U.S. patent application number 10/870508 was filed with the patent office on 2004-11-18 for curved tip for an insertion device.
This patent application is currently assigned to SPAN-AMERICA MEDICAL SYSTEMS, INC.. Invention is credited to Pike, Kevin H., Spinks, Thomas L..
Application Number | 20040230164 10/870508 |
Document ID | / |
Family ID | 32775466 |
Filed Date | 2004-11-18 |
United States Patent
Application |
20040230164 |
Kind Code |
A1 |
Spinks, Thomas L. ; et
al. |
November 18, 2004 |
Curved tip for an insertion device
Abstract
The present invention is directed to an insertion device, such
as a catheter, including a tip having a hollow, substantially
radial cross sectional configuration and a substantially parabolic
longitudinal configuration with a circular tip curvature. The outer
wall of the novel tip of the invention is completely curved, and
contains no straight or angled outer walls within the length of the
tip. The inner wall of the tip defines a substantially straight
passageway through which a piercing device such as a needle may be
inserted.
Inventors: |
Spinks, Thomas L.;
(Sylvania, OH) ; Pike, Kevin H.; (Clinton,
MI) |
Correspondence
Address: |
GARDNER CARTON & DOUGLAS LLP
ATTN: PATENT DOCKET DEPT.
191 N. WACKER DRIVE, SUITE 3700
CHICAGO
IL
60606
US
|
Assignee: |
SPAN-AMERICA MEDICAL SYSTEMS,
INC.
Greenville
SC
29606
|
Family ID: |
32775466 |
Appl. No.: |
10/870508 |
Filed: |
June 17, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10870508 |
Jun 17, 2004 |
|
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|
09698621 |
Oct 27, 2000 |
|
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6770059 |
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60162322 |
Oct 28, 1999 |
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Current U.S.
Class: |
604/264 |
Current CPC
Class: |
A61M 5/3286 20130101;
A61M 25/0068 20130101; A61M 25/0631 20130101 |
Class at
Publication: |
604/264 |
International
Class: |
A61M 025/00 |
Claims
What is claimed is:
1. An insertion device comprising: a tube including a first end and
a second end, the first and second ends defining a first
passageway; a tip located at the first end, the tip including an
inner wall and an outer wall and having a substantially curved
surface profile; wherein the outer wall contains no linear surfaces
and the inner wall defines a substantially straight second
passageway; and wherein the second end is adapted to receive an
attachment device.
2. The insertion device of claim 1 wherein the second passageway is
adapted to receive a piercing device.
3. A catheter comprising: a tube having substantially parallel
walls and having a generally cylindrical profile; a tip having a
profile, an insertion end; and a connecting surface; wherein the
tip profile is substantially and generally parabolic beginning at a
point at which the cylindrical profile of the catheter tube first
begins to narrow; and wherein the insertion end has a point of
insertion having a substantially circular profile.
4. The insertion device of claim 1, wherein the tip further
comprises an insertion end including point of insertion having a
substantially arcuate profile, the arc being described by a circle
having a radius "r", wherein the measurement of "r" is in the range
of from about 0.0001 inches to about 0.0030 inches.
5. An insertion device comprising: a tube including a tip having a
profile, the tube further including a substantially cylindrical
body; wherein the tip comprises an insertion end and a surface
section connecting said insertion end with the substantially
cylindrical body, and the tip having a profile; wherein the tip has
a substantially curved surface profile; and wherein the insertion
end and the connecting surface section together define a length
"L".
6. The catheter of claim 3 wherein the tube is a catheter and
wherein the second end includes attachment means for attaching the
catheter to a device.
7. The catheter of claim 3, wherein the tube is comprised of
plastic.
8. The catheter of claim 7, wherein said plastic is
polyurethane.
9. The insertion device of claim 1 wherein the tube is comprised of
plastic.
10. The insertion device of claim 1, wherein the tube includes an
interior surface and an exterior surface, said interior surface
being adapted to receive a needle.
11. The catheter of claim 3, wherein the tube includes an interior
surface and an exterior surface, said interior surface being
adapted to receive a needle.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/162,322, filed 28 Oct. 1999.
