U.S. patent number RE45,896 [Application Number 14/502,544] was granted by the patent office on 2016-02-23 for systems and methods for providing a catheter assembly.
This patent grant is currently assigned to Becton, Dickinson and Company. The grantee listed for this patent is Weston F. Harding, S. Ray Isaacson, Yiping Ma, Austin Jason McKinnon, Marty L. Stout. Invention is credited to Weston F. Harding, S. Ray Isaacson, Yiping Ma, Austin Jason McKinnon, Marty L. Stout.
United States Patent |
RE45,896 |
Stout , et al. |
February 23, 2016 |
Systems and methods for providing a catheter assembly
Abstract
A system for controlling fluid flow in a catheter assembly is
disclosed herein. An intravenous catheter assembly has a catheter
adapter and a needle hub, and the catheter adapter has an inner
lumen. A septum is disposed within a portion of the inner lumen,
and a slit is formed through the septum. A Parylene coating is
disposed within the slit of the septum, the Parylene coating has a
thickness of between approximately 0.00005 to 0.0005 millimeters.
An introducer needle has a first end coupled to the needle hub and
the second end extending through the inner lumen of the catheter
adapter. A middle portion of the introducer needle is positioned
within a portion of the septum.
Inventors: |
Stout; Marty L. (South Jordan,
UT), Harding; Weston F. (Lehi, UT), Isaacson; S. Ray
(Roy, UT), Ma; Yiping (Layton, UT), McKinnon; Austin
Jason (Herriman, UT) |
Applicant: |
Name |
City |
State |
Country |
Type |
Stout; Marty L.
Harding; Weston F.
Isaacson; S. Ray
Ma; Yiping
McKinnon; Austin Jason |
South Jordan
Lehi
Roy
Layton
Herriman |
UT
UT
UT
UT
UT |
US
US
US
US
US |
|
|
Assignee: |
Becton, Dickinson and Company
(Franklin Lakes, NJ)
|
Family
ID: |
55314853 |
Appl.
No.: |
14/502,544 |
Filed: |
September 30, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12703336 |
Jun 25, 2013 |
8469928 |
|
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12544625 |
Mar 5, 2013 |
8388583 |
|
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61151775 |
Feb 11, 2009 |
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Reissue of: |
13042154 |
Mar 7, 2011 |
8679063 |
Mar 25, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M
25/0606 (20130101); A61M 25/0045 (20130101); A61M
25/0009 (20130101); A61M 39/06 (20130101); A61M
39/0606 (20130101); A61M 39/0208 (20130101); A61M
25/0097 (20130101); A61M 25/0693 (20130101); A61L
29/085 (20130101); A61L 29/085 (20130101); C08L
65/04 (20130101); Y10T 29/49982 (20150115); A61M
2039/0646 (20130101); A61M 2039/0633 (20130101); A61M
2205/0238 (20130101); A61M 2039/062 (20130101); A61M
39/26 (20130101); Y10T 29/49826 (20150115); A61M
2039/064 (20130101); A61M 2039/0036 (20130101) |
Current International
Class: |
A61M
5/178 (20060101); A61M 25/00 (20060101); A61M
39/06 (20060101); A61M 25/06 (20060101); A61M
39/26 (20060101) |
Field of
Search: |
;604/164.01,164.02,167.01,167.02,167.03,167.04,167.05,167.06,168.01,224-226 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2133053 |
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Mar 1995 |
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CA |
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WO 99/34849 |
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Jul 1999 |
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WO |
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WO 2008/022258 |
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Feb 2008 |
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WO |
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WO 2008/045761 |
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Apr 2008 |
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WO |
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Other References
Silva, Elson, Email Regarding "Respecting Hydrology Science and IP
Rights--US Pat. Application 20110130728," pp. 1-6, Jun. 2, 2011.
cited by applicant.
|
Primary Examiner: Wehner; Cary
Attorney, Agent or Firm: Lukasavage; Jeanne Metcalf; Craig
McConkie; Kirton
Parent Case Text
RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent
application Ser. No. 12/703,336, filed Feb. 10, 2010, entitled
SYSTEMS AND METHODS FOR PROVIDING A FLUSHABLE CATHETER ASSEMBLY,
which claims the benefit of U.S. Provisional Application No.
61/151,775, filed Feb. 11, 2009, entitled CATHETER VALVE ASSEMBLY,
and which is also a continuation-in-part of U.S. patent application
Ser. No. 12/544,625 "SYSTEMS AND METHODS FOR PROVIDING A FLUSHABLE
CATHETER ASSEMBLY," filed Aug. 20, 2009. This application claims
the benefit of and incorporates by reference each of the
above-referenced applications.
Claims
The invention claimed is:
1. A system for controlling fluid flow in a catheter assembly,
comprising: an intravenous catheter assembly having a catheter
adapter and a needle hub, the catheter adapter having an inner
lumen; a septum disposed within a portion of the inner lumen; a
ventilation channel interposed between the septum and an inner
surface of the inner lumen of the catheter adapter, the ventilation
channel having a surface area and perimeter selected to permit
passage of air and prevent passage of blood; a slit formed through
the septum; a coating, formed of vapor deposited polyxylylene
polymers, disposed .[.within the slit.]. .Iadd.on at least a
portion of the surface .Iaddend.of the septum, the coating having a
thickness of between approximately 0.00005 to 0.0005 millimeters;
and an introducer needle having a first end and a second end, the
first end being coupled to the needle hub and the second end
extending through the inner lumen of the catheter adapter, a middle
portion of the introducer needle being positioned within a portion
of the septum.
2. The system of claim 1, wherein the thickness of the coating is
between 0.0001 to 0.0002 millimeters.
3. The system of claim 2, further comprising a lumen forming a
fluid pathway through .[.the.]. .Iadd.a .Iaddend.septum activator,
the lumen having an inner diameter configured to permit passage of
the introducer needle.
4. The system of claim 1, further comprising a septum activator
disposed within a portion of the inner lumen adjacent to the
septum, a distal end of the septum activator contacting a proximal
surface of the septum, and a proximal end of the septum activator
being positioned adjacent to an opening of the catheter adapter,
wherein the proximal end of the septum activator is accessed by
inserting an external device into the opening of the catheter
adapter.
5. The system of claim 1, .[.wherein the.]. .Iadd.further
comprising a .Iaddend.septum activator .[.comprises.]..Iadd., said
septum activator comprising .Iaddend.a plurality of vents and flow
diverters configured to improve circulation of a fluid within at
least one of the septum activator and an interstitial space between
the septum activator and the inner surface of the inner lumen.
6. The system of claim 1, further comprising a flow vent interposed
between an outer surface of the introducer needle and an inner
surface of .[.the.]. .Iadd.a .Iaddend.septum activator lumen,
wherein a rate of flow through the flow vent is determined by
adjusting at least one of an outer diameter of the introducer
needle and the inner diameter of the septum activator lumen.
7. A method manufacturing a catheter assembly having features for
controlling fluid flow within the catheter assembly, the method
comprising: providing an intravenous catheter assembly having a
catheter adapter and a needle hub, the catheter adapter having an
inner lumen; disposing a septum within the inner lumen, the septum
having a slit therethrough; providing a ventilation channel between
the septum and an inner surface of the inner lumen of the catheter
adapter, the ventilation channel having a surface area and
perimeter selected to permit passage of air and prevent passage of
blood; coating .Iadd.at least a portion of the surface of
.Iaddend.the septum .[.and the slit.]. with a coating having a
thickness of between approximately 0.00005 to 0.0005 millimeters,
the coating being formed of vapor deposited polyxylylene polymers;
positioning an introducer needle within the catheter adapter,
wherein a first end of the introducer needle is coupled to the
needle hub and a second end of the introducer needle extends
through the inner lumen of the catheter adapter, a middle portion
of the introducer needle being positioned within a portion of the
septum.
8. The method of claim 7, wherein the thickness of the coating is
between 0.0001 to 0.0002 millimeters.
9. The method of claim .[.8.]. .Iadd.7.Iaddend., further comprising
providing a lumen forming a fluid pathway through .[.the.]. .Iadd.a
.Iaddend.septum activator, the lumen having an inner diameter
configured to permit passage of the introducer needle.
10. The method of claim 7, further comprising disposing a septum
activator within a portion of the inner lumen adjacent to the
septum, a distal end of the septum activator contacting a proximal
surface of the septum, and a proximal end of the septum activator
being positioned adjacent to an opening of the catheter adapter,
wherein the proximal end of the septum activator is accessed by
inserting an external device into the opening of the catheter
adapter.
