U.S. patent application number 11/042941 was filed with the patent office on 2005-06-16 for iv catheter introducer with retractable needle.
Invention is credited to Shaw, Thomas J., Zhu, Judy.
Application Number | 20050131350 11/042941 |
Document ID | / |
Family ID | 34651924 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050131350 |
Kind Code |
A1 |
Shaw, Thomas J. ; et
al. |
June 16, 2005 |
IV catheter introducer with retractable needle
Abstract
An IV catheter introducer having a retractable needle holder and
a tubular plunger that are held by a detent structure in a
preferred positional relationship prior to and during insertion of
the catheter. Following insertion, the plunger is pushed past the
detent structure, permitting a compressed spring to force the
needle holder upwardly into the plunger. A vented end cap in the
plunger permits rapid venting of air displaced during retraction of
the needle holder. The needle holder includes a flash chamber that
is easily viewable through a clear plastic housing. Wings are
provided on the housing to facilitate one-handed operation of the
device. A method for assembling the subject catheter introducer is
also disclosed.
Inventors: |
Shaw, Thomas J.; (Little
Elm, TX) ; Zhu, Judy; (Plano, TX) |
Correspondence
Address: |
RHEON AUTOMATIC MACHINERY CO
2-3 NOZAWA-MACHI UTSUNOMIYA-SHI
TOCHIGI-KEN
JP
|
Family ID: |
34651924 |
Appl. No.: |
11/042941 |
Filed: |
January 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11042941 |
Jan 25, 2005 |
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10047662 |
Oct 26, 2001 |
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6872193 |
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Current U.S.
Class: |
604/168.01 ;
604/263 |
Current CPC
Class: |
A61M 25/0631 20130101;
A61M 25/0606 20130101; A61M 5/3232 20130101; A61M 25/0693
20130101 |
Class at
Publication: |
604/168.01 ;
604/263 |
International
Class: |
A61M 005/178; A61M
005/00 |
Claims
1. An IV catheter introducer comprising a tubular housing; a needle
holder assembly having a tubular body slidably engaged inside the
housing; a retraction mechanism seated in an annular space between
the housing and the needle holder assembly; a plunger assembly
having a plunger tube releasably engaged with the tubular body
inside the housing; and a catheter attached by frictional
engagement to the tubular housing; wherein the needle holder
assembly comprises a flash chamber with an interior space that is
viewable through no more than two layers of clear plastic.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 10/047,662, filed Oct. 26, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention is a medical device used to insert a catheter
into a patient's body, especially for the intravenous delivery of a
fluid. More particularly, the invention is a catheter introducer
having a retractable needle that prevents reuse and avoids needle
stick injuries to medical personnel and others.
[0004] 2. Description of Related Art
[0005] Catheter insertion devices are well known. When a catheter
is inserted into a patient for the intravenous delivery of a fluid,
a disposable needle passing through the catheter is utilized to
puncture a vein to permit entry of the catheter. The needle is then
withdrawn, leaving the catheter in place for connection to an IV
bag or bottle, or to be capped for later use.
[0006] In recent years, because of the prevalence of blood-borne
pathogens such as HIV hepatitis, there has been an increasing need
for catheter introducers that prevent accidental needle stick
injuries to medical personnel and to other employees who handle
trash, laundry or other refuse containing used needles. As a
result, new products have been designed that incorporate special
needle covers or mechanisms for retracting the needle following
use. Such devices are disclosed, for example, in U.S. Pat. Nos.
4,747,831; 4,828,548; 5,129,884; 5,501,675; 5,817,058 and
5,989,220. Many of the prior art devices contain numerous
complicated parts that substantially increase manufacturing costs
and interfere with the user's ability to feel when the needle is
properly inserted into the patient. Other devices require
two-handed operation or are prone to premature needle retraction
during shipment, storage and handling.
