 |
Description  |
|
|
BACKGROUND AND SUMMARY
While it is apparent that catheters for post-surgical drainage and other
medical purposes should be securely positioned so that they are not
inadvertently dislodged or withdrawn by patient movement or by bedside
activities of physicians and hospital staff, and while it is apparent that
the wound or incision area, including the skin surrounding the point of
entry, should be protected against the irritating and excoriating effects
of fluid contact, prior devices have generally fallen far short of
achieving such objectives, at least without introducing additional
problems that offset the improvements. For example, to help immobilize an
indwelling catheter, it is a common practice to suture the catheter to a
retention device and also suture the retention device to a patient's skin.
The former does not always insure against catheter movement, and the
latter may result in irritation, infection, and considerable patient
discomfort over the typical period of catheter placement (usually 5 to 7
days). Thus, in published UK application No. 2,147,811A, sutures are shown
for the purpose of securing the device to the patient's skin, although the
use of adhesives is also mentioned. In U.S. Pat. No. 4,392,854, adhesive
tape may be used to hold the device in place but sutures are indicated for
connecting the catheter to the supporting device.
Other catheter retention devices are disclosed in U.S. Pat. Nos. 4,360,025,
4,261,363, 3,138,158, 3,682,180, and 4,490,141. The use of adhesives is
frequently disclosed for attaching a retention device to a patient's skin,
but in some cases the retaining devices block medical inspection of the
wound or incision, and in other cases the catheters are not supported at
generally right angles (normal to) the surface of the skin. In still other
instances, attachment of the supporting devices is relatively awkward and
inconvenient, increasing the possibilities of patient discomfort. Thus, a
construction that requires a catheter to be threaded through an opening in
the supporting device for application or removal of that device is
believed undesirable. In general, while a variety of catheter retention
devices have been disclosed in the art, and while some of them have
advantageous features, all of them are believed to have one or more
serious shortcomings involving construction, operation, and/or
effectiveness in use.
An important aspect of this invention therefore lies in providing an
improved catheter retention device that is simple in construction and
reliable in operation, may be securely attached to a patient without
sutures, without threading the catheter through the device, and without
obstructing visual inspection of the site after the device is in place,
and is easily manipulated to clamp and immobilize a catheter and, if
necessary, permit selective repositioning of the catheter in relation to
the device. Furthermore, the device supports the catheter so that it
extends at right angles to the skin at the entry point, protects the skin
over a wide surrounding area, and at the same time exposes the immediate
area of the incision or wound for direct visual inspection. The device may
be easily manipulated by one hand, leaving the physician's other hand free
for positioning the catheter or for performing other operations. Because
of the security of the attachment between the device and the catheter,
sutures connecting the two are unnecessary, but the retention device is
designed to permit the use of such sutures in those exceptional
circumstances where supplementary suturing is desired.
In brief, the device takes the form of an apertured, flexible, and
resilient adhesive barrier pad upon which a molded plastic catheter
support structure is mounted. An entry slit leads from the periphery of
the pad to its central aperture or opening. The support structure includes
an arcuate base affixed to the pad, a pair of spaced flexible support arms
formed integrally with the base and projecting upwardly at opposite sides
of the opening, and a pair of elongated clamping bars joined at
intermediate points along their lengths to the upper ends of the flexible
support arms. In a preferred embodiment, the bars are permanently joined
together at one of their ends, have ratchet coupling means at their
opposite ends, and have their axes askew so that the ratchet elements are
disaligned and uncoupled when the device is supplied to a user. However,
since the latching bars extend along parallel planes and are disposed in
contiguous relation in an untensioned state, they are already in a
relationship that approximates their closed condition and, when finally
shifted into closed positions during use, have no internal forces or
stresses urging them to spring apart into unlatched condition and exert no
shear stresses at the interface between the support structure and pad.
Such a construction allows a user to position a catheter through the
opening of the barrier pad by spreading the edges of the pad defining the
entry slit, then simply urging the catheter laterally through that slit to
the opening, and finally urging the edges of the slit together while at
the same time adhesively securing the pad to the patient. The sealant
barrier material of the pad joins together to close the slit and provide a
continuous or uninterrupted annular barrier zone about the exit site,
thereby protecting the surrounding skin from the excoriating effects
caused by contact with exudate. In a preferred embodiment, the barrier
material of the pad is covered with a layer of resilient foam to which the
base of the support structure is secured. During the steps of closing the
slit and adhesively securing the pad to a patient's skin, the edges of the
resilient foam layer are also brought into contact with each other thereby
enhancing the protection afforded by the pad. To facilitate closing of the
slit during the steps of applying the pad, the base of the support
structure is provided with a notch facing the inner end of the slit, the
notch allowing the sections of the base on opposite sides of the slit to
be urged together as the barrier pad is re-formed to close the slit and
adhere the pad to the patient's skin.
Other features, objects, and advantages of the invention will become
apparent from the specification and drawings.
DRAWINGS
FIG. 1 is a perspective view of a catheter retention device in the form it
could be supplied to a user (with outer wrapping or packaging removed).