11. The method of claim 7, further comprising .[.modifying the.].
.Iadd.providing a .Iaddend.septum activator .[.to include.].
.Iadd.including .Iaddend.a plurality of vents and flow diverters
configured to improve circulation of a fluid within at least one of
the septum activator and an interstitial space between the septum
activator and the inner surface of the inner lumen.
12. The method of claim 8, further comprising providing a flow vent
interposed between an outer surface of the introducer needle and an
inner surface of the septum activator lumen, wherein a rate of flow
through the flow vent is determined by adjusting at least one of an
outer diameter of the introducer needle and the diameter of the
septum activator lumen.
13. An intravenous catheter assembly, comprising: a catheter
adapter having an inner lumen, the inner lumen having a proximal
end, a distal end and a middle portion; a recess forming the middle
portion of the inner lumen; a septum disposed within the recess,
the septum forming a defeatable barrier between the proximal end
and the distal end of the inner lumen; a ventilation channel
interposed between the septum and an inner surface of the inner
lumen of the catheter adapter, the ventilation channel having a
surface area and perimeter selected to permit passage of air and
prevent passage of blood; a coating disposed .[.within a slit.].
.Iadd.on at least a portion of the surface .Iaddend.of the septum,
the coating having a thickness of between approximately 0.00005 to
0.0005 millimeters, the coating being formed of vapor deposited
polyxylylene polymers; an introducer needle positioned within the
inner lumen, a portion of the needle extending through the inner
lumen, such that a tip portion of the introducer needle extends
beyond the catheter adapter, a portion of the introducer needle
being inserted through the septum; a septum activator positioned
within the proximal end of the inner lumen, the septum activator
having a pathway through which the introducer needle is inserted,
the septum activator further having a first end for biasing open a
slit of the septum, and a second end having a contact surface; and
an opening forming a proximal end of the catheter adapter, wherein
an external device is inserted through the opening to contact the
contact surface of the septum activator thereby advancing the first
end of the septum activator through the slit of the septum and
against the coating.
14. The assembly of claim 13, wherein the thickness of the coating
is between 0.0001 to 0.0002 millimeters.
15. The assembly of claim 13, further comprising a flow vent
interposed between an outer surface of the introducer needle and an
inner surface of the septum activator pathway, wherein a rate of
flow through the flow vent is determined by adjusting at least one
of an outer diameter of the introducer needle and an inner diameter
of the septum activator pathway.
16. The assembly of claim 13, wherein the septum activator further
comprises a plurality of vents and flow diverters configured to
improve circulation of a fluid within at least one of the septum
activator pathway and an interstitial space between the septum
activator and the inner surface of the catheter adapter inner
lumen.
17. The assembly of claim 13, wherein a proximal surface of the
septum further includes a cavity for housing a distal end of the
septum activator, and wherein a distal surface of the septum is
dome-shaped.
Description
BACKGROUND
The current invention relates to infusion devices, specifically to
peripheral intravenous (IV) catheters. In particular, the invention
relates to a flushable peripheral IV catheter assembly having
features to enable selective activation of fluid flow through the
catheter assembly.
Catheters are commonly used for a variety of infusion therapies.
For example, catheters are used for infusing fluids, such as normal
saline solution, various medicaments, and total parenteral
nutrition into a patient, withdrawing blood from a patient, as well
as monitoring various parameters of the patient's vascular
system.
Catheters or needles are typically coupled to a catheter adapter to
enable attachment of IV tubing to the catheter. Thus, following
placement of the catheter or needle into the vasculature of a
patient, the catheter adapter is coupled to a fluid source via a
section of IV tubing. In order to verify proper placement of the
needle and/or catheter in the blood vessel, the clinician generally
confirms that there is "flashback" of blood in a flashback chamber
of the catheter assembly.
Once proper placement of the catheter is confirmed, the clinician
must then attach the catheter adapter to a section of IV tubing.
This process requires the clinician to manually occlude the vein to
prevent undesirable exposure to blood. Manual occlusion of the
patient vein requires the clinician to awkwardly maintain pressure
on the vein of the patient while simultaneously coupling the
catheter adapter and the IV tubing.
A common, yet undesirable practice is to permit blood to
temporarily and freely flow from the catheter adapter while the
clinician locates and couples the IV tubing to the catheter
adapter. Another common practice is to attach the catheter adapter
to the IV tubing prior to placing the needle or catheter into the
vein of the patient. While this method may prevent undesirable
exposure to blood, positive pressure within the IV line may also
prevent desirable flashback.
Complications associated with infusion therapy include significant
morbidity and even mortality. Such complications may be caused by
regions of stagnant fluid flow within the vascular access device or
nearby areas of the extravascular system. These are regions in
which the flow of fluid is limited or non-existent due to the
conformation of the septum or valve mechanism in the extravascular
system or the fluid dynamics within that area of the extravascular
system. Blood, air bubbles or infused medications may become
trapped within these regions of stagnant flow as a result of the
limited or non-existent fluid flow. When blood is trapped within
the extravascular system bacteria can breed which can lead to
infections. When a different medication is infused into the
extravascular system, or the extravascular system is exposed to
physical trauma, the extravascular system's fluid flow may become
altered, releasing trapped air bubbles or residual medications back
into the active fluid path of the extravascular system. This
release of air bubbles and residual medication into the active
fluid path extravascular system may result in significant
complications.
Released air bubbles may block fluid flow through the extravascular
system and prevent its proper functioning. More seriously, released
air bubbles may enter the vascular system of the patient and block
blood flow, causing tissue damage and even stroke. In addition,
residual medications may interact with presently infused
medications to cause precipitates within the extravascular system
and prevent its proper functioning. Furthermore, residual
medications may enter the vascular system of the patient and cause
unintended and/or undesired effects.
Accordingly, there is a need in the art for a catheter assembly
that permits controlled, desirable flashback without the risk of
encountering undesirable exposure to blood. Furthermore, there is a
need in the art to provide a valve mechanism in a catheter assembly
that eliminates, prevents, or limits regions of stagnant flow
within vascular access devices and extravascular system to provide
better flush properties. Such a catheter assembly is disclosed
herein.
SUMMARY
In order to overcome the limitations discussed above, the present
invention relates to a flushable peripheral IV catheter assembly
having features to enable selective activation of fluid flow
through the catheter assembly. The catheter assembly of the present
invention generally includes a catheter coupled to a catheter
adapter. The catheter generally includes a metallic material, such
as titanium, surgical steel or an alloy as is commonly known in the
art. In some embodiments, a polymeric catheter may be used in
combination with a metallic introducer needle, as is commonly known
and used in the art.
In some embodiments of the present invention, a septum is
positioned within a lumen of the catheter assembly to prevent or
limit flow of a fluid through the catheter adapter. The septum
generally includes a flexible or semi-flexible material that is
compatible with exposure to blood, medicaments, and other fluids
commonly encountered during infusion procedures. In some
embodiments, a groove is provided on an inner surface of the
catheter adapter, wherein the septum is seated within the groove.
As such, the position of the septum within the catheter adapter is
maintained.
In some implementations of the present invention, a closed or
partially closed pathway, such as a slit or small hole is further
provided in a barrier surface of the septum. The pathway permits
fluid to bypass the septum and flow though the catheter adapter. In
some embodiments, the pathway is a slit that is closed prior to
being opened or activated by a probe or septum activator positioned
within the lumen of the catheter adapter. Prior to being opened or
activated, the slit prevents passage of fluid through the catheter
adapter. Thus, in some embodiments a plurality of air vent channels
are interposed between the septum and the groove to permit air flow
through the catheter adapter prior to the slit being opened. The
air vents prevent buildup of positive pressure within the catheter
adapter thereby permitting flashback of blood into the catheter and
a forward chamber of the catheter adapter.
The septum activator generally includes a plastic or metallic
tubular body having a probing end and a contact end. The probing
end is positioned adjacent to the pathway of the septum, and the
contact end is positioned adjacent to a proximal opening of the
catheter adapter. The probing end of the septum activator is
advanced through the pathway of the septum when a probe is inserted
into the proximal opening of the catheter adapter. As the probe
contacts the contact surface of the septum activator, the septum
activator is advanced in a distal direction through the catheter
adapter whereupon the probing end of the septum activator opens the
pathway through the septum. Once opened, free flow of fluid is
enabled through the catheter assembly.
In some aspects, a Parylene coating is disposed on the surface of
the septum, include within the surfaces of the slit of the septum.