[0007] An IV catheter introducer is therefore needed that can be
manufactured economically and reliably at high speed, that will not
retract the needle prematurely, that can be operated with one hand,
and that will fully protect the user and others from accidental
sticks and exposure to blood-borne pathogens. These and other
advantages are provided by the invention disclosed below.
SUMMARY OF THE INVENTION
[0008] A single use IV catheter introducer is disclosed that
provides significant advantages over prior art devices, even those
comprising retractable needles. Principal structural improvements
include a reliable detent structure that holds the needle holder
and plunger in proper positional alignment prior to needle
retraction; following insertion of the catheter; a plunger end cap
that vents air displaced from inside the plunger bore during needle
retraction; and a transparent viewing area that permits the user to
view the flash chamber of the needle holder more easily through the
clear plastic housing. Other improvements include barrel wings that
facilitate one-handed operation and prevent the catheter introducer
from rolling when placed on a surface, a needle holder opening that
is tapered to permit easy insertion of the flash chamber plug
during manufacture, and a needle holder configuration that prevents
the blunt needle end from being occluded during manufacture and
makes the flow of blood into the flash chamber more visible.
[0009] The IV catheter introducers of the invention have few parts,
can be manufactured reliably at high speed, significantly reduce
the likelihood of premature needle retraction during storage and
handling, are easily useable in one hand, and will protect medical
and other ancillary personnel from accidental needle sticks and the
possibility of resultant infection by blood-borne pathogens. Use of
the present invention also affords significant economic benefits to
health care providers and insurers through reduced testing and
follow-up costs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The apparatus of the invention is further described and
explained in relation to the following figures of the drawing
wherein:
[0011] FIG. 1 is a simplified perspective view of the IV catheter
introducer of the invention with the catheter needle ready for
use;
[0012] FIG. 2 is an enlarged, cross-sectional elevation view taken
along line 2-2 of FIG. 1;
[0013] FIG. 3 is a view as in FIG. 2, but with the needle retracted
following use;
[0014] FIG. 4 is an enlarged detail view taken from FIG. 2, and
depicts the detent structure holding the landed front opening of
the plunger tube in the desired position relative to the
retractable needle holder prior to retraction;
[0015] FIG. 5 is an enlarged plan view of the vented plunger end
cap; and
[0016] FIG. 6 is a cross-sectional elevation view taken along line
66 of FIG. 5.
[0017] Like reference numerals are used to describe like parts in
all figures of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] Referring to FIGS. 1-2, IV catheter introducer 10 preferably
comprises tubular plastic housing 12, needle holder assembly 14,
retraction mechanism 16, plunger assembly 18 and IV catheter 20.
Plastic housing 12 has an internal bore 22 that narrows
progressively between open end 24 and reduced diameter tip 26,
except for a short distance below inwardly projecting annular ring
102, as described below. Plastic housing 12 is preferably injection
molded from a substantially transparent polymeric resin such as
polycarbonate to permit easy viewing through sidewall 28. The
outside diameter of housing 12 generally follows the tapered
narrowing of internal bore 22, so that sidewall 28 has a
substantially constant thickness except where it flares outwardly
to form laterally extending wings 30 and to provide a
longitudinally spaced series of annular ridges 31 nearer to tip 26
to create a textured gripping area for the fingers of the user.
[0019] Needle holder assembly 14 is retractably mounted within the
lower portion of housing 12 and preferably comprises a tapered,
elongate tubular body 32, needle 34 and porous plug 36. Body 32 of
needle holder assembly 14 is preferably injection molded from a
substantially transparent polymeric resin such as polycarbonate and
comprises a tapering sidewall of substantially constant thickness
that further defines flash chamber 42, spring guide section 44 and
needle support section 46, each of which has a progressively
smaller diameter. Tubular body 32 of needle holder assembly 14 is
desirably shaped so as to permit needle holder assembly 14 to be
inserted into sliding engagement with housing 12 during assembly,
as described in greater detail below. The upper end portion of
tubular body 32 is adapted to releasably engage lower end 56 of
plunger assembly 18 as described below in relation to FIG. 4. As
viewed in FIG. 2, retraction mechanism 16, which is preferably a
spring, is confined within annular space 90 between housing 12 and
spring guide section 44 of tubular body 32, and is held in
compression between downwardly facing shoulder 92 of tubular body
32 and upwardly facing shoulder 94 of housing 12. Although this
embodiment uses a compressed spring that exerts a retraction force
by expanding, other similarly effective means such as an extension
spring can likewise be used to retract the needle.
