wall tube 14 to the edge 42 of
lumen 40 closest to the outer tube wall 14. Thus, the wall
thickness (distances from the lumen outer wall to the catheter
outer wall) progressively increases in both directions from the d3
designation.
[0051] Nose 32, as noted above, can also include side venous
(delivery) openings 48 formed through the outer wall 14 wall in
fluid communication with lumen 40, also functioning to return blood
to the patient's body. Side openings or ports can be angled
outwardly if desired to facilitate delivery of blood in the
direction of blood flow and lessen mechanical hemolysis. These
additional openings help maintain the desired flow volume by
distributing the blood through multiple holes. In a preferred
embodiment, two openings are provided spaced 120.degree. apart
(i.e. each spaced 60 degrees from a bottom wall as viewed in the
orientation of FIG. 1 of the catheter 10. It is also contemplated
that additional or fewer openings can be provided and the openings
can be axially displaced with respect to each other. The openings
can be equidistantly spaced about the circumference of the outer
wall 14 or asymmetrically spaced. Additional set(s) of openings can
also be provided spaced proximally or distally from side openings
48. The nose 32 at the catheter distal portion is elongated and has
a diameter less than the diameter of the intermediate portion 35 of
catheter 10. By way of example, in one embodiment, the outer
diameter of the distal nose portion 32 can be about 0.114 inches
and the outer diameter of the intermediate portion 35 can be about
0.208 inches. Clearly other dimensions are contemplated.
[0052] The transition portion 47 provides a smooth transition
between the intermediate portion 35 and the distal portion 31 as it
tapers in a distal direction. Formed in the transition portion 47
(FIG. 1) are two widened open areas 50a, 60a of arterial lumens 50,
60, respectively, separated by a reinforcing rib 47a extending
longitudinally. Thus, the intake (arterial) openings terminate in
longitudinally aligned openings at the transition portion 47. As
shown, the rib 47a, formed during the manufacturing step, extends
from the transition region 47 longitudinally and along the reduced
diameter nose section 42 to increase rigidity of the catheter. Rib
47a angles toward and into the outer wall 14 of the catheter 10,
terminating proximally of venous lumen opening 49. The distal end
47b of the rib 47a can be radiused as it extends longitudinally
before blending into the catheter wall 14.
[0053] The changing configuration of the catheter 10 at the
transition portion 47 can be appreciated by comparing FIGS. 1A-1C
which show transverse cross-sectional views along the transition
area. As shown, the wall edges 14b transition to a rounder shape in
FIG. 1B as they transition to a circular wall of FIG. 1C. Also, the
height of the rib 47A decreases in a distal direction (compare
height H2 to height H1).
[0054] With reference to FIGS. 1, 4 and 4A, catheter 10 also has a
pair of independent arterial (withdrawal) lumens 50 and 60
extending longitudinally along the length of the catheter body 11,
each terminating at open areas 50a, 60a in transition region 47 so
that their opening is proximal to the opening 49 of venous lumen
40. As shown in FIGS. 4 and 4A, lumens 50 and 60 each have an outer
curved wall 51, 61 along the side closest to the outer side (wall)
of the tube 11. The wall of the tube 11 forming the arterial lumen
50 and arterial lumen 60 advantageously forms a bridge or arch to
add to stability of the catheter and limit kinking of the catheter
10 during insertion and use.
[0055] More specifically, wall portion 17 of a first arterial lumen
region of the catheter has a thicker area 17a and 17b, thereby
forming an arch with pinnacle 17c. In an exemplary embodiment,
wherein the diameter of the tube (proximal of the nose portion 32)
is about 0.114 inches and the diameter of the venous lumen is about
0.082 inches, the distances d4 and d5 from the edge of the lumen 50
to the tube outer wall (see tangent lines L4, L5) is between about
0.041 inches to about 0.042 inches. This can be compared to the
distance d6 of about 0.018 inches taken from the outer wall 14 to
the edge of the lumen 50 closest to the outer wall 14. Thus, the
wall thickness progressively increases in both directions from the
d6 designation.