The thickness of the coating is between 0.00005 to 0.0005
millimeters in order to enable the septum to properly open and
close. In other embodiments, the thickness of the coating is
between 0.0001 to 0.0002 millimeters. The septum can comprise a
silicone rubber material and have a tri-slit configuration (three
slits meeting at a center point, to form a single opening.)
Finally, the presence of the septum activator within the lumen of
the catheter adapter may result in aberrant fluid flow leading to
undesirable stagnation and coagulation of fluids within the
catheter assembly. Thus, in some embodiments of the present
invention the septum activator further includes various flow
deflectors and/or flow diversion channels to maintain proper fluid
flow within the catheter adapter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In order that the manner in which the above-recited and other
features and advantages of the invention are obtained will be
readily understood, a more particular description of the invention
briefly described above will be rendered by reference to specific
embodiments thereof which are illustrated in the appended drawings.
These drawings depict only typical embodiments of the invention and
are not therefore to be considered to limit the scope of the
invention.
FIG. 1 is a cross-sectioned view of an indwelling catheter having a
PRIOR ART flow control valve mechanism.
FIG. 2 is a cross-sectioned view of the PRIOR ART indwelling
catheter of FIG. 1 following removal an introducer needle.
FIG. 3 is a cross-sectioned view of the PRIOR ART indwelling
catheter of FIGS. 1 and 2 following insertion of a connector from a
vascular access device.
FIG. 4 is a perspective view of an embodiment of a catheter
assembly in accordance with the present invention.
FIG. 5A is an exploded cross-sectioned view of a catheter assembly
in accordance with the present invention.
FIG. 5B is a perspective view of an embodiment of a septum in
accordance with the present invention.
FIG. 6A is a cross-sectioned view of an interior lumen of a
catheter adapter demonstrating fluid flow without the presence of a
septum activator in accordance with a representative embodiment of
the present invention.
FIG. 6B is a perspective view of an embodiment of a septum
activator in accordance with the present invention.
FIG. 6C is a side view of an embodiment of a septum activator
disposed in an inner lumen of a catheter adapter in accordance with
the present invention, following activation.
FIG. 6D is a side view of an embodiment of a septum activator
disposed in an inner lumen of a catheter adapter in accordance with
the present invention, demonstrating fluid flow through the
catheter adapter.
FIG. 7 is a cross-sectioned view of an assembled catheter assembly
in accordance with the present invention, prior to activation.
FIG. 8 is a cross-sectioned view of an assembled catheter assembly
in accordance with the present invention, following activation.
FIG. 9 is a cross-sectioned view of an assembled over-the-needle
catheter assembly in accordance with the present invention, prior
to activation.
FIG. 10 is a cross-sectioned view of an assembled over-the-needle
catheter assembly in accordance with a representative embodiment of
the present invention, following removal of the introducer
needle.
FIGS. 11A through 11D are cross-sectioned views of septum having
various features and configuration in accordance with
representative embodiments of the present invention.
FIG. 12 is a cross-sectioned view of an assembled over-the-needle
catheter assembly in accordance with a representative embodiment of
the present invention, following activation.
FIG. 13 is a cross-sectioned view of a catheter body having a flow
control valve mechanism and a septum activator in accordance with a
representative embodiment of the present invention, prior to
activation.
FIG. 14 is a cross-sectioned view of a catheter body having a flow
control valve mechanism and a septum activator in accordance with a
representative embodiment of the present invention, following
activation.
FIG. 15 is a cross-sectioned view of a catheter body having a flow
control valve mechanism and septum activator in accordance with a
representative embodiment of the present invention, prior to
activation.
FIG. 16 is a cross-sectioned view of a catheter body having a flow
control valve mechanism according to the representative embodiment
shown in FIG. 15, following activation.
FIG. 17 is a cross-sectioned view of a catheter body having a flow
control valve mechanism and septum activator in accordance with a
representative embodiment of the present invention, prior to
activation.
FIG. 18 is a cross-sectioned view of a catheter body having a flow
control valve mechanism according to the representative embodiment
shown in FIG. 17, following activation.
FIG. 19 is a cross-sectioned view of a catheter body having a flow
control valve mechanism and septum activator in accordance with a
representative embodiment of the present invention, prior to
activation.
FIG. 20 is a cross-sectioned view of a catheter body having a flow
control valve mechanism according to the representative embodiment
shown in FIG. 19, following activation.
DETAILED DESCRIPTION OF THE INVENTION
The presently preferred embodiment of the present invention will be
best understood by reference to the drawings, wherein like
reference numbers indicate identical or functionally similar
elements. It will be readily understood that the components of the
present invention, as generally described and illustrated in the
figures herein, could be arranged and designed in a wide variety of
different configurations. Thus, the following more detailed
description, as represented in the figures, is not intended to
limit the scope of the invention as claimed, but is merely
representative of presently preferred embodiments of the
invention.
The term "proximal" is used to denote a portion of a device which,
during normal use, is nearest the user and furthest from the
patient. The term "distal" is used to denote a portion of a device
which, during normal use, is farthest away from the user wielding
the device and closest to the patient. The term "activation" of
valve mechanism or septum is used to denote the action of opening
or closing of such valve.
An example of a prior art extravascular system is disclosed in U.S.
Pat. No. 7,008,404 and shown in FIGS. 1 to 3. An indwelling
catheter has, as shown in FIG. 1, a hollow catheter body 1, a
catheter 2 fitted into a holder 1b provided at a distal end of the
catheter body 1, a septum 3 fitted inside the catheter body 1, and
a hollow pusher 4 slidably fitted inside the catheter body 1. The
catheter tube 2, septum 3, and the pusher 4 are coaxially aligned
in this order.
The catheter body 1 has a tubular shape. An inner surface 1a is
tapered toward the distal end, with a gradually reduced diameter.
The catheter body 1 is preferably of a transparent or
semi-transparent material so as to show the interior, enabling
checking of movement inside. Suitable materials for catheter body 1
include, but are not limited to, thermoplastic polymeric resins
such as polycarbonate, polystyrene, polypropylene and the like.
The catheter 2 is press-fitted into the tube holder 1b which
communicates at its proximal end with the inside of the catheter
body 1. It is preferred that a lubricating coating is provided to
the entirety or part of the catheter 2 so as to reduce resistance
caused by insertion through skin or into a blood vessel. Suitable
materials for catheter 2 include, but are not limited to,
thermoplastic resins such as fluorinated ethylene propylene (FEP),
polytetrafluoroethylene (PTFE), polyurethane and the like.
Preferably, catheter 2 is formed from a thermoplastic hydrophilic
polyurethane that softens with exposure to physiological conditions
present in the patient's body.
The septum 3 is of a generally tubular shape having a proximal end
8 and a membrane section 9 having a planar flat surface 10 located
at the distal end 11. Typically, septum 3 further includes a single
needle slit 3a or valve aperture located about the centre of
membrane section 9, extending through membrane section 9, to
facilitate penetration of septum 3 by introducer needle 5. The
opposing slit surfaces of the needle slit 3a are designed to
closely conform to the shape of introducer needle 5 during storage
and prevent an outflow of fluid during and following removal of the
introducer needle 5, then to seal upon removal of the introducer
needle 5. With the pusher 4 inserted therethrough, slit 3a expands
forward in the distal direction and opens, providing fluid
communication between the catheter 2 and the rear of the catheter
body 1. An annular protrusion 3b is provided on the inner surface
of a rear opening of the septum 3, to engage shoulder 4c at the
distal end of the pusher 4 so as to limit the movement of pusher 4
in the proximal direction and prevent the dislocation of the pusher
4 from septum 3. A plurality of gaps 3c are defined between an
outer periphery of the septum 3 and the inner surface 1a of the
catheter body 1. Distal and proximal spaces divided by the septum 3
communicate with each other through the gaps 3c. Thus the septum 3
slides smoothly with air passing through the gaps 3c.
The pusher 4 is typically made from a rigid thermoplastic material
or a like material, and has a lumen extending therethrough. The
pusher 4 has a tubular portion 4a, a conical flange 4b connected to
the rear proximal end of the tubular portion 4a, and a shoulder 4c
protruding from an outer periphery of the tubular portion 4a. Thus
an annular shaped interstitial space is created between tubular
portion 4a and the inner surface 1a of the catheter body 1. The
distal front end of the tubular portion 4a is chamfered to
facilitate its penetration into slit 3a of the septum 3, and is
slidably supported by the annular protrusion 3b of the septum 3.
The conical flange 4b has a conical inner surface so as to
facilitate insertion of the needle 5 thereinto. The peripheral
surface of the flange 4b contacts the inner surface 1a of the
catheter body 1 and serves to provide stability to the pusher 4 and
maintain the coaxial position with respect to the catheter 2.
