U.S. patent application number 14/474467 was filed with the patent office on 2014-12-18 for catheter positioning system.
The applicant listed for this patent is William F. Urmey. Invention is credited to William F. Urmey.
Application Number | 20140371720 14/474467 |
Document ID | / |
Family ID | 48082480 |
Filed Date | 2014-12-18 |
United States Patent
Application |
20140371720 |
Kind Code |
A1 |
Urmey; William F. |
December 18, 2014 |
CATHETER POSITIONING SYSTEM
Abstract
A catheter positioning system includes a catheter needle
assembly comprising a catheter having a permanent hub and a needle
carried in the catheter lumen. A releasable clamp is used to
compress the catheter against the needle to prevent axial movement
of one relative to the other. The clamp is periodically released
after being moved a short distance toward the target vessel or
nerve and is repositioned a short distance from the skin entry
point to further advance the catheter needle assembly. The clamp is
configured to be removed from the catheter by movement in a
direction other than along the longitudinal axis of the catheter
while the catheter hub remains in place. After successful placement
of the catheter, the clamp may be snapped apart or opened along a
hinge without moving the catheter from its final position.
Inventors: |
Urmey; William F.;
(Larchmont, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Urmey; William F. |
Larchmont |
NY |
US |
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|
Family ID: |
48082480 |
Appl. No.: |
14/474467 |
Filed: |
September 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13649713 |
Oct 11, 2012 |
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14474467 |
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61547432 |
Oct 14, 2011 |
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Current U.S.
Class: |
604/510 |
Current CPC
Class: |
A61M 25/013 20130101;
A61N 1/36017 20130101; A61N 1/0551 20130101; A61M 25/0606 20130101;
A61M 25/0105 20130101; A61M 25/0113 20130101; A61N 1/36021
20130101 |
Class at
Publication: |
604/510 |
International
Class: |
A61M 25/01 20060101
A61M025/01; A61M 25/06 20060101 A61M025/06 |
Claims
1. A method for intravascular placement of a flexible catheter
within a target vessel, the catheter having a distal end, a
proximal end having a hub permanently affixed thereto and a lumen,
a needle within the lumen and a clamp having separable components
positioned on the catheter, the method comprising the steps of: a)
extending a tip of the needle beyond the distal end of the
catheter, b) precluding movement of the needle tip relative to the
distal end of the catheter by engaging the clamp to compress the
catheter against the needle, c) advancing the catheter and needle
at a skin entry point through dermal layers toward and into the
target vessel by grasping and manipulating the engaged clamp, d)
disengaging the clamp when the distal end of the catheter is at a
desired position within the vessel, e) withdrawing the needle while
maintaining the catheter in position, and f) removing the clamp
from the catheter by separating the separable components.
2. A method for intravascular placement of a flexible catheter in
accordance with claim 1 wherein step f) is performed by: snapping
the separable components apart.
3. A method for intravascular placement of a flexible catheter in
accordance with claim 1 wherein step f) is performed by: releasing
a latch.
4. A method for intravascular placement of a flexible catheter in
accordance with claim 1 wherein step f) is performed by: rotating
the components about a hinge.
5. A method for intravascular placement of a flexible catheter in
accordance with claim 1 wherein one of the components comprises a
collar and step f) is performed by: rotating the collar.
6. A method for intravascular placement of a flexible catheter in
accordance with claim 1 wherein step b) includes positioning the
clamp approximately 2 cm from the distal end of the catheter before
engaging the clamp.
7. A method for intravascular placement of a flexible catheter in
accordance with claim 1 wherein step c) includes positioning and
engaging the clamp approximately 2 cm from the skin entry point,
advancing the catheter and needle until the clamp approaches the
skin entry point and if the distal end of the catheter is not at a
desired end position within the vessel, releasing and repositioning
the clamp approximately 2 cm from the skin entry point, reengaging
the clamp and continuing to advance the catheter and needle.