FIELD OF THE INVENTION
[0002] The present invention relates to a tip for an insertion
device. More specifically, the invention is directed to a curved
tip for an insertion device such as a catheter. The surface profile
of the novel tip of the invention is completely curved and includes
a generally parabolic tubular surface profile with an insertion end
that assumes a generally circular surface profile.
BACKGROUND OF THE INVENTION
[0003] A catheter is usually inserted through the skin of a patient
by use of a sharp instrument, such as a needle. In many
applications, the needle extends through the catheter wherein the
point of the needle is adjacent to and extending slightly beyond
the tip of the catheter. The needle pierces the skin of the patient
to form an opening and the tip of the catheter follows the needle
into the opening.
[0004] Traditional catheter tips generally have straight edges and
blunt insertion ends. The bluntness of traditional tips impedes the
forward progress of the catheter into the opening in the skin. The
force required to insert a blunt ended, straight edged catheter tip
into the skin, which is also known as "transition force," is
generally sufficiently high to cause pain to the patient upon
insertion.
[0005] Attempts have been made to reduce the transition force
required to insert a catheter into the skin of a patient. An
example of such a catheter is shown in U.S. Pat. No. 4,588,398. In
this patent, the tip of the catheter is angular, although still
with straight edges and a blunt insertion end.
[0006] It has been found that there is a need for a catheter tip
that provides for the smooth and easy transition from a needle to a
catheter as the device moves through the skin, to reduce the
transition force during insertion of a catheter into a patient. The
present invention satisfies this need.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to an insertion device,
such as a catheter, including a tip having a hollow, substantially
radial cross sectional configuration and a substantially parabolic
longitudinal configuration with a longitudinally circular tip
curvature. The outer wall of the novel tip of the invention is
completely curved, and contains no straight or angled outer walls
within the length of the tip. The inner wall of the tip defines a
substantially straight passageway through which a piercing device
such as a needle may be inserted.
[0008] An embodiment of the present invention provides an insertion
device that reduces the transition force required to insert the
device into the skin of a patient.
[0009] An embodiment of the present invention also provides a tip
for an insertion device having an entirely curved outer wall in the
longitudinal dimension.
[0010] An embodiment of the invention further provides a catheter
tip configuration which is thin enough to reduce the
above-referenced transition force yet tough enough to eliminate
splitting, tearing, or bunching of the catheter tubing material
during insertion.
[0011] An embodiment of the present invention provides a catheter
tip with a smoothly convex outer wall.
[0012] Other embodiments and advantages of the present invention
shall become apparent to those skilled in the art upon a review of
the following detailed description of the preferred embodiments and
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a plan view of the insertion device according to
the present invention positioned on a handle assembly with a needle
extending through the insertion device;
[0014] FIG. 2 is a side view cutaway of the generally parabolic tip
of the invention, illustrating the completely curved outer wall of
the tip and the longitudinally circularly curved insertion end of
the tip.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The preferred embodiment and best mode of the present
invention will now be described in detail with reference being made
to the drawings. The insertion device such as a catheter is
indicated generally in the drawings by the reference number 10.
[0016] Referring to FIGS. 1 and 2, the catheter 10 includes a
longitudinally extending tube 12 having a tip 14 and a second end
16. The second end 16 includes an attachment device 20 for
attaching the catheter 10 to, for example, a safety needle
retraction assembly 22 or a luer-fitted coupling device (not
shown). The tube 12 includes an interior surface 24 and an exterior
surface 26. The interior surface 24 is adapted to receive a needle
28 having a pointed end 30.
[0017] The catheter 10 is typically comprised of a plastic
material. In a preferred embodiment, the plastic material is
polyurethane, but it can also be TEFLON or any commonly known
catheter material. It has been found that polyurethane has a
relatively low coefficient of drag or friction, but the invention
contemplates that other suitable materials may also be used. A low
coefficient of friction aids the insertion of the catheter 10 into
the skin of a patient in a smooth and efficient manner. The
catheter 10 and/or the needle 28 can be treated with a lubricant.
In the preferred embodiment, the lubricant is a conventional
silicone-based compound. The lubricant reduces friction between the
catheter 10 and the skin of a patient during insertion.