[0020] Needle 34 is hollow and has a beveled end 48, which is
inserted into a patient's vein during use, and a blunt end 50 that
extends into flash chamber 42. A longitudinally extending bore
provides fluid communication through needle 34 between beveled end
48 and blunt end 50. Needle 34 is preferably insert molded into
needle support section 46 of tubular body 32 to create an insert
molded needle. However, needle 34 can be glued or sonically welded
into body 32 if desired. A tapered needle insertion opening 47 is
desirably provided at the lower end of needle support section 46 if
needle 34 is to be inserted after molding needle support section
46. By using a needle 34 that is long enough to extend into flash
chamber 42, the bore of needle 34 will not become occluded during
insert molding. Also, because a minor amount of blood flows
upwardly through needle 34 into flash chamber 42 whenever needle 34
is introduced into the vein of a patient, making blunt end 50
visible in flash chamber 42 permits the user to view blood as soon
as it enters flash chamber 42, confirming to the user that needle
34 is properly positioned inside the vein.
[0021] At the top of flash chamber 42 of needle holder assembly 14,
end 52 of tubular body 32 is blocked with porous plug 36 that
frictionally engages the walls of annular recess 55 in body 32. The
insertion of porous plug 36 into tubular body 32 is preferably made
easier by tapered inside wall 54 adjacent to end 52. Porous plug 36
is preferably made of any suitable porous material that will allow
air to be displaced out of needle 34 and flash chamber 42 by blood
rising through needle 34 following insertion into a vein, but will
prevent any such minor amount of blood from exiting flash chamber
42. A significant advantage of IV catheter introducer 10 disclosed
herein is that flash chamber 42 is visible through only two layers
of clear plastic: the transparent wall of tubular body 32 around
flash chamber 42; and the transparent wall of housing 12. With many
devices disclosed in the prior art, the user must peer through
three or more plastic layers to view the flash chamber, making it
more difficult to observe when blood begins entering the
chamber.
[0022] Plunger assembly 18 preferably comprises a polymeric plunger
tube 40 having a substantially cylindrical sidewall with a lower
end portion 56 that is proximal to end 52 of tubular body 32 of
needle holder assembly 14, and an upper end portion 58 that
projects longitudinally outward from open end 24 of housing 12.
Plunger tube 40 is preferably injection molded from a polymeric
resin, and most preferably, from a substantially transparent
polymer such as polycarbonate. Lower end portion 56 of plunger
assembly 18 releasably engages tubular body 32 of needle holder
assembly 14 and cooperates with needle holder assembly 14 to form
the detent structure of the invention as described in greater
detail below in relation to FIG. 4. Upper end portion 58 of plunger
tube 40 preferably comprises a small, radially extending annular
flange 60 surrounding a tapered annular recess 62 in surface 64
that receives and frictionally engages end cap 66, which is further
described and explained in relation to FIGS. 5 and 6. With IV
catheter introducer 10 prepared for use, upper end 58 of plunger
assembly 18 desirably extends from about 1.5 to about 3 inches from
housing 12 so that upper end 58 can be nestled against the palm of
the hand while the user's fingers grip wings 30 or annular ridges
31 of housing 12 to facilitate one-handed operation. Pulling back
on housing 12 with the fingers triggers retraction of needle holder
assembly 14, as discussed below in relation to FIG. 3.