8. A method of CVC placement of a flexible catheter within a
vascular system, the catheter having a distal end, a proximal end
having a hub permanently affixed thereto and a lumen, a needle
having a shaft within the lumen and a clamp positioned on the
catheter, the clamp having separable components, the method
comprising the steps of: a) extending a tip of the needle beyond
the distal end of the catheter, b) precluding movement of the
needle tip relative to the distal end of the catheter by engaging
the clamp to compress the catheter against the needle shaft, c)
advancing the catheter and needle at a skin entry point through
dermal layers and toward a jugular vein of the vascular system by
grasping and manipulating the engaged clamp, d) disengaging the
clamp to permit relative axial movement of the needle shaft
relative to the catheter when the distal end of the catheter is at
a first position within the jugular vein, e) partially withdrawing
the needle shaft until the needle tip lies within the catheter
lumen while maintaining the distal end of the catheter at the first
position, f) engaging the clamp to compress the catheter against
the needle shaft and advancing the catheter and needle further into
the vascular system, g) disengaging the clamp to permit relative
axial movement of the needle shaft relative to the catheter and
withdrawing the needle shaft from the catheter lumen while
maintaining the distal end of the catheter at a second position
within the vascular system, h) engaging the clamp to grip the
catheter and advancing the catheter within the jugular vein until
the distal end of the catheter is at a desired final position
within the vascular system, i) removing the clamp from the catheter
by separating the components, and j) affixing the catheter to the
skin adjacent the skin entry point.
9. A method of CVC placement of a flexible catheter in accordance
with claim 8 wherein step i) is performed by snapping the separable
components apart.
10. A method of CVC placement of a flexible catheter in accordance
with claim 8 wherein step i) is performed by releasing a latch.
11. A method of CVC placement of a flexible catheter in accordance
with claim 8 wherein step i) is performed by rotating the
components about a hinge.
12. A method of CVC placement of a flexible catheter in accordance
with claim 8 wherein one of the components comprises a collar and
step i) is performed by rotating the collar.
13. A method of CVC placement of a flexible catheter in accordance
with claim 8 wherein step b) includes positioning the clamp
approximately 2 cm from the distal end of the catheter before
engaging the clamp.
14. A method of CVC placement of a flexible catheter in accordance
with claim 8 wherein step c) includes positioning and engaging the
clamp approximately 2 cm from the skin entry point, advancing the
catheter and needle toward and/or into the jugular vein until the
clamp approaches the skin entry point and if the distal end of the
catheter is not at a desired position within the vascular system,
releasing and repositioning the clamp approximately 2 cm from the
skin entry point, reengaging the clamp and continuing to advance
the catheter and needle.
15. A method of CVC placement of a flexible catheter in accordance
with claim 8 wherein step h) includes positioning and engaging the
clamp approximately 2 cm from the skin entry point, advancing the
catheter within the vascular system until the clamp approaches the
skin entry point and if the distal end of the catheter is not at a
desired end position within the vascular system, releasing and
repositioning the clamp approximately 2 cm from the skin entry
point, reengaging the clamp and continuing to advance the
catheter.
16. A method for intravascular placement of a flexible catheter in
accordance with claim 1 wherein the target vessel comprises a
jugular vein.
17. A method for intravascular placement of a flexible catheter in
accordance with claim 16 wherein step f) is performed by: snapping
the separable components apart.
18. A method of CVC placement of a flexible catheter within a
vascular system, the catheter having a distal end, a proximal end
having a hub permanently affixed thereto and a lumen, a needle
having a shaft within the lumen and a clamp positioned on the
catheter, the clamp having separable components, the method
comprising the steps of: a) extending a tip of the needle beyond
the distal end of the catheter, b) precluding movement of the
needle tip relative to the distal end of the catheter by engaging
the clamp to compress the catheter against the needle shaft, c)
advancing the catheter and needle at a skin entry point through
dermal layers and toward a jugular vein of the vascular system by
grasping and manipulating the engaged clamp, d) disengaging the
clamp to permit relative axial movement of the needle shaft
relative to the catheter when the distal end of the catheter is at
a first position within the jugular vein, e) partially withdrawing
the needle shaft until the needle tip lies within the catheter
lumen while maintaining the distal end of the catheter at the first
position, f) engaging the clamp to compress the catheter against
the needle shaft and advancing the catheter and needle further into
the vascular system, g) disengaging the clamp to permit relative
axial movement of the needle shaft relative to the catheter and
withdrawing the needle shaft from the catheter lumen while
maintaining the distal end of the catheter at a second position
within the vascular system, h) inserting a flexible wire into the
catheter, i) precluding movement of the flexible wire relative to
the catheter by engaging the clamp to compress the catheter lumen
against the flexible wire and advancing the catheter and flexible
wire within the vascular system until the distal end of the
catheter is at a desired final position, j) removing the clamp from
the catheter by separating the components, k) withdrawing the
flexible wire and l) affixing the catheter to the skin adjacent the
skin entry point.