However the peripheral surface of the flange 4b does not form a
fluid seal with inner surface 1a.
The indwelling catheter is prepared for use in such a state as
shown in FIG. 1 with the front end of the needle 5 protruding from
the front end of the catheter 2. In this state, the needle 5
penetrates through the septum 3, providing water-tight connection
therebetween, and thereby preventing leakage of blood.
The indwelling catheter in this state is inserted into the body of
a patient. Then, as shown in FIG. 2, the needle 5 is removed with
the tube 2 retained in the body of the patient. Septum 3 maintains
a fluid seal upon removal of needle 5, being retained catheter body
1 by an annular protrusion 1e. Pusher 4 is retained in a proximal
position buy the interaction of annular protrusion 3b and shoulder
4c.
A connector 6 (e.g. a luer connector) of a vascular access device
is then inserted from the proximal end of the catheter body 1. When
pressed into the catheter body 1, the connector 6 pushes at its
distal end the pusher 4. The pusher 4 thus slides forward in distal
direction to press at its distal end slit 3a of the septum 3 open
thereby activating the flow control valve to the open position. The
septum 3 is then pressed against the inner surface of a tapered
cavity 1c of the catheter body 1 which stops the forward movement
of pusher 4 at a distal position as shown in FIG. 3, thus providing
communication between the catheter 2 and the vascular access
device. The tapered inner surface 1a of the catheter body 1 allows
for smooth insertion of the connector 6 and tight contact between
an outer surface 6a of the connector 6 and the inner surface 1a
through press fitting in order to prevent fluid leaking out of the
proximal end of catheter body 1.
However, it should be noted that this valve mechanism has small
interstitial spaces/areas within the catheter body 1 into which
fluids can flow during use, which give rise to areas of low or no
fluid flow. For example, in use, fluid can flow between the
peripheral surface of the flange 4b and the inner surface 1a of
catheter body 1 and into the interstitial space 98 between the
outer periphery of tubular portion 4a and the inner surface 1a. In
addition, fluid can flow into interstitial space 99 which is gap 3c
between the outer periphery of septum 3 and the inner surface 1a of
the catheter body 1. The low or no fluid flow that exists in
spaces/areas 98 and 99 makes it very difficult to subsequently
flush out any blood, medicament or air bubbles which may flow into
these areas during use of the catheter.
Referring now to FIG. 4, a catheter assembly 101 is illustrated.
The catheter assembly 101 generally includes a catheter 12 coupled
to a distal end 32 of a catheter adapter 14. The catheter 12 and
the catheter adapter 14 are integrally coupled such that an
internal lumen 16 of the catheter adapter 14 is in fluid
communication with a lumen 18 of the catheter 12. The catheter 12
generally comprises a biocompatible material having sufficient
rigidity to withstand pressures associated with insertion of the
catheter into a patient. In some embodiments, the catheter 12
comprises a metallic material, such as titanium, stainless steel,
nickel, molybdenum, surgical steel, and alloys thereof. In other
embodiments, the catheter 12 comprises a rigid, polymer material,
such as vinyl. A tip portion 20 of the catheter is generally
configured to include a beveled cutting surface 48. The beveled
cutting surface 48 is utilized to provide an opening in a patient
to permit insertion of the catheter 12 into the vascular system of
the patient.
The features of the catheter assembly may be incorporated for use
with an over-the-needle catheter assembly. For example, a flexible
or semi-flexible polymer catheter may be used in combination with a
rigid introducer needle to enable insertion of the catheter into a
patient. Surgically implanted catheters may also be used.
Once inserted into a patient, the catheter 12 and catheter adapter
14 provide a fluid conduit to facilitate delivery of a fluid to
and/or retrieval of a fluid from a patient, as required by a
desired infusion procedure. Thus, in some embodiments the material
of the catheter 12 and the catheter adapter 14 are selected to be
compatible with bio-fluids and medicaments commonly used in
infusion procedures. Additionally, in some embodiments a portion of
the catheter 12 and/or catheter adapter 14 is configured for use in
conjunction with a section of intravenous tubing 40 to further
facilitate delivery of a fluid to or removal of a fluid from a
patient.
In some embodiments, a proximal end 22 of the catheter adapter 14
includes a flange 28. The flange 28 provides a positive surface
which may be configured to enable coupling of an intravenous tubing
or patient conduit 40 to the catheter assembly 101. In some
embodiments, the flange 28 includes a set of threads 30. The
threads 30 are generally provided and configured to compatibly
receive a complementary set of threads 44 comprising a portion of a
male luer or conduit coupler 42. The conduit coupler 42 is
generally coupled to an end portion of the patient conduit 40 in a
fluid-tight manner. In some embodiments, an inner portion of the
conduit coupler 42 is extended outwardly to provide a probe surface
46.
The probe surface 46 is generally configured to compatibly insert
within a proximal end 22 of the catheter adapter 14. Following
insertion of the probe 46 into the proximal end 22 of the catheter
adapter 14, the conduit coupler 42 is rotated to interlock the
coupler 42 and the flange 28 (via the sets of threads 30 and 44).
During the process of interlocking the coupler 42 and the flange
28, the probe 46 is advanced into the lumen 16 of the catheter
adapter 14 to an inserted position (as shown in FIG. 8). The
inserted position of the probe surface 46 activates the catheter
assembly 101 to enable flow of fluid through the catheter 12 and
catheter adapter 14. Once the conduit coupler 42 and the catheter
adapter 14 are attached, a fluid may be delivered to a patient via
the patient conduit 40 and the inserted catheter 12.
Referring now to FIG. 5A, an exploded, cross-sectional view of a
catheter assembly 101 is shown. In some embodiments, the catheter
adapter 14 includes various design features and components to
control and/or limit flow of fluid through the catheter assembly
101. For example, in some embodiments of the present invention a
septum 50 is positioned within the inner lumen 16 of the catheter
adapter 14. The septum 50 generally comprises a flexible, or
semi-flexible polymer plug having an outer diameter that is
configured to compatibly seat within a groove or channel 60 formed
on an inner surface 24 of the catheter adapter 14. In some
embodiments, the septum 50 is barrel shaped having a barrier
surface 52 comprising a distal end of the septum 50 and further
having an opening 54 comprising a proximal end of the septum 50.
When positioned within the channel 60, the barrier surface 52 of
the septum 50 divides the inner lumen 16 of the catheter adapter 14
into a forward fluid chamber 62 and a rearward fluid chamber 64.
Thus, the presence of the septum 50 controls or limits passage of
fluid between the forward and rearward fluid chambers 62 and 64.
Specifically, a chosen configuration of the barrier surface 52 of
the septum 50 largely determines the ability of a fluid to flow
through the inner lumen 16 of the catheter adapter 14.
For example, in some embodiments the barrier surface 52 of the
septum 50 is configured to include a slit 56. The slit 56 is
configured to provide selective access or flow of a fluid through
the barrier surface 52. In some embodiments, slit 56 is configured
to remain in a closed, fluid-tight position until activated or
opened by advancing a septum activator 80 through the slit 56 in a
distal direction 390. In some embodiments, the barrier surface 52
comprises one slit 56. In other embodiments, the barrier surface 52
is modified to include multiple slits 56 and 66, as shown in FIG.
8. For example, the septum 50 can include a tri-slit configuration,
wherein three slits meeting at a center point, to form a single
opening. In some embodiments, the septum 50 comprises a silicone
rubber material. In some embodiments, the septum 50 consists
essentially of a silicone rubber material.
In some aspects, a Parylene coating is disposed on the surface of
the septum 50, include within the surfaces of the slit 56 of the
septum 50. Parylene is a chemically resistant coating with good
barrier properties for inorganic and organic fluids, strong acids,
caustic solutions, gases and water vapors. In some embodiments, a
Parylene coating is applied to the outer surface of the septum 50
via vapor deposition. A Parylene coating is a harder material than
the substrate material of the septum, such as silicon rubber or a
like material. When the septum 50 is coated with the typical
industry Parylene thickness, which is greater than 1 micrometer,
the edges of the slit 50 become very stiff. The typical coating
thickness for Parylene in the industry is in the range of 0.001 to
over 0.025 millimeters. The harder edge of the slit leaf could
indent the soft face of the slit thus prevent the slit from closing
properly after the withdrawal of the needle. This increased
resistance to close makes the seal not as effective. Additionally,
when the septum 50 is coated with an industry-standard, thick layer
of Parylene, the friction coefficient between the septum 50 and the
inner surface 24 of the catheter adapter 14 is reduced, thus reduce
the force required to remove the septum 50 from within the catheter
adapter 14. On the other hand, when the septum is not coated with
Parylene, the silicone septum is tacky and difficult to feed in the
automated process.
