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Description  |
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FIELD OF THE INVENTION
The invention relates generally to enteral tubes and more particularly to
mechanical connections between enteral tubes and feeding sets containing
food or medication.
DESCRIPTION OF THE RELATED ART
Enteral tubes for providing food and medication to a patient are well
known. For example, U.S. Pat. No. 4,666,433, entitled Gastrostomy Feeding
Device, invented by Parks and issued May 19, 1987; and U.S. Pat. No.
4,701,163, entitled Gastrostomy Feeding Device, invented by Parks and
issued Oct. 20, 1987; and U.S. Pat. No. 4,798,592, entitled Gastrostomy
Feeding Device, invented by Parks and issued Jan. 17, 1989; and U.S. Pat.
No. 4,685,901, entitled Gastro-Jejunal Feeding Device, invented by Parks
and issued Aug. 11, 1987 disclose earlier feeding tubes.
Referring to the illustrative drawing of FIG. 1A, there is shown a
perspective view of an earlier enteral feeding device 20. The device 20
includes an elongated tubular member 51 formed from a stretchable
elastomeric material such as silicone. FIG. 1B is an illustrative
cross-sectional view of the tubular member 51 of the earlier device. The
member 51 defines a jejunal tube 22, a gastronomy tube 34 and a fluid line
46.
The jejunal feeding tube 22 includes an outlet end portion 24 which can
extend through a patient's stomach into the jejunum. The jejunal tube
outlet end portion includes perforations 26 which permit liquid food or
medication to pass therethrough. The tube 22 is integrally connected to a
jejunal tube inlet end portion 28 which defines a jejunal inlet port 30
having a removable plug cover 32.
The gastrostomy tube 34 is shorter than the jejunal tube 22 and includes a
plurality of drainage inlets or food outlet ports such as inlet/outlet 36.
A gastrostomy tube end portion 37 defines a gastrostomy inlet port 38
having a plug cover 40.
An inflatable balloon 42 is provided near the end of the gastrostomy tube
34 and is inflatable through a valve 44. The valve 44 is used to supply
fluid to the balloon 42 through the fluid line 46.
Frictional contact between the elongated tubular member 51 and a locking
ring 56 is sufficiently great to prevent the member 51 from moving further
into the stomach. The locking ring 56 to remains in contact with a
patient's abdominal wall during use. However, the frictional contact also
is sufficiently low to permit adjustment of placement of the member 51
relative to a patient's abdomen.
Referring to the illustrative drawings of FIG. 2, there is shown a
perspective view of an earlier device 20 in use. The inflated balloon 42
forms a gasket that seals the entrance to the stomach, and together with
the locking ring 56, secures the device 20 in place.
While prior feeding tubes generally have been acceptable, there have been
shortcomings with their use. In particular, for example, in order to
provide food or medication to the jejunal inlet port 30 of device 20, a
connector, such as a first connector 58 illustrated in FIG. 3 or a second
connector 60 illustrated in FIG. 4, is inserted through the jejunal inlet
port 30. The inserted connector 58 or 60 is mechanically coupled to the
jejunal inlet port 30 and serves as a conduit between the jejunal tube 22
and an external feeding tube 62 or 64, shown in FIGS. 3 and 4. The
external tube 62 or 64 is connected to a source of food such as a feeding
bag (not shown).
In practice, connectors 58 or 60 such as those shown in FIGS. 3 and 4, for
example, may be inserted into and removed from the jejunal inlet port 30
or the gastrostomy inlet port 38 numerous times during the course of use
of the device 20 which can be installed in a patient's stomach for
extended periods of time. As mentioned above, the member 51 which defines
the jejunal tube inlet end 28, and the gastrostomy tube end portion 37 can
be formed from a stretchable elastomeric material such as silicone. In
order to produce an adequate mechanical coupling between the connector 58
or 60 and either the jejunal inlet port 30 or the gastrostomy inlet port
38, the connector is forced into place so as to produce a frictional
engagement. Repeated insertions and removals of such connectors 58 or 60
can cause the jejunal inlet port 30 or the gastrostomy inlet port 38 to
become somewhat stretched and deformed over time.