[0056] Lumen 60 is similarly dimensioned to lumen 50, with catheter
wall portion 19 of second arterial lumen region having a thicker
area 19a and 19b, thereby forming an arch with pinnacle 19c. In an
exemplary embodiment, wherein the diameter of the tube (proximal of
the nose portion 32) is about 0.114 inches and the diameter of the
venous lumen is about 0.082 inches, the distance d6', d7 from the
edge of the lumen 60 to the tube outer wall (see tangent lines L6,
L7) is between about 0.041 inches to about 0.042 inches. This can
be compared to the distance d8 of about 0.018 inches taken from
outer wall 14 to the edge of the lumen 60 closest to the outer tube
wall. Thus, the wall thickness progressively increases in both
directions from the d8 designation.
[0057] Note, in a preferred embodiment, distances d4, d5, d6' and
d7 are substantially equal and distances d6 and d8 are
substantially equal.
[0058] The shortest distance d9 between the two arterial lumens is
preferably about 0.022 inches. Due to the radiused sides, the
distance can progressively increase in both directions away from d9
to about 0.024 inches. The distance d10 and d11 between the
respective arterial lumens 50, 60 and the venous lumen 40 is
preferably about 0.016 inches. Note that the arterial lumen 50 lies
in the second and third quadrants, with the center of the lumen 50
and a major portion of the lumen 50 lying in the second quadrant.
Note that the arterial lumen 60 lies in the first and fourth
quadrants, with the center of the lumen 60 and a major portion of
the lumen 60 lying in the first quadrant. Thus, the pinnacle of the
arch adjacent the arterial lumen 50 lies in the second quadrant and
the pinnacle of the arch adjacent the arterial lumen 60 lies in the
first quadrant.
[0059] As can be appreciated, the various dimensions provided
herein are provided by way of example, it being understood that
other dimensions are also contemplated to achieve the arch support
to achieve the balance of maximized blood flow with sufficient wall
thickness to limit catheter kinking. That is, the lumen
configurations are uniquely designed to achieve maximum flow rates
through the catheter for enabling procedures such as dialysis while
ensuring the catheter is resistant to kinking since kinking will
adversely affect blood flow and could reduce the long term
effectiveness of the catheter which is designed for long term use.
The lumens are also uniquely designed to provide smooth edges so as
to prevent blood clotting which could occur with sharper edges. The
arches of the catheter wall achieve this. Also, the shape of the
venous lumen and the shape of the arterial lumens achieve this. As
discussed above, the venous lumen is preferably substantially
circular in configuration. Each of the arterial lumens is
asymmetrically configured.
[0060] More specifically, arterial lumen 50 includes a curved outer
wall 51 adjacent the edge closest to the catheter wall 14. Somewhat
opposite curved wall 51 is curved or concave inner wall 52. Walls
51 and 52 are joined in quadrant III by a radiused wall 54. A wall
58 with a slight radius with respect to a line (see phantom line P)
parallel to a diameter C1 of the catheter dividing the first and
fourth quadrants from the second and third quadrants, connects to
inner wall 52 via radiused wall 56. Radiused wall 58 transitions
into a larger radius wall 59 to join with outer wall 51. Thus, this
asymmetrical arterial lumen 50 has radiused walls along all of its
sides. The arterial lumen 50 can also be considered somewhat "liver
shaped."
[0061] Lumen 60 is the mirror image of lumen 50 and thus faces in
the opposite direction. Thus, lumen 60 includes a curved outer wall
61 adjacent the edge closest to the catheter wall 14. Somewhat
opposite curved wall 61 is curved or concave inner wall 62. Walls
61 and 62 are joined in quadrant IV by a radiused wall 64. A wall
68 with a slight radius with respect to line P connects to inner
wall 62 via radiused wall 66. Radiused wall 68 transitions into a
larger radius wall 69 to join with outer wall 61. Thus, this
asymmetrical arterial lumen 60 has radiused walls along all of its
sides. The arterial lumen 60 can also be considered somewhat "liver
shaped."
[0062] By way of example, walls 59 and 69 can have a radius of
curvature of about 0.005 inches to about 0.030 inches, and
preferably about 0.013 inches. Walls 58 and 68 can have a radius of
curvature of about 0.050 inches to about 0.250 inches, and
preferably about 0.150 or about 0.144 inches. The radius of
curvature of outer walls 51 and 61 can be about 0.070 inches to
about 0.050 inches, and preferably about 0.060 inches. The radius
of curvature of walls 56 and 66 can be about 0.005 inches to about
0.030, inches, and preferably about 0.018 inches. Inner radiused
walls 52 and 62 can have a radius of curvature of about 0.090
inches to about 0.130 inches, and preferably about 0.114 inches.