Accordingly, in some configurations, the thickness of the coating
can be between 0.00005 to 0.0005 millimeters. In other embodiments,
the thickness of the coating is between 0.0001 to 0.0035
millimeters. In other embodiments, the thickness of the coating is
between 0.0001 to 0.0002 millimeters. With this type of thin layer
of Parylene coating, the slit 56 will close easily after the needle
withdraws. In addition, the reduced thickness of Parylene coating
will provide additional friction force between the outer surface of
the septum 50 and the inner surface 24 of the catheter adapter 14,
increasing the retention force of the septum 50.
For some infusion therapy techniques, it may be desirable to permit
a controlled flow of fluid through the septum 50 prior to
activating the septum 50 with the septum activator 80. Thus, in
some embodiments the slit 56 further comprises a leak orifice 58.
The leak orifice 58 is positioned in the barrier surface 52 and
comprises an opening diameter calculated to permit controlled flow
of liquid or air between the forward and rearward chambers 62 and
64. In some embodiments, the barrier surface 52 is modified to
include a single leak orifice 58. In other embodiments, the barrier
surface 52 is configured to include multiple leak orifices. Still,
in other embodiments the barrier surface 52 does not include a slit
56, but rather includes at least one leak orifice 58. For these
embodiments, the septum 50 generally comprises an elastic material
such that when the septum activator 80 is advanced in a distal
direction 390, a leading edge 92 of the septum activator 80
contacts the barrier surface 52 and stretches the leak orifice 58
to provide a larger orifice thereby permitting increased flow of
air and/or fluid through the catheter adapter 14.
The groove or channel 60 into which the septum is seated comprises
a recessed portion of the inner surface 24 of the catheter adapter
14. The outer diameter of the septum 50 is generally configured to
compatibly and securely seat within the channel 60. For example, in
some embodiments the outer diameter of the septum 50 is selected to
be both slightly smaller than the diameter of the channel 60 and
slightly larger than the diameter of the inner lumen 16. As such,
the septum 50 is retained within the channel 60 during use of the
catheter assembly 101.
For some infusion therapy techniques, air flow between the forward
and rearward chambers 62 and 64 may be desirable. For example, for
those embodiments comprising a septum 50 having a fluid-tight slit
56, passage of air from the forward chamber 62 to the rearward
chamber 64 is prohibited prior to opening or activating the septum
50 via the septum activator 80, as previously discussed. Thus, when
the catheter 12 of the catheter assembly 101 is inserted into the
vascular system of a patient, a positive pressure develops within
the forward chamber 62 thereby preventing a desired flashback of
the patient's blood into the catheter adapter 14. An observable
flashback is generally desirable to confirm accurate placement of
the catheter tip 20 within the vein of the patient. Thus, some
embodiments of the present invention include features or elements
to enable airflow between the forward chamber 62 and the rearward
chamber 64, without requiring activation of the septum 50 with the
septum activator 80. As such, some embodiments of the present
invention provide an observable flashback, as generally desired for
infusion procedures.
For example, in some embodiments the barrier surface 52 of the
septum 50 is modified to include leak orifice 58, as previously
discussed. In other embodiments, a plurality of air vent channels
70 is interposed between the septum 50 and the inner surface 24 of
the catheter adapter 14. The air vent channels 70 relieve the
positive pressure within the forward chamber 62 by providing an
access for air to bypass the septum 50 into the rearward chamber
64. In some embodiments, the air vent channels 70 are constructed
by removing portions of the channel 60 surface, resulting in a
plurality of generally parallel grooves.
In addition to permitting air flow between the forward and rearward
chambers 62 and 64, the vent channels 70 may be configured to
permit fluid to flow through the catheter adapter 14 prior to
activating or opening the slit 56 with the septum activator 80. In
some embodiments, the rate at which air and/or fluid flows between
the forward and rearward chambers 62 and 64 is adjusted by
manufacturing the catheter adapter 14 to include a greater or
lesser number of vent channels 70. In other embodiments, the rate
at which air and/or fluid flows between the forward and rearward
chambers 62 and 64 is adjusted by manufacturing the catheter
adapter 14 to include vent channels 70 having a greater or lesser
cross-sectioned area. Thus, in some embodiments the rate at which
air and/or fluid flows between the forward and rearward chambers 62
and 64 is increased by manufacturing a catheter adapter 14 having
either an increased number of vent channels 70, or vent channels 70
having a greater cross-sectioned area. Conversely, in other
embodiments the rate at which air and/or fluid flows between the
forward and rearward chambers 62 and 64 is decreased by
manufacturing a catheter adapter 14 having either a decreased
number of vent channels 70, or vent channels 70 having a lesser
cross-sectioned area.
With continued reference to FIG. 5A, the septum activator 80
comprises a probe-like structure that is primarily housed in the
rearward chamber 64 of the catheter adapter 14. The septum
activator 80 generally comprises a tubular body 82 having a distal
end 84 and a proximal end 86. The tubular body 82 comprises a rigid
or semi-rigid material, such as a plastic or metallic material. The
tubular body 82 further comprises an inner lumen 88 for
facilitating flow of a fluid and/or liquid through the septum
activator 80.
The distal end 84 of the tubular body 82 is configured to
compatibly insert within the opening 54 of the septum 50. The
distal end 84 further includes a probing surface 90 which extends
through the opening 54 of the septum 50 to a position proximal to
the barrier surface 52 of the septum 50, as shown in FIG. 8. The
probing surface 90 is advanced through the slit 56 and 66, or
through the leak orifice 58 as the septum activator is advanced
through the catheter adapter 14 in a distal direction 390.
Advancement of the septum activator 80 through the catheter adapter
14 will be discussed in detail below, in connection with FIGS. 7
and 8.
Still, in other embodiments the septum 50 is coated with a
hydrophobic coating, or a polymeric swelling coating to repel or
prevent fluid from flowing through the vent channels 70. A
hydrophobic coating is generally selected to reduce the surface
energy of the septum 50 and/or adapter 14 to inhibit blood wicking
into the air vents 70. In some embodiments, a surface of the septum
50 or catheter adapter 14 is coated with a polyxylylene polymer
material, such as Parylene. In other embodiments, a polyxylylene
polymer coating is applied to a vent channel 70 via vapor
deposition.
In some embodiments, a dehydrated polymer material is applied to a
surface of the septum 50 or catheter adapter 14 which comprises the
vent channels 70. A dehydrated polymer is generally selected to
expand or swell upon contact with fluid. As such, when the
dehydrated polymer swells, a flow through the vent channels 70 is
blocked or occluded by the swollen polymer. Initially, the
dehydrated polymer generally comprises a thin profile prior to
exposure to moisture. However, when exposed to moisture the polymer
absorbs the moisture which increases the profile of the polymer to
block flow through the vent 70. Therefore, by coating the septum 50
and/or catheter adapter 14 with a desired coating, flow of air is
permitted between the forward and rearward chambers 62 and 64, yet
fluid flow through the vent channels 70 is prevented.
Referring now to FIG. 5B, an embodiment of a septum 150 is shown.
In some embodiments, an outer surface 166 of the septum 150 is
modified to include a plurality of recessed grooves 72. The
recessed grooves 72 provide pathways between the forward and
rearward chambers 62 and 64 through which air and/or fluid may
flow. Thus, in some embodiments the channel 60 does not include air
vent channels 70, but rather the outer surface 166 of the septum
150 is modified to provide desired flow between the forward and
rearward chambers 62 and 64.
The blood pressure of the patient is largely responsible for the
rate at which blood and air flows through the septum 50 and 150 of
the catheter assembly 101. As such, the flow rate through the
system is affected by the combined effective hydraulic diameter of
all flow paths. Thus, in some embodiments the hydraulic diameter of
the vent channels 70 and/or recessed grooves 72 are modified to
increase or decrease the rate of flow through the catheter assembly
101. In other embodiments, the hydraulic diameter of the vent
channels 70 and/or recessed grooves 72 are decreased thereby
resulting in substantially reduced or stopped flow through the
ventilation means. The governing equation for controlling the flow
rate through the ventilation means is given in Equation 1, where BP
is the blood pressure, A is the surface area of the ventilation
means, o is the surface tension of the blood, and P is the
perimeter of the ventilation means. BP(A)=o(P) Equation 1:
Thus, according to Equation 1, when the perimeter of the
ventilation means is small, the ventilation means will allow air
venting, but will prevent blood flow due to the relatively high
surface tension (o) of blood. However, when the perimeter of the
ventilation means is increased, the surface tension between the
blood and the vent is decreased thereby enabling the blood to
slowly leak through the vents and around the septum to provide
desirable, yet controlled flashback. Therefore, by adjusting the
various variable of Equation 1, a desired flow will be achieved.