19. A method of CVC placement of a flexible catheter within a
vascular system in accordance with claim 18 wherein step i) is
performed by snapping the separable components apart.
20. A method of CVC placement of a flexible catheter within a
vascular system in accordance with claim 18 wherein step c)
includes positioning and engaging the clamp approximately 2 cm from
the skin entry point, advancing the catheter and needle through the
skin entry point until the clamp approaches the skin entry point
and if the distal end of the catheter is not at a desired end
position within the vessel, releasing and repositioning the clamp
approximately 2 cm from the skin entry point.
Description
RELATED APPLICATIONS
[0001] This application is a division of application Ser. No.
13/649,713, filed Oct. 11, 2012 which claims the benefit of U.S.
Provisional Application No. 61/547,432, filed Oct. 14, 2011, the
entirety of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to the placement of
intravascular catheters as well as catheters for the administration
of regional anesthesia. More particularly, relating to
intravascular catheter placement, a system for positioning a
catheter for such procedures as central venous pressure monitoring
or infusions of fluids or medications. With respect to regional
anesthesia, the invention relates to a system for positioning a
catheter and nerve stimulator or other needle in conjunction with
various procedures, such as, the administration of an anesthetic
blockade and for continuous infusion of anesthetic through the
catheter.
[0004] 2. Antecedents of the Invention
[0005] The field of regional anesthesia relates to the practice of
administering anesthesia to a specific body region during surgery,
for the relief of postoperative pain, and for extended relief of
trauma or chronic pain. Often, regional anesthesia has been found
to be preferable to general anesthesia because of increased safety,
the availability of postoperative pain control and decreased
anesthetic costs.
[0006] Regional anesthesia delivery techniques strove to optimize
administration of a local anesthetic in close proximity to a target
or nerve plexus so as to establish a neural blockade. Successful
administration of regional anesthesia was dependent upon the
accurate placement of the anesthetic in relation to the target
nerve or nerves.
[0007] Various techniques have been employed to assist in placement
of an administration needle in close proximity to the target nerve,
which was not externally visible. One of the traditional methods of
needle placement involved eliciting paresthesia. Among the
disadvantages of this technique was the lack of accurate patient
responses amongst patients who were disoriented and/or sedated.
[0008] A prevalent technique employed the use of nerve stimulators
electrically coupled to a nerve stimulator needle. Such method was
premised upon the phenomenon that an electrical pulse is capable of
stimulating a motor nerve fiber to contract an innervated muscle or
cause paraesthesia, in the case of sensory nerve stimulation.
[0009] The nerve stimulator needle was placed within the tissue of
the patient's body in the vicinity of the nerve to be blocked and
then advanced until stimulation of the target nerve was achieved as
determined by visually detecting muscle contractions or by
eliciting a report that the patient felt the stimulus in response
to the current flow through the stimulator needle.
[0010] The current supplied by the nerve stimulator was reduced as
the nerve stimulator needle was further advanced, until stimulation
of the target nerve was achieved using a reduced current level
associated with a prescribed distance between the needle tip and
the target nerve.
[0011] Thereafter, a portion of the anesthetic dose was
administered through the needle to terminate the response to the
nerve stimulation current. If the response was terminated by the
initial administration, the needle was deemed to be properly
positioned in proximity to the target nerve and the remaining dose
of anesthetic was administered and the needle was withdrawn upon
completion of the surgical procedure.
[0012] Placement of catheters for continuous infusion of local
anesthetics or other drugs during surgical procedures and primarily
postoperatively has been achieved by use of an intra-catheter which
was placed or threaded through the internal lumen of a larger
needle or stiff cannula, or by use of an extra-catheter which was
placed or threaded over an internal needle or smaller stiff
cannula. Each technique has been associated with certain
disadvantages and limitations that have resulted in less than
optimal results for achieving successful continuous plexus or nerve
block in clinical practice. These disadvantages have severely
limited the use of continuous anesthesia or analgesia, resulting in
under-utilization of continuous techniques in favor of more
predictably successful, less invasive and usually less traumatic
and therefore safer nerve or plexus blockade utilizing only a nerve
stimulation needle for anesthesia or analgesia administration as
previously described.