Walls 54 and 64 can have a radius of curvature of about 0.005
inches to about 0.030 inches, and preferably about 0.010 inches. As
can be appreciated, other dimensions are also contemplated.
[0063] Although lumens 50 and 60 are isolated along the length of
the catheter, they have a common flow source flowing into the
separate inflow tubes of catheter 10 via hub 12.
[0064] As noted above, in the illustrated embodiment, the venous
(return) lumen size preferably ranges from about 0.005 inches to
about 0.006 inches.sup.2 in cross-sectional area, and is more
preferably about 0.00528 inches.sup.2. The cross-sectional area of
each of the arterial (intake) lumens 50, 60 preferably ranges from
about 0.0040 inches to about 0.0048 inches.sup.2, and more
preferably about 0.00473 inches.sup.2, bringing the total
cross-sectional area of the intake lumens to about 0.0080 inches to
about 0.0096 inches.sup.2, and more preferably about 0.00946
inches.sup.2. This means that the ratio of total cross sectional
area of the return lumen to the intake lumens is preferably about
0.56 to about 1.0. It should be appreciated that other dimensions
are also contemplated.
[0065] To facilitate insertion, the catheter 10 is configured to
receive a stiffening member such as a stiffening member 80 shown in
FIG. 8. Stiffing member 80 has a lumen 81 extending therethrough to
receive a guidewire, e.g. guidewire 20. Stiffening member (or rod)
80 is inserted into circular venous lumen 40 of catheter 10 to
stiffen the flexible catheter for ease in over the wire insertion
and navigation through the small vessels. That is, the catheter 10
with stiffener 80 attached thereto and extending through venous
lumen 40 is threaded over guidewire 20 (guidewire 20 can be
backloaded through the distal opening of lumen 81 of stiffening
member 80). The stiffening member 80 can have an internal thread on
knob 84 at the proximal portion to be connected to the screw thread
15 of inflow (venous) tube 16 (see FIG. 5). This temporarily
secures the stiffening rod within the catheter 10 during insertion.
External thread 85 is configured for threaded attachment of a
syringe (not shown) for fluid flushing of the stiffener 80 (through
lumen 81) prior to use. An example of a stiffening rod that also
can be utilized is described in U.S. Pat. No. 7,077,829, the entire
contents of which are incorporated herein by reference.
[0066] After the catheter 10 is positioned at the desired site, the
stiffening member 80 is unthreaded from the proximal thread 15 of
venous (return) tube 16 and removed from the venous lumen 50 of the
catheter 10 and from the venous (return) tube 16.
[0067] It should be appreciated that the stiffening member 80 can
alternatively be temporarily (removably) attached at its proximal
end to the tube 16 by other means such as a bayonet lock, snap fit,
etc. The stiffening member could first be manually twisted and then
mounted by these various means for retention in its torqued
position.
[0068] A dilator 90, illustrated in FIG. 6, can also be utilized
during the insertion method. The dilator has a lumen 92 extending
therethrough which receives the guidewire, e.g. guidewire 20. That
is, the guidewire is threaded through the distal opening 93 in the
distal end 91 of the dilator 90 and exits through proximal opening
95 at proximal end 97. The dilator 90 dissects tissue as it is
advanced into the vessel over the guidewire. A tapered distal
region helps to achieve such dissection. The proximal end 97 of
dilator 90 has an external thread 99 to threadingly receive a
syringe for flushing the dilator 90 with fluid through lumen 92
prior to use. Longitudinally extending raised surfaces 98 at the
proximal end facilitate gripping of the dilator.