FIG. 2 is an enlarged end view illustrating details of the relationship as
shown in FIG. 1.
FIG. 3 is an enlarged perspective view similar to FIG. 1 but showing the
relationship of the clamping jaws when the device is in use.
FIG. 4 is a somewhat schematic enlarged sectional view taken along line
4--4 of FIG. 1.
FIG. 5 is a top plan view of the support structure of the device in its
original molded condition.
FIG. 6 is a plan view similar to FIG. 5 but showing the subsequent step in
the fabrication of the catheter retention device.
FIG. 7 is a fragmentary top plan view of the device, shown in reduced
scale, illustrating the steps of closing the slit of the pad in connection
with adhering the pad to a patient.
FIG. 8 is a perspective view depicting a second embodiment of the
invention.
FIG. 9 is a top view of the embodiment of FIG. 8.
FIG. 10 is a front view of the embodiment of FIG. 8.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the embodiment depicted in FIGS. 1-7, the numeral 10 generally
designates a catheter retention device composed of a barrier pad 11 and a
catheter support structure 12. The pad is planar and has a generally
circular periphery 13 although other shapes may be selected. An opening 14
is provided at or near the center of the pad and a radial entry slit 15
extends between that opening and the pad's outer periphery.
The materials and construction of the pad may be varied considerably as
long as the thin, planar pad is flexible and therefore generally
conformable with body contours, is sufficiently deformable to permit the
edges of slit 15 to be brought into tight contact with each other, and is
provided along its underside with a suitable pressure-sensitive adhesive
material that not only immobilizes the pad on the patient's skin but,
preferably, also performs a sealing function in protecting the skin
against fluid contact. A particularly advantageous construction is
depicted in the drawings where pad 11 is shown to be composed of a top
layer 16 of resilient, flexible, fine-celled thermoplastic foam (such as a
polyolefin or polyurethane foam), a lower layer 17 of soft, tacky, and
deformable skin barrier material (such as karaya or a barrier composition
of the type designated as "Hollihesive" by Hollister Incorporated,
Libertyville, Ill.), and a surrounding layer 18 of a suitable microporous
material (such as the gas-permeable but liquid-barrier non-woven
microporous material disclosed in U.S. Pat. No. 4,213,458). The underside
of the surrounding microporous layer 18 is coated with any suitable
medical-grade pressure-sensitive adhesive 19, such as a hypo-allergenic
acrylic adhesive commonly used in medical applications. The
pressure-sensitive adhesive of the microporous border layer 18, and the
tacky surface of barrier layer 17, may be covered by removable
silicone-coated release sheets 20 (FIG. 4).
The catheter support structure 12 is molded in one piece from any suitable
polymeric material having the requirements of flexibility, toughness, and
durability. Nylon has been found effective, but other thermoplastic
materials such as polysulfone or polycarbonate may be used.
Support structure 12 comprises an arcuate or curved planar base 21 secured
to the upper surface of pad 11 about central opening 14. The base is
interrupted at 22 with its ends spaced equally on opposite sides of slit
15 in the pad. Diametrically opposite from the interrupted zone, and from
slit 15, is a V-shaped notch 23 that extends outwardly from the inner
periphery of the arcuate planar base.
A pair of flexible support arms 24 project upwardly from the base at
opposite sides of the opening 14 and from points spaced equally from a
vertical mid plane x extending through slit 15 and V-shaped notch 23. Each
arm has an upstanding portion 24a and, at its upper end, an
inwardly-turned portion 24b. The inwardly-turned portions of the two arms
merge with a pair of elongated clamping bars 25 and 26. As shown most
clearly in FIGS. 2 and 3, the clamping bars extend along, and are
generally disposed on opposite sides of, the same vertical mid plane that
passes through slit 15 and notch 23. The bars are spaced a substantial
distance above opening 14 and generally extend in the same direction as
the plane of pad 11. Each bar is in the form of a thin
horizontally-elongated strip having a width (measured vertically)
substantially greater than its thickness. It will also be observed that
each of the clamping bars has planar end portions 25a, 26a and arcuate
intermediate portions 25b, 26b that together define an aperture for
receiving and holding a portion of a catheter C in a direction
perpendicular or normal to the plane of pad 11.
Means are provided for connecting the two bars together at their opposite
ends when a catheter C is to be clamped in place as shown in FIG. 3. In
the preferred embodiment shown, such connecting means includes a permanent
connection at 27 between two corresponding end portions 25a and 26a of the
clamping bars. The permanent connection may be in the form of a fusion
bond, a heat seal, one-way snap fit, or some other form of secure
interlock or interconnection between the parts. At their opposite or free
ends, the clamping bars are provided with suitable latching means in the
form of a ratchet 30 formed integrally with one of the bars 25 and a
latching recess 31 formed in the end portion of the opposing clamping bar
26. The ratchet arm 30 of clamping bar 25 extends in the direction of the
other bar 26, is receivable in aperture 31, and has a series of teeth 32
for holding the free ends of the clamping bars together in any of a
variety of partially and fully closed positions.