Unfortunately, as the jejunal and gastrostomy inlet ports 30, 38 become
more and more stretched in this manner, the tendency of a medical
attendant responsible for coupling such a connector to the inlet ports
30,38 often is to more forcibly push the connector into the jejunal or
gastrostomy ports 30 or 38 resulting in still further stretching.
Moreover, more force often must be exerted to dislodge a connector after
such a forced insertion. Additionally, as the interior of the inlet ports
30, 38 becomes soiled with food oils, for example, an attendant may
attempt to push a connector into the port even more forcibly in order to
compensate for the slipperiness of such oils, causing further deformation
of the port opening.
The problem of achieving a tight fit between a jejunal or gastrostomy inlet
port 30 or 38 and such connectors 58 or 60, for example, has been
exacerbated by the fact that in the past, such connectors often have been
available in a variety of shapes and sizes. This variety will be apparent
from the illustrative drawings of FIGS. 3 and 4 in which the first and
second connectors 58, 60 have quite different shapes. Consequently, in the
past it often has been desirable to construct jejunal or gastrostomy inlet
ports, that can accommodate any of a variety of such differently shaped
connectors. Unfortunately, such earlier inlet ports often could not
readily accommodate such a variety of differently shaped connectors
without the need to forcibly insert or forcibly remove the connectors.
Thus, there has been a need for a device to permit any of a variety of
different shapes and sizes of connectors to be inserted into or removed
from an inlet port of a feeding tube without the need to use excessive
force and substantially without deforming the feeding tube inlet port. The
present invention meets these needs.
SUMMARY OF THE INVENTION
In one aspect, the invention provides a ferrule for use with a feeding tube
formed from a flexible material. The ferrule includes an inner wall
defining a conduit extending between an inlet opening and an outlet
opening. A first taper-lock surface is defined by a first region of the
inner wall, and a second taper-lock surface is defined by a second region
of the inner wall.
In another aspect, the invention provides a feeding device. The feeding
device includes an elongated tube formed from a flexible material. An
inlet end portion formed from the flexible material is integrally
connected to the elongated tube. The inlet end portion defines an inlet
port opening. A ferrule is disposed within the inlet end portion. The
ferrule includes an inner wall defining a conduit extending between an
inlet opening and an outlet opening. A first taper-lock surface is defined
by a first region of the inner wall, and a second taper-lock surface is
defined by a second region of the inner wall.
Thus, the present invention provides a ferrule and feeding device that can
readily form a taper lock with connectors without the use of excessive
force. Conversely, connectors can be readily removed from such a ferrule
or feeding device without the use of excessive force. Consequently, a
feeding tube is not as likely to be stretched out of shape through
repeated insertions and removals of such connectors.
These and other features and advantages of the present invention will
become more apparent from the following description of exemplary
embodiments thereof, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The purpose and advantages of the present invention will be apparent to
those skilled in the art from the following detailed description in
conjunction with the appended drawings in which:
FIG. 1A is a perspective view of an earlier feeding tube;
FIG. 1B is a cross-sectional view along line 1--1 of FIG. 1A illustrating
the disposition of the jejunal and gastrostomy tubes and the connecting
line;
FIG. 2 is a perspective partially cutaway view of an earlier feeding tube
installed in a patient;
FIGS. 3 and 4 are side elevation views of earlier connectors for insertion
into end portions of a feeding tube;
FIG. 5 is a perspective view of a ferrule in accordance with the present
invention;
FIGS. 6A and 6B are top and bottom elevation views of the ferrule of FIG.
5;
FIG. 7 is a cross-sectional side elevation view of the ferrule of FIG. 5;
FIG. 8 is a cross-sectional side elevation view of the ferrule of FIG. 5
incorporated into an end portion of a feeding tube;
FIG. 9 is an alternative embodiment of a ferrule in accordance with the
invention;
FIG. 10 is a cross-sectional side elevation view of the ferrule of FIG. 9
incorporated into a feeding tube.