[0069] Tissue tunneling trocar device 100, shown in FIG. 7, has a
proximal portion 102 and a distal portion 104. The trocar 100 can
be in the form of a solid member. Proximal end 105 frictionally
fits within the open distal end of the catheter, and particularly
in the opening in the venous lumen 40. Bumps 106, 108, on the outer
wall of the trocar 100 enhance the frictional engagement. The
distal portion 104 has a curved region, terminating into an
atraumatic tip 109 to bluntly dissect tissue as the catheter is
inserted through the tissue tunnel. In use, bumps 106, 108 are
inserted into the venous lumen 40 of the catheter, frictionally
connecting the tunneling trocar 100 to the catheter 10. With the
trocar 100 attached, the catheter 10 is inserted through the
subcutaneous tissue tunnel with the tip 109 bluntly dissecting
tissue. After the catheter emerges from the tissue tunnel, the
trocar 100 is removed. A stiffener can then be inserted through the
venous lumen 40 of the catheter as described above to receive the
guidewire as described above.
[0070] A venous extension tube 16 and two arterial extension tubes
18a, 18b extend through the hub 12 to communicate with the lumens
of the catheter tube 11 as shown in FIGS. 3 and 5. Tubes 18a, 18b
are stacked in a vertical relationship. A venous clamp 27 is shown
positioned over the venous tube 16 and an arterial clamp 29 is
shown positioned over the two stacked arterial tubes 18a, 18b to
cut off blood flow through both tubes 18a, 18b, preferably
substantially simultaneously. An arterial tag 29a and venous tag
27a, to provide indication of priming volume or other information,
are shown attached to the respective arterial and venous clamps.
Additional details of the clamps and tags, e.g. the clamp posts to
limit lateral movement of the stacked arterial extension tubes, are
disclosed in U.S. Patent Publication 2008-0312578, the entire
contents of which are incorporated herein by reference.
[0071] The catheter can optionally include a surface treatment on
the exterior and/or the interior. The surface treatments can
include for example, a hydrophilic coating to increase lubricity
and facilitate insertion, a drug coating such as heparin or
containing lib, Ma inhibitors, inert coating substances such as
Sorins carbon coating, and/or active coatings such as a silver ion
coating.
[0072] One method of insertion of the catheter of the present
invention provides an entire over the wire system. This is achieved
by the provision of a trocar such as disclosed in U.S. Patent
Publication 2008-0312578, the entire contents of which are
incorporated herein by reference. The trocar has a lumen formed
therethrough dimensioned for reception of a guidewire. The blunt
distal tip of the trocar bluntly dissects tissue to create a
subcutaneous tissue tunnel for subsequent securement of the
catheter.
[0073] In use in a complete over the wire insertion method, first a
needle is inserted into the internal jugular vein to properly
locate the vessel and a guidewire is inserted through the needle
into the right internal jugular vein "a" and into the superior vena
cava "b". The guidewire is further advanced into the right atrium
"c", and preferably into the inferior vena cava. The needle is then
withdrawn, leaving the guidewire in place, extending out of the
patient's body at the proximal portion. A dilator such as dilator
90 of FIG. 6 can be inserted over the guidewire to dilate tissue.
Next, a trocar is inserted through a first incision in the patient,
bluntly dissecting and tunneling under the skin, and forced out of
the tissue at a second incision or site, creating a subcutaneous
tunnel "t" under the tissue. This provides a way to secure the
catheter. The guidewire is then threaded through the trocar lumen,
with the proximal portion first inserted through trocar distal
opening so it emerges out of a proximal opening. The trocar is then
withdrawn from the body, leaving the guidewire in place, extending
from the right atrium and superior vena cava, out through the right
internal jugular vein and through the tissue tunnel "t".
[0074] Catheter 10 is then threaded over the guidewire with the
proximal portion of the guidewire inserted through the distal tip
lumen of the catheter, e.g. distal opening 49, through the length
of the venous lumen 40, and through the hub 12 into the inflow tube
16. The catheter 10 is thus threaded over the wire, through the
tissue tunnel "t" where a cuff is positioned in the tissue tunnel
"t" to aid in securement of the catheter by enabling tissue
ingrowth over a period of time. The catheter is further advanced
over the guidewire down into the right internal jugular vein, into
the superior vena cava, and into the right atrium "c". The
guidewire 20 is then withdrawn, leaving the catheter 10 in place
for use. Note a stiffening member such as stiffener 80 of FIG. 8,
is preferably utilized, i.e. inserted into lumen 40 of catheter 10
and inserted over the guidewire through the fitting 15, inflow tube
16, and hub 12 to help guide the catheter as described herein.