[0013] Problems associated with the use of an intra-catheter
included the fact that a very large and therefore more traumatic
introducing needle, e.g. 17 or 18, gauge was necessary to allow
passage of a smaller usually 19 or 20 gauge flexible catheter. This
caused increase pain and discomfort during the placement. The
catheter was passed through the bore of the introducing needle with
little control of the final position of the distal end of the
catheter because the flexibility of the catheter did not allow the
practitioner to accurately determine where the catheter will travel
once it passed beyond the needle tip.
[0014] Stimulating catheters have been developed with a flexible
metal stylet inside the catheter which allowed for the ability to
electrically stimulate the nerve or nerves, but these too, were
difficult to control in terms of the final positioning of the
catheter tip once it passed beyond the needle tip.
[0015] Another problem with intra-catheter systems has been
persistent leaking of the injected medication at the entry point of
the removed introducing needle on the skin surface. This occurred
because the catheter diameter was smaller than the needle diameter
and the diameter of the hole left by the introducing needle.
Leakage was especially pronounced after placement of continuous
catheters for superficial nerves or nerve plexus.
[0016] An additional problem relates to the fact that the catheter
passed through a needle does not maintain a predictably straight
trajectory once the catheter tip passes beyond the needle tip. This
makes visualization of the catheter difficult or impossible when
using ultrasonographic imaging to assist in placement of the
catheter. A controlled straight trajectory allows precise placement
at the proper anatomical position or endpoint when utilizing
imaging techniques.
[0017] Placement of a catheter through a needle requires the
separate attachment of a typically removable hub or mechanism for
connecting to larger bore infusion tubing such as intravenous
tubing after the external introducing needle is withdrawn over the
proximal end of the placed catheter. These affixed hubs have
associated disadvantages that include frequent kinking or occlusion
of the smaller catheter, disconnection and bacterial or other
contamination of the unprotected smaller catheter, or leakage at
the connection site.
[0018] Major problems associated with the use of an extra-catheter
system included the fact that extra-catheters have had to be made
of larger gauges than desirable and have been stiffer than
desirable to allow adequate stability for advancement over the
smaller internal needle. A catheter with the desired flexibility
and small diameter was difficult to pass or thread over the needle
due to undesired buckling or bending. The length of the
extra-catheter was therefore limited because longer extra-catheter
systems of very small diameter were too flexible and therefore
unstable and difficult to pass. Shorter catheters are not able to
reach the more distant desired position required for central venous
monitoring or infusions.
[0019] The longer a thin catheter or thin needle was, the more
unstable it was. This was because each additional unit of length
compounded its flexibility. Such catheters would bend when advanced
through the skin and deeper tissues, making targeted accurate
placement difficult. Additionally, extra-catheters were required to
freely slide off of the internal needle, cannula, or stylet and
therefore often had undesired movement in relation to the internal
needle during use, especially upon advancement and withdrawal. If
the extra-catheter was more tightly fitted to the internal needle,
withdrawal of the stylet or needle often put undue traction on the
catheter, resulting in undesired movement of the catheter tip from
the optimal position that was already achieved.
[0020] In U.S. Pat. No. 7,699,809, issued to Applicant herein, a
system for positioning a catheter that included a nerve stimulator
needle carried within the bore of the catheter was described. The
needle includes a microelectrode configured as a needle tip
protruding beyond the distal end of the catheter. The catheter and
needle are fixed against relative axial movement by a releasable
clamp which is grasped by the practitioner to compress the catheter
bore against the needle without deforming the needle. The clamp is
positioned on the catheter at a relatively short distance, e.g. 2
cm, from the skin entry point to minimize flexure when advancing or
withdrawing the catheter and needle assembly to simultaneously
position the distal end of catheter and needle tip in close
proximity to the target nerve or nerve plexus. A plurality of
clamps may be employed and each clamp released as it contacts the
entry point or a single clamp is released and repositioned after it
contacts the entry point.