FIG. 11 is a cross-sectional side elevation view of a first branched
ferrule in accordance with the invention;
FIG. 12 is a cross-sectional side elevation view of a second branched
ferrule in accordance with the invention;
FIG. 13 is a cross-section side elevation view of a ferrule in accordance
with the invention;
FIG. 14 is a cross-sectional side elevation view of an alternative
embodiment of a ferrule in accordance with the invention in which a
locking taper inner wall region forms a concentric spiral step of
decreasing diameter between an inlet opening and an outlet opening;
FIG. 15 is a cross-sectional side elevation view of an alternative
embodiment of a ferrule in accordance with the invention in which a
locking taper inner wall region forms a series of concentric steps of
decreasing diameter between an inlet opening and an outlet opening;
FIG. 16 is a cross-sectional side elevation view of an alternative
embodiment of a ferrule in accordance with the invention in which an inner
wall region forms a concentric spiral path within a first segment between
an inlet opening and an outlet opening and forms a series of concentric
steps within a second segment between the inlet opening and the outlet
opening;
FIG. 17 is a cross-sectional side elevation view of an alternative
embodiment of a ferrule in accordance with the invention in which an inner
wall region forms a ball socket within a first segment, forms a taper lock
surface in which a tapered inner wall diameter gradually decreases with
increasing distance from an inlet opening within a second segment and
forms an inner thread within a third segment between an inlet opening and
an outlet opening;
FIG. 18 is a cross-sectional side elevation view of an alternative
embodiment of a ferrule in accordance with the invention in which a
tapered inner wall diameter gradually decreases with increasing distance
from an inlet opening within a first segment and in which an exterior wall
forms a external barbed connector surrounding the tapered inner wall
segment;
FIG. 19 is a cross-sectional side elevation view of an alternative
embodiment of a ferrule in accordance with the invention in which a first
tapered inner wall diameter gradually decreases with increasing distance
from an inlet opening in a first segment, in which the inner wall forms an
inner ridge which follows a threaded spiral path in a second segment, and
in which a second tapered inner wall diameter gradually decreases with
increasing distance from the inlet opening within a third segment;
FIG. 20A is a cross-sectional side elevation view of an alternative
embodiment of a ferrule in accordance with the invention in which first
and second tapered inner wall regions are offset from each other; and
FIG. 20B is a perspective view of a connector to lock in the ferrule of
FIG. 20A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention comprises a novel ferrule and a related enteral
feeding device incorporating a ferrule. The following description is
presented to enable any person skilled in the art to make and use the
invention, and is provided in the context of particular applications and
their requirements. Various modifications to the preferred embodiments
will be readily apparent to those skilled in the art, and the generic
principles defined herein may be applied to other embodiments and
applications without departing from the spirit and scope of the invention.
Thus, the present invention is not intended to be limited to the
embodiments shown, but is to be accorded the widest scope consistent with
the principles and features disclosed herein.
Referring to the illustrative drawings of FIG. 5, there is shown a
perspective view of a ferrule 70 in accordance with a present embodiment
of the invention. The ferrule 70 is generally cylindrical in shape and has
top, middle and bottom annular ribs 72, 74 and 76 extending outwardly
therefrom. FIGS. 6A and 6B respectively show top elevation and bottom
elevation views of the ferrule 70. In FIG. 6A, there is shown an inlet
opening 78 surrounded by the top annular rib 72. In FIG. 6B, there is
shown an outlet opening 80 surrounded by the bottom annular rib 76. In the
preferred embodiment, the ferrule 70 is formed from a hard substantially
deformable material such as plastic, metal, glass or polyvinylchloride.
Preferably the ferrule 70 is formed from a material that is acid-resistant
and gamma-stabilized so that it can withstand a sterilization process
involving irradiation.
The illustrative drawing of FIG. 7, shows a cross-sectional side elevation
view of the ferrule 70. First, second and third interior wall regions 82,
84 and 86 define a conduit 88 extending between the inlet opening 78 and
the outlet opening 80. The respective first, second and third interior
wall regions 82, 84 and 86 each have substantially cylindrical contours
and are aligned along a central axis 90 of the conduit 88.