Thus, based on the size and/or number of vents around the septum,
the catheter assembly design will provide customized, controlled
and predictable blood flow around the septum 50 or 150. In some
embodiments, it is desirable to permit slow, controlled blood flow
as a means for providing a visual indicator that the catheter is in
the blood vessel, without the risk of immediate exposure to the
blood. In other embodiments, it is desirable to only permit air to
pass through the vents.
Referring now to FIG. 6A, a cross-section view of an interior lumen
of a catheter adapter 14 is shown. In some embodiments, catheter
adapter 14 includes a forward fluid chamber 62 and a rearward fluid
chamber 64 fluidly connected via a narrowed channel or port 160. As
configured and in some embodiments, a fluid pathway 170 is defined
whereby a fluid 146 flows downstream from the rearward fluid
chamber 64, through the port 160 and into the forward fluid chamber
62. The fluid pathway 170 continues through the forward fluid
chamber 62 and exits the distal end 32 into a catheter (not shown)
or other downstream conduit. While fluid 146 fills the entire lumen
of the catheter adapter 14, the fluid pathway 170 is generally
restricted to a narrow pathway through a central portion of the
cross-section of the catheter adapter 14. Accordingly, fluid 146
that is not part of the narrow fluid pathway 170 stagnates or
circulates within dead zones 156. Fluid 146 trapped within these
dead zones is prevented from sufficiently mixing with fluid 146 in
the fluid pathway 170. In some embodiments, stagnation results in
increased, localized concentrations of chemicals, bodily fluids
and/or medicaments that may lead to precipitation, coagulation or
administration of dangerously high doses of medications. Therefore,
in some embodiments of the present invention, a septum activator 80
is provided having features to eliminate dead zones 156 within the
catheter adapter 14 lumen.
Referring now to FIG. 6B, a perspective view of the septum
activator 80 is shown. In some embodiments, the distal end 84 of
the tubular body 82 comprises a first diameter 100 that is less
than a second diameter 102 of the proximal end 86. The narrower
distal end 84 is configured to compatibly insert within the opening
54 of the septum 50, while the wider proximal end 86 is configured
to compatibly seat within the rearward chamber 64 of the catheter
adapter 14. In some embodiments, the septum activator further
includes a tapered middle section 104 to couple the distal 84 and
proximal 86 ends.
In some embodiments, the proximal end 86 of the septum activator 80
further includes a retention spring 110. The retention spring 110
generally comprises an outwardly biased portion of the tubular body
82 configured to compatibly engage a septum activator retention
groove 68, as shown in FIGS. 5A, and 7-8. The interaction between
the retention spring 110 and the groove 68 limits the lateral
movement of the septum activator 80 within the lumen 16 of the
catheter adapter 14. Thus, the width of the retention groove 68
determines or limits the distance of travel for the septum
activator 80 within the catheter adapter 14. Additionally, the
interaction between retention spring 110 and the groove 68 prevents
removal of the septum activator 80 from the catheter adapter 14. In
some embodiments, the septum activator 80 comprises a plurality of
retention springs 110, while in other embodiments the septum
activator 80 comprises a single retention spring 110.
In some embodiments, the septum activator 80 further comprises
features for directing or diverting fluid flow around and/or
through the septum activator 80. Flow diversion may be important to
prevent stagnation or coagulation of fluids within dead zones 156
of the septum activator 80 and/or the lumen 16 of the catheter
adapter 14 resulting in blockages. Additionally, stagnation of
fluid flow through the catheter assembly 101 may result in a build
up of undesirable concentrations of medicaments within the catheter
adapter 14 and/or the septum activator 80, as previously discussed.
Undesirable high concentrations may result in ineffective treatment
causing serious side effects, including death. Thus, in some
embodiments the septum activator 80 is modified to include flow
deflectors 120 and flow diversion channels 130 to provide a
flushable catheter assembly 101 system.
The flow deflectors 120 generally comprise inwardly and outwardly
angled portions of the septum activator 80 outer surface. The flow
deflectors 120 are positioned so as to be protrude into a flow path
through the catheter adapter 14. Thus, as the fluid contacts the
flow deflectors 120 the path of the fluid flow is disturbed. This
disturbance results in redirecting the fluid flow both through the
inner lumen 88 of the septum activator 80, and between the outer
surface of the septum activator 80 and the inner surface 24 of the
catheter adapter 14. In some embodiment, the retention spring 110
also serves as a flow deflector 120.
A flow diversion channel 130 is provided to permit exchange of
fluid between the lumen of the catheter adapter 16 and the inner
lumen 88 of the septum activator 80. Thus, the flow diversion
channel 130 prevents stagnation and/or clotting of fluid between
the inner surface 24 of the catheter adapter 14 and the outer
surface of the septum activator 80. In some embodiments, the flow
diversion channel 130 comprises a window or opening in the surface
of the tubular body 82. In other embodiments, the flow diversion
channel 130 further comprises a flap or angled surface to further
direct fluid to flow through the channel 130.
The proximal end 86 of the septum activator 80 further includes a
contact surface 140. The contact surface 140 comprises the most
proximal end portion of the septum activator 80 and is positioned
within the rearward chamber 64 of the catheter adapter 14 adjacent
to the proximal opening 26 of the catheter adapter 14, as shown in
FIG. 7, below.
Referring now to FIG. 6C, an embodiment of a septum activator 180
is shown as positioned in the lumen of a catheter adapter 14 (shown
in phantom). In some embodiments, septum activator 180 is
configured to include various re-circulation features. For example,
in some embodiments septum activator 180 includes various vents 200
configured to divert fluid from the fluid pathway 170 into the dead
zones 156. Thus, as fluid flows into and through the septum
activator 180, the fluid within the septum activator 180 passes
through the vents 200 and into the dead zones 156 between the outer
surface of the activator 180 and the inner wall surface of the
catheter adapter 14. The diverted fluid intermixes with the fluid
in the dead zones 156 to flush fluid from the dead zones 156 and
thus prevent stagnation and/or overconcentration, as previously
discussed.
In some embodiments, septum activator 180 is further modified to
include flushing fins 220. Flushing fins 220 generally comprise
perpendicular extension of the outer surface of the activator 180
that extend into the dead zones 156 between the activator 180 and
the inner wall surface of the catheter adapter 14. The flushing
fins 220 are provided to divert and redirect fluid within the fluid
pathway 170 into the dead zones 156. As such, fluid within the dead
zones 156 is intermixed with fluid in the fluid pathway 170 to
prevent stagnation and/or overconcentration of fluid within the
catheter adapter 14.
Finally, in some embodiments the flow diversion channel 130 is
modified to include a flow deflector 230. The flow deflector 230
comprises a beveled, distal surface of the flow diversion channel
130 positioned to divert fluid within the fluid pathway 170 into
the dead zones 156 of the forward fluid chamber 62. Thus, as fluid
146 flows through the septum activator 180, a portion of the fluid
is diverted through the flow diversion channel 130 and into the
dead zone 156 via the flow deflector 230, as shown in FIG. 6D.
With continued reference to FIG. 6D, a cross-sectioned septum
activator 180 positioned within a cross-sectioned catheter adapter
14. As previously discussed, recirculation features may be added to
both the proximal 86 and distal 186 ends of the septum activator
180. In some embodiments, the proximal end 86 of the septum
activator 180 is modified to include curved window features 240
that redirect the flow of a fluid 246 into the dead zones 156 of
the rearward fluid chamber 64. Thus, the curved surface 242 of the
window feature 240 alone and/or in combination with the other
recirculation features promotes intermixing of the fluid within the
dead zones 156 to prevent stagnation and overconcentration of
fluids within the catheter adapter 14.
In some embodiments, the recirculation features are positioned in a
symmetrical configuration to induce best flushing. In other
embodiments, the recirculation features are positioned in an
asymmetrical configuration to induce best flushing. Finally, in
some embodiments the recirculation features are used in combination
with additional diffusing, circulating and recirculating features
of the septum activator 180 to aid the fluid flushing capability of
the septum activator 180. In light of the foregoing disclosure,
additional surfaces of the septum activator 180 may be modified to
increase or decrease flow efficiency, mixing and flushing of fluids
within the septum activator 180, as desired.