[0021] Upon attaining the desired needle tip position in proximity
to the nerve as determined by electrical stimulation,
ultrasonographic imaging, etc., a dosage of anesthetic is
administered through the needle. With the clamp or clamps fully or
partially released so as to fully open the catheter bore, the
needle can be freely withdrawn from the catheter. The proximal end
of the catheter is thereafter coupled to a syringe, tubing, pump or
other device for continuous administration of an anesthetic or
other medication.
[0022] Presently, 5-6 million central venous catheters (CVC) are
placed each year, in the U.S., alone. By contrast to the placement
of catheters utilized for regional anesthesia, intravenous
catheters require a permanent hub to avoid the serious complication
of the accidental placement or migration of the entire catheter
into the central or other venous circulation, a so-called "catheter
embolization".
[0023] Central venous catheter placements have been performed using
a technique that was first described by Seldinger in 1953, now
referred to as the "Seldinger Technique". The Seldinger methodology
has been to access the vein with a large-gauge sharply pointed
needle, after which a flexible wire was placed through the lumen of
the needle. The needle is then removed over the wire following
which, a long flexible central venous catheter with a permanent hub
was placed over the wire, often after using a scalpel and firm
"dilator" to open a space in the skin and underlying subcutaneous
tissue, to facilitate the passage of the softer catheter into the
vein. The wire was then removed, leaving the catheter in the
desired intravascular final position. Needless to say, the
procedure was somewhat traumatic and often led to difficulty and
contamination during the process of passing the wire and the
exchange between needle, wire, and catheter.
[0024] Currently, the advocated methodology for central venous
catheter placement involves the use of direct ultrasongraphic
imaging to guide the initial needle placement into the targeted
vein. After needle placement, the ultrasongraphic probe was put
down and the remainder of the procedure done under the older,
landmark-based methodology that has been used for more than 50
years. The use of ultrasongraphic guidance has improved success
rates and decreased complications when compared to the conventional
blind landmark-based technique.
[0025] Several major medical societies have now endorsed the use of
ultrasongraphic guidance for CVC placement. These include the
American Society of Anesthesiologists, the American Society of
Echocardiologists, the Society of Cardiovascular Anesthesiologists
and the Centers for Disease Control and Prevention.
[0026] The risk of complications during conventional central venous
catheter placement include pneumothorax (0 to 6.6%), carotid artery
puncture (6%), subclavian artery puncture (0.5 to 4%), hemothorax
(1%), and unsuccessful placement in the internal jugular vein
(12%). Central venous catheter associated infections have been
identified as a major cause of hospital morbidity and
mortality.
[0027] The American Society of Anesthesiologists as well as The
American Society of Echocardiography with the Society of
Cardiovascular Anesthesiologists have recently published guidelines
for CVC placement.
[0028] While the use of ultrasongraphic imaging during initial
placement has reduced complications and additional imaging during
catheter placement will further reduce the risk of complications,
there remains a need to simplify CVC placement and further reduce
the associated risks.
SUMMARY OF THE INVENTION
[0029] A flexible catheter is fitted over a smaller gauge needle,
with the needle tip precisely positioned to protrude just beyond
the tapered catheter tip. A single-hand releasable, removable,
clamp or grip is used to grasp the catheter and needle to prevent
axial movement of one relative to the other. The clamp is used to
manipulate the needle and catheter assembly as a unit by initially
positioning the clamp a short distance, e.g. 2 cm, from the skin
entry point to minimize flexure or deformation when introducing and
advancing the catheter-needle assembly, preferably under
ultrasonographic imaging. The clamp is periodically released after
being moved a short distance toward the target vessel or nerve and
is repositioned a short distance from the skin entry point to
further advance the catheter needle assembly.
[0030] In contrast to the previous invention described in U.S. Pat.
No. 7,699,809, which is incorporated herein in its entirety by
reference, the catheter has a permanent hub or larger lumen
connection port at its proximal end for connection to larger bore
infusion tubing, e.g. standard intravenous tubing.
[0031] An aspect of invention is that the releasable clamp or grip
is configured to open or snap apart so that it can be removed from
the catheter, with the catheter hub remaining in place. After
successful placement of the catheter, the clamp is snapped apart or
opened along a hinge without moving the catheter from its final
position. This eliminates the need for a subsequently attached
connecting hub to couple the small gauge catheter to standard
intravenous or other larger gauge tubing and significantly, enables
CVC placement.