[0023] Referring to FIGS. 5 and 6, end cap 66 is preferably molded
from a polymeric resin and, most preferably, from a resin that is
pigmented in a color chosen to correspond to the gauge of needle
34, shown in FIGS. 1-2, to assist users in readily differentiating
among IV catheter introducers 10 having different sized needles.
End cap 66 preferably further comprises a substantially continuous,
circular end wall 68 connected to a longitudinally extending
annular skirt 70 that is inwardly tapered to provide contacting
frictional engagement with annular recess 62 of plunger tube 40 as
previously described. It should be understood that there are many
ways of engaging end cap 66 into upper end portion 58 of plunger
tube 40. End cap 66 may be glued, snapped-on, sonically welded,
dual shot molded or engaged by any other similarly effective means.
Dual shot molding refers to any molding process that allows
different materials or different colored materials to be molded
concurrently. Vent hole 72 is preferably centrally disposed in end
wall 68 and is desirably surrounded by surface relief features such
as a plurality of outwardly extending molded ribs 74 that extend
across surface 68. Ribs 74 are preferably of sufficient number,
spacing and height that vent hole 72 is not blocked by the hand of
the user, even when part of the hand is placed over end cap 66
during operation of IV catheter introducer 10. Vent hole 72 is
preferably large enough to rapidly vent the volume of air displaced
from retraction cavity 76 when needle holder assembly 14 is
retracted into plunger tube 40 following insertion of the
catheter.
[0024] Referring again to FIGS. 1-2, IV catheter 20 preferably
includes a flexible rubber or plastic cannula 78 and a hub 80
having a needle channel 82 and a tubular section 84 with an annular
flange 86 defining an opening 88 having a diameter such that
opening 88 will receive and frictionally engage tip 26 of housing
12. At the end of cannula 78 is an inwardly tapered end 81 that
provides an interference fit near beveled end 48 of needle 34.
During the attachment of hub 80 to tip 26, needle 34 is inserted
through flexible cannula 78 and inwardly tapered end 81, with
beveled end 48 extending slightly beyond the inwardly tapered end
81. The inside diameter of cannula 78 is preferably slightly
greater than the outside diameter of needle 34 to permit easy
retraction of needle 34 through cannula 78 following insertion. Hub
80 is preferably also adapted for easy connection to a convention
IV tubing connector following retraction of needle 34 and removal
of tip 26 from tubular section 84 of hub 80.
[0025] Referring to FIG. 2, IV catheter introducer 10 of the
invention is preferably assembled by dropping retraction spring 16
through opening 22 into housing 12. Retraction spring 16, which is
a coil spring biased against compression, preferably has a diameter
that causes it to seat just above inclined annular shoulder 94
inside housing 12, where it is supported in substantially vertical
alignment by section 33 of sidewall 28. Pre-manufactured needle
holder assembly 14 is then inserted downwardly through open end 22
of housing 12, with beveled end 48 of needle 34 passing downwardly
through retraction spring 16 and tip 26 of housing 12, until
inclined annular shoulder 96 of tubular body 32 abuts against
shoulder 94 of housing 12. Alternatively, spring 16 can be placed
over needle holder assembly 14 prior to insertion of needle holder
assembly 14 into housing 12. Also, if desired, needle 34 can be
glued or sonically welded into needle holder assembly 14 after
needle holder assembly 14 is inserted into housing 12. Inclined
annular shoulder 92 of tubular body 32 preferably will not contact
inclined annular shoulder 98, to permit shoulder 96 to seat
properly against shoulder 94.
[0026] Referring to FIGS. 2 and 4, lower end portion 56 of
pre-manufactured plunger assembly 18 is next introduced into
housing 12 through opening 22. As plunger tube 40 travels
downwardly into housing 12, nose 104 of plunger tube 40 reaches and
slides over end 52 of tubular body 32 of needle holder assembly 14.