As explained more fully below, the first, second and third interior wall
regions define three separate taper lock surfaces. Each of these three
interior wall regions can be sized and contoured to conform to the shape
of a different connector portion from a different connector. Neither a
connector nor any portion of a connector forms any part of the present
invention. For example, the first interior wall region 82 can be sized and
contoured to conform to the shape of a portion 83 of the first connector
58 of FIG. 3. The second interior wall region 86, for example, can be
sized and contoured to conform to the shape of a portion 87 of the second
connector 60 of FIG. 4. It will be appreciated that the interior wall
regions of FIG. 7 are drawn to a different scale than the connectors of
FIGS. 3 and 4. Moreover, the second interior wall region 84, for example,
can be sized and contoured to conform to the shape of yet another
connector (not shown).
A taper lock is caused by a frictional engagement force that results when a
connector becomes lodged within the ferrule 70. The different sizing and
contouring of the three different interior wall regions 82, 84 and 86
ensures that differently sized and contoured connector portions can become
lodged against different interior wall regions.
Thus, when the first connector 58 is inserted into the inlet opening 78 of
the ferrule 70, it becomes lodged against the first interior wall region,
forming a taper lock with it. Likewise, when the second connector 60 is
inserted into the inlet opening 78 of the ferrule 70, it becomes lodged
against the third interior wall region 86, forming a taper lock with it.
A more detailed description of the sizing and contour of the ferrule 70
follows. The first interior wall region 82 has interior walls that are
inclined relative to the central axis 90 so as to define a generally
conical shape in which a diameter of a first segment of the conduit 88
defined by the first interior wall region 82 decreases with increasing
distance from the inlet opening 78. A first interior annular shoulder 92
demarcates the end of the first interior wall region 82.
A second segment of the conduit 88 is defined by the second interior wall
region 84 which also is substantially conical in shape. Like the first
interior wall region, the interior walls of the second interior wall
region 84 are inclined relative to the central axis 90 such that the
diameter of a second conduit segment decreases with increasing distance
from the inlet opening 78. A second interior annular shoulder 94
demarcates the end of the second interior wall region 84.
A third segment of the conduit 88 is defined by the third conical interior
wall region 86. The interior walls of the third interior wall region are
inclined relative to the central axis 90 such that the diameter of the
third conduit segment decreases with increasing distance from the inlet
opening 78. In the presently preferred embodiment, the dimensions of the
third interior wall region are those of a luer. Moreover, it will be
appreciated that in operation, a taper lock between a connector portion
such as portions 83 or 87 inserted into the inlet opening 78 results
because the diameter of an interior wall region, such as region 82, 84 or
86, decreases or tapers down, with increasing distance from an inlet to
the region. It is the tapered inner wall region diameter of regions 82, 84
or 86 that facilitate the formation of taper locks in these wall regions.
Moreover, it is desirable that the taper lock form a liquid tight seal.
One will appreciate that, although the presently preferred embodiment
discloses smooth inner wall regions 82, 84 and 86, a taper lock can be
formed in which inner wall regions have contours formed in them such as
ridges, steps or bumps. In alternative embodiments such as those discussed
below in relation to FIGS. 14, 16, 17 and 19, for example, spiral threaded
ridges or steps or other structures formed in inner wall regions can
afford a better lock by permitting the twisting of a connector portion
into engagement with the inner wall regions.
In an alternative embodiment of a ferrule 300 illustrated in the drawings
of FIG. 14, tapered inner walls 302 form a smooth taper about a central
axis 307 within a first inner wall segment such that the inner wall
diameter decreases with increasing distance from an inlet opening 306. In
a second inner wall segment, inwardly extending concentric ridges 304 form
a spiral step about the central axis 307, such that the inner wall
diameter decreases with increasing distance from the inlet opening 306.
The tapered inner walls 302 and the spiral ridges 304 are concentrically
aligned with the central axis 307 which extends between the inlet opening
306 and an outlet opening 308. One will appreciate that a taper lock can
be formed with the surfaces of the first or second inner wall regions.