[0032] From the foregoing compendium, it will be appreciated that a
feature of the present invention is to provide a catheter
positioning system of the general character described which
simplifies CVC placement procedures.
[0033] A consideration of the present invention is to provide a
catheter positioning system of the general character described
which increases the efficiency of intravascular catheter
placement.
[0034] An aspect of the present invention is to provide a catheter
positioning system of the general character described suitable for
implementation with catheters having permanent hubs.
[0035] A further consideration of the present invention is to
provide a catheter positioning system of the general character
described which avoids the necessity of making incisions during CVC
placement.
[0036] To provide a catheter positioning system of the general
character described which is well suited for continuous regional
anesthesia or analgesia is a further consideration of the present
invention.
[0037] Yet another aspect of the present invention is to provide a
catheter positioning system of the general character described
which facilitates simple and accurate positioning of a
catheter.
[0038] A still further feature of the present invention is to
provide a catheter positioning system of the general character
described which is relatively low in cost.
[0039] An additional consideration of the present invention is to
provide a catheter positioning system of the general character
described with reduced patient trauma.
[0040] A further aspect of the present invention is to provide a
catheter positioning system of the general character described with
reduced risk of complications.
[0041] Another consideration of the present invention is to provide
a catheter positioning system for CVC placement of the general
character described which eliminates the need for a separate wire
guide.
[0042] Other aspects, features and considerations of the present
invention in part will be obvious and in part will be pointed out
hereinafter.
[0043] With these ends in view, the invention finds embodiment in
certain combinations of elements, arrangements of parts and series
of steps by which the aforesaid aspects, features and
considerations and certain other aspects, features and
considerations are attained, all with reference to the accompanying
drawings and the scope of which will be more particularly pointed
out and indicated in the appended claims.
DESCRIPTION OF THE DRAWINGS
[0044] In the accompanying drawings in which is shown some of the
various possible exemplary embodiments of the invention:
[0045] FIG. 1 is an elevational view of a practitioner advancing a
catheter and needle assembly by grasping a clamp in accordance with
the invention;
[0046] FIG. 2 is an enlarged scale axial sectional view through the
catheter and needle assembly and illustrating a permanent hub
affixed to the end of the catheter;
[0047] FIG. 3 is a transverse sectional view through the clamp,
taken along the plane 3-3 of FIG. 2 showing a living hinge and a
flexible latch for opening the clamp;
[0048] FIG. 4 is an isometric view of a catheter and needle
assembly with an alternate snap apart clamp and showing a distal
guideway secured by a threaded collar and a proximal guideway, both
configured to snap apart for removal of the catheter;
[0049] FIG. 5 is an enlarged scale fragmentary exploded isometric
view of the distal guideway with the collar removed; and
[0050] FIG. 6 is a diagrammatic illustration of the catheter and
needle assembly and the alternate clamp during an intravascular
placement procedure.
DESCRIPTION OF THE INVENTION
[0051] Referring now in detail to the drawings, wherein like
numerals designate like components throughout, the reference
numeral 10 denotes generally a catheter positioning system
constructed in accordance with and embodying the invention. The
catheter positioning system 10 includes a catheter needle assembly
12 comprising a thin, e.g. 27 gauge, needle 14 having a sharp
cutting tip 16 at a distal end.
[0052] A thin, e.g. 22 gauge, catheter 18 includes a tapered distal
end 20, a permanent hub 22 at its proximal end and a lumen 24 which
receives the shaft of the needle 14. The diameter of the lumen 24
is greater than the diameter of the needle shaft, leaving a
clearance space 26 such that if unrestrained, the needle 14 may
move axially relative to the catheter 18 with relative freedom.
[0053] Pursuant to the invention, there is provided one or more
releasable clamps 28 through which the catheter needle assembly 12
extends. Illustrated in FIG. 1 is an exemplary releasable clamp 28
having a bore 30 through which the catheter needle assembly 12 is
threaded and a pair of diametrically opposed cylindrical gates 32
which extend along an axis perpendicular to the axis of the bore
30. Each gate 32 includes an enlarged head 34. Positioned within
annular channels registered with the heads 34 are a pair of coil
springs 36 which urge the gates 32 radially outwardly to a released
position, wherein the clearance space 30 is maintained. By pressing
both heads 34 inwardly, the gates deform the catheter 18 to axially
fix the catheter 18 relative to the needle shaft, as illustrated in
FIG. 2.