When nose 104 reaches end 52, radially extending annular boss 100
on plunger tube 40 is still disposed above inwardly projecting
annular ring 102 of housing 12, and the inside diameter of plunger
tube 40 at nose 104 is sufficiently greater than the outside
diameter of end 52 to permit lower end portion 56 of plunger tube
40 to slidably engage the portion of tubular body 32 that is
adjacent to end 52. As plunger assembly 18 is inserted farther into
housing 12, annular boss 100 engages and overrides annular ring
102. Annular ring 102 then resists rearward movement of plunger
tube assembly 18 and combined needle holder assembly 14 once they
are installed in the housing with the needle extended for use. If
there is an attempt to withdraw the plunger tube assembly 18 from
housing 12, the shoulder of annular boss 100 will contact the
shoulder of annular ring 102 and prevent the withdrawal unless
there is an exertion of substantial force. However, it should be
understood that annular ring 102 is desirably sufficiently small to
allow for the withdrawal of a molding tool during the manufacturing
process. Referring to FIG. 4, a detail view taken from FIG. 2,
plunger tube 40 continues to slide downwardly over tubular body 32
of the needle holder assembly until inwardly facing annular boss
106 on the inside surface of lower end portion 56 reaches and snaps
into engagement with cooperatively sized and aligned, outwardly
facing annular recess 108 of tubular body 32. Referring to FIGS. 2
and 4, the configuration and dimensions of annular boss 106 and
annular recess 108 cause boss 106 to be biased radially inward into
annular recess 108.
[0027] It should be understood that boss 106 on the inside of
plunger tube 40, is not required to be circumferentially
coextensive with annular recess 108 of tubular body 32. Thus, for
example, boss 106 can instead comprise a circumferentially spaced
array of discrete, inwardly extending bumps that are biased into
engagement with recess 108. It is preferred, however, that recess
108 extend completely around tubular body so that the slidable
engagement between plunger tube 40 and tubular body 32 does not
require a specific rotational alignment between the two parts. The
configuration and dimensions of boss 106 and recess 108 are
preferably such that the force required to slidably disengage boss
106 from recess 108 by forcing plunger tube 40 farther down into
housing 12 is greater than the biasing force being exerted against
needle holder assembly 14 by compressed retraction spring 16 and by
the additional force that is exerted upwardly on the needle 34
during catheter insertion procedures. IV catheter 20 can be
assembled to tip 26 of housing 12 prior to the insertion of needle
holder assembly 14 and plunger assembly 18 into housing 12.
Alternatively, plunger assembly 18 and needle holder assembly 14
(sometimes referred to as a needle support assembly) can also be
assembled to each other prior to insertion into housing 12. The
frictional engagement between boss 106 and recess 108 when they are
cooperatively engaged is preferably sufficient to permit needle
holder assembly 14 and plunger assembly 18 to be inserted together
into housing 12.
[0028] Beveled needle end 48 and a portion of cannula 78 are
desirably inserted into a patient's vein while grasping annular
ridges 31 of housing 12 with the thumb and fingers. Following
insertion of the catheter into a patient, needle holder assembly 14
is retracted by grasping wings 30 or annular ridges 31 with one's
fingers, or thumb and fingers, and then using the palm or heel of
the hand against end cap 66 to force plunger tube 40 farther down
into housing 12. When this occurs, the frictional engagement
between boss 106 and recess 108, as seen in FIG. 4, is
over-pressured, causing boss 106 to ride up onto surface 112 of
tubular body 32. Continued downward movement of plunger tube 40
relative to tubular body 32, which is firmly seated against housing
12, causes boss 106 to drop off inclined shoulder 114 of tubular
body 32. When this occurs, there is no remaining significant
frictional force being exerted against compressed retraction spring
16, and spring 16 rapidly expands, causing needle holder assembly
14 to be propelled upwardly into retraction cavity 76,
simultaneously withdrawing needle 34 at least to a position where
beveled end 48 is withdrawn into housing 12.