[0018] Referring now to FIG. 2, in one preferred embodiment of a
catheter having a tip formed according to the present invention,
the tip 14 is substantially generally parabolic in profile having a
length "L" 36, over which length the catheter tube 12 is smoothly
and gradually reduced from its original wall thickness "t" 38 to
intersect the surface of the needle 28 at catheter insertion end
40. The insertion end 40 is the end that is inserted, along with a
needle 28, through a patient's skin. Over the length "L", the
surface profile of the catheter tip 14 generally follows a smooth,
substantially parabolic curve 32 except at the point of insertion
into a patient's skin, 40. At this point, the surface profile of
the insertion end becomes substantially circular, and is described
by an arc on a circle having a radius "r", 42, as shown in FIG. 2.
Length "L" may vary, and the generally parabolic surface profile 32
of tip 14 substantially flattens at or near point 34 where it
assumes the generally cylindrical profile of the catheter tube with
substantially parallel walls, with thickness "t" being relatively
constant over the remaining length of tube 12 from point 34 to the
second end 16 (as shown in FIG. 1). Thus, it will be seen that the
substantially parabolic surface profile of tip 14 includes a
narrowing of the profile to intersect the surface of needle 28 and
includes a muting of the tip of the insertion end 40, which
insertion end 40 assumes the shape of a an arc on a circle of
radius "r" 42, at some point before the parabola intersects the
surface of needle 28. The insertion end 40 then follows this
circular profile until it intersects the needle surface 28, as
illustrated in FIG. 2. It is this unique combination of the
smoothly convex, generally parabolic narrowing-down of the catheter
tube 14, terminating in a slight muting of the parabolic curve by
means of the circular surface contour at the insertion end 40, that
reduces the transition force while maintaining the physical
integrity of the catheter material at the insertion end 40.
[0019] It should be noted that the parabolic profile is not
configured such that its apex would intersect the circumference of
the circle; if it did, it could create a dimple in the smoothly
convex overall outer wall configuration. Rather, the apex of the
parabola lies on the surface of the needle just beyond the point at
which the circle of radius "r" intersects the surface of needle
(28). Point "p" (46) defines a smooth, dimple-free transition
between the parabolic and circular profiles of the tip 14 of the
invention. Thus, the convex, parabolic shape is analogous to a
comet tail, rolling over and out from the ball of the comet.
[0020] It is to be emphasized that the geometric characteristics
described above are key in providing physical and operational
integrity of the tip (i.e., prevent splitting and bunching and
other side effects), and to minimize the transition force. The
radius "r" is determined as an optimization between material
strength and catheter penetration force. If "r" is too large the
bulk profile of the tip makes penetration into the skin and vein
high and not acceptable. If "r" is too small the material integrity
is such that the tip can buckle going into the skin and vein and
thus requires a high entry force. If "r" is too small the tip may
also split or tear. Radius "r" is generally independent of catheter
gauge.
[0021] We have found that "r" may vary between 0.0001 inch and
0.0030 inches, preferably between 0.0001 inch and 0.0020 inches,
and most preferably between 0.0005 inches and 0.0010 inches, for
most common catheter materials. It should be understood that other
values or "r" may be readily achieved using different
materials.
[0022] In addition, it is important that the tip 14 be of overall
convex configuration and that a convex, smoothly curving shape be
maintained from the tip over the entire length "L". Length "L" will
vary depending upon the gauge of the catheter, and various lengths
are considered within the scope of the invention.
[0023] By way of example and not by way of limitation, various
dimensions for tips of the invention are provided in Table 1,
wherein the radius and length are referenced in FIG. 2. Of course,
different gauge catheters will have differently dimensioned tips,
and the examples provided here are not intended to be exhaustive of
all possible dimensions. For instance, for a very large catheter,
"r" may be larger than the dimensions shown below. The lengths
provided in table 1 are nominal lengths.
1 TABLE 1 Sample Gage Radius, r (inch) Length, L (inch) 1 18
0.00040 0.075 2 18 0.00015 0.075 3 18 0.00010 0.075 4 18 0.00011
0.075 5 22 0.00010 0.063 6 22 0.00020 0.063
[0024] The above detailed description of the present invention is
given for explanatory purposes. It will be apparent to those
skilled in the art that numerous changes and modifications can be
made without departing from the scope of the invention.
Accordingly, the whole of the foregoing description is to be
construed in an illustrative and not a limitative sense, the scope
of the invention being defined solely by the appended claims.
* * * * *