[0054] The compressed state of the gates can be locked by rotating
the heads 34, such that a radially projecting pin 38, normally
seated in an axial groove, extends into an annular notch or groove.
The gates are released by rotating the heads 34 in the opposite
direction to reseat the pins in their axial grooves.
[0055] A clamp 28 having a single gate 32 may also be employed,
with the catheter being compressed between the single gate and the
diametrically opposed portion of the bore 30 to fix the conduit
relative to the needle shaft.
[0056] The clamp 28 differs, however, from the clamp described U.S.
Pat. No. 7,699,809 so as to enable the clamp 28 to be removed from
the catheter 18. Because the proximal end of the catheter has
affixed thereto the hub 22, the clamp 28 can no longer be removed
by sliding off the proximal end of the catheter.
[0057] With reference to FIGS. 1-3, it will be seen that the clamp
28 comprises two segments 27, 29, with one half of the bore 30
(split along an axial plane) being formed in each segment. The
segments 27, 29 pivot about a living hinge 40 after a flexible
latch 42 is released to thereby open the bore 30 of the clamp for
removal of the clamp 28 from the catheter 18.
[0058] Illustrated in FIG. 4 is an alternate clamp 28A, similar to
that described in U.S. Pat. No. 7,699,809. The clamp 28A is formed
of molded thermoplastic construction and includes a pair of axially
registered generally cylindrical proximal and distal guideways 44A,
46A through which a catheter needle assembly 12A extends. It should
be noted that the portion of the catheter needle assembly
projecting from the distal guideway 46A includes a needle tip 16A
and a distal end taper 20A of a catheter 18A.
[0059] The releasable clamp 28A includes a concave platen 48A which
extends between the guideways 44A, 46A. A flexible leaf hinge 50A
joins the proximal guideway 44A to a maxillary convex jaw 52A. A
yoke 54A, at the distal end of the convex jaw 52A, contacts the
guideway 46A to limit the travel of the convex jaw 52A and prevent
permanent deformation of the nerve stimulator needle 14A. In use, a
practitioner grasps the outer surfaces of the convex jaw and the
concave platen between the forefinger and thumb and squeezes the
jaw and platen together.
[0060] It should be appreciated that when the convex jaw is urged
against the concave platen, the convex jaw contacts the catheter
and deforms it toward the concave platen such that the catheter and
the needle are fixed against axial movement relative to one
another. The arc of curvature of the mating convex jaw and concave
platen may be such to slightly bend, but not permanently deform the
nerve stimulator needle.
[0061] In order to facilitate removal of the alternate clamp 28A
from the catheter needle assembly 12A, the distal guideway 46A is
formed of two break away segments 56A, 58A, joined along a
substantially horizontal (as viewed in FIG. 4) axial plane 59A
which extends through a bore of the guideway 46A which receives the
catheter needle assembly. One half of the bore is formed in each
segment 56A, 58A.
[0062] A most distal portion of the distal guideway 46A includes a
threaded nipple 60A. An internally threaded collar 62A, engages the
threaded nipple 60A when the clamp 28A is being used. When the
catheter needle assembly has reached its final position and the
clamp 28A is to be removed, the threaded collar 62A is disengaged
from the nipple 60A and the segments 56A, 58A are separated.
[0063] Similarly, the proximal guideway 44A is formed of upper and
lower segments 64A, 66A with on half of a bore carrying the
catheter needle assembly being formed in each segment. The segments
64A, 66A, are joined along a corrugated, generally horizontal seam
68A to be snapped apart for removal of the clamp 28A from the
catheter needle assembly. The hinge 50A and maxillary convex jaw
52A are preferably formed in one piece with the upper segment
64A.
[0064] After removal of the clamp 28A, the threaded collar 62A may
is secured to the hub 22A, which includes a threaded nipple 70A for
receiving the collar.