[0029] Referring to FIG. 3, retraction spring 16 is fully expanded
and top end 52 of needle holder assembly 14 is at least partially
withdrawn into retraction cavity 76. Air previously present in
retraction cavity 76 of plunger tube 40 has been vented through
vent hole 72 as needle holder assembly 14 moved upwardly within the
cavity in response to expansion by retraction spring 16. Top end 52
of needle holder assembly 14 has moved upward within retraction
cavity 76 sufficiently that beveled end 48 of needle 34 is
withdrawn into housing 12. When needle 34 is in the position shown
in FIG. 3, tip 26 of housing 12 can be safely detached from IV hub
80.
[0030] The improved IV catheter introducer of the invention is well
suited for automated manufacture and assembly. Aside from the
catheter, needle and spring, only a housing, retractable needle
holder and a capped, vented plunger tube are needed. Although
housing 12 can be made in a straight configuration with a straight
internal wall, it is preferably made with a stepped configuration
that, with the exception of the lower shoulder of annular ring 102,
tapers inwardly from top to bottom. This taper makes it easy to
withdraw a core mandrel used in the molding process. Although not
illustrated in the drawings, it should be understood that beveled
end 48 of needle 34 is preferably protected during the
manufacturing process, shipping and storage by a tubular cover that
slides upwardly over the outside of cannula 78, preventing the
needle from being damaged.
[0031] An important aspect of the subject IV catheter introducer is
the fact that the operator can conveniently operate the retractable
introducer structure with one hand. One handed operation is
possible because the plunger tube desirably extends about 1.5 to
about 3 inches past where the wings of the housing are located.
This allows force to be applied against the plunger tube by the
fleshy part of the palm while using the fingers behind the wings or
the annular ridges of the housing to resist the force and smoothly
initiate retraction. The other hand remains free to grasp the hub
of the catheter. Timing for freeing the hub from the introducer
device and attaching an IV tube to the hub is under complete
control of the operator. In one motion, the hub of the catheter can
be separated from the insertion device, which can then be safely
set aside while the connection is then made to the IV tube or other
device that is to be connected to the patient. The catheter
introducer can be safely set aside without concern onto a bed or
tray, because the needle has already been safely retracted before
the catheter assembly is disconnected from the housing. When the
fingers pull back on the wings or annular ridges of the housing to
trigger retraction, the operator can both hear and see that the
needle is safely retracted and immediately disengage and safely set
aside the device to free his hand for use in making the necessary
IV connection before loss of fluid from the patient occurs.
[0032] The IV catheter introducer of the invention does not have to
resist as much force imposed by the needle on the retraction parts
as does a conventional syringe that is required to puncture a
rubber seal commonly used on vials. Consequently, the retractable
parts need only be able to resist the force encountered during
normal clinical use without retracting. With the apparatus
disclosed herein, dimensional tolerances and differential thermal
expansion rates are less critical than with devices where the only
frictional engagement is provided by surface-to-surface contact
between smooth facing surfaces.
[0033] The IV catheter introducer disclosed herein is less likely
to retract the needle prematurely than prior art devices, even when
subjected to rough handling and widely varying temperatures and
humidity during shipment and storage prior to use. The invention
has a simple, streamlined shape and a retraction spring that is
simpler to operate and more reliable than others previously used.
The device can be operated with one hand in any rotational position
where the wings are accessible because it has no external latches
that require placing the device in a particular orientation.
Further, the wings prevent the catheter introducer from rolling
when placed on an oblique surface. With the device held in the
hand, the retraction force is applied linearly along the main
longitudinal axis. A very short stroke movement is sufficient to
trigger retraction. Successful retraction is noted both visually
and audibly because the operator can easily see the retracted parts
in the housing and retraction creates an unobtrusive noise.
[0034] Other alterations and modifications of the preferred
embodiment described above will become apparent to those of
ordinary skill in the art upon reading this disclosure, and it is
intended that the scope of the invention disclosed herein be
limited only by the broadest interpretation of the appended claims
to which the inventor is legally entitled.
* * * * *