In an alternative embodiment of a ferrule 400 illustrated in the drawings
of FIG. 15, tapered inner walls 402 form a smooth taper about a central
axis 407 within a first inner wall segment such that the inner wall
diameter decreases with increasing distance from an inlet opening 406. In
a second inner wall segment, inwardly extending concentric ridges 404 form
a series of concentric steps about the central axis 407, such that the
inner wall diameter decreases with increasing distance from the inlet
opening 406. The tapered inner walls 402 and the ridges 404 are
concentrically aligned with a central axis 407 which extends between the
inlet opening 406 and an outlet opening 408. A taper lock can be formed
either with surfaces of the first or second inner wall segments.
In an alternative embodiment of a ferrule 500 illustrated in the drawings
of FIG. 16, a first inner wall segment includes a spiral-threaded path 504
about a central axis 507. A connector (not shown) having appropriately
sized outwardly extending spiral threads can be screwed into place within
the first inner wall segment. In a second inner wall segment, inwardly
extending concentric inclined steps 505 are formed about the central axis
507. For each respective step 505, the inner wall diameter decreases with
each increasing distance from an inlet opening 506. The spiral ridges 504
and the steps 505 are concentrically aligned with the central axis 507
which extends between the inlet opening 506 and an outlet opening 508.
In an alternative embodiment of a ferrule 600 illustrated in the drawings
of FIG. 17, in a first inner wall segment, inner walls 603 are shaped to
conform to a ball connector (not shown). In a second segment, tapered
inner walls 602 form a smooth taper about a central axis 607 such that the
inner wall diameter decreases with increasing distance from an inlet
opening 606. In a third segment, inwardly extending concentric spiral
ridges 604 form a spiral thread sized to form a threaded interconnect with
an appropriately sized connector (not shown) having complementary spiral
threads. The first inner walls 603 inner walls 602 and the concentric
ridges 604 are concentrically aligned with the central axis 607 which
extends between the inlet opening 606 and an outlet opening 608.
In an alternative embodiment of a ferrule 700 illustrated in the drawings
of FIG. 18, tapered inner walls 702 form a smooth taper about a central
axis 707 within a first segment of the ferrule 700 such that the inner
wall diameter decreases with increasing distance from an inlet opening
706. Outwardly extending barbs 704 are formed in an exterior wall of the
first segment and are used to form a gripping interconnect with an
appropriately sized connector (not shown). The tapered inner walls 702 are
concentrically aligned with the central axis 707 which extends between the
inlet opening 706 and an outlet opening 708.
In an alternative embodiment of a ferrule 800 illustrated in the drawings
of FIG. 19, first tapered inner walls 802 form a smooth taper about a
central axis 807 within a first inner wall segment such that the inner
wall diameter decreases with increasing distance from an inlet opening
806. In a second inner wall segment, inwardly extending concentric spiral
ridges 804 form a spiral thread about the central axis 807, such that an
appropriately sized connector having complementary spiral threads (not
shown) can be secured in place. Second tapered inner walls 805 form a
second smooth taper about the central axis 807 within a third inner wall
segment such that the inner wall diameter decreases with increasing
distance from the inlet opening 806. The first and second tapered inner
walls 802 and 805 and the spiral ridges 804 are concentrically aligned
with the central axis 807 which extends between the inlet opening 806 and
an outlet opening 808.
In FIG. 20A, an alternative embodiment of a ferrule 900 used to form an
offset lock is shown. As illustrated in the drawings of FIG. 20A, inner
walls 902 are formed about a first axis 903 within a first inner wall
segment. In a second inner wall segment, second inner walls 905 are formed
about a second axis 906. The first and second tapered inner walls 902, 905
define a path between inlet opening 904 and an outlet opening 907.
In FIG. 20B, there is shown a connector 908, which forms no part of the
present invention, which can be interconnected with the offset lock
ferrule 900 of FIG. 20A.