[0065] A description of usage of the present invention in
connection with nerve anesthesia or analgesia via catheter infusion
as well as central venus or other intravascular placement of a
flexible catheter follows:
[0066] Peripheral or Plexus Nerve Anesthesia/Analgesia Via Catheter
Infusion:
[0067] The flexible catheter, e.g. 20 gauge, is fitted over a
smaller gauge needle, e.g. 24 gauge, either stimulating or
non-stimulating needle, with the needle tip precisely fitted to
protrude just beyond the tapered catheter tip. A single-hand
releasable, removable, clamp or grip is used to grasp the catheter
and needle to prevent axial movement of one relative to the other.
This is used to introduce the needle and catheter as in U.S. Pat.
No. 7,699,809 by initially positioning the clamp a short distance,
e.g. 2 cm, from the skin entry point to minimize flexure or
deformation when introducing the catheter-needle system. The clamp
is periodically released after being moved more proximal a short
distance to further advance the catheter and needle. In contrast to
U.S. Pat. No. 7,699,809, the catheter has a permanent hub or larger
lumen connection port for connection to larger bore infusion
tubing, e.g. standard intravenous tubing.
[0068] An aspect of the present invention is that the adjustable
clamp contains a "break-away" hinge allowing the clamp to be
removed with only the permanently hubbed catheter remaining in
place. This eliminates the need for a subsequently attached
connecting hub to couple the small gauge catheter to standard
intravenous or other larger gauge tubing. After successful
placement, the clamp is broken away to leave the catheter in the
final position.
[0069] Central Venous or Other Intravascular Placement of a Small
Gauge Flexible Catheter:
[0070] Although the system can be used to place a catheter
intravascularly without ultrasonographic imaging modalities, the
preferred technique or method involves the use of ultrasonographic
imaging to ascertain the correct placement of the needle and
catheter tip in the proper vessel, e.g internal jugular vein. This
is confirmed by aspiration through the hub of the inner needle. The
flexible catheter for central line placement is typically larger,
e.g. 16 gauge, than the perineural catheter described above. The
releasable clamp 28, 28A is used in a similar method as described
above for perineural catheter placement. The catheter is compressed
against the smaller internal needle, e.g. 18 gauge, and inserted
with the aid of ultrasonographic imaging until the needle and
catheter tip are well within the desired vessel, e.g. proximal
internal jugular vein, in the neck.
[0071] This is confirmed by aspiration of venous blood from the
needle hub. The clamp or grip is then released, allowing free axial
movement of the needle relative to the overlying catheter. The
needle is withdrawn a small distance, e.g. 4 mm, so that the sharp
needle tip is fully within the lumen of the catheter and the vessel
is therefore protected from damage from the needle tip. The clamp
is used to re-grip the catheter needle assembly approximately 2 cm
from the skin entry point and is used to advance the needle and
catheter into the more distal jugular vein a short distance, e.g. 1
cm. In the preferred method, the needle is then completely removed
from within the lumen of the catheter and the clamp is used to grip
and advance the central venous catheter in approximately 2 cm
increments to the desired endpoint.
[0072] An alternative method entails removal of the needle at the
same point described above and substitution of the needle with a
precisely fitted internal flexible wire such as a J-wire which is
then either placed through the catheter and the catheter
subsequently passed over, or alternatively placed within the
catheter for added stability forming a catheter wire assembly and
the releasable clamp or grip used to advance the two together in
approximately 2 cm increments while maintaining the relative axial
position of each with regard to the other.
[0073] Following achievement of the endpoint with any of the above
methods, once the catheter is in the desired final position, the
clamp or grip is "broken-away" and the catheter affixed to the skin
using standard methodology for central venous catheters. This
eliminates a step in the present prevailing method for central line
catheterization that is associated with instability of the needle
relative to the vessel during standard central venous line
placement and therefore simplifies central venous catheter
placement.
[0074] Thus it will be seen that there is provided a catheter
positioning system which achieves the various aspects, features and
considerations of the present invention and which is well suited to
meet the conditions of practical usage.
[0075] As various possible further embodiments might be made of the
present invention and various changes might be made in the
illustrative embodiments above set forth without departing from the
spirit of the invention, it is to be understood that all matter
herein described or shown in the accompanying drawings is to be
interpreted as illustrative and not in a limiting sense.
* * * * *