Thus, the guidewire would extend through the venous lumen of
catheter by extending through the central lumen of the stiffening
member which is positioned within the venous lumen 40 of the
catheter.
[0075] As can be appreciated, the catheter will be inserted in a
similar fashion through the left internal jugular vein. In this
method, the subcutaneous tissue tunnel will be formed on the left
side by the trocar, and the catheter inserted over the guidewire
through the tissue tunnel and through the left internal jugular
vein or subclavian vein and into the superior vena cava and right
atrium in the same way as described for right side insertion
[0076] In an alternative method of insertion, instead of forming a
second incision site adjacent the incision site through which the
needle and guidewire are introduced into the internal jugular vein,
the trocar emerges from the needle/guidewire insertion site. In
this method, the trocar is inserted through a first incision to
create a subcutaneous tissue tunnel; however, unlike the
aforementioned method, the trocar does not emerge at a second
incision site. Instead, the trocar is advanced subcutaneously to
the needle incision site and emerges through that site. Thus, the
distal end of the trocar exits the incision site alongside the
guidewire. The guidewire is then inserted (threaded) through the
opening in the trocar as described above and then the trocar is
withdrawn through the tissue tunnel "t" and out through the first
incision such that the guidewire extends through the tunnel. After
the guidewire 20 exits the tunnel "t" and out through the first
incision, the trocar is removed, leaving the guidewire 20 in place.
The guidewire is positioned to form a guidewire loop to facilitate
insertion of the catheter.
[0077] The catheter 10 is then advanced over the guidewire and
through the tissue tunnel and exiting the needle incision site into
the internal jugular vein "a", tracking the loop of the guidewire,
and then advanced downwardly through the internal jugular vein, the
superior vena cava and into the right atrium "c". The guidewire is
then withdrawn and the catheter is pushed downwardly and/or pulled
back to straighten the loop. If the catheter is inserted with a
stiffening member, the guidewire would extend through the lumen of
the stiffening member as the stiffening member is positioned in the
lumen of the catheter.
[0078] It should be appreciated that formation of the loop in the
guidewire and the catheter is optional and the procedure can be
performed without the loop.
[0079] In an alternative approach, a trocar is provided which does
not provide for an entire over the wire system, however, it is used
with an approach providing a partial over the wire system which
eliminates the need for a tear way introducer sheath which often
times is utilized to guide the dialysis catheter through the
vessels into the right atrium. To avoid the use of the tear away
sheath, the catheter in this alternate method can be advanced over
a guidewire which can be placed in the manner described above. In
this method, the trocar such as trocar 100 of FIG. 7, is attached
to the distal end of the catheter by insertion of a barbed end into
a mating fitting, or by other ways to temporarily attach the
trocar. The trocar has a blunt distal tip and is advanced through a
first tissue incision and out through a second tissue incision,
bluntly dissecting tissue and forming a subcutaneous tissue tunnel
in a similar manner as described above, except without the
guidewire. Since the trocar is attached to the catheter, it pulls
the catheter through the tissue tunnel, so it emerges out through
the second incision. The trocar is then detached from the catheter.
The catheter is then bent as necessary and threaded over the
guidewire into jugular vein, superior vena cava, and right
atrium.
[0080] In another method, a curved needle is used to create access
to the site. A wire is passed through the needle to the site, the
needle is then removed, and a dilator, such as dilator 90 of FIG.
6, is inserted over the wire. After dilating the tissue, the
dilator is removed and the catheter 10 with a stiffening member
positioned therein, such as stiffening member 80 of FIG. 8, are
inserted over the guidewire into the right atrium.
[0081] It should be appreciated that although the catheter is
described herein as a dialysis catheter for hemodialysis, the
catheter disclosed herein could have other surgical applications,
such as drug delivery or blood sampling.
[0082] While the above description contains many specifics, those
specifics should not be construed as limitations on the scope of
the disclosure, but merely as exemplifications of preferred
embodiments thereof. Those skilled in the art will envision many
other possible variations that are within the scope and spirit of
the disclosure as defined by the claims appended hereto.
* * * * *