Referring now to FIG. 7, a cross-sectional view of the assembled
catheter assembly 101 is shown prior to activation of the septum 50
via the septum activator 80. Prior to activation, the septum
activator 80 is entirely positioned within the rearward fluid
chamber 64 of the catheter adapter 14. Additionally, the retention
springs 110 are engaged within the retention groove 68 and
positioned near the proximal end of the retention groove 68. The
contact surface 140 of the septum activator 80 is positioned near
the opening 26 of the catheter adapter 14, such that a proximal
opening 142 of the septum activator 80 is in a plane generally
parallel to the plane of the catheter adapter opening 26. Finally,
the outwardly biased retention springs 110 bind on the surface of
the groove 68 thereby maintaining the inactivated position of the
septum activator 80 within the catheter adapter 14.
Referring now to FIG. 8, a cross-sectional view of the catheter
assembly 101 is shown following activation of the septum 50 via the
septum activator 80. Upon insertion of the coupler 42 into the
proximal opening 26 of the catheter adapter 14, the probe portion
46 of the coupler 42 contacts the contact surface 140 of the septum
activator 80. The septum activator 80 is advanced in a distal
direction 390 as the coupler 42 is further inserted into the
proximal opening 26 of the catheter adapter 14. As the coupler 42
is advanced further into the proximal opening 26, the probing
surface 90 of the septum activator 80 passes through the barrier
surface 52 of septum 50. As such, the probing surface 90 of the
septum activator 80 is positioned within the forward chamber 62
providing a fluid pathway through the septum 50.
In some embodiments, the catheter assembly 101 is configured to
permit the septum activator 80 to return to a position entirely
within the rearward chamber 64 following removal of the coupler 42
from the catheter adapter 14. Thus, when the coupler 46 is removed
or detached from the catheter assembly 101, the fluid pathway
through the septum 50 is reclosed. In some embodiments, the
retention spring 110 is configured to flex inwardly upon contact
between the contact surface 140 of the septum activator 80 and the
probe 46 of the coupler 42. When the retention spring 110 flexes
inwardly, the probing surface 90 of the septum activator 80 is
temporarily advanced in a distal direction 390 to bias open the
slits 66 and 56, or the leak orifice 58. When contact between the
probe 46 and the contact surface 140 ceases, the retention spring
110 returns to its relaxed position. The relaxed position
withdrawals the probing surface 90 of the septum activator 80 from
the barrier surface 52 thereby permitting closure of the slits 66
and 56.
Referring now to FIG. 9, a cross-sectional view of a catheter
assembly 300 is shown incorporating an introducer needle 350. The
proximal end 352 of the needle 350 may be coupled to a needle hub
(not shown) or an insertion assembly (not shown) to facilitate a
user in holding and manipulating the needle 350 during
catheterization. For purposes of clarity in the present
illustration the remainder of the needle assembly has been
removed.
Prior to activation, septum activator 380 is entirely positioned
within the rearward chamber 364 of catheter adapter 314. A pathway
is provided through the inner lumen 316 of the activator 380 so as
to allow passage of introducer needle 350. A middle portion of the
needle 350 passes through septum 356 and continues through the
forward chamber 362 and into the flexible catheter 312. A tip
portion (not shown) of the needle 350 extends beyond a tip portion
(not shown) of the catheter 312 such that the needle tip is
available to gain access to the vasculature of a patient.
The slit 366 of septum 356 is biased open by introducer needle 350.
In some embodiments, a seal is formed between the outer surface of
the needle 350 and the slit 366. Thus, fluid and air flow are
prevented from bypassing the septum by way of the interface between
the needle 350 and the slit 366. In some embodiments, a channel or
pathway is provided between the slit 366 and the needle 350 to
permit controlled leakage or flow between these two components.
In other embodiments, a lubricant such as a non-wetting lubricant
is applied to the interface between the needle 350 and the slit 366
to further eliminate possible leakage of fluid and/or air. A
non-wetting lubricant may also be beneficial to prevent tearing or
other damage to the slit that may occur when the needle is removed
from the catheter assembly following catheterization. A non-wetting
lubricant may also facilitate proper realignment of the slit 366
halves following removal of the needle 350. Non-limiting examples
of a non-wetting lubricant include known Teflon based non-wetting
materials such as Endura, from Endura Coating Co.; A20, E-20,
1000-S20, FEP Green, PTFE and X-40 from Tiodize; Cammie 2000 from
AE Yale; 21845 from Ladd Research; MS 122-22, MS 122DF, MS-143DF,
MS-122V MS-122VM, MS143V, MS-136W, MS-145W, U0316A2, U0316B2,
MS-123, MS-125, MS-322 and MS-324 from Miller-Stepheson; and 633T2
from Otto Bock can also be used. Various non-Teflon based
non-wetting lubricant type materials include Dylyn, from ART;
Nyebar, Diamonex, NiLAD, TIDLN, Kiss-Cote, Titanium oxide; Fluocad
Fluorochemical Coating FC-722, from 3M; Permacote from Dupont;
Plasma Tech 1633 from Plasma Tech, Inc.; and silicone sprays.
In some embodiments, distal end 384 of the septum activator 380 is
elongated such that contact surface 340 is positioned closer to
proximal opening 326 of the catheter adapter 314. Accordingly, a
coupler having a shortened probe portion (not shown) may
sufficiently contact the contact surface 340 to advance the distal
end 384 through the septum 356. In other embodiments, the distal
end 384 of the septum activator 380 is configured to include an
inner diameter of substantially the same size and the outer
diameter of the introducer needle 350. As such the inner diameter
of the distal end 384 is configured to allow passage of the needle
350 while maintaining minimal tolerance 382 between the outer
surface of the needle 350 and the inner surface of the septum
activator 380 distal end 384. This minimal tolerance 382 provides a
seal thereby preventing leakage or flow of blood between the needle
350 and the septum activator 380 while withdrawing the needle 350
from the catheter assembly 300.
In some embodiments, a translating groove 368 is provided within
the rearward chamber 364. The translating groove 368 generally
comprises an annular recess having a determined length 370.
Translating groove 368 is further configured to receive flushing
fins 320 such that the flushing fins 320 are retained within the
groove 368. Thus, length 370 represents the maximum lateral
distance which septum activator 380 is permitted to travel within
the rearward chamber 364. In some embodiments, a proximal end of
groove 368 is defined by an annular ridge 372. In other
embodiments, a distal end of groove 368 is defined by a second
annular ridge 374. Still, in other embodiments the second annular
ridge 374 forms a proximal end of septum channel 60.
Referring now to FIG. 10, a cross-sectional view of catheter
assembly 300 is shown following removal of introducer needle 350.
Upon removal of introducer needle 350, slit 366 of septum 356 is no
longer biased open and therefore recloses and seals to prevent flow
of fluids and/or air via the slit 366. As previously discussed, in
some embodiments slit 366 includes a leak orifice (not shown) to
permit controlled flow between the forward and rearward chambers
362 and 364. In other embodiments, a plurality of ventilation
channels 70 are provided between the outer surface of the septum
356 and the septum channel 60.
Referring now to FIGS. 11A through 11D, septum 356 may include
various configurations and features to stabilize distal end 384 of
the septum activator 380. For example, in some embodiments septum
356 is configured to include an inner diameter 358 sized
substantially equal to the outer diameter of the distal end 384 of
septum activator 380, as shown in FIG. 11A. In other embodiments,
septum 356 is configured to have an interior annular ridge or
protrusion 360 having an inner diameter 358 sized substantially
equal to the outer diameter of distal end 384, as shown in FIG.
11B. Thus, in both of these embodiments distal end 384 is radially
supported by septum 356.
With reference to FIG. 11C, in some embodiments an interior surface
376 of septum 356 is modified to include one or more reliefs 391.
In some embodiments, relief 391 comprises a concave annular recess
configured to receive a positive feature 392 comprising a portion
of distal end 384 of the septum activator 380. In other
embodiments, relief 391 comprises a singular indent sized and
configured to receive feature 392 of the septum activator 380.
Still, in other embodiments relief 391 comprises a positive feature
and feature 392 comprises a negative or recessed feature (not
shown). Thus, in some embodiments the interaction between relief
391 and feature 392 provides both radial support and axial
retention of the septum activator 380 within the catheter adapter
314. This configuration may eliminate the need for additional
retention features, such as clips and retention grooves.