Of particular significance is the fact that when the two bars have their
ends joined together at permanent connection 27 they are disposed in
contiguous relation, extending along mid plane x, but their longitudinal
axes are slightly askew so that ratchet arm 30 does not extend through
opening 31 but, as illustrated in FIGS. 1 and 2, extends over the top of
edge of bar 26. Under such conditions, the clamping bars are generally
untensioned. The result is that the clamping bars of the support structure
are biased into closed positions, since any forces tending to separate the
free ends of the bars will be resisted by restorative forces tending to
urge free end portions 25a and 26a back into contiguous relation.
In use, the catheter retention device 10 would obviously be applied to a
patient in which a catheter or drainage tube is already in place. The
outer end of the catheter would ordinarily be connected to a receptacle or
to some other medical equipment, so that threading the outer end of the
catheter through opening 14 would be most inconvenient. Such problems are
avoided by the present construction because a user may easily position the
catheter in opening 14 by simply spreading apart the edges of slit 15 and
then shifting the pad so that the catheter is moved laterally inwardly
along the expanded slit to the central opening 14.
With the catheter extending through the opening of the pad and the
uncovered adhesive surfaces of the pad disposed directly above the skin
area surrounding the wound, the user simply urges the edges of the slit 15
together (in the directions represented by arrows 40 in FIG. 7) and
simultaneously brings the adhesive surfaces of the barrier pad into
contact with the patient's skin. The flexible and resilient construction
of the pad readily allows such limited deformation, and the notch 23 of
base 21 insures that the base will not interfere with such closure of the
slit 15. At the closed edges of the slit, the layer of karaya or other
tacky sealant material merges or flows together to produce a continuous
ring of protective barrier material about the wound. The edges of the foam
layer 16 are also brought together and contribute to the protective effect
by helping to maintain an uninterrupted sealing zone about the wound.
Catheter C is positioned in the aperture defined by the arcuate
intermediate portions 25b and 26b of the clamping bars simply by spreading
the free ends of the bars sufficiently to allow lateral placement of the
catheter into position between arcuate portions 25b and 26b. The clamping
bars are then closed (or allowed to close by reason of the restorative
forces already described), except that the user first urges the free end
of bar 26 upwardly, and the free end of bar 25 downwardly, to bring
ratchet arm 32 into alignment with opening 31. The extent of clamping
force is selectively controlled by latching the free ends together at any
of the increments defined by teeth 32. In FIG. 7, the clamping bars are
shown to be closed to their maximum extent.
To insure against sliding movement of the catheter with respect to the
clamping arms, the arcuate inner surfaces of the intermediate portions 25b
and 26b are provided with a plurality of small pointed lugs or barbs 34.
It has been found that secure, highly effective retention is achieved by
the clamping action described; however, should the physician decide that
an additional need would be fulfilled by the use of sutures, openings 35
are provided in the clamping bars 25, 26 through which such sutures may be
inserted and anchored.
Despite the fact that the clamping bars of the support structure are biased
into closed positions, it has been found that such structure may still be
molded in one piece following a sequence of steps indicated in FIGS. 5 and
6. FIG. 5 schematically illustrates the support structure 12 in the
condition it is molded, with base 21 generally circular in outline and,
more importantly, clamping arms 25 and 26 spaced well apart. Following
such molding, the sides of the base (i.e., the portions of the base on
opposite sides of vertical mid plane x) are urged towards each other until
the clamping bars 25 and 26 are disposed in contiguous parallel relation
(FIG. 6). As the clamping bars are brought together in this manner, they
are simultaneously twisted slightly so that ratchet arm 30 will pass above
(or below) the end portion 26a of bar 26. The opposite end portions of the
respective bars are then permanently joined together and base 21 is sealed
adhesively or by any other means to the upper surface of pad 11 to produce
the final structure depicted in FIG. 1.
The embodiment of FIGS. 7-9 is similar to the device already described
except for the construction of clamping bars 125 and 126 and the fact that
such bars are biased into normally open positions rather than into closed
or clamping positions. It will be noted that bars 125, 126 are not
permanently joined at one end but instead are provided with ratchet
assemblies 130, 131 at both ends. The device is used in the same manner
already described, with the slitted barrier pad 11 being fitted about a
catheter, its slit then being closed, but with squeezing forces being
applied at both ends of the respective clamping bars for the purpose of
clamping a catheter between the arcuate intermediate portions of the bars.
In the embodiments shown, central opening 14 in pad 11 is substantially
larger in diameter than the width of slit 15. Specifically, opening 14 has
a diameter that approximates the inside diameter of base 21. While such a
size relationship is preferred, it is to be understood that the device
might instead be supplied to a user with opening 14 of reduced size,
possibly no greater in diameter than the width of slit 15, with the
expectation that a nurse or doctor might, if desired, cut the pad to form
a central opening of greater size to suit the particular catheter exit
site.
While in the foregoing we have disclosed embodiments of the invention in
considerable detail for purposes of illustration, it will be understood by
those skilled in the art that many of these details may be varied without
departing from the spirit and scope of the invention.
* * * * *
|
|
 |
|
 |
Description |
|