Thus, it will be appreciated that a ferrule in accordance with the present
invention can be constructed with any of a variety of gripping mechanisms
for gripping different external connectors (which form no part of the
present invention). Moreover, while a variety of combinations of gripping
mechanisms such as smooth tapers, spiral and nonspiral steps, threads,
barbs, ball and socket and offset locks have been specifically described,
alternative gripping mechanisms and different combinations of gripping
mechanisms can be employed without departing from the invention.
It will be understood that an alternative ferrule (not shown) could be
constructed in accordance with the invention in which different taper lock
regions were aligned along different parallel nonaligned axes or along
different nonparallel axes as explained below with respect to FIGS. 11 and
12.
The outer edges of the middle and bottom outwardly extending annular ribs
74, 76 are inclined relative to the central axis 90 such that the diameter
of each of these respective annular ribs 74, 76 decreases with increasing
distance from the inlet opening 78. Moreover, the respective shoulders 96,
98 and 100 of the top, middle and bottom annular rings are rounded. The
inclined and rounded edges of the outwardly protruding annular ribs can
facilitate the process of inserting the ferrule 70 into an inlet end
portion of a feeding tube as explained more fully below.
Referring now to FIG. 8, there is shown a cross-sectional elevation view of
an inlet end portion 102 of an enteral tube, in accordance with the
presently preferred embodiment of the invention, which incorporates the
ferrule 70. An enteral feeding tube feeds into the digestive tract. The
feeding tube is formed from an elastomeric silicone material and can be
formed by injection molding. The inlet end portion 102 defines an inlet
port opening 104 and defines a first passage 106 between the inlet port
opening 104 and the inlet opening 78 of the ferrule 70. The outlet opening
80 of the ferrule 70 communicates with a second elongated passage 108
defined by an elongated tube portion 110 of the feeding tube, only a short
segment of which is shown.
An arm 112 is integrally formed with the end portion 102 and has a plug 114
extending therefrom. The arm 112 can be bent, and the plug 114 can be
inserted into the inlet port opening 104, whereupon it becomes lodged in a
space 116 between two inwardly projecting annular protrusions 118, 120
integrally formed in the inlet end portion 102. In this manner, the
opening 104 can be closed when the end portion 102 is not in use.
Moreover, when the inlet end portion 102 is in use and a connector, such as
the first or the second connector 58 or 60, is inserted through the inlet
port opening 104 and has formed a taper lock with one of the inner wall
regions of the ferrule 70, the inwardly projecting annular protrusions
118, 120 abut against the connector. The protrusions 118, 120
advantageously produce a fluid seal with a connector inserted through the
inlet port opening 104 to prevent fluid leakage from the opening 104. It
will be appreciated that such annular protrusions alternatively could be
invalid within an annular inset (not shown) in the ferrule 70 or could be
positioned downstream from the ferrule 70 adjacent to the ferrule outlet
port 80.
The outwardly projecting annular ribs 74, 76, 78 of the ferrule 70 grip
inwardly projecting annular ribs 122, 124 which are integrally formed in
the end portion and which are contoured to fit snugly between the ribs 74,
76, 78. In this manner, the ribs 74, 76, 78 hold the ferrule 70 in place
within the inlet end portion 102. It will be appreciated that although
annular ribs 74, 76, 78 are used to grip the end portion 102, differently
shaped objects could be used to accomplish that purpose. For example, the
outer surface of the ferrule 70 could be abraded so as to roughen it to
allow it to grip the interior of the end portion 102. Alternatively, for
example, the outer surface of the ferrule 70 could have protrusions in the
shape of individual upstanding barbs or in the shape of helical ridges. In
certain applications, for example, it may be desirable to install a
removable ferrule in the end portion 102. Annular ribs 74, 76 of ferrule
70 afford such removability as do similar annular ribs of ferrule 126 and
of the alternative ferrules of FIGS. 14-19. Removability can be important,
for example, in situations where one type of ferrule is to be removed and
another type is to be inserted in order to accommodate a variety of
different connectors. For example, in one application a connector (which
forms no part o | | |