Referring now to FIG. 11D, septum 356 includes a domed profile 394
to counteract pressure applied to the distal side 386 of the septum
356 following removal of introducer needle 350. The domed profile
394 provides additional strength to the distal side 386 of the
septum 356 thereby increasing the fluid pressure required to defeat
the septum 356. In some embodiments, as the blood reaches the
septum 356 the domed profile 394 assists the septum 356 in closing
due to the pressure from the blood flow within the forward chamber
362. In other embodiments, septum 356 comprises a generally flat
profile, as shown in FIGS. 5A, 5B and 7 through 11C or may include
a combination of flat and curved surfaces (not shown).
Referring now to FIG. 12, a cross-sectional view of catheter
assembly 300 is shown following activation of septum 356 via septum
activator 380. Upon insertion of a coupler 342 into the proximal
opening 326 of the catheter adapter 314, the probe portion 346 of
the coupler 342 contacts the contact surface 340 of septum
activator 380. Septum activator 380 is accordingly advanced in a
distal direction 390 as the coupler 342 is further inserted into
proximal opening 326 thereby causing flushing fins 320 to translate
within translating groove 368. As coupler 342 is advanced further
into the proximal opening 326, probing surface 348 of the septum
activator 380 passes through the slit 366 of septum 356. As such,
the probing surface 348 of the septum activator 380 is positioned
within the forward chamber 362 providing a fluid pathway through
the septum 356.
Referring now to FIGS. 13 through 20, a number of valves in
accordance with some embodiments are shown which aim to further
eliminate or reduce areas of low or no fluid flow occurring within
a vascular access device containing a valve mechanism comprising a
septum and septum activator or pusher.
FIGS. 13 and 14 show an embodiment of the invention in which a
sleeve 45 is used to prevent fluid from flowing into any
interstitial spaces which are low or no flow fluid areas.
FIG. 13 shows a septum 43 which forms a fluidic seal in the lumen
341 of catheter body 41 after removal of the needle, with septum
activator or pusher 344 in the proximal position. Sleeve 45 is
attached around pusher 344 to form a fluid seal between an outer
periphery 53 of proximal portion 348 of pusher 344 and inner
surface 354 of lumen 341. Thus, no fluid can flow between the
proximal end of pusher 344 and the inner surface 354 of lumen 341
into the interstitial space 498. FIG. 14 shows pusher 344 in the
distal position in which fluid can only flow via the lumen 51 of
pusher 344. Sleeve 45 still maintains a fluidic seal between outer
periphery 53 of pusher 344 and inner surface 54 of lumen 341. Thus,
no fluid can flow into the interstitial spaces 498. In addition,
the tapered outer surface 351 of the distal portion of sleeve 45
reduces the size of the interstitial space 498 when pusher 344 is
in the distal position. Sleeve 45 is made from a softer elastomeric
material, such as liquid silicone rubber for example, and is
attached to pusher 344 through suitable molding procedures, such as
insert molding, injection molding, and other molding techniques or
a combination of molding techniques.
FIGS. 15 and 16 show another embodiment of the invention having
valve mechanism which uses a seal at the proximal end 65 and distal
end 75 of a tubular septum activator 365, to prevent fluid from
flowing into interstitial spaces 698 and 699 between activator 365
and the inner surface 74 of the lumen 363 of the catheter body 61.
Distal seal 75 is incorporated into septum 63 to prevent any fluid
flowing between the distal end of activator 365 and the proximal
surface of septum 63 when pusher is in the proximal position as
shown in FIG. 15 or the distal position as shown in FIG. 16.
Proximal seal 65 is a continuous torus or toroidal-shaped band
around the outer circumference of the proximal end of activator 365
which forms a fluid seal with the inner surface 74 of the lumen 363
of the catheter body 61 in both the proximal and distal activator
positions. The proximal seal 65 is made from a softer elastomeric
material, such as liquid silicone rubber for example and is
over-molded onto activator 365 and retained in position by lip 367
on the outer surface of the proximal end of activator 365.
Activator 365 has a number of fins 369 extending from and evenly
distributed around the circumference of the outer surface 371.
These fins 369 are sufficiently long to contact a portion 73 of the
inner surface 74 of lumen 363 and are used to limit the movement of
activator 365 along the catheter body by contact with the septum 63
in the distal direction and contact with indent or step 378 of the
inner surface 74 in the proximal direction.
FIGS. 17 through 20 show some embodiments having valve mechanisms
which are configured to exclude small confined interstitial spaces,
thereby eliminating areas of no to low fluid flow.
FIGS. 17 and 18 show an embodiment in which the septum 83 encases
the majority of activator 383. Activator 383 includes a head
section, tubular section and a plunger. Plunger 381 which has a
diameter at least equal to that of lumen 385 of the catheter body
81 such that no fluid can pass between the inner surface 94 and
plunger 80 is located at the proximal end of activator 383. Septum
83 has an external diameter at least equal to that of lumen 82
along its entire length such that no interstitial space is present
between septum 83 and inner surface 94 of lumen 385. In addition,
septum 83 has a lumen 85, the internal diameter of which is equal
to the external diameter of tubular section 87 of activator 383
thereby forming an additional fluid seal along the length of
tubular section 87. Furthermore, the relative lengths of activator
383 and septum 83 are such that the distal face 389 of plunger 381
is in intimate contact with the proximal end 388 of septum 83 when
activator 383 is in the distal position, as shown in FIG. 18. Thus,
there is no interstitial space between plunger 381 and septum 83.
The head section is located at the distal end of activator 383 and
includes longitudinal slots 387 in the side wall of lumen 91 in
order to allow fluid flow to diverge out of lumen 91 of activator
383 and reduce the possibility of a no or low flow area 393 around
the distal face of septum 83 at the inner surface 74.
FIGS. 19 and 20 show a further embodiment of a valve mechanism in
which a septum 103 includes a tubular section 107 having a distal
end 108 and a membrane section 109 having a proximal planar surface
located at the proximal end 105. The tubular section 107 of septum
103 is substantially disposed within septum housing 111 and is
prevented from distal movement by shoulder or annular recess 121
formed in surface of lumen 385. A fluidic seal is formed between
the periphery of membrane section 109 and inner surface 114 of the
proximal section 110 of lumen 385 to prevent fluid leakage past
septum 103 when the valve is closed. In some embodiments, septum
103 further includes a needle slit 113 or valve aperture located
about the centre of membrane section 109, extending through
membrane section 109, to facilitate penetration of septum 103 by
introducer needle 5. A septum activator 304 is located in the
proximal section of lumen 385 and includes a tubular portion 115.
In some embodiments, tubular or sleeve portion 115 further includes
a plurality of longitudinal slots or flow channels 116 in the side
wall, distributed evenly around the circumference of tubular potion
115 and located at the distal or actuating end 117 such that a gap
is formed between the actuating end 117 and membrane 109.
FIG. 19 shows septum activator 304 in the proximal position
following removal of introducer needle 5. In particular, the
actuating end 117 of septum activator 304 is positioned against the
proximal planar surface of membrane section 109 of septum 103 to
form an interface. The diameter of lumen 385 in proximal section
310 is approximately equal to the external diameter of connector
106 (e.g. a luer connector) of a vascular access device, septum
activator 304 and membrane section 109, such that there are no
interstitial spaces between the connector 106 (shown in FIG. 20), a
contact end of septum activator 304 and membrane section 109. The
inner surface 114 and proximal section 310 of the first lumen 385
are further sealed by membrane section 109.
Referring now to FIG. 20, septum activator 304 is shown in the
distal position whereby connector 106 has repositioned septum
activator 304 forward in a distal direction thereby causing
actuating end 117 of septum activator 304 to deform membrane
section 109. This deformation results in the formation of a fluid
pathway whereby fluid bypasses membrane section 109 via slots 116,
thereafter flowing between periphery of membrane section 109 and
inner surface 114, and guided through opening 118 in the side wall
of tubular portion 107. This divergent fluid path around the
periphery of membrane section 109 causes a turbulent fluid flow
which reduces the possibility of stagnation or a low flow area
occurring near shoulder 119 in lumen 385. Fluid then continues to
flow along the internal diameter of tubular portion 107 and into
the distal section 112 of lumen 385.
Any septum described herein may be made of a variety of suitable
materials and through a variety of suitable manufacturing methods.
For example, the septum may be formed from liquid silicone rubber
through suitable molding procedures, such as insert molding,
injection molding, other molding techniques, or a combination of
molding techniques. The septum 103, or any septum described herein,
may also include a coating of antimicrobial substance on any of its
surfaces, especially those surfaces which have contact with
fluid.
The present invention may be embodied in other specific forms
without departing from its structures, methods, or other essential
characteristics as broadly described herein and claimed
hereinafter. The described embodiments are to be considered in all
respects only as illustrative, and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims,
rather than by the foregoing description. All changes that